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Berglund, Anders
Publications (10 of 83) Show all publications
Cunha, M., Macedo, N., Wilson, J., Rosenqvist, G., Berglund, A. & Monteiro, N. (2019). Reduced sexual size dimorphism in a pipefish population where males do not prefer larger females. Ecology and Evolution
Open this publication in new window or tab >>Reduced sexual size dimorphism in a pipefish population where males do not prefer larger females
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2019 (English)In: Ecology and Evolution, ISSN 2045-7758, E-ISSN 2045-7758Article in journal (Refereed) Epub ahead of print
Abstract [en]

Within a species' distribution, populations are often exposed to diverse environmentsand may thus experience different sources of both natural and sexual selection.These differences are likely to impact the balance between costs and benefits toindividuals seeking reproduction, thus entailing evolutionary repercussions. Here, welook into an unusual population (Baltic Sea) of the broadnosed pipefish, Syngnathustyphle, where males do not seem to select females based on size and hypothesizethat this pattern may derive from a reduction in direct benefits to the male. We furtherhypothesize that if larger females do not persistently secure a higher reproductivesuccess, either through pre‐ or postcopulatory sexual selection, a decrease insexual size dimorphism in the Baltic population should be apparent, especially whencontrasted with a well‐studied population, inhabiting similar latitudes (Swedish westcoast), where males prefer larger females. We found that, in the Baltic population,variation in female quality is low. We were unable to find differences in abortion ratesor protein concentration in oocytes produced by females of contrasting sizes. Directbenefits from mating with large partners seem, thus, reduced in the Baltic population.We also found no evidence of any postcopulatory mechanism that could favorlarger mothers as embryo development was unrelated to female size. While femalesize can still be selected through intrasexual competition or fecundity selection, thepressure for large female body size seems to be lower in the Baltic. Accordingly, wefound a noticeable decrease in sexual size dimorphism in the Baltic population. Weconclude that, although far from negating the significance of other selective processes,sexual selection seems to have a decisive role in supporting pipefish sexualsize asymmetries.

Place, publisher, year, edition, pages
Hoboken, New Jersey: , 2019
Keywords
embryonic development, male pregnancy, postcopulatory selection, sexual selection, Syngnathidae
National Category
Ecology
Research subject
Biology with specialization in Animal Ecology
Identifiers
urn:nbn:se:uu:diva-396312 (URN)10.1002/ece3.5760 (DOI)
Available from: 2019-11-02 Created: 2019-11-02 Last updated: 2019-11-08Bibliographically approved
Ahnesjö, I., Berglund, A., Forsgren, E., Karlsson, A., Kvarnemo, C., Magnhagen, C., . . . Östlund Nilsson, S. (2018). En beteende-ekologisk forskningsperiod på Klubbans biologiska station: Rapport från återträff med Doktorer som disputerade (1983-2001) på avhandlingar med fältarbete på Klubbans Biologiska station. I en värld av kantnålar, stubbar, spiggar och nudingar.. Uppsala: Uppsala universitet
Open this publication in new window or tab >>En beteende-ekologisk forskningsperiod på Klubbans biologiska station: Rapport från återträff med Doktorer som disputerade (1983-2001) på avhandlingar med fältarbete på Klubbans Biologiska station. I en värld av kantnålar, stubbar, spiggar och nudingar.
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2018 (Swedish)Report (Other (popular science, discussion, etc.))
Abstract [en]

We had the fortune as PhD-students and scientists in Animal Ecology at Uppsala University, to spend joyful and creative field work summers at Klubban Biological Station, during the 1980-90’s. A reunion in June 2018 resulted in this report highlighting research on pipefishes, gobies, sticklebacks and nudibranchs. Our research on these animals have provided novel insights and knowledge of the process of sexual selection and paternal care. These animals have, in many aspects, now become model organisms in evolutionary behavioral ecology in marine environments. Our list of publications provides many examples of how environmental factors influence how sexual selection and mate choice operate, how predictors like potential reproductive rates, operational sex ratios work and how male parental care is prominent in influencing selection. This research, that started at Klubban, has broadened our understanding of the ecological importance of shallow marine areas. The evolutionary understanding of how males and females can behave and how adaptive traits are selected in interaction with social and an increasingly changing ambient environment is in focus in our continued scientific endeavors. We have happily compiled this report illustrating how science and scientist can stimulate each other at a wonderful place like Klubban Biological Station, with the access to amazing organisms like pipefishes, gobies, sticklebacks and nudibranchs.

Place, publisher, year, edition, pages
Uppsala: Uppsala universitet, 2018. p. 30
National Category
Ecology Zoology
Identifiers
urn:nbn:se:uu:diva-376734 (URN)
Available from: 2019-02-08 Created: 2019-02-08 Last updated: 2019-02-11Bibliographically approved
Cunha, M., Berglund, A., Mendes, S. & Monteiro, N. (2018). The ‘Woman in Red’ effect: pipefish males curb pregnancies at the sight of an attractive female. Proceedings of the Royal Society of London. Biological Sciences, 285(1885), Article ID 20181335.
Open this publication in new window or tab >>The ‘Woman in Red’ effect: pipefish males curb pregnancies at the sight of an attractive female
2018 (English)In: Proceedings of the Royal Society of London. Biological Sciences, ISSN 0962-8452, E-ISSN 1471-2954, Vol. 285, no 1885, article id 20181335Article in journal (Refereed) Published
Abstract [en]

In an old Gene Wilder movie, an attractive woman dressed in red devastated a man’s current relationship. We have found a similar ‘Woman in Red’ effect in pipefish, a group of fish where pregnancy occurs in males. We tested for the existence of pregnancy blocks in pregnant male black-striped pipefish (Syngnathus abaster). We allowed pregnant males to see females that were larger and even more attractive than their original high-quality mates and monitored the survival and growth of developing offspring. After exposure to these extremely attractive females, males produced smaller offspring in more heterogeneous broods and showed a higher rate of spontaneous offspring abortion. Although we did not observe a full pregnancy block, our results show that males are able to reduce investment in current broods when faced with prospects of a more successful future reproduction with a potentially better mate. This ‘Woman in Red’ life-history trade-off between present and future reproduction has similarities to the Bruce effect, and our study represents, to our knowledge, the first documentation of such a phenomenon outside mammals.

National Category
Ecology
Identifiers
urn:nbn:se:uu:diva-357921 (URN)10.1098/rspb.2018.1335 (DOI)000443163500027 ()
Available from: 2018-08-22 Created: 2018-08-22 Last updated: 2018-11-01Bibliographically approved
Berglund, A., Sundin, J. & Rosenqvist, G. (2017). Baltic pipefish females need twice as many males as they get. Behavioral Ecology, 28(3), 827-832
Open this publication in new window or tab >>Baltic pipefish females need twice as many males as they get
2017 (English)In: Behavioral Ecology, ISSN 1045-2249, E-ISSN 1465-7279, Vol. 28, no 3, p. 827-832Article in journal (Refereed) Published
Abstract [en]

Sex role reversal in 2 pipefish species, Syngnathus typhle and Nerophis ophidion, is potentially explained by females reproducing twice as fast as males. Moreover, in oceanic populations from the Swedish west coast, females compete for males with males pre- ferring to mate with larger females. However, in a brackish Baltic population of S. typhle, males do not prefer larger mates, whereas choosiness remains in the local N. ophidion population. We explore whether this absence of male choice in brackish S. typhle can be explained by males and females having more similar potential reproductive rates here, whereas the sex difference may remain in the local N. ophidion population. Contrary to our expectations, in both species, females out-reproduced males by a factor of more than 2, just as in the oceanic populations. We measured this experimentally as the number of males a female potentially could fill with eggs within the time span of 1 male pregnancy, in relation to males available in nature. Thus, we conclude that sexual selection on females is as strong in brackish as in oceanic populations of both species but that targets of selection via male choice are shifted to traits other than body size in S. typhle. Hence, costs and benefits of choice are probably more important than potential reproductive rates to understand mate choice. We suggest that it may be misleading to use targets of sexual selection, such as choice for large body size, as an indicator of the strength of sexual selection. 

Keywords
brackish population, pipefish, potential reproductive rate, sex roles, sexual selection
National Category
Ecology
Research subject
Biology with specialization in Animal Ecology
Identifiers
urn:nbn:se:uu:diva-318900 (URN)10.1093/beheco/arx046 (DOI)000401942800031 ()
Funder
Swedish Research Council, 621-2007-5191
Available from: 2017-03-29 Created: 2017-03-29 Last updated: 2019-03-19Bibliographically approved
Cunha, M., Berglund, A. & Monteiro, N. (2017). Female ornaments signal own and offspring quality in a sex-role-reversed fish with extreme male parental care. Marine Ecolocy, 38, Article ID e12461.
Open this publication in new window or tab >>Female ornaments signal own and offspring quality in a sex-role-reversed fish with extreme male parental care
2017 (English)In: Marine Ecolocy, ISSN 0173-9565, E-ISSN 1439-0485, Vol. 38, article id e12461Article in journal (Refereed) Published
Abstract [en]

Although female ornaments have been described in many taxa, the full spectrum of information conveyed by such traits together with the potential male fitness benefits are far from fully understood. Here, we used a sex-role-reversed species, the black-striped pipefish, Syngnathus abaster, where females are the ornamented sex and intensively compete for mates who present an extreme form of paternal care (male pregnancy). We investigated what information is conveyed by female traits and if males are using it during mate choice. We further assessed which traits would reflect offspring quality at birth. We found that although body length generally portrays information on female reproductive potential (gonadosomatic index and oocyte diameter),it does so indirectly. Different aspects of the female traits, such as stripe width and trunk broadness, were found to be better direct indicators. When size is kept constant, males prefer females with wider stripes. Moreover, stripe coloration was found to reflect offspring quality as darker-striped females produced larger newborns. Our observations suggest that in a species with exclusive paternal care, independently from the male’s direct investment in reproduction, female contribution decisively impacts male fitness. Thus, at least in sex-role-reversed species such as the black striped pipefish, female ornaments can be selected in an analogous way to those of males in species with conventional sex roles (i.e. by mate choice).

Place, publisher, year, edition, pages
Wiley-Blackwell Publishing Inc., 2017
Keywords
fitness, multiple ornaments, offspring quality, secondary sexual traits, sexual selection
National Category
Ecology
Identifiers
urn:nbn:se:uu:diva-332013 (URN)10.1111/maec.12461 (DOI)000413483000011 ()
Available from: 2017-10-22 Created: 2017-10-22 Last updated: 2018-02-07Bibliographically approved
Sundin, J., Aronsen, T., Rosenqvist, G. & Berglund, A. (2017). Sex in murky waters: algal induced turbidity increases sexual selection in pipefish. Behavioral Ecology and Sociobiology, 71(5), Article ID 78.
Open this publication in new window or tab >>Sex in murky waters: algal induced turbidity increases sexual selection in pipefish
2017 (English)In: Behavioral Ecology and Sociobiology, ISSN 0340-5443, E-ISSN 1432-0762, Vol. 71, no 5, article id 78Article in journal (Refereed) Published
Abstract [en]

Algal induced turbidity has been shown to alter several important aspects of reproduction and sexual selection. However, while turbidity has been shown to negatively affect reproduction and sexually selected traits in some species, it may instead enhance reproductive success in others, implying that the impact of eutrophication is far more complex than originally believed. In this study, we aimed to provide more insight into these inconsistent findings. We used molecular tools to investigate the impact of algal turbidity on reproductive success and sexual selection on males in controlled laboratory experiments, allowing mate choice, mating competition and mate encounter rates to affect reproduction. As study species we used the broad-nosed pipefish, Syngnathus typhle, a species practicing male pregnancy and where we have previously shown that male mate choice is impaired by turbidity. Here, turbidity instead enhanced sexual selection on male size and mating success as well as reproductive success. Effects from mating competition and mate encounter rates may thus override effects from mate choice based on visual cues, producing an overall stronger sexual selection in turbid waters. Hence, seemingly inconsistent effects of turbidity on sexual selection may depend on which mechanisms of sexual selection that have been under study.

Place, publisher, year, edition, pages
Springer, 2017
Keywords
Climate change, Eutrophication, Syngnathidae, Baltic Sea, Sex-role reversal
National Category
Ecology
Research subject
Biology with specialization in Animal Ecology
Identifiers
urn:nbn:se:uu:diva-318896 (URN)10.1007/s00265-017-2310-8 (DOI)000401148300002 ()28450759 (PubMedID)
Available from: 2017-03-29 Created: 2017-03-29 Last updated: 2019-05-14Bibliographically approved
Sundin, J., Rosenqvist, G., Myhren, S. & Berglund, A. (2016). Algal Turbidity Hampers Ornament Perception, but Not Expression, in a Sex-Role-Reversed Pipefish. Ethology, 122(3), 215-225
Open this publication in new window or tab >>Algal Turbidity Hampers Ornament Perception, but Not Expression, in a Sex-Role-Reversed Pipefish
2016 (English)In: Ethology, ISSN 0179-1613, E-ISSN 1439-0310, Vol. 122, no 3, p. 215-225Article in journal (Refereed) Published
Abstract [en]

Sexual ornaments are used both in intra- and intersexual contexts, and these signals have evolved to function in the particular habitat the animal is adapted to. Habitat characteristics may, however, change rapidly due to anthropogenic effects, sometimes at rates too fast for many organisms to adaptively respond. In aquatic ecosystems, eutrophication is currently changing chemical as well as visual properties of the environment. Algae blooms increase water turbidity, and the reduction of water transparency thus has the potential to alter visual ornaments and their perception. However, results are not congruent. Rather, algae turbidity may decrease, increase, or leave ornaments unaffected. The effect seems to depend on exposure time, condition, population and species. Here, we found that the perception of sexual signals, but not their expression, was hampered by turbidity in the sex-role-reversed pipefish Nerophis ophidion. In a laboratory experiment we found that female sexual ornaments (i.e., blue color markings and a skinfold) and fecundity was unaffected by turbidity. Male adaptive mate choice for larger females with large ornament was, however, hampered under turbid conditions, whereas in clear water males choose larger, more ornamented females. Thus, we show that water turbidity had no effect on signal expression but did hamper ornament perception and consequently randomized mate choice.

Place, publisher, year, edition, pages
John Wiley & Sons, 2016
Keywords
eutrophication; intersexual selection; syngnathidae; sexual signals
National Category
Behavioral Sciences Biology
Research subject
Biology with specialization in Animal Ecology
Identifiers
urn:nbn:se:uu:diva-275043 (URN)10.1111/eth.12461 (DOI)000368805700003 ()
Funder
Swedish Research Council, 186163/V40
Available from: 2016-01-28 Created: 2016-01-28 Last updated: 2017-11-30Bibliographically approved
Cunha, M., Berglund, A., Alves, T. & Monteiro, N. (2016). Reduced cannibalism during male pregnancy. Behaviour, 153(1), 91-106
Open this publication in new window or tab >>Reduced cannibalism during male pregnancy
2016 (English)In: Behaviour, ISSN 0005-7959, E-ISSN 1568-539X, Vol. 153, no 1, p. 91-106Article in journal (Refereed) Published
Abstract [en]

Cannibalism provides energetic benefits but is also potentially costly, especially when directed towards kin. Since fitness costs increase with time and energy invested in offspring, cannibalism should be infrequent when parental investment is high. Thus, filial cannibalism in male syngnathids, a group known for the occurrence of male pregnancy, should be rare. Using the pipefish (Syngnathus abaster) we aimed to investigate whether cannibalism does occur in both sexes and how it is affected by reproductive and nutritional states. Although rare, we witnessed cannibalism both in the wild and in the laboratory. Unlike non-pregnant males and females, pregnant and postpartum males largely refrained from cannibalising juveniles. Reproducing males decreased their feeding activity, thus rendering cannibalism, towards kin or non-kin, less likely to occur. However, if not continuously fed, all pipefish adopted a cannibal strategy, revealing that sex and life history stages influenced the ratio between the benefits and costs of cannibalism.

Place, publisher, year, edition, pages
Brill Academic Publishers, 2016
National Category
Behavioral Sciences Biology
Identifiers
urn:nbn:se:uu:diva-268619 (URN)10.1163/1568539X-00003328 (DOI)000365978700006 ()
Available from: 2015-12-08 Created: 2015-12-08 Last updated: 2017-12-01Bibliographically approved
Sundin, J., Rosenqvist, G. & Berglund, A. (2015). Hypoxia delays mating in the broad-nosed pipefish. Marine Biology Research, 11(7), 747-754
Open this publication in new window or tab >>Hypoxia delays mating in the broad-nosed pipefish
2015 (English)In: Marine Biology Research, ISSN 1745-1000, E-ISSN 1745-1019, Vol. 11, no 7, p. 747-754Article in journal (Refereed) Published
Abstract [en]

Courtship is an important part of the reproductive process, ensuring reproductive compatibility and conveying individual quality. One factor in aquatic environments that has the potential to influence courtship behaviours and mating propensity is the level of dissolved oxygen. Furthermore, hypoxic areas are currently spreading due to anthropogenic disturbance, such as eutrophication. In marine environments, hypoxia often occurs in shallow coastal regions that are particularly important areas for reproduction. Here, we investigated how types of reproductive behaviour were affected by mild hypoxia using the well-studied broad-nosed pipefish, Syngnathus typhle. More precisely, we investigated the impact of acute hypoxia on the reproductive behaviour preceding mating, and on the probability of mating, as well as on the latency until these occurred. We found that the latency period to courting and copulation occurring was prolonged in the low-oxygen environment. However, the total time spent courting as well as the probability of mating was unaffected by hypoxia. Other types of reproductive behaviour found in this species, such as dancing, and the unique male pouch-flap behaviour, were also unaffected by the low-oxygen treatment. We conclude that although latency to courting and copulating was prolonged in the hypoxic environment, most reproductive behaviour investigated was unaffected by hypoxia. Thus, hypoxia commonly occurring in shallow coastal regions has the potential to delay certain components of reproduction, but overall the broad-nosed pipefish shows robustness to hypoxic conditions.

Keywords
Climate change, courtship behaviours, dissolved oxygen, eutrophication, sex-role reversal, Syngnathus
National Category
Biological Sciences
Identifiers
urn:nbn:se:uu:diva-256559 (URN)10.1080/17451000.2015.1007874 (DOI)000354984700007 ()
Available from: 2015-06-24 Created: 2015-06-24 Last updated: 2017-12-04Bibliographically approved
Cunha, M., Berglund, A. & Monteiro, N. (2015). The intrinsically dynamic nature of mating patterns and sexual selection. Environmental Biology of Fishes, 98(4), 1047-1058
Open this publication in new window or tab >>The intrinsically dynamic nature of mating patterns and sexual selection
2015 (English)In: Environmental Biology of Fishes, ISSN 0378-1909, E-ISSN 1573-5133, Vol. 98, no 4, p. 1047-1058Article in journal (Refereed) Published
Abstract [en]

Selection processes are influenced by both biotic and abiotic variables, most of which seasonally fluctuate. Therefore, selection may also vary temporally. Specifically, sexual selection, an integral component of natural selection, will inevitably exhibit temporal variation but the scale at which these changes occur are still not well understood. In this study, performed on a wild population of the sex-role reversed black striped pipefish Syngnathus abaster (Risso, 1827), we contrast variables such as male reproductive success, mating success, female investment, mate choice and operational sex ratio between two periods, either near the onset or end of the breeding season. Sexual selection is stronger early in the breeding season. Male reproductive and mating success are significantly affected by male size during the onset of the breeding season but not during the end. Moreover, we found that larger females reproduce mainly during the onset while smaller females had increased chances of reproducing towards the end. As our sampling was performed in two consecutive years, it could be argued that our results stem primarily from between-year variation. Nevertheless, variation in demographic parameters from the onset to the end of the breeding season is similar to that observed in past sampling events. Hence, we suggest that the change in mating patterns within the breeding season derives from seasonal fluctuations in several abiotic (e.g., temperature) and biotic variables (e.g., operational sex ratio), rendering the expression of selective forces, such as sexual selection, inherently dynamic.

Keywords
Mating system . Female investment . Mate choice . Reproduction . Variation . Selection
National Category
Ecology
Research subject
Biology with specialization in Animal Ecology
Identifiers
urn:nbn:se:uu:diva-246280 (URN)10.1007/s10641-014-0338-4 (DOI)000350567300007 ()
Available from: 2015-03-04 Created: 2015-03-04 Last updated: 2017-12-04Bibliographically approved
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