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  • 1. Alho, J. S.
    et al.
    Herczeg, G.
    Laugen, A. T.
    Raesaenen, K.
    Laurila, Anssi
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Population and Conservation Biology.
    Merila, J.
    Allen's rule revisited: quantitative genetics of extremity length in the common frog along a latitudinal gradient2011In: Journal of Evolutionary Biology, ISSN 1010-061X, E-ISSN 1420-9101, Vol. 24, no 1, 59-70 p.Article in journal (Refereed)
    Abstract [en]

    Ecogeographical rules linking climate to morphology have gained renewed interest because of climate change. Yet few studies have evaluated to what extent geographical trends ascribed to these rules have a genetic, rather than environmentally determined, basis. This applies especially to Allen's rule, which states that the relative extremity length decreases with increasing latitude. We studied leg length in the common frog (Rana temporaria) along a 1500 km latitudinal gradient utilizing wild and common garden data. In the wild, the body size-corrected femur and tibia lengths did not conform to Allen's rule but peaked at mid-latitudes. However, the ratio of femur to tibia length increased in the north, and the common garden data revealed a genetic cline consistent with Allen's rule in some trait and treatment combinations. While selection may have shortened the leg length in the north, the genetic trend seems to be partially masked by environmental effects.

  • 2. Cano, J. M.
    et al.
    Li, M-H
    Laurila, Anssi
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Population and Conservation Biology.
    Vilkki, J.
    Merila, J.
    First-generation linkage map for the common frog Rana temporaria reveals sex-linkage group2011In: Heredity, ISSN 0018-067X, E-ISSN 1365-2540, Vol. 107, no 6, 530-536 p.Article in journal (Refereed)
    Abstract [en]

    The common frog (Rana temporaria) has become a model species in the fields of ecology and evolutionary biology. However, lack of genomic resources has been limiting utility of this species for detailed evolutionary genetic studies. Using a set of 107 informative microsatellite markers genotyped in a large full-sib family (800 F1 offspring), we created the first linkage map for this species. This partial map-distributed over 15 linkage groups-has a total length of 1698.8 cM. In line with the fact that males are the heterogametic sex in this species and a reduction of recombination is expected, we observed a lower recombination rate in the males (map length: 1371.5 cM) as compared with females (2089.8 cM). Furthermore, three loci previously documented to be sex-linked (that is, carrying male-specific alleles) in adults from the wild mapped to the same linkage group. The linkage map described in this study is one of the densest ones available for amphibians. The discovery of a sex linkage group in Rana temporaria, as well as other regions with strongly reduced male recombination rates, should help to uncover the genetic underpinnings of the sex-determination system in this species. As the number of linkage groups found (n = 15) is quite close to the actual number of chromosomes (n = 13), the map should provide a useful resource for further evolutionary, ecological and conservation genetic work in this and other closely related species.

  • 3. Cano, JM
    et al.
    Laurila, Anssi
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Ecology and Evolution. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Ecology and Evolution, Population Biology. populationsbiologi.
    Palo, J
    Merilä, J
    Population differentiation in G matrix structure due to natural selection in Rana temporaria2004In: Evolution, Vol. 58, 2013-2020 p.Article in journal (Refereed)
  • 4.
    Carreira, Bruno M.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Animal ecology. Univ Lisbon, Fac Ciencias, Ctr Ecol Evolut & Environm Changes cE3c, Lisbon, Portugal.
    Segurado, Pedro
    Univ Lisbon, Inst Super Agron, Ctr Estudos Florestais, Lisbon, Portugal..
    Laurila, Anssi
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Animal ecology.
    Rebelo, Rui
    Univ Lisbon, Fac Ciencias, Ctr Ecol Evolut & Environm Changes cE3c, Lisbon, Portugal..
    Can heat waves change the trophic role of the world's most invasive crayfish?: Diet shifts in Procambarus clarkii2017In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 12, no 9, e0183108Article in journal (Refereed)
    Abstract [en]

    In the Mediterranean basin, the globally increasing temperatures are expected to be accompanied by longer heat waves. Commonly assumed to benefit cold-limited invasive alien species, these climatic changes may also change their feeding preferences, especially in the case of omnivorous ectotherms. We investigated heat wave effects on diet choice, growth and energy reserves in the invasive red swamp crayfish, Procambarus clarkii. In laboratory experiments, we fed juvenile and adult crayfish on animal, plant or mixed diets and exposed them to a short or a long heat wave. We then measured crayfish survival, growth, body reserves and Fulton's condition index. Diet choices of the crayfish maintained on the mixed diet were estimated using stable isotopes (C-13 and N-15). The results suggest a decreased efficiency of carnivorous diets at higher temperatures, as juveniles fed on the animal diet were unable to maintain high growth rates in the long heat wave; and a decreased efficiency of herbivorous diets at lower temperatures, as juveniles in the cold accumulated less body reserves when fed on the plant diet. Heat wave treatments increased the assimilation of plant material, especially in juveniles, allowing them to sustain high growth rates in the long heat wave. Contrary to our expectations, crayfish performance decreased in the long heat wave, suggesting that Mediterranean summer heat waves may have negative effects on P. clarkii and that they are unlikely to boost its populations in this region. Although uncertain, it is possible that the greater assimilation of the plant diet resulted from changes in crayfish feeding preferences, raising the hypotheses that i) heat waves may change the predominant impacts of this keystone species and ii) that by altering species' trophic niches, climate change may alter the main impacts of invasive alien species.

  • 5.
    Cortazar-Chinarro, Maria
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Animal ecology.
    Lattenkamp, Ella Z.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Animal ecology. Max Planck Inst Psycholinguist, Dept Neurogenet Vocal Commun, Box 310, NL-6500 Nijmegen, Netherlands..
    Meyer-Lucht, Yvonne
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Animal ecology.
    Luquet, Emilien
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Animal ecology. Univ Claude Bernard Lyon I, CNRS, UMR 5023, LEHNA, 3-6 Rue Raphael Dubois,Batiments Darwin C & Forel, F-69622 Villeurbanne 43, France..
    Laurila, Anssi
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Animal ecology.
    Höglund, Jacob
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Animal ecology.
    Drift, selection, or migration?: Processes affecting genetic differentiation and variation along a latitudinal gradient in an amphibian2017In: BMC Evolutionary Biology, ISSN 1471-2148, E-ISSN 1471-2148, Vol. 17, 189Article in journal (Refereed)
    Abstract [en]

    Background: Past events like fluctuations in population size and post-glacial colonization processes may influence the relative importance of genetic drift, migration and selection when determining the present day patterns of genetic variation. We disentangle how drift, selection and migration shape neutral and adaptive genetic variation in 12 moor frog populations along a 1700 km latitudinal gradient. We studied genetic differentiation and variation at a MHC exon II locus and a set of 18 microsatellites. Results: Using outlier analyses, we identified the MHC II exon 2 (corresponding to the beta-2 domain) locus and one microsatellite locus (RCO8640) to be subject to diversifying selection, while five microsatellite loci showed signals of stabilizing selection among populations. STRUCTURE and DAPC analyses on the neutral microsatellites assigned populations to a northern and a southern cluster, reflecting two different post-glacial colonization routes found in previous studies. Genetic variation overall was lower in the northern cluster. The signature of selection on MHC exon II was weaker in the northern cluster, possibly as a consequence of smaller and more fragmented populations. Conclusion: Our results show that historical demographic processes combined with selection and drift have led to a complex pattern of differentiation along the gradient where some loci are more divergent among populations than predicted from drift expectations due to diversifying selection, while other loci are more uniform among populations due to stabilizing selection. Importantly, both overall and MHC genetic variation are lower at northern latitudes. Due to lower evolutionary potential, the low genetic variation in northern populations may increase the risk of extinction when confronted with emerging pathogens and climate change.

  • 6.
    Dahl, Emma
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Population and Conservation Biology.
    Orizaola, German
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Population and Conservation Biology.
    Nicieza, A. G.
    Laurila, Anssi
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Population and Conservation Biology.
    Time constraints and flexibility of growth strategies: Geographic variation in catch-up growth responses in amphibian larvae2012In: Journal of Animal Ecology, ISSN 0021-8790, E-ISSN 1365-2656, Vol. 81, no 6, 1233-1243 p.Article in journal (Refereed)
    Abstract [en]

    1. As size is tightly associated with fitness, compensatory strategies for growth loss can be vital for restoring individual fitness. However, immediate and delayed costs of compensatory responses may prevent their generalization, and the optimal strategy may depend on environmental conditions. Compensatory responses may be particularly important in high-latitude habitats with short growing seasons, and thus, high-latitude organisms might be more efficient at compensating after periods of unfavourable growth conditions than low-latitude organisms. 2. We investigated geographical differences in catch-up growth strategies of populations of the common frog (Rana temporaria) from southern and northern Sweden in two factorial common garden experiments involving predation risk and two different causes of growth arrest (nutritional stress and low temperatures) to evaluate how the compensatory strategies can be affected by context-dependent costs of compensation. Larval and metamorphic traits, and post-metamorphic performance were used as response variables. 3. Only northern tadpoles exposed to low food completely caught up in terms of metamorphic size, mainly by extending the larval period. Low food decreased survival and post-metamorphic jumping performance in southern, but not in northern tadpoles, suggesting that northern tadpoles have a better ability to compensate after periods of restricted food. 4. Both northern and southern tadpoles were able to metamorphose at the same size as control tadpoles after being exposed to low temperatures, indicating that consequences of variation in temperature and food availability differed for tadpoles. However, the combination of low temperatures and predation risk reduced survival in both southern and northern tadpoles. Also, predation risk decreased energy storage in both experiments. 5. Our results highlight the influence of climatic variation and the type of stressor as selective factors shaping compensatory strategies.

  • 7.
    Dahl, Emma
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Population and Conservation Biology.
    Orizaola, German
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Population and Conservation Biology.
    Winberg, Svante
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Neuroscience, Physiology.
    Laurila, Anssi
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Population and Conservation Biology.
    Geographic variation in corticosterone response to chronic predator stress in tadpoles2012In: Journal of Evolutionary Biology, ISSN 1010-061X, E-ISSN 1420-9101, Vol. 25, no 6, 1066-1076 p.Article in journal (Refereed)
    Abstract [en]

    Chronic stress often affects growth and development negatively, and these effects are often mediated via glucocorticoid hormones, which elevate during stress. We investigated latitudinal variation in corticosterone (CORT) response to chronic predator stress in Rana temporaria tadpoles along a 1500-km latitudinal cline in Sweden tadpoles, in a laboratory experiment. We hypothesized that more time-constrained high-latitude populations have evolved a lower CORT response to chronic stress to maintain higher growth under stressful conditions. Southern tadpoles had higher CORT content in response to predators after 1 day of exposure, whereas there was no increase in CORT in the northern populations. Two weeks later, there were no predator-induced CORT elevations. Artificially elevated CORT levels strongly decreased growth, development and survival in both northern and southern tadpoles. We suggest that the lower CORT response in high-latitude populations can be connected with avoidance of CORT-mediated reduction in growth and development, but also discuss other possible explanations.

  • 8.
    Dijk, Ben
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Animal ecology.
    Laurila, Anssi
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Animal ecology.
    Orizaola, German
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Animal ecology.
    Johansson, Frank
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Animal ecology.
    Is one defence enough?: Disentangling the relative importance of morphological and behavioural predator-induced defences2016In: Behavioral Ecology and Sociobiology, ISSN 0340-5443, E-ISSN 1432-0762, Vol. 70, no 2, 237-246 p.Article in journal (Refereed)
    Abstract [en]

    Many organisms show predator-induced behavioural and morphological phenotypic plasticity. These defence mechanisms are often expressed simultaneously. To estimate the relative importance of these two defences, we conducted a laboratory experiment using tadpoles of the common frog (Rana temporaria) as prey and Aeshna dragonfly larvae as predators. We first raised tadpoles in the presence and absence of caged predators to induce differences in defensive morphology, and then conducted free ranging predator trials in environments that were either with or without the presence of predation cues to induce differences in defensive behaviour. This 2 x 2 design allowed us to separate the effects of inducible morphology from inducible behaviour. Caged predators induced deeper bodies and tailfins and reduced activity levels in tadpoles. The time to first capture was shortest in tadpoles without morphological or behavioural defences. Tadpoles with a behavioural defence had a significantly longer time to first capture. Tadpoles with only antipredator morphology tended to have a longer time to first capture as compared to those without any induced defences. This treatment also had a higher number of injured tadpoles as compared to other treatments, suggesting that inducible morphology facilitates predator escape due to the 'lure effect'. However, tadpoles with both behavioural and morphological defences did not have a longer time to first capture as compared to tadpoles with only morphological or behavioural induced defences. Our results suggest that both behavioural and morphological antipredator responses contribute to reduced capture efficiency by predators, but their simultaneous expression did not have any additive effect to the time of first capture and survival, and that the morphology response is most effective when tadpoles are active.

  • 9. Egea-Serrano, Andres
    et al.
    Hangartner, Sandra
    Laurila, Anssi
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Animal ecology.
    Rasanen, Katja
    Multifarious selection through environmental change: acidity and predator-mediated adaptive divergence in the moor frog (Rana arvalis)2014In: Proceedings of the Royal Society of London. Biological Sciences, ISSN 0962-8452, E-ISSN 1471-2954, Vol. 281, no 1780Article in journal (Refereed)
    Abstract [en]

    Environmental change can simultaneously cause abiotic stress and alter biological communities, yet adaptation of natural populations to co-changing environmental factors is poorly understood. We studied adaptation to acid and predator stress in six moor frog (Rana arvalis) populations along an acidification gradient, where abundance of invertebrate predators increases with increasing acidity of R. arvalis breeding ponds. First, we quantified divergence among the populations in anti-predator traits (behaviour and morphology) at different rearing conditions in the laboratory (factorial combinations of acid or neutral pH and the presence or the absence of a caged predator). Second, we evaluated relative fitness (survival) of the populations by exposing tadpoles from the different rearing conditions to predation by free-ranging dragonfly larvae. We found that morphological defences (relative tail depth) as well as survival of tadpoles under predation increased with increasing pond acidity (under most experimental conditions). Tail depth and larval size mediated survival differences among populations, but the contribution of trait divergence to survival was strongly dependent on prior rearing conditions. Our results indicate that R. arvalis populations are adapted to the elevated predator pressure in acidified ponds and emphasize the importance of multifarious selection via both direct (here: pH) and indirect (here: predators) environmental changes.

  • 10. Givskov Sørensen, Jesper
    et al.
    Loeschcke, Volker
    Merilä, Juha
    Laurila, Anssi
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Population and Conservation Biology.
    Effects of predator exposure on Hsp70 expression and survival in tadpoles of the Common Frog (Rana temporaria)2011In: Canadian Journal of Zoology, ISSN 0008-4301, E-ISSN 1480-3283, Vol. 89, no 12, 1249-1255 p.Article in journal (Refereed)
    Abstract [en]

    Predator-induced changes in prey behavior and morphology are widespread, but little is known about physiological and cellular-level responses in prey in response to predation risk. We investigated whether predator (larvae of the dragonfly Aeshna Fabricius, 1775) presence elevated the expression level of heat-shock protein 70 (Hsp70)-a commonly found response to stress-in tadpoles of the Common Frog (Rana temporaria L., 1758). In another experiment, we tested the survival of tadpoles in the presence of a free-ranging predator. Prior to this encounter, the tadpoles were exposed to either an Hsp-inducing environmental stress in the form of heat (31 degrees C) or to predator cues from a caged predator. We found no evidence for increased Hsp70 expression in tadpoles either in the presence of fed or starved predators. We did not find any effects of prior exposure to neither heat nor predator presence on survival at the end of experiment. Our results do not point to either Hsp70-mediated effect of predator-induced responses or to beneficial effects of the stress response on survival under predation risk.

  • 11.
    Griesser, Michael
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Evolutionary Biology. Univ Zurich, Dept Anthropol;Univ Bern, Inst Ecol & Evolut.
    Mourocq, Emeline
    Univ Zurich, Dept Anthropol;Univ Bern, Inst Ecol & Evolut.
    Barnaby, Jonathan
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Evolutionary Biology.
    Bowgen, Katharine M.
    Bournemouth Univ, Fac Sci & Technol, Dept Life & Environm Sci.
    Eggers, Sonke
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Evolutionary Biology. Swedish Univ Agr Sci, Dept Ecol.
    Fletcher, Kevin
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Animal ecology.
    Kozma, Radoslav
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Animal ecology.
    Kurz, Franziska
    Laurila, Anssi
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Animal ecology.
    Nystrand, Magdalena
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Evolutionary Biology.
    Sorato, Enrico
    Linkoping Univ, IFM Biol..
    Ekman, Jan
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Animal ecology.
    Experience buffers extrinsic mortality in a group-living bird species2017In: Oikos, ISSN 0030-1299, E-ISSN 1600-0706, Vol. 126, no 9, 1258-1268 p.Article in journal (Refereed)
    Abstract [en]

    Extrinsic mortality has a strong impact on the evolution of life-histories, prey morphology and behavioural adaptations, but for many animals the causes of mortality are poorly understood. Predation is an important driver of extrinsic mortality and mobile animals form groups in response to increased predation risk. Furthermore, in many species juveniles suffer higher mortality than older individuals, which may reflect a lower phenotypic quality, lower competitiveness, or a lack of antipredator or foraging skills. Here we assessed the causes of mortality for 371 radio tagged Siberian jays. This sedentary bird species lives in family groups that contain a breeding pair as well as related and unrelated non-breeders. Ninety-five percent of death were due to predation (n = 59 out of 62 individuals) and most individuals were killed by Accipiter hawks. Multivariate Cox proportional hazards models showed that non-breeders had a lower survival than breeders, but only in territories in managed forest with little visual cover. Examining breeders, only sex influenced survival with males having a lower survival than females. For non-breeders, juveniles had lower survival than older non-breeders, and those on managed territories had lower survival than those on unmanaged territories. Additionally, a low feather quality reduced the survival probability of non-breeders only. Thus, living on managed territories and having a low feature quality affected only non-breeders, particularly juveniles. These findings add to previous research demonstrating that juvenile Siberian jays acquire critical antipredator skills from experienced group members. Thus, experience can buffer extrinsic mortality, highlighting that group living not only provides safety in numbers, but also provide social opportunities to learn critical life-skills.

  • 12. Hangartner, S.
    et al.
    Laurila, Anssi
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Population and Conservation Biology.
    Raesaenen, K.
    The quantitative genetic basis of adaptive divergence in the moor frog (Rana arvalis) and its implications for gene flow2012In: Journal of Evolutionary Biology, ISSN 1010-061X, E-ISSN 1420-9101, Vol. 25, no 8, 1587-1599 p.Article in journal (Refereed)
    Abstract [en]

    Knowledge on the relative contribution of direct genetic, maternal and environmental effects to adaptive divergence is important for understanding the drivers of biological diversification. The moor frog (Rana arvalis) shows adaptive divergence in embryonic and larval fitness traits along an acidification gradient in south-western Sweden. To understand the quantitative genetic basis of this divergence, we performed reciprocal crosses between three divergent population pairs and reared embryos and larvae at acid and neutral pH in the laboratory. Divergence in embryonic acid tolerance (survival) was mainly determined by maternal effects, whereas the relative contributions of maternal, additive and nonadditive genetic effects in larval life-history traits differed between traits, population pairs and rearing environments. These results emphasize the need to investigate the quantitative genetic basis of adaptive divergence in multiple populations and traits, as well as different environments. We discuss the implications of our findings for maintenance of local adaptation in the context of migrant and hybrid fitness.

  • 13. Hangartner, Sandra
    et al.
    Laurila, Anssi
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Population and Conservation Biology.
    Effects of the disinfectant Virkon S on early life-stages of the moor frog (Rana arvalis)2012In: Amphibia-Reptilia, ISSN 0173-5373, E-ISSN 1568-5381, Vol. 33, no 3-4, 349-353 p.Article in journal (Refereed)
    Abstract [en]

    Emerging diseases, such as the chytrid fungus Batrachochytrium dendrobatidis, contribute to global population declines of amphibians. Virkon S is one of the most commonly used disinfectants to reduce risk of spreading such pathogens. Virkon S is classified as harmful to aquatic organisms, but until today no negative effects on tadpoles have been reported. We studied the effects of three concentrations of Virkon S on early life-stages (embryos and hatchlings) of the moor frog Rana anvils. Overall, Virkon S had no significant effects. However, hatching success was highest in the control treatment, suggesting that Virkon S may have weak negative effects on amphibian embryos. We suggest that further studies are needed to assess the negative effect of Virkon S on amphibians, and recommend that Virkon S is used with care and a minimized run-off into natural wetlands.

  • 14. Hangartner, Sandra
    et al.
    Laurila, Anssi
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Population and Conservation Biology.
    Räsänen, Katja
    Adaptive Divergence in Moor Frog (Rana Arvalis) Populations Along an Acidification Gradient: Inferences from QST-FST Correlations2012In: Evolution, ISSN 0014-3820, E-ISSN 1558-5646, Vol. 66, no 3, 867-881 p.Article in journal (Refereed)
    Abstract [en]

    Microevolutionary responses to spatial variation in the environment seem ubiquitous, but the relative role of selection and neutral processes in driving phenotypic diversification remain often unknown. The moor frog (Rana arvalis) shows strong phenotypic divergence along an acidification gradient in Sweden. We here used correlations among population pairwise estimates of quantitative trait (PST or QST from common garden estimates of embryonic acid tolerance and larval life-history traits) and neutral genetic divergence (FST from neutral microsatellite markers), as well as environmental differences (pond pH, predator density, and latitude), to test whether this phenotypic divergence is more likely due to divergent selection or neutral processes. We found that trait divergence was more strongly correlated with environmental differences than the neutral marker divergence, suggesting that divergent natural selection has driven phenotypic divergence along the acidification gradient. Moreover, pairwise PSTs of embryonic acid tolerance and QSTs of metamorphic size were strongly correlated with breeding pond pH, whereas pairwise QSTs of larval period and growth rate were more strongly correlated with geographic distance/latitude and predator density, respectively. We suggest that incorporating measurements of environmental variation into QSTFST studies can improve our inferential power about the agents of natural selection in natural populations.

  • 15. Hangartner, Sandra
    et al.
    Laurila, Anssi
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Population and Conservation Biology.
    Räsänen, Katja
    Adaptive divergence of the moor frog (Rana arvalis) along an acidification gradient2011In: BMC Evolutionary Biology, ISSN 1471-2148, E-ISSN 1471-2148, Vol. 11, 366- p.Article in journal (Refereed)
    Abstract [en]

    Background: Environmental stress can result in strong ecological and evolutionary effects on natural populations, but to what extent it drives adaptive divergence of natural populations is little explored. We used common garden experiments to study adaptive divergence in embryonic and larval fitness traits (embryonic survival, larval growth, and age and size at metamorphosis) in eight moor frog, Rana arvalis, populations inhabiting an acidification gradient (breeding pond pH 4.0 to 7.5) in southwestern Sweden. Embryos were raised until hatching at three (pH 4.0, 4.3 and 7.5) and larvae until metamorphosis at two (pH 4.3 and 7.5) pH treatments. To get insight into the putative selective agents along this environmental gradient, we measured relevant abiotic and biotic environmental variables from each breeding pond, and used linear models to test for phenotype-environment correlations.

    Results: We found that acid origin populations had higher embryonic and larval acid tolerance (survival and larval period were less negatively affected by low pH), higher larval growth but slower larval development rates, and metamorphosed at a larger size. The phenotype-environment correlations revealed that divergence in embryonic acid tolerance and metamorphic size correlated most strongly with breeding pond pH, whereas divergence in larval period and larval growth correlated most strongly with latitude and predator density, respectively.

    Conclusion: Our results suggest that R. arvalis has diverged in response to pH mediated selection along this acidification gradient. However, as latitude and pH were closely spatially correlated in this study, further studies are needed to disentangle the specific agents of natural selection along acidification gradients. Our study highlights the need to consider the multiple interacting selective forces that drive adaptive divergence of natural populations along environmental stress gradients.

  • 16. Hettyey, Attila
    et al.
    Laurila, Anssi
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Ecology and Evolution. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Ecology and Evolution, Population Biology. populationsbiologi.
    Herczeg, G
    Jönsson, KI
    Kovacs, T
    Merilä, Juha
    Does testis weight decline towards the Subarctic? A case study on the common frog, Rana temporaria2005In: Naturwissenschaften, Vol. 92, 188-192 p.Article in journal (Refereed)
  • 17.
    Hjernquist, Mårten B.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Population and Conservation Biology.
    Söderman, Fredrik
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Population and Conservation Biology.
    Jonsson, K. Ingemar
    Herczeg, Gabor
    Laurila, Anssi
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Population and Conservation Biology.
    Merila, Juha
    Seasonality determines patterns of growth and age structure over a geographic gradient in an ectothermic vertebrate2012In: Oecologia, ISSN 0029-8549, E-ISSN 1432-1939, Vol. 170, no 3, 641-649 p.Article in journal (Refereed)
    Abstract [en]

    Environmental variation connected with seasonality is likely to affect the evolution of life-history strategies in ectotherms, but there is no consensus as to how important life-history traits like body size are influenced by environmental variation along seasonal gradients. We compared adult body size, skeletal growth, mean age, age at first reproduction and longevity among 11 common frog (Rana temporaria) populations sampled along a 1,600-km-long latitudinal gradient across Scandinavia. Mean age, age at first reproduction and longevity increased linearly with decreasing growth season length. Lifetime activity (i.e. the estimated number of active days during life-time) was highest at mid-latitudes and females had on average more active days throughout their lives than males. Variation in body size was due to differences in lifetime activity among populations-individuals (especially females) were largest where they had the longest cumulative activity period-as well as to differences between populations in skeletal growth rate as determined by skeletochronological analyses. Especially, males grew faster at intermediate latitudes. While life-history trait variation was strongly associated with latitude, the direction and shape of these relationships were sex- and trait-specific. These context-dependent relationships may be the result of life-history trade-offs enforced by differences in future reproductive opportunities and time constraints among the populations. Thus, seasonality appears to be an important environmental factor shaping life-history trait variation in common frogs.

  • 18.
    Johansson, Magnus P.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Animal ecology.
    Laurila, Anssi
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Animal ecology.
    Maximum thermal tolerance trades off with chronic tolerance of high temperature in contrasting thermal populations of Radix balthica2017In: Ecology and Evolution, ISSN 2045-7758, E-ISSN 2045-7758, Vol. 7, no 9, 3149-3156 p.Article in journal (Refereed)
    Abstract [en]

    Thermal adaptation theory predicts that thermal specialists evolve in environments with low temporal and high spatial thermal variation, whereas thermal generalists are favored in environments with high temporal and low spatial variation. The thermal environment of many organisms is predicted to change with globally increasing temperatures and thermal specialists are presumably at higher risk than thermal generalists. Here we investigated critical thermal maximum (CTmax) and preferred temperature (T-p) in populations of the common pond snail (Radix balthica) originating from a small-scale system of geothermal springs in northern Iceland, where stable cold (ca. 7 degrees C) and warm (ca. 23 degrees C) habitats are connected with habitats following the seasonal thermal variation. Irrespective of thermal origin, we found a common T-p for all populations, corresponding to the common temperature optimum (T-opt) for fitness-related traits in these populations. Warm-origin snails had lowest CTmax. As our previous studies have found higher chronic temperature tolerance in the warm populations, we suggest that there is a trade-off between high temperature tolerance and performance in other fitness components, including tolerance to chronic thermal stress. T-p and CTmax were positively correlated in warm-origin snails, suggesting a need to maintain a minimum "warming tolerance" (difference in CTmax and habitat temperature) in warm environments. Our results highlight the importance of high mean temperature in shaping thermal performance curves.

  • 19.
    Jones, M
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Evolutionary Biology. Department of Ecology and Evolution, Population Biology.
    Laurila, A
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Evolutionary Biology. Department of Ecology and Evolution, Population Biology. populationsbiologi.
    Peuhkuri, N
    Piironen, J
    Seppä, T
    Timing an ontogenetic niche shift: responses of emerging salmon alevins to chemical cues from predators and competitors2003In: Oikos, Vol. 102, 155-163 p.Article in journal (Refereed)
  • 20.
    Laugen, Ane T
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Ecology and Evolution. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Ecology and Evolution, Population Biology. populationsbiologi.
    Kruuk, LEB
    Laurila, Anssi
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Ecology and Evolution. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Ecology and Evolution, Population Biology. populationsbiologi.
    Räsänen, Katja
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Ecology and Evolution. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Ecology and Evolution, Population Biology. populationsbiologi.
    Stone, J
    Merilä, Juha
    Quantitative genetics of larval life-history traits in Rana temporaria in different environmental conditions2005In: Genetical research, Vol. 86, 161-170 p.Article in journal (Refereed)
  • 21.
    Laugen, Ane T.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Evolutionary Biology, Population Biology.
    Laurila, Anssi
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Evolutionary Biology, Population Biology.
    Jönsson, J. Ingemar
    Söderman, Fredrik
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Evolutionary Biology, Population Biology.
    Merilä, Juha
    Do common frogs (Rana temporaria) follow Bergmann’s rule?2005In: Evolutionary Ecology Research, ISSN 1522-0613, E-ISSN 1937-3791, Vol. 7, no 5, 717-731 p.Article in journal (Refereed)
    Abstract [en]

    Questions: Does intraspecific extension of Bergmanns rule – larger size within a species incooler areas – hold true for ectotherms in general, and for the common frog (Rana temporaria)in particular? What is the relative importance of genetic and environmental factors (i.e. directenvironmental induction) in determining latitudinal patterns of body size variation in commonfrogs?Methods: We tested for a positive association between mean body size and latitude incommon frogs (Rana temporaria) across a 1600 km long latitudinal gradient in Scandinaviaboth for wild-collected adults and laboratory-reared metamorphs.Results: In adults, the mean body size increased from south to mid-latitudes, and declinedthereafter. This occurred despite the fact that the mean age of adult frogs increased withincreasing latitude, and age and body size were positively correlated. The latitudinal pattern ofbody size variation in metamorphs reared in a common garden experiment was similar to thatobserved among wild-caught adults.Conclusions: The results suggest that the concave pattern of body size variation across thelatitudinal cline may be at least partly genetically determined, and that although there isconsiderable geographic variation in mean body size of R. temporaria, this variation does notconform with Bergmann’s rule.

  • 22.
    Laugen, Ane T.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Evolutionary Biology, Population Biology.
    Laurila, Anssi
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Evolutionary Biology, Population Biology.
    Merilä, Juha
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Evolutionary Biology, Population Biology.
    Latitudinal and temperature-dependent variation in embryonic development and growth in Rana temporaria2003In: Oecologia, ISSN 0029-8549, E-ISSN 1432-1939, Vol. 135, no 4, 548-554 p.Article in journal (Refereed)
    Abstract [en]

    Variation in seasonal time constraints and temperature along latitudinal gradients are expected to select for life history trait differentiation, but information about the relative importance of these factors in shaping patterns of divergence in embryonic traits remains sparse. We studied embryonic survival, growth and development rates in the common frog (Rana temporaria) along a 1,400-km latitudinal gradient across Sweden by raising embryos from four populations in the laboratory at seven temperatures (9 degrees C, 12 degrees C, 15 degrees C, 18 degrees C, 21 degrees C, 24 degrees C, 27 degrees C). We found significant differences in mean values of all traits between the populations and temperature treatments, but this variation was not latitudinally ordered. In general, embryonic survival decreased at the two highest temperatures in all populations, but less so in the southernmost as compared to the other populations. The northernmost population developed slowest at the lowest temperature, while the two mid-latitude populations were slowest at the other temperatures. Hatchling size increased with increasing temperature especially in the two northern populations, whereas the two southern populations showed peak hatchling size at 15 degrees C. Analyses of within-population genetic variation with a half-sib design revealed that there was significant additive genetic variation in all traits, and egg size-related maternal effects were important in the case of hatchling size. Overall, our results indicate that unlike larval growth and development, variation in embryonic development and growth in R. temporaria cannot be explained in terms of a latitudinal gradient in season length. While adaptation to a latitudinal variation in temperature might have contributed to the observed differentiation in embryonic performance, the effects of other, perhaps more local environmental factors, seem to have overridden them in importance.

  • 23.
    Laugen, Ane T.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Evolutionary Biology, Population Biology.
    Laurila, Anssi
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Evolutionary Biology, Population Biology.
    Merilä, Juha
    Maternal and genetic contributions to geographical variation in Rana temporaria larval life-history traits2002In: Biological Journal of the Linnean Society, ISSN 0024-4066, E-ISSN 1095-8312, Vol. 76, no 1, 61-70 p.Article in journal (Refereed)
    Abstract [en]

    The relative importance of genetic, environmental, and maternal effects as determinants of geographical variation in vertebrate life-histories has not often been explored. We examined the role of genetic and maternal effects as determinants of population divergence in survival and three important larval life-history traits (growth rate, age, and size at metamorphosis) using reciprocal crosses between two latitudinally separated populations of the common frog (Rana temporaria Linnaeus). Genetic effects were important in all three traits as indicated by the significant effect of male origin, but there was also evidence for nonadditive genetic contributions on metamorphic size and growth rate. Likewise, maternal effect contributions to population divergence were large, partially environment dependent, and apparently acting primarily through egg size in two of three traits. These results suggest that both genetic and maternal effects are important determinants of geographical variation in amphibian life-histories, and that much of the differentiation resulting from maternal effects is mediated through variation in egg size.

  • 24.
    Laugen, Ane T.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Evolutionary Biology, Population Biology.
    Laurila, Anssi
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Evolutionary Biology, Population Biology.
    Räsänen, Katja
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Evolutionary Biology, Population Biology.
    Merilä, Juha
    Latitudinal countergradient variation in the common frog (Rana temporaria) developmental rates: evidence for local adaptation2003In: Journal of Evolutionary Biology, ISSN 1010-061X, E-ISSN 1420-9101, Vol. 16, no 5, 996-1005 p.Article in journal (Refereed)
    Abstract [en]

    Adaptive genetic differentiation along a climatic gradient as a response to natural selection is not necessarily expressed at phenotypic level if environmental effects on population mean phenotypes oppose the genotypic effects. This form of cryptic evolution--called countergradient variation--has seldom been explicitly demonstrated for terrestrial vertebrates. We investigated the patterns of phenotypic and genotypic differentiation in developmental rates of common frogs (Rana temporaria) along a ca. 1600 km latitudinal gradient across Scandinavia. Developmental rates in the field were not latitudinally ordered, but displayed large variation even among different ponds within a given latitudinal area. In contrast, development rates assessed in the laboratory increased strongly and linearly with increasing latitude, suggesting a genetic capacity for faster development in the northern than the southern larvae. Experiments further revealed that environmental effects (temperature and food) could easily override the genetic effects on developmental rates, providing a possible mechanistic explanation as to why the genetic differentiation was not seen in the samples collected from the wild. Our results suggest that the higher developmental rates of the northern larvae are likely to be related to selection stemming from seasonal time constrains, rather than from selection dictated by low ambient temperatures per se. All in all, the results provide a demonstration of environmental effects concealing substantial latitudinally ordered genetic differentiation understandable in terms of adaptation to clinal variation in time constrains.

  • 25.
    Laurila, Anssi
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Ecology and Evolution. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Ecology and Evolution, Population Biology. Populationsbiologi.
    Järvi-Laturi, Maria
    Pakkasmaa, Susanna
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Ecology and Evolution, Population Biology.
    Merilä, Juha
    Temporal variation in predation risk: stage-dependency, graded responses and fitness costs in tadpole antipredator defences2004In: Oikos, Vol. 107, 90-99 p.Article in journal (Refereed)
  • 26.
    Laurila, Anssi
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Ecology and Evolution. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Ecology and Evolution, Population Biology. populationsbiologi.
    Pakkasmaa, Susanna
    Merilä, Juha
    Population divergence in growth rate and antipredator defences in Rana arvalis.2006In: Oecologia, Vol. 147, no 4, 585-595 p.Article in journal (Refereed)
    Abstract [en]

    Growth and development rates often differ among populations of the same species, yet the factors maintaining this differentiation are not well understood. We investigated the antipredator defences and their efficiency in two moor frog Rana arvalis populations differing in growth and development rates by raising tadpoles in outdoor containers in the nonlethal presence and absence of three different predators (newt, fish, dragonfly larva), and by estimating tadpole survival in the presence of free-ranging predators in a laboratory experiment. Young tadpoles in both populations reduced activity in the presence of predators and increased hiding behaviour in the presence of newt and fish. Older tadpoles from the slow-growing Gotland population (G) had stronger hiding behaviour and lower activity in all treatments than tadpoles from the fast-growing Uppland population (U). However, both populations showed a plastic behavioural response in terms of reduced activity. The populations differed in induced morphological defences especially in response to fish. G tadpoles responded with relatively long and deep body, short tail and shallow tail muscle, whereas the responses in U tadpoles were often the opposite and closer to the responses induced by the other predators. U tadpoles metamorphosed earlier, but at a similar size to G tadpoles. There was no evidence that growth rate was affected by predator treatments, but tadpoles metamorphosed later and at larger size in the predator treatments. G tadpoles survived better in the presence of free-ranging predators than U tadpoles. These results suggest that in these two populations, low growth rate was linked with low activity and increased hiding, whereas high growth rate was linked with high activity and less hiding. The differences in behaviour may explain the difference in survival between the populations, but other mechanisms (i.e. differences in swimming speed) may also be involved. There appears to be considerable differentiation in antipredator responses between these two R. arvalis populations, as well as with respect to different predators.

  • 27. Lesbarreres, D
    et al.
    Primmer, Craig
    Laurila, Anssi
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Ecology and Evolution. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Ecology and Evolution, Population Biology. populationsbiologi.
    Merilä, Juha
    Environmental and population dependency of genetic variability-fitness correlations in Rana temporaria.2005In: Molecular ecology, Vol. 14, 311-323 p.Article in journal (Refereed)
  • 28.
    Lindgren, Beatrice
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Ecology and Evolution. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Ecology and Evolution, Population Biology. populationsbiologi.
    Laurila, Anssi
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Ecology and Evolution. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Ecology and Evolution, Population Biology. populationsbiologi.
    Proximate causes of adaptive growth rates: growth efficiency variation among latitudinal populations of Rana temporaria.2005In: Journal of Evolutionary Biology, Vol. 18, no 820-828Article in journal (Refereed)
  • 29.
    Magnus, Johansson
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Animal ecology.
    Friederike, Ermold
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Animal ecology.
    Kristjánsson, Bjarni
    Hólar University Collage, Iceland.
    Anssi, Laurila
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Animal ecology.
    Local adaptation of gastropod life history to contrasting thermal environments in a geothermal lakeArticle in journal (Refereed)
  • 30. Merilä, Juha
    et al.
    Laurila, Anssi
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Ecology and Evolution. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Ecology and Evolution, Population Biology. populationsbiologi.
    Laugen, Ane T
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Ecology and Evolution. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Ecology and Evolution, Population Biology. populationsbiologi.
    Räsänen, Katja
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Ecology and Evolution, Population Biology.
    Heads or tails? Variation in tadpole body proportions in response to temperature and food stress.2004In: Evolutionaru Ecology Research, Vol. 6, 727-738 p.Article in journal (Refereed)
  • 31. Merilä, Juha
    et al.
    Laurila, Anssi
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Ecology and Evolution. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Ecology and Evolution, Population Biology. populationsbiologi.
    Lindgren, Beatrice
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Ecology and Evolution. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Ecology and Evolution, Population Biology. populationsbiologi.
    Variation in the degree and costs of adaptive phenotypic plasticity among Rana temporaria populations2004In: Journal of Evolutionary Biology, Vol. 17, 1132-1140 p.Article in journal (Refereed)
  • 32. Merilä, Juha
    et al.
    Söderman, Fredrik
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution, Population Biology.
    O'Hara, Robert
    Räsänen, Katja
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution, Population Biology.
    Laurila, Anssi
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution, Population Biology.
    Local adaptation and genetics of acid-stress tolerance in the moor frog, Rana arvalis2004In: Conservation Genetics, ISSN 1566-0621, E-ISSN 1572-9737, Vol. 5, no 4, 513-527 p.Article in journal (Refereed)
    Abstract [en]

    As potential to adapt to environmental stress can be essential for population persistence, knowledge on the genetic architecture of local adaptation is important for conservation genetics. We investigated the relative importance of additive genetic, dominance and maternal effects contributions to acid stress tolerance in two moor frog (Rana arvalis) populations originating from low and neutral pH habitats. Experiments with crosses obtained from artificial matings revealed that embryos from the acid origin population were more tolerant to low pH than embryos from the neutral origin population in embryonic survival rates, but not in terms of developmental stability, developmental and growth rates. Strong maternal effect and small additive genetic contributions to variation were detected in all traits in both populations. In general, dominance contributions to variance in different traits were of similar magnitude to the additive genetic effects, but dominance effects outweighed the additive genetic and maternal effects contributions to early growth in both populations. Furthermore, the expression of additive genetic variance was independent of pH treatment, suggesting little additive genetic variation in acid stress tolerance. The results suggest that although local genetic adaptation to acid stress has taken place, the current variation in acid stress tolerance in acidified populations may owe largely to non-genetic effects. However, low but significant heritabilities ( h(2) approximate to 0.07 - 0.22) in all traits - including viability itself - under a wide range of pH conditions suggests that environmental stress created by low pH is unlikely to lower moor frog populations' ability to respond to selection in the traits studied. Nevertheless, acid conditions could lower populations' ability to respond to selection in the long run through reduction in effective population size.

  • 33.
    Murillo-Rincon, Andrea P.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Animal ecology. Christian Albrechts Univ Kiel, Inst Zool, D-24118 Kiel, Germany..
    Kolter, Nora A.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Animal ecology.
    Laurila, Anssi
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Animal ecology.
    Orizaola, German
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Animal ecology.
    Intraspecific priority effects modify compensatory responses to changes in hatching phenology in an amphibian2017In: Journal of Animal Ecology, ISSN 0021-8790, E-ISSN 1365-2656, Vol. 86, no 1, 128-135 p.Article in journal (Refereed)
    Abstract [en]

    1. In seasonal environments, modifications in the phenology of life-history events can alter the strength of time constraints experienced by organisms. Offspring can compensate for a change in timing of hatching by modifying their growth and development trajectories. However, intra-and interspecific interactions may affect these compensatory responses, in particular if differences in phenology between cohorts lead to significant priority effects (i.e. the competitive advantage that early-hatching individuals have over late-hatching ones). 2. Here, we conducted a factorial experiment to determine whether intraspecific priority effects can alter compensatory phenotypic responses to hatching delay in a synchronic breeder by rearing moor frog (Rana arvalis) tadpoles in different combinations of phenological delay and food abundance. 3. Tadpoles compensated for the hatching delay by speeding up their development, but only when reared in groups of individuals with identical hatching phenology. In mixed phenology groups, strong competitive effects by non-delayed tadpoles prevented the compensatory responses and delayed larvae metamorphosed later than in single phenology treatments. Non-delayed individuals gained advantage from developing with delayed larvae by increasing their developmental and growth rates as compared to single phenology groups. 4. Food shortage prolonged larval period and reduced mass at metamorphosis in all treatments, but it did not prevent compensatory developmental responses in larvae reared in single phenology groups. 5. This study demonstrates that strong intraspecific priority effects can constrain the compensatory growth and developmental responses to phenological change, and that priority effects can be an important factor explaining the maintenance of synchronic life histories (i.e. explosive breeding) in seasonal environments.

  • 34.
    Murillo-Rincon, Andrea P.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Animal ecology. Christian Albrechts Univ Kiel, Inst Zool, Kiel, Germany..
    Laurila, Anssi
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Animal ecology.
    Orizaola, Germán
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Animal ecology.
    Compensating for delayed hatching reduces offspring immune response and increases life-history costs2017In: Oikos, ISSN 0030-1299, E-ISSN 1600-0706, Vol. 126, no 4, 565-571 p.Article in journal (Refereed)
    Abstract [en]

    Organisms are exposed to multiple sources of stress in nature. When confronted with a stressful period affecting growth and development, compensatory responses allow the restoration of individual fitness, providing an important buffering mechanism against climatic and other environmental variability. However, tradeoffs between increased growth/development and other physiological traits are predicted to prevent these high growth and development rates from becoming constitutive. Here, we investigated how compensatory responses in growth and development affect immune responses. By using low temperature to stop embryonic development, we exposed moor frog Rana arvalis tadpoles to two levels of time-constraints: non-delayed hatching and 12-day delayed hatching. In a common garden experiment, we recorded larval growth and development, as well as their immune response, measured as the inflammatory reaction after the injection of phytohaemagglutinin (PHA). Tadpoles originating from delayed hatching treatments had a lower immune response to PHA challenge than those from the non-delayed hatching treatment. In general, tadpoles from the delayed hatching treatment reached metamorphosis faster and at a smaller size than control tadpoles. However, immune-challenged tadpoles were not able to accelerate their development in response to delayed hatching. Our results indicate that 1) the innate immune response can be reduced in organisms undergoing compensatory developmental responses in growth and development and 2) compensatory capacity can be reduced when organisms are immunologically challenged. These dual findings reveal the complexity of handling multiple stressors and highlight the importance of examining the costs and limits of mounting an immune response in the context of increasing phenological instability ascribed to climate change.

  • 35.
    Nunes, Ana L.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Animal ecology.
    Orizaola, German
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Animal ecology.
    Laurila, Anssi
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Animal ecology.
    Rebelo, Rui
    Morphological and life-history responses of anurans to predation by an invasive crayfish: an integrative approach2014In: Ecology and Evolution, ISSN 2045-7758, E-ISSN 2045-7758, Vol. 4, no 8, 1491-1503 p.Article in journal (Refereed)
    Abstract [en]

    Predator-induced phenotypic plasticity has been widely documented in response to native predators, but studies examining the extent to which prey can respond to exotic invasive predators are scarce. As native prey often do not share a long evolutionary history with invasive predators, they may lack defenses against them. This can lead to population declines and even extinctions, making exotic predators a serious threat to biodiversity. Here, in a community-wide study, we examined the morphological and life-history responses of anuran larvae reared with the invasive red swamp crayfish, Procambarus clarkii, feeding on conspecific tadpoles. We reared tadpoles of nine species until metamorphosis and examined responses in terms of larval morphology, growth, and development, as well as their degree of phenotypic integration. These responses were compared with the ones developed in the presence of a native predator, the larval dragonfly Aeshna sp., also feeding on tadpoles. Eight of the nine species altered their morphology or life history when reared with the fed dragonfly, but only four when reared with the fed crayfish, suggesting among-species variation in the ability to respond to a novel predator. While morphological defenses were generally similar across species (deeper tails) and almost exclusively elicited in the presence of the fed dragonfly, life-history responses were very variable and commonly elicited in the presence of the invasive crayfish. Phenotypes induced in the presence of dragonfly were more integrated than in crayfish presence. The lack of response to the presence of the fed crayfish in five of the study species suggests higher risk of local extinction and ultimately reduced diversity of the invaded amphibian communities. Understanding how native prey species vary in their responses to invasive predators is important in predicting the impacts caused by newly established predator-prey interactions following biological invasions.

  • 36.
    Nunes, Ana L.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Animal ecology.
    Orizaola, German
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Animal ecology.
    Laurila, Anssi
    Rebelo, Rui
    Rapid evolution of constitutive and inducible defenses against an invasive predator2014In: Ecology, ISSN 0012-9658, E-ISSN 1939-9170, Vol. 95, no 6, 1520-1530 p.Article in journal (Refereed)
    Abstract [en]

    Invasive alien predators can impose strong selection on native prey populations and induce rapid evolutionary change in the invaded communities. However, studies on evolutionary responses to invasive predators are often complicated by the lack of replicate populations differing in coexistence time with the predator, which would allow the determination of how prey traits change during the invasion. The red swamp crayfish Procambarus clarkii has invaded many freshwater areas worldwide, with negative impacts for native fauna. Here, we examined how coexistence time shapes antipredator responses of the Iberian waterfrog (Pelophylax perezi) to the invasive crayfish by raising tadpoles from five populations differing in historical exposure to P. clarkii (30 years, 20 years, or no coexistence). Tadpoles from non-invaded populations responded to the presence of P. clarkii with behavioral plasticity (reduced activity), whereas long-term invaded populations showed canalized antipredator behavior (constant low activity level). Tadpoles from one of the long-term invaded populations responded to the crayfish with inducible morphological defenses (deeper tails), reflecting the use of both constitutive and inducible antipredator defenses against the exotic predator by this population. Our results suggest that, while naive P. perezi populations responded behaviorally to P. clarkii, the strong predation pressure imposed by the crayfish has induced the evolution of qualitatively different antipredator defenses in populations with longer coexistence time. These responses suggest that strong selection by invasive predators may drive rapid evolutionary change in invaded communities. Examining responses of prey species to biological invasions using multiple populations will help us better forecast the impact of invasive predators in natural communities.

  • 37.
    Nunes, Ana L.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Population and Conservation Biology.
    Richter-Boix, Alex
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Population and Conservation Biology.
    Laurila, Anssi
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Population and Conservation Biology.
    Rebelo, Rui
    Do anuran larvae respond behaviourally to chemical cues from an invasive crayfish predator?: A community-wide study2013In: Oecologia, ISSN 0029-8549, E-ISSN 1432-1939, Vol. 171, no 1, 115-127 p.Article in journal (Refereed)
    Abstract [en]

    Antipredator behaviour is an important fitness component in most animals. A co-evolutionary history between predator and prey is important for prey to respond adaptively to predation threats. When non-native predator species invade new areas, native prey may not recognise them or may lack effective antipredator defences. However, responses to novel predators can be facilitated by chemical cues from the predators' diet. The red swamp crayfish Procambarus clarkii is a widespread invasive predator in the Southwest of the Iberian Peninsula, where it preys upon native anuran tadpoles. In a laboratory experiment we studied behavioural antipredator defences (alterations in activity level and spatial avoidance of predator) of nine anurans in response to P. clarkii chemical cues, and compared them with the defences towards a native predator, the larval dragonfly Aeshna sp. To investigate how chemical cues from consumed conspecifics shape the responses, we raised tadpoles with either a tadpole-fed or starved crayfish, or dragonfly larva, or in the absence of a predator. Five species significantly altered their behaviour in the presence of crayfish, and this was largely mediated by chemical cues from consumed conspecifics. In the presence of dragonflies, most species exhibited behavioural defences and often these did not require the presence of cues from predation events. Responding to cues from consumed conspecifics seems to be a critical factor in facilitating certain behavioural responses to novel exotic predators. This finding can be useful for predicting antipredator responses to invasive predators and help directing conservation efforts to the species at highest risk.

  • 38. O'Gorman, Eoin J.
    et al.
    Pichler, Doris E.
    Adams, Georgina
    Benstead, Jonathan P.
    Cohen, Haley
    Craig, Nicola
    Cross, Wyatt F.
    Demars, Benoit O. L.
    Friberg, Nikolai
    Gislason, Gisli Mar
    Gudmundsdottir, Rakel
    Hawczak, Adrianna
    Hood, James M.
    Hudson, Lawrence N.
    Johansson, Liselotte
    Johansson, Magnus P.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics. Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution, Population and Conservation Biology.
    Junker, James R.
    Laurila, Anssi
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics. Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution, Population and Conservation Biology.
    Manson, J. Russell
    Mavromati, Efpraxia
    Nelson, Daniel
    Olafsson, Jon S.
    Perkins, Daniel M.
    Petchey, Owen L.
    Plebani, Marco
    Reuman, Daniel C.
    Rall, Bjoern C.
    Stewart, Rebecca
    Thompson, Murray S. A.
    Woodward, Guy
    Impacts of Warming on the Structure and Functioning of Aquatic Communities: Individual-to Ecosystem-Level Responses2012In: Advances in Ecological Research, Vol 47: Global Change in Multispecies Systems, Pt 2, Elsevier, 2012, 81-176 p.Chapter in book (Refereed)
    Abstract [en]

    Environmental warming is predicted to rise dramatically over the next century, yet few studies have investigated its effects in natural, multi-species systems. We present data collated over an 8-year period from a catchment of geothermally heated streams in Iceland, which acts as a natural experiment on the effects of warming across different organisational levels and spatiotemporal scales. Body sizes and population biomasses of individual species responded strongly to temperature, with some providing evidence to support temperature size rules. Macroinvertebrate and meiofaunal community composition also changed dramatically across the thermal gradient. Interactions within the warm streams in particular were characterised by food chains linking algae to snails to the apex predator, brown trout These chains were missing from the colder systems, where snails were replaced by much smaller herbivores and invertebrate omnivores were the top predators. Trout were also subsidised by terrestrial invertebrate prey, which could have an effect analogous to apparent competition within the aquatic prey assemblage. Top-down effects by snails on diatoms were stronger in the warmer streams, which could account for a shallowing of mass-abundance slopes across the community. This may indicate reduced energy transfer efficiency from resources to consumers in the warmer systems and/or a change in predator-prey mass ratios. All the ecosystem process rates investigated increased with temperature, but with differing thermal sensitivities, with important implications for overall ecosystem functioning (e.g. creating potential imbalances in elemental fluxes). Ecosystem respiration rose rapidly with temperature, leading to increased heterotrophy. There were also indications that food web stability may be lower in the warmer streams.

  • 39.
    Orizaola, Germa
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Population and Conservation Biology.
    Dahl, Emma
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Population and Conservation Biology.
    Laurila, Anssi
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Population and Conservation Biology.
    Reversibility of predator-induced plasticity and its effect at a life-history switch point2012In: Oikos, ISSN 0030-1299, E-ISSN 1600-0706, Vol. 121, no 1, 44-52 p.Article in journal (Refereed)
    Abstract [en]

    In natural systems, organisms are frequently exposed to spatial and temporal variation in predation risk. Prey organisms are known to develop a wide array of plastic defences to avoid being eaten. If inducible plastic defences are costly, prey living under fluctuating predation risk should be strongly selected to develop reversible plastic traits and adjust their defences to the current predation risk. Here, we studied the induction and reversibility of antipredator defences in common frog Rana temporaria tadpoles when confronted with a temporal switch in predation risk by dragonfly larvae. We examined the behaviour and morphology of tadpoles in experimental treatments where predators were added or withdrawn at mid larval development, and compared these to treatments with constant absence or presence of predators. As previous studies have overlooked the effects that developing reversible anti-predator responses could have later in life (e.g. at life history switch points), we also estimated the impact that changes in antipredator responses had on the timing of and size at metamorphosis. In the presence of predators, tadpoles reduced their activity and developed wider bodies, and shorter and wider tails. When predators were removed tadpoles switched their behaviour within one hour to match that found in the constant environments. The morphology matched that in the constant environments in one week after treatment reversal. All these responses were highly symmetrical. Short time lags and symmetrical responses for the induction/reversal of defences suggest that a strategy with fast switches between phenotypes could be favoured in order to maximise growth opportunities even at the potential cost of phenotypic mismatches. We found no costs of developing reversible responses to predators in terms of life-history traits, but a general cost of the induction of the defences for all the individuals experiencing predation risk during some part of the larval development (delayed metamorphosis). More studies examining the reversibility of plastic defences, including other type of costs (e.g. physiological), are needed to better understand the adaptive value of these flexible strategies.

  • 40.
    Orizaola, German
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Population and Conservation Biology.
    Dahl, Emma
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Population and Conservation Biology.
    Nicieza, Alfredo G.
    Laurila, Anssi
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Population and Conservation Biology.
    Larval life history and anti-predator strategies are affected by breeding phenology in an amphibian2013In: Oecologia, ISSN 0029-8549, E-ISSN 1432-1939, Vol. 171, no 4, 873-881 p.Article in journal (Refereed)
    Abstract [en]

    Seasonal time constraints can pose strong selection on life histories. Time-constrained animals should prioritise fast development over predation risk to avoid unfavourable growing conditions. However, changes in phenology could alter the balance between anti-predator and developmental needs. We studied variation of anti-predator strategies in common frog (Rana temporaria) tadpoles in four populations from the two extremes of a latitudinal gradient across Sweden. We examined, under common conditions in the laboratory, the anti-predator responses and life histories of tadpoles raised with predatory Aeshna dragonfly larvae in two consecutive years with a difference of 20 days in breeding time in the north, but no difference in breeding time in the nouth. In a year with late breeding, northern tadpoles did not modify their behaviour and morphology in the presence of predators, and metamorphosed faster and smaller than tadpoles born in a year with early breeding. In the year with early breeding, northern tadpoles showed a completely different anti-predator strategy by reducing activity and developing morphological defences in the presence of predators. We discuss the possible mechanisms that could activate these responses (likely a form of environmentally-mediated parental effect). To our knowledge, this is the first study to show that a vertebrate modifies the anti-predator strategy of its offspring in response to natural variation in reproductive phenology, which highlights the need to consider phenology in studies of life-history evolution.

  • 41.
    Orizaola, German
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Animal ecology.
    Laurila, Anssi
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Animal ecology.
    Developmental plasticity increases at the northern range margin in a warm-dependent amphibian2016In: Evolutionary Applications, ISSN 1752-4571, E-ISSN 1752-4571, Vol. 9, no 3, 471-478 p.Article in journal (Refereed)
    Abstract [en]

    Accurate predictions regarding how climate change affects species and populations are crucial for the development of effective conservation measures. However, models forecasting the impact of climate change on natural environments do not often consider the geographic variation of an organism's life history. We examined variation in developmental plasticity to changing temperature in the pool frog (Pelophylax lessonae) across its distribution by studying populations from central areas (Poland), edge populations (Latvia) and northern marginal populations (Sweden). Relative to central and edge populations, northern populations experience lower and less variable temperature and fewer episodes of warm weather during larval development. Plasticity in larval life-history traits was highest at the northern range margin: larvae from marginal populations shortened larval period and increased growth rate more than larvae from central and edge populations when reared at high temperature. Maintaining high growth and development under the scarce spells of warm weather is likely adaptive for high-latitude populations. The detection of high levels of developmental plasticity in isolated, marginal populations suggests that they may be better able to respond to the temperature regimes expected under climate change than often predicted, reflecting the need to incorporate geographic variation in life-history traits into models forecasting responses to environmental change.

  • 42.
    Orizaola, Germán
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Animal ecology.
    Dahl, Emma
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Animal ecology.
    Laurila, Anssi
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Animal ecology.
    Compensatory growth strategies are affected by the strength of environmental time constraints in anuran larvae2014In: Oecologia, ISSN 0029-8549, E-ISSN 1432-1939, Vol. 174, no 1, 131-137 p.Article in journal (Refereed)
    Abstract [en]

    Organisms normally grow at a sub-maximal rate. After experiencing a period of arrested growth, individuals often show compensatory growth responses by modifying their life-history, behaviour and physiology. However, the strength of compensatory responses may vary across broad geographic scales as populations differ in their exposition to varying time constraints. We examined differences in compensatory growth strategies in common frog (Rana temporaria) populations from southern and northern Sweden. Tadpoles from four populations were reared in the laboratory and exposed to low temperature to evaluate the patterns and mechanisms of compensatory growth responses. We determined tadpoles' growth rate, food intake and growth efficiency during the compensation period. In the absence of arrested growth conditions, tadpoles from all the populations showed similar (size-corrected) growth rates, food intake and growth efficiency. After being exposed to low temperature for 1 week, only larvae from the northern populations increased growth rates by increasing both food intake and growth efficiency. These geographic differences in compensatory growth mechanisms suggest that the strategies for recovering after a period of growth deprivation may depend on the strength of time constraints faced by the populations. Due to the costs of fast growth, only populations exposed to the strong time constraints are prone to develop fast recovering strategies in order to metamorphose before conditions deteriorate. Understanding how organisms balance the cost and benefits of growth strategies may help in forecasting the impact of fluctuating environmental conditions on life-history strategies of populations likely to be exposed to increasing environmental variation in the future.

  • 43.
    Pahkala, M
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Evolutionary Biology. Department of Ecology and Evolution, Population Biology. populationsbiologi.
    Laurila, A
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Evolutionary Biology. Department of Ecology and Evolution, Population Biology. populationsbiologi.
    Merilä, J
    Effects of ultraviolet-B radiation on behaviour and growth of three species of amphibian larvae2003In: Chemosphere, Vol. 51, 197-204 p.Article in journal (Refereed)
  • 44.
    Pahkala, Maarit
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Evolutionary Biology. Department of Ecology and Evolution, Population Biology. populationsbiologi.
    Merilä, J
    Ots, I
    Laurila, A
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Evolutionary Biology. Department of Ecology and Evolution, Population Biology. populationsbiologi.
    Effects of ultraviolet-B radiation on metamorphic traits in the common frog Rana temporaria2003In: Chemosphere, Vol. 259, 57-62 p.Article in journal (Refereed)
  • 45.
    Pakkasmaa, Susanna
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Ecology and Evolution. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Ecology and Evolution, Population Biology. populationsbiologi.
    Laurila, Anssi
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Ecology and Evolution. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Ecology and Evolution, Population Biology. populationsbiologi.
    Are the effects of kinship modified by environmental conditions in Rana temporaria tadpoles?2004In: Annales Zoologici Fennici, Vol. 41, 413-420 p.Article in journal (Refereed)
  • 46. Palo, JU
    et al.
    Schmeller, DS
    Laurila, Anssi
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Ecology and Evolution. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Ecology and Evolution, Population Biology. populationsbiologi.
    Primmer, CR
    Kuzmin, SL
    Merilä, Juha
    High degree of population subdivision in a widespread amphibian2004In: Molecular ecology, Vol. 13, 2631-2644 p.Article in journal (Refereed)
  • 47. Palo, Jukka
    et al.
    O'Hara, Robert B.
    Laugen, Ane T.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Evolutionary Biology, Population Biology.
    Laurila, Anssi
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Evolutionary Biology, Population Biology.
    Primmer, Craig R
    Merilä, Juha
    Latitudinal divergence of common frog (Rana temporaria) life-history traits by natural selection: evidence for a comparison of molecular and quantitative genetic data2003In: Molecular Ecology, ISSN 0962-1083, E-ISSN 1365-294X, Vol. 12, no 7, 1963-1978 p.Article in journal (Refereed)
    Abstract [en]

    The relative roles of natural selection and direct environmental induction, as well as of natural selection and genetic drift, in creating clinal latitudinal variation in quantitative traits have seldom been assessed in vertebrates. To address these issues, we compared molecular and quantitative genetic differentiation between six common frog (Rana temporaria) populations along an approximately 1600 km long latitudinal gradient across Scandinavia. The degree of population differentiation (QST approximately 0.81) in three heritable quantitative traits (age and size at metamorphosis, growth rate) exceeded that in eight (neutral) microsatellite loci (FST = 0.24). Isolation by distance was clear for both neutral markers and quantitative traits, but considerably stronger for one of the three quantitative traits than for neutral markers. QST estimates obtained using animals subjected to different rearing conditions (temperature and food treatments) revealed some environmental dependency in patterns of population divergence in quantitative traits, but in general, these effects were weak in comparison to overall patterns. Pairwise comparisons of FST and QST estimates across populations and treatments revealed that the degree of quantitative trait differentiation was not generally predictable from knowledge of that in molecular markers. In fact, both positive and negative correlations were observed depending on conditions where the quantitative genetic variability had been measured. All in all, the results suggest a very high degree of genetic subdivision both in neutral marker genes and genes coding quantitative traits across a relatively recently (< 9000 years) colonized environmental gradient. In particular, they give evidence for natural selection being the primary agent behind the observed latitudinal differentiation in quantitative traits.

  • 48. Patrelle, Cecile
    et al.
    Hjernquist, Mårten B.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Animal Ecology.
    Laurila, Anssi
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Population and Conservation Biology. Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Animal ecology.
    Soderman, Fredrik
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Population and Conservation Biology. Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Animal ecology.
    Merila, Juha
    Sex differences in age structure, growth rate and body size of common frogs Rana temporaria in the subarctic2012In: Polar Biology, ISSN 0722-4060, E-ISSN 1432-2056, Vol. 35, no 10, 1505-1513 p.Article in journal (Refereed)
    Abstract [en]

    The thermal environment and length of the activity season are important factors in shaping life-history trait variation in ectotherms. Many ectothermic vertebrates living at high latitudes or altitudes tend to be larger and older than their conspecifics living at lower latitudes or altitudes. However, detailed data on age, body size and growth variation-and how they may differ between males and females-are still scarce, especially from extreme high-latitude environments. We studied growth (body length increment), age and size structure of common frogs (Rana temporaria) in subarctic Finland (69A degrees 04'N) by applying skeletochronological methods to individually marked adults (n = 169) captured and recaptured between 1999 and 2003. We found that breeding males were on average younger (mean = 8.5 years) than females (11.9 years) and that males started reproducing earlier (a parts per thousand yen3-4 years of age) than females (> 4-5 years). The oldest encountered individual was an 18-year-old female, which to our knowledge is the oldest wild common frog ever reported. Females were on average larger (mean body length = 76.6 mm) than males (70.7 mm), and this appeared to be mainly due to their older age as compared to males. While body length increased and growth rate decreased with age in both sexes, growth rate declined significantly faster with age in males than in females. The latter finding provides a proximate explanation for the observation that even after accounting for age differences among sexes (females > males), females were longer than males.

  • 49.
    Persson, M.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution, Population and Conservation Biology.
    Räsänen, Katja
    Laurila, Anssi
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution, Population and Conservation Biology.
    Merilä, Juha
    Maternally determined adaptation to acidity in Rana arvalis: Are laboratory and field estimates of embryonic stress tolerance congruent?2007In: Canadian Journal of Zoology, ISSN 0008-4301, E-ISSN 1480-3283, Vol. 85, no 7, 832-838 p.Article in journal (Refereed)
    Abstract [en]

    Geographic variation indicating local adaptation, as well as its quantitative genetic basis, is commonly investigated in common garden experiments in the laboratory. However, the applicability of laboratory results to the complex conditions experienced by populations in the wild may be limited. Our previous laboratory experiments showed maternally determined local adaptation in embryonic acid-stress tolerance (viz. survival) of the moor frog, Rana arvalis Nilsson, 1842. Here we tested whether this laboratory finding holds even when embryos are exposed to acid stress in the wild. We conducted reciprocal crosses between an acid-origin population and a neutral-origin population of R. arvalis and transplanted the embryos to an acid site (pH ~4) in the field. Embryonic survival was much lower in the field experiment than in previous laboratory experiments, but, consistent with laboratory work, embryos from acid-origin females had threefold higher survival than embryos from neutral-origin females. These results suggest that laboratory tests can provide appropriate estimates of among population variation, as well as the quantitative genetic basis of acid-stress tolerance in amphibians.

  • 50.
    Quintela, Maria
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Animal ecology.
    Johansson, Magnus P.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Animal ecology.
    Kristjansson, Bjarni K.
    Barreiro, Rodolfo
    Laurila, Anssi
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Animal ecology.
    AFLPs and Mitochondrial Haplotypes Reveal Local Adaptation to Extreme Thermal Environments in a Freshwater Gastropod2014In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 9, no 7, e101821- p.Article in journal (Refereed)
    Abstract [en]

    The way environmental variation shapes neutral and adaptive genetic variation in natural populations is a key issue in evolutionary biology. Genome scans allow the identification of the genetic basis of local adaptation without previous knowledge of genetic variation or traits under selection. Candidate loci for divergent adaptation are expected to show higher F-ST than neutral loci influenced solely by random genetic drift, migration and mutation. The comparison of spatial patterns of neutral markers and loci under selection may help disentangle the effects of gene flow, genetic drift and selection among populations living in contrasting environments. Using the gastropod Radix balthica as a system, we analyzed 376 AFLP markers and 25 mtDNA COI haplotypes for candidate loci and associations with local adaptation among contrasting thermal environments in Lake Myvatn, a volcanic lake in northern Iceland. We found that 2% of the analysed AFLP markers were under directional selection and 12% of the mitochondrial haplotypes correlated with differing thermal habitats. The genetic networks were concordant for AFLP markers and mitochondrial haplotypes, depicting distinct topologies at neutral and candidate loci. Neutral topologies were characterized by intense gene flow revealed by dense nets with edges connecting contrasting thermal habitats, whereas the connections at candidate loci were mostly restricted to populations within each thermal habitat and the number of edges decreased with temperature. Our results suggest microgeographic adaptation within Lake Myvatn and highlight the utility of genome scans in detecting adaptive divergence.

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