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  • 1.
    Abbott, Jessica K.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution, Animal Ecology.
    Svensson, Erik I.
    Lund University.
    Morph-specific variation in intersexual genetic correlations in an intra-specific mimicry system2010In: Evolutionary Ecology Research, ISSN 1522-0613, E-ISSN 1937-3791, Vol. 12, no 1, p. 105-118Article in journal (Refereed)
    Abstract [en]

    Background: Positive intersexual genetic correlations are typically viewed as constraining the evolution of sexual dimorphism, when traits are subject to sexually antagonistic selection. Our study species, the damselfly Ischnura elegans, has a female-limited colour polymorphism with three female colour morphs (males are monomorphic), one of which is considered a male mimic.

    Question: Are there morph-specific differences in the magnitude of intersexual genetic correlations in I. elegans? Specifically, do male-mimic (Androchrome) females have higher intersexual genetic correlations for morphological traits than non-mimic (Infuscans) females?

    Methods: We collected copulating pairs in the field and raised offspring from these pairs in the laboratory. We measured five morphological traits in both parent and offspring generations and investigated their heritabilities and genetic correlations.

    Results: We found a negative overall relationship between the degree of sexual dimorphism for a trait and its intersexual genetic correlation. But the magnitude and direction of intersexual genetic correlations depended on the female morph. As expected, male mimic (Androchrome) females had higher intersexual genetic correlations. In addition, the genetic correlations between the morphs were in all cases significantly lower than unity. Male mimic (Androchrome) females had higher mother-son covariances than the non-mimic (Infuscans) morph, and this difference is the proximate explanation for the difference in intersexual genetic correlations between the morphs.

  • 2.
    Arbuthnott, Devin
    et al.
    Univ British Columbia, Dept Zool, 4200-6270 Univ Blvd, Vancouver, BC V6T 1Z4, Canada.;Univ British Columbia, Biodivers Res Ctr, 4200-6270 Univ Blvd, Vancouver, BC V6T 1Z4, Canada..
    Mautz, Brian S.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Animal ecology.
    Rundle, Howard D.
    Univ Ottawa, Dept Biol, Ottawa, ON, Canada..
    Rugged fitness landscapes and by-product adaptation in experimental populations of Drosophila melanogaster2018In: Evolutionary Ecology Research, ISSN 1522-0613, E-ISSN 1937-3791, Vol. 19, no 1, p. 15-28Article in journal (Refereed)
    Abstract [en]

    Background: While the concept of the fitness landscape is central to evolutionary theory, empirical characterizations of fitness landscapes have remained difficult. Recently, a number of laboratory experiments using microbes have suggested that fitness landscapes are often rugged, though there is some variation across environments and species. However, there have been very few characterizations of fitness landscapes in sexual organisms, making it unclear whether the conclusions from studies of microbes are applicable to other groups. Questions: Are fitness landscapes smooth or rugged in simplified laboratory environments for sexual organisms? How does landscape topography influence patterns of adaptation? Methods: We conducted a series of experiments using replicate populations of Drosophila melanogaster adapted to either cadmium-or ethanol-enriched food to characterize the fitness and phenotypes of these populations in a simplified laboratory environment (ethanol-enriched media). Results: We found that replicate populations adapted to different laboratory environments have diverged phenotypically in physiology, mating behaviour, and offspring production in alternate environments. However, both ethanol-and cadmium-adapted populations show high fitness in the ethanol-enriched environment relative to their founding population, and cadmium-adapted males actually outcompete ethanol-adapted males for mates in an ethanol environment. Conclusions: Our data indicate that the simplified ethanol-enriched medium represents a rugged fitness landscape, and that alternately adapted populations occupy different fitness peaks on this landscape. Because cadmium-adapted populations were never exposed to ethanol previously, it appears that these populations adapted to ethanol as a by-product of adaptation to their cadmium-enriched environment. Therefore, even in simplified laboratory environments, we find evidence for rugged fitness landscapes, and the overlap of fitness peaks on the phenotypic landscape allowed for by-product adaptation.

  • 3.
    Bergek, Sara
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution, Animal Ecology.
    Olsson, Jens
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution, Limnology.
    Spatiotemporal analysis shows stable genetic differentiation and barriers to dispersal in the Eurasian perch (Perca fluviatilis L.)2009In: Evolutionary Ecology Research, ISSN 1522-0613, E-ISSN 1937-3791, Vol. 11, no 5, p. 827-840Article in journal (Refereed)
    Abstract [en]

    Background: Recently, unexpected or cryptic barriers to gene flow causing genetic discontinuities have been found in a number of animal taxa, even in apparently highly connected areas such as aquatic environments. 

    Goal: Investigate the temporal stability of previously documented microgeographic genetic structure in a fish.

    Organism: Eurasian perch (Perca fluviatilis L.)

    Method: We sampled four locations over a period of 2 years. We used six microsatellites to investigate population differentiation. We compared within-year to between-year differentiation.

    Results: The significant genetic differentiation found between locations in 2004 was still present in 2006. The strongest barriers to gene flow in the lake were consistent over both sampling periods. Furthermore, temporal differentiation existed within each site between the years. Populations of perch appear to cluster in different patches in the lake that harbour genetically differentiated groups of fish. Hence, limited migration and barriers to dispersal can persist over time, even at a very small geographical scale and in an open aquatic environment.

  • 4.
    Björklund, Mats
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Animal ecology.
    Ranta, Esa
    Kaitala, Veijo
    Lundberg, Per
    Bach, Lars
    Stenseth, Nils Christian
    Environmental forcing and genetic differentiation in subdivided populations2008In: Evolutionary Ecology Research, ISSN 1522-0613, E-ISSN 1937-3791, Vol. 10, p. 1-9Article in journal (Refereed)
  • 5. Kuparinen, Anna
    et al.
    Laugen, Ane T.
    Laurila, Anssi
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Population and Conservation Biology.
    Merilä, Juha
    Developmental threshold model challenged by temperature2010In: Evolutionary Ecology Research, ISSN 1522-0613, E-ISSN 1937-3791, Vol. 12, no 7, p. 821-829Article in journal (Refereed)
    Abstract [en]

    Question: Does the L-shape of the reaction norm for age and size at ontogenetic transitions arise irrespective of temperature? The developmental threshold model suggests that this shape arises due to a threshold in body size to undertake the transition. Data studied: Ages and sizes at metamorphosis measured in a common garden experiment in Rana temporaria originating from six populations along a latitudinal gradient. Individuals were exposed to three temperature treatments and two levels of food. Search method: Population-specific age and size at metamorphosis were plotted against each other, and the shape of the reaction norm across populations was further illustrated by an exponential decay function. The observed patterns were further explored via linear mixed-effect models. Conclusion: The L-shape of the reaction norm depends on temperature, suggesting that at low temperature a developmental threshold in age rather than in size regulates the process of metamorphosis.

  • 6.
    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, p. 717-731Article 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.

  • 7.
    Meyer-Lucht, Yvonne
    et al.
    Leibniz-Institute for Zoo- and Wildlife Research.
    Sommer, S.
    Leibniz-Institute for Zoo- and Wildlife Research.
    Number of MHC alleles is related to parasite loads in natural populations of yellow necked mice, Apodemus flavicollis2009In: Evolutionary Ecology Research, ISSN 1522-0613, E-ISSN 1937-3791, Vol. 11, no 7, p. 1085-1097Article in journal (Refereed)
    Abstract [en]

    Hypothesis: Low levels of immune gene variation (major histocompatibility complex) in it Population arc associated with increased parasite load and infection Intensity. Organism: Different Populations of the yellow necked mouse (Apodemus flavicollis). a common rodent in European deciduous and mixed forest habitats Methods: We assessed genetic diversity at selectively neutral, non-coding markers (microsatellites) and adaptive genetic variation at a functionally important part of the immune complex MHC (major histocompatibility complex). We investigated the load with gastrointestinal parasites non-invasively by faecal egg counts and assessed the influence of population genetic variation on parasite burden Results: Both neutral and adaptive genetic diversity differed between mice populations. We could not detect an effect of neutral genetic diversity on the parasite burden in a population Heterozygosity at the MFIC did not reveal an effect on the parasite burden either. However, we did identify significant effects of the number of different MHC alleles in a population oil parasite burden Mice populations with a large number of different MHC alleles displayed lower parasite loads than those populations with few different MHC alleles

  • 8. Mobley, Kenyon B.
    et al.
    Ruiz, Rocio Colas
    Johansson, Frank
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Population and Conservation Biology.
    Englund, Goran
    Bokma, Folmer
    No evidence that stickleback spines directly increase risk of predation by an invertebrate predator2013In: Evolutionary Ecology Research, ISSN 1522-0613, E-ISSN 1937-3791, Vol. 15, no 2, p. 189-198Article in journal (Refereed)
    Abstract [en]

    Background: Some populations of stickleback have a reduced number and/or relative size of spines. Hypothesis: Macroinvertebrate predators such as dragonfly larvae cause selective pressure against spines by capturing more stickleback with pelvic spines than stickleback that are spineless. Organisms: Ninespine stickleback (Pungitius pungitius) and dragonfly larvae (Aeshna grandis). Methods: We used 10 stickleback, five with pelvic spines and five with their pelvic spines removed. We put them in containers with two dragonfly larvae. Every day for 4 days we monitored how many stickleback were captured by the larvae. We repeated this experiment ten times at two different densities of fish and predators. We also developed a model to determine whether selection for spinelessness can be distinguished from drift. Results: Dragonfly larvae caught as many stickleback with spines as without. The absence of spines was not associated with a decrease in predation risk. We substituted Bayesian estimates of the selection coefficient into quantitative genetic models of allele frequency change, and the results of the models suggest that the selective advantage of spine loss is so small that its effects cannot be distinguished from drift.

  • 9.
    Olsson, Jens
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution, Limnology.
    Eklöv, Peter
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution, Limnology.
    Habitat structure, feeding mode and morphological reversibility: factors influencing phenotypic plasticity in perch2005In: Evolutionary Ecology Research, ISSN 1522-0613, E-ISSN 1937-3791, Vol. 7, no 8, p. 1109-1123Article in journal (Refereed)
    Abstract [en]

    Questions: Do both habitat structure and feeding mode contribute to morphological divergence within fish populations? To what extent may an induced morphology be reversed?

    Organism: Young-of-the-year Eurasian perch (Perca fluviatilis L.).

    Methods: An aquarium experiment with a 2 × 2 factorial design (two levels of habitat structure and two levels of feeding mode). The habitat structure and feeding mode were reversed for perch in two habitat treatments midway through the experiment.

    Results: Both habitat structure and feeding mode contributed to morphological divergence (40.7% and 4.9% of the total variation respectively), which suggests that both habitat complexity and prey type diversity influence morphological adaptations in this fish species. Perch morphology is highly plastic and can be reversed in as short a time as 4 weeks.

     

  • 10. Pitala, Natalia
    et al.
    Siitari, Heli
    Gustafsson, Lars
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution, Animal Ecology.
    Brommer, Jon E.
    Ectoparasites help to maintain variation in cell-mediated immunity in the blue tit-hen flea system2009In: Evolutionary Ecology Research, ISSN 1522-0613, E-ISSN 1937-3791, Vol. 11, no 1, p. 79-94Article in journal (Refereed)
    Abstract [en]

    Hypothesis: Host-parasite interactions have the potential to maintain genetic variation, especially in traits related to defence against parasites. Organism: Blue tit (Cyanistes caeruleus) nestlings. Methods: Rear nestlings in artificially created conditions of low and high abundance of ectoparasitic hen fleas (Ceratophyllus gallinae). Cross-foster siblings between these environments to estimate parasite-induced genotype-environment interactions. Measure components of phenotypic variance in morphology (tarsus length and body mass) and in immune defence (plasma immunoglobulins and cell-mediated immunocompetence). Results: Hen flea infestation lowered growth, cell-mediated immunocompetence, and haematocrit. Genotype-environment interactions were observed in cell-mediated immunocompetence, body mass, and haematocrit, with significant crossing reaction norms for cell-mediated immunocompetence and haematocrit. Immunoglobulin concentrations were unaffected by fleas. Thus, host-parasite interactions constrain the expression and evolvability of some traits, but also create genotype-environment interactions with the potential to maintain genetic variation in immune defence.

  • 11. Ranta, Esa
    et al.
    Bach, Lars A.
    Kaitala, Veijo
    Björklund, Mats
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution, Animal Ecology.
    Lundberg, Per
    Competition enhances spatial genetic differentiation2009In: Evolutionary Ecology Research, ISSN 1522-0613, E-ISSN 1937-3791, Vol. 11, no 8, p. 1251-1258Article in journal (Refereed)
    Abstract [en]

    Questions: How does the number of species in a community affect the level of genetic diversity of its constituent species? What is the relation between competitive interactions and the spatial distribution of genetic variation? When spatially structured, how is the genetic differentiation among subpopulations affected by competition and size of the community? Model features and key assumptions: A model combining one-locus two-allele genetics with density-dependent regulation in population renewal (Ricker function) and demographic stochasticity is extended to incorporate S-species Lotka-Volterra competition. The system is embedded into a spatial context where 1000 populations are connected with stepping-stone dispersal. Beginning from random genotype composition, the system is simulated and the resulting community composition and genetic diversity across space are recorded. Conclusions: Genetic differentiation in the ensemble increases with the number of competing species in the community (0.30 +/- 0.13, normalized coefficient with 95% confidence limit) and with the intensity of pair-wise competition (0.20 +/- 0.05) but most strongly with their interaction (0.62 +/- 0.22). Although the system-wide differentiation increases, one finds that the process leads to local paucity of genotypes and hence a negative correlation between species diversity and local genetic diversity.

  • 12. Ranta, Esa
    et al.
    Kaitala, Veijo
    Björklund, Mats
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution, Animal Ecology.
    Lundberg, Per
    Bach, Lars A.
    Stenseth, Nils Chr.
    Environmental forcing and genetic differentiation in subdivided populations2008In: Evolutionary Ecology Research, ISSN 1522-0613, E-ISSN 1937-3791, Vol. 10, no 1, p. 1-9Article in journal (Refereed)
    Abstract [en]

    Questions: How will genetic differentiation and genetic drift in spatially structured populations be affected by different classes of autocorrelated environmental noise? How does dispersal interact with fluctuations generated from the demographic and environmental forcing in shaping the neutral genetic patterns? Model and key assumptions: Populations are regulated locally by density-dependent feedback including demographic stochasticity but they are also here forced by environmental noise (white, red, and blue noise corresponding to random, positive, and negative autocorrelation respectively). Spatial structure consists of a looped string of populations connected by dispersal and each with a predefined carrying capacity (one-dimensional stepping stone structure). Method: Simulations initialized by randomly distributing individuals, and thus genotypes, in space (no fitness differences, no mutation, no recombination, no selection). Conclusions: In an unpredictable way, red noise reinforces the genetic differentiation among populations more than white or blue noise. Dispersal appears unable to dilute the differentiation effect of positively autocorrelated forcing. In modelling the effect of environmental stochasticity, details about the type of environmental noise are of paramount importance for the results and their biological and management implications.

  • 13.
    Roufidou, Chrysoula
    et al.
    Stockholm Univ, Dept Zool, SE-10691 Stockholm, Sweden..
    Sebire, Marion
    Ctr Environm Fisheries & Aquaculture Sci Cefas, Weymouth, England..
    Katsiadaki, Ioanna
    Ctr Environm Fisheries & Aquaculture Sci Cefas, Weymouth, England..
    Mustafa, Arshi
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology. Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Neuroscience, Physiology.
    Schmitz, Monika
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology.
    Mayer, Ian
    Norwegian Univ Life Sci, Fac Vet Med & Biosci, Oslo, Norway..
    Shao, Yi Ta
    Natl Taiwan Ocean Univ, Inst Marine Biol, Keelung, Taiwan..
    Borg, Bertil
    Stockholm Univ, Dept Zool, SE-10691 Stockholm, Sweden..
    Overripening of eggs and changes in reproductive hormones in the threespine stickleback, Gasterosteus aculeatus2016In: Evolutionary Ecology Research, ISSN 1522-0613, E-ISSN 1937-3791, Vol. 17, no 3, p. 583-601Article in journal (Refereed)
    Abstract [en]

    Background: Female threespine sticklebacks, Gasterosteus aculeatus, are batch spawners. As in most teleosts, the ovulated eggs are kept in the ovarian cavity until spawning. If spawning or spontaneous release of the eggs does not take place, they can become overripe and harden, and in most cases remain in the ovary. The overripe eggs are lost for reproduction and also block further spawnings. Reproductive hormones regulate egg production and may be involved in the mechanism of overripening. Question: What are the reproductive endocrinological parameters characterizing overripening of ovulated eggs in the threespine stickleback? Organism: Wild-caught adult threespine sticklebacks from the southern Baltic at Skare in southern Sweden and the island of Asko in northwestern Baltic Proper in Sweden. Experiments: We collected blood samples for hormone measurements, as well as pituitaries and brains for measurement of mRNA from both sexually mature non-overripe (non-ovulated and/or ovulated) and overripe (egg-bound) females. For the Skare fish, sexual maturation was induced under laboratory conditions by exposure to a long photoperiod and we compared the non-overripe (including non-ovulated, with oocytes in different maturing or ripening stages, and ovulated females) with the overripe females. The Asko fish were sampled directly from nature, during the natural summer breeding season and we compared the non-overripe (including non-ovulated, with oocytes in different maturing or ripening stages, and ovulated females) with the overripe females. Methods: In the fish collected from Skare, we used radioimmunoassay to measure the plasma levels of four steroids: testosterone, estradiol, 17,20 beta-dihydroxypregn-4-en-3-one (17,20 beta-P), and 17,20 beta, 21-trihydroxypregn-4-en-3-one (17,20 beta,21-P). We also measured the mRNA levels of gonadotropins [GTHs: follicle-stimulating hormone (fsh-beta) and luteinizing hormone (lh-beta)] in the pituitary, and of gonadotropin-releasing hormones (GnRHs: gnrh2, gnrh3) and kisspeptin (kiss2) and its G protein-coupled receptor (gpr54) in the brain by real-time quantitative PCR. In the fish collected from Asko, we measured only progestogens (17,20 beta-P and 17,20 beta,21-P). Results: In the fish from Skare, overripe female sticklebacks had significantly lower levels of circulating plasma steroid hormones (testosterone, estradiol, 17,20 beta-P), as well as of pituitary lh-beta and brain kiss2 and gpr54 mRNA than the non-overripe females. In the fish caught from Asko, overripe females had lower 17,20 beta-P levels than the non-overripe non-ovulated females, but there was no difference between the non-overripe ovulated and the overripe females. The 17,20 beta,21-P plasma levels were under the limit of detection in all groups.

  • 14.
    South, Sandra H.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Animal Ecology.
    Arnqvist, Göran
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Animal Ecology.
    Morphological variation of an ornament expressed in both sexes of the mosquito Sabethes cyaneus2009In: Evolutionary Ecology Research, ISSN 1522-0613, E-ISSN 1937-3791, Vol. 11, no 1, p. 1-21Article, review/survey (Refereed)
    Abstract [en]

    Question: Do elaborate ornaments expressed in both sexes show patterns of phenotypic variation consistent with selection via mutual mate choice? Data description: Detailed morphometric data on the striking leg 'paddle' ornament of the sabethine mosquito Sabethes cyaneus: ornament size and shape and size of general morphological traits. Data derive from 80 males and 80 females from a wild-type laboratory colony established with individuals collected in Panama. Search method: Shape variation was analysed using geometric morphometric methods (elliptic Fourier analyses). We investigated sex differences in the relationships between body size on the one hand and leg length, ornament size, and ornament shape on the other, using general linear models. We also explored morphological variation in asymmetry, allometry, and in the magnitude of phenotypic variation across traits. Conclusions: These ornaments showed many of the classic hallmarks of a sexually selected and condition-dependent ornament: (i) phenotypic variation in size was much greater than for any other trait; (ii) the size of the major part of the paddle showed positive allometry; and (iii) the degree of fluctuating asymmetry in one component of the shape of the leg paddles decreased with body size. Remarkably, these patterns were more pronounced in females and sexual dimorphism in size and shape of the leg paddle ornament was slight. Although data on the current pattern of morphological variation alone does not allow firm conclusions about past selection, our results are consistent with the maintenance of these ornaments in both sexes by sexual selection via mutual mate choice.

  • 15.
    Svanbäck, Richard
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Ecology and Evolution, Limnology.
    Eklöv, Peter
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Ecology and Evolution, Limnology.
    Genetic variation and phenotypic plasticity: causes of morphological variation in Eurasian perch2006In: Evolutionary Ecology Research, ISSN 1522-0613, E-ISSN 1937-3791, Vol. 8, no 1, p. 37-49Article in journal (Refereed)
    Abstract [en]

    Question: What is the importance of genetic variation and phenotypic plasticity in formingthe morphological difference between littoral and pelagic perch?

    Organism: Juveniles of Eurasian perch (Perca fluviatilis L.).

    Site: Enclosures (2 × 2 m) in a pond, Röbäcksdalen, Umeå, Sweden.

    Methods: Adults from the littoral and pelagic habitats were bred separately andtheir offspring were raised in enclosures with either open water or vegetation in an artificialpond.

    Results: Offspring from littoral parents had a higher proportion of littoral prey types in theirdiet than pelagic offspring even though there were no differences in prey community betweentreatments. Littoral offspring had a deeper body than pelagic offspring raised in the sameenvironment. However, most of the phenotypic variation in this experiment was explained byphenotypic plasticity: offspring from both parental types raised in open water displayedpelagic-type characteristics, whereas offspring raised in vegetation displayed littoral-typecharacteristics.

    Conclusion: Previous long-term studies on perch show that they experience a fluctuatingenvironment due to population dynamics. The plasticity in perch could therefore be importantas fluctuating environments favour plasticity.

  • 16.
    Teplitsky, Celine
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution.
    Räsänen, Katja
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution.
    Laurila, Anssi
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution, Population and Conservation Biology.
    Adaptive plasticity in stressful environments: Acidity constrains inducible defences in Rana arvalis2007In: Evolutionary Ecology Research, ISSN 1522-0613, E-ISSN 1937-3791, Vol. 9, no 3, p. 447-458Article in journal (Refereed)
    Abstract [en]

    Questions: How do environmental stressors affect the expression of adaptive phenotypicplasticity? Is there inter-population variation in these effects?   Hypothesis: Acid stress constrains the expression of inducible defences by decreasinginvestment in defences or by increasing the costs of investment. Organisms originating fromneutral environments suffer more from acid stress than organisms originating from acidenvironments.   Organism: Tadpoles of Rana arvalis, originating from two different populations (acid andneutral). This species displays inducible defences in response to insect predators (here dragonflylarvae).   Methods: A laboratory experiment with a factorial design crossing two factors: predatorpresence (present vs. absent) and acidity (neutral vs. acid). We tested the effects of experimentaltreatment on tadpole morphology as well as age and size at metamorphosis.   Results: Tadpoles from the neutral origin population invested less in inducible defences (tailfin depth) in the acid than in the neutral treatment. In contrast, tadpoles from the acid originpopulation were able to respond equally well to predators in both pH treatments. pH-relatedcosts differed between populations: while tadpoles from the neutral origin population sufferedfrom acid stress in terms of reduced developmental rate, those from the acid origin populationseemed to suffer from neutral stress in terms of reduced size at metamorphosis.

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