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Ahnesjö, Ingrid
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Publications (10 of 50) Show all publications
Ahnesjö, I. & Braga Goncalves, I. (2019). Mate choice in males and females (2ed.). In: Choe J.C. (Ed.), Encyclopedia of Animal Behavior: (pp. 432-440). Elsevier
Open this publication in new window or tab >>Mate choice in males and females
2019 (English)In: Encyclopedia of Animal Behavior / [ed] Choe J.C., Elsevier, 2019, 2, p. 432-440Chapter in book (Refereed)
Abstract [en]

To find a “dream mate” is important for fitness in all sexually reproducing animals because half of the genome of one’soffspring comes from the chosen mate. Individuals that choose their mates may gain both direct benefits (i.e., care or other resources) and indirect benefits (genes that improve offspring viability or attractiveness). Mate choice occurs in males and females, and individuals may both be choosy and compete to be chosen. Both processes often result in sexual selection and in the evolution of secondary sexual characters. Mate choice is context-dependent, operates on multiple traits and varies in time and space.

Place, publisher, year, edition, pages
Elsevier, 2019 Edition: 2
National Category
Natural Sciences
Research subject
Biology with specialization in Animal Ecology
Identifiers
urn:nbn:se:uu:diva-375677 (URN)9780128132517 (ISBN)
Available from: 2019-01-31 Created: 2019-01-31 Last updated: 2019-02-01Bibliographically 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
Tsuboi, M., Lim, A. C., Ooi, B. L., Yip, M. Y., Chong, V. C., Ahnesjö, I. & Kolm, N. (2017). Brain size evolution in pipefishes and seahorses: the role of feeding ecology, life history and sexual selection. Journal of Evolutionary Biology, 30(1), 150-160
Open this publication in new window or tab >>Brain size evolution in pipefishes and seahorses: the role of feeding ecology, life history and sexual selection
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2017 (English)In: Journal of Evolutionary Biology, ISSN 1010-061X, E-ISSN 1420-9101, Vol. 30, no 1, p. 150-160Article in journal (Refereed) Published
Abstract [en]

Brain size varies greatly at all taxonomic levels. Feeding ecology, life history and sexual selection have been proposed as key components in generating contemporary diversity in brain size across vertebrates. Analyses of brain size evolution have, however, been limited to lineages where males predominantly compete for mating and females choose mates. Here, we present the first original data set of brain sizes in pipefishes and seahorses (Syngnathidae) a group in which intense female mating competition occurs in many species. After controlling for the effect of shared ancestry and overall body size, brain size was positively correlated with relative snout length. Moreover, we found that females, on average, had 4.3% heavier brains than males and that polyandrous species demonstrated more pronounced (11.7%) female-biased brain size dimorphism. Our results suggest that adaptations for feeding on mobile prey items and sexual selection in females are important factors in brain size evolution of pipefishes and seahorses. Most importantly, our study supports the idea that sexual selection plays a major role in brain size evolution, regardless of on which sex sexual selection acts stronger.

Keywords
brain evolution, phylogenetic comparative analysis, pipefishes & seahorses, sexual selection & conflicts
National Category
Evolutionary Biology
Identifiers
urn:nbn:se:uu:diva-320072 (URN)10.1111/jeb.12995 (DOI)000394852200012 ()27748990 (PubMedID)
Funder
Helge Ax:son Johnsons stiftelse Swedish Research Council, 621-2012-3624
Available from: 2017-04-13 Created: 2017-04-13 Last updated: 2017-05-03Bibliographically approved
Ahnesjö, I. & Braga Goncalves, I. (2017). Mate Choice in Males and Females. In: Reference Module in Life Sciences: (pp. 394-398). Elsevier
Open this publication in new window or tab >>Mate Choice in Males and Females
2017 (English)In: Reference Module in Life Sciences, Elsevier, 2017, p. 394-398Chapter in book (Other academic)
Abstract [en]

To find a “dream mate” is important for fitness in all sexually reproducing animals because half of the genome of one’s offspring comes from the chosen mate. Individuals that choose their mates may gain both direct benefits (ie, care or other resources) and indirect benefits (genes improving offspring viability or attractiveness). Mate choice occurs in males and females, and individuals may simultaneously be choosy and compete to be chosen. Processes that often result in sexual selection and in the evolution of secondary sexual characters. Mate choice is context-dependent, operates on multiple traits and varies in time and space.

Place, publisher, year, edition, pages
Elsevier, 2017
National Category
Natural Sciences
Identifiers
urn:nbn:se:uu:diva-325035 (URN)10.1016/B978-0-12-809633-8.01285-1 (DOI)978-0-12-809633-8 (ISBN)
Available from: 2017-06-20 Created: 2017-06-20 Last updated: 2017-06-29Bibliographically approved
Sagebakken, G., Kvarnemo, C. & Ahnesjö, I. (2017). Nutritional state - a survival kit for brooding pipefish fathers. Biological Journal of the Linnean Society, 121(2), 312-318
Open this publication in new window or tab >>Nutritional state - a survival kit for brooding pipefish fathers
2017 (English)In: Biological Journal of the Linnean Society, ISSN 0024-4066, E-ISSN 1095-8312, Vol. 121, no 2, p. 312-318Article in journal (Refereed) Published
Abstract [en]

A parent's nutritional state may influence its ability to provide care to offspring and ability to handle infections. In the broad-nosed pipefish, Syngnathus typhle, males care for their offspring by brooding the developing embryos in a brood pouch, providing nutrients and oxygen, resembling a pregnancy. Here, we demonstrate that the nutritional state of pregnant males covaries with their own survival during a selective event. Brooding males surviving a Vibrio sp. infection were in a significantly better nutritional state, as estimated by their hepatosomatic index. Furthermore, a higher nutritional state of the brooding male correlated with a lower embryo mortality, while feeding treatment (low vs. high) had no effect on male survival, nutritional state or embryo mortality. Finally, males brooding heavier embryos also showed a lower embryo mortality. This may reflect a maternal effect (if large eggs result in higher embryo survival), a paternal effect (if higher provisioning of male care promotes both embryo growth and survival), or a combination thereof (males caring more for large embryos). The results demonstrate the importance of a good nutritional state for a caring parent when their immunity is challenged.

Place, publisher, year, edition, pages
OXFORD UNIV PRESS, 2017
Keywords
brood reduction, condition, embryo mortality, immunity, parental care, Syngnathidae, Syngnathus typhle
National Category
Biological Sciences
Identifiers
urn:nbn:se:uu:diva-330737 (URN)10.1093/biolinnean/blx002 (DOI)000405207800008 ()
Funder
Helge Ax:son Johnsons stiftelse Swedish Research Council
Available from: 2017-10-09 Created: 2017-10-09 Last updated: 2017-10-09Bibliographically approved
Sagebakken, G., Ahnesjö, I. & Kvarnemo, C. (2016). Costs and Benefits to Pregnant Male Pipefish Caring for Broods of Different Sizes. PLoS ONE, 11(5), Article ID e0156484.
Open this publication in new window or tab >>Costs and Benefits to Pregnant Male Pipefish Caring for Broods of Different Sizes
2016 (English)In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 11, no 5, article id e0156484Article in journal (Refereed) Published
Abstract [en]

Trade-offs between brood size and offspring size, offspring survival, parental condition or parental survival are classic assumptions in life history biology. A reduction in brood size may lessen these costs of care, but offspring mortality can also result in an energetic gain, if parents are able to utilize the nutrients from the demised young. Males of the broad-nosed pipefish (Syngnathus typhle) care for the offspring by brooding embryos in a brood pouch. Brooding males can absorb nutrients that emanate from embryos, and there is often a reduction in offspring number over the brooding period. In this study, using two experimentally determined brood sizes (partially and fully filled brood pouches), we found that full broods resulted in larger number of developing offspring, despite significantly higher absolute and relative embryo mortality, compared to partial broods. Male survival was also affected by brood size, with males caring for full broods having poorer survival, an effect that together with the reduced embryo survival was found to negate the benefit of large broods. We found that embryo mortality was lower when the brooding males were in good initial condition, that embryos in broods with low embryo mortality weighed more, and surprisingly, that males in higher initial condition had embryos of lower weight. Brood size, however, did not affect embryo weight. Male final condition, but not initial condition, correlated with higher male survival. Taken together, our results show costs and benefits of caring for large brood sizes, where the numerical benefits come with costs in terms of both embryo survival and survival of the brooding father, effects that are often mediated via male condition.

National Category
Ecology
Identifiers
urn:nbn:se:uu:diva-298870 (URN)10.1371/journal.pone.0156484 (DOI)000377146100041 ()27243937 (PubMedID)
Funder
Helge Ax:son Johnsons stiftelse Knut and Alice Wallenberg FoundationSwedish Research Council
Available from: 2016-07-11 Created: 2016-07-11 Last updated: 2017-11-28Bibliographically approved
Goncalves, I. B., Ahnesjö, I. & Kvarnemo, C. (2016). Evolutionary ecology of pipefish brooding structures: embryo survival and growth do not improve with a pouch. Ecology and Evolution, 6(11), 3608-3620
Open this publication in new window or tab >>Evolutionary ecology of pipefish brooding structures: embryo survival and growth do not improve with a pouch
2016 (English)In: Ecology and Evolution, ISSN 2045-7758, E-ISSN 2045-7758, Vol. 6, no 11, p. 3608-3620Article in journal (Refereed) Published
Abstract [en]

For animals that reproduce in water, many adaptations in life-history traits such as egg size, parental care, and behaviors that relate to embryo oxygenation are still poorly understood. In pipefishes, seahorses and seadragons, males care for the embryos either in some sort of brood pouch, or attached ventrally to the skin on their belly or tail. Typically, egg size is larger in the brood pouch group and it has been suggested that oxygen supplied via the pouch buffers the developing embryos against hypoxia and as such is an adaptation that has facilitated the evolution of larger eggs. Here, using four pipefish species, we tested whether the presence or absence of brood pouch relates to how male behavior, embryo size, and survival are affected by hypoxia, with normoxia as control. Two of our studied species Entelurus aequoreus and Nerophis ophidion (both having small eggs) have simple ventral attachment of eggs onto the male trunk, and the other two, Syngnathus typhle (large eggs) and S. rostellatus (small eggs), have fully enclosed brood pouches on the tail. Under hypoxia, all species showed lower embryo survival, while species with brood pouches suffered greater embryo mortality compared to pouchless species, irrespective of oxygen treatment. Behaviorally, species without pouches spent more time closer to the surface, possibly to improve oxygenation. Overall, we found no significant benefits of brood pouches in terms of embryo survival and size under hypoxia. Instead, our results suggest negative effects of large egg size, despite the protection of brood pouches.

Keywords
Egg size, embryo growth, embryo survival, environmental conditions, low oxygen, parental care, paternal care, Syngnathidae
National Category
Evolutionary Biology
Identifiers
urn:nbn:se:uu:diva-298859 (URN)10.1002/ece3.2139 (DOI)000377043200013 ()
Available from: 2016-07-11 Created: 2016-07-11 Last updated: 2017-11-28Bibliographically approved
Tsuboi, M., Shoji, J., Sogabe, A., Ahnesjö, I. & Kolm, N. (2016). Within species support for the expensive tissue hypothesis: a negative association between brain size and visceral fat storage in females of the Pacific seaweed pipefish. Ecology and Evolution, 6(3), 647-655
Open this publication in new window or tab >>Within species support for the expensive tissue hypothesis: a negative association between brain size and visceral fat storage in females of the Pacific seaweed pipefish
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2016 (English)In: Ecology and Evolution, ISSN 2045-7758, E-ISSN 2045-7758, Vol. 6, no 3, p. 647-655Article in journal (Refereed) Published
Abstract [en]

The brain is one of the most energetically expensive organs in the vertebrate body. Consequently, the high cost of brain development and maintenance is predicted to constrain adaptive brain size evolution (the expensive tissue hypothesis, ETH). Here, we test the ETH in a teleost fish with predominant female mating competition (reversed sex roles) and male pregnancy, the pacific seaweed pipefish Syngnathus schlegeli. The relative size of the brain and other energetically expensive organs (kidney, liver, heart, gut, visceral fat, and ovary/testis) was compared among three groups: pregnant males, nonpregnant males and egg producing females. Brood size in pregnant males was unrelated to brain size or the size of any other organ, whereas positive relationships were found between ovary size, kidney size, and liver size in females. Moreover, we found that the size of energetically expensive organs (brain, heart, gut, kidney, and liver) as well as the amount of visceral fat did not differ between pregnant and nonpregnant males. However, we found marked differences in relative size of the expensive organs between sexes. Females had larger liver and kidney than males, whereas males stored more visceral fat than females. Furthermore, in females we found a negative correlation between brain size and the amount of visceral fat, whereas in males, a positive trend between brain size and both liver and heart size was found. These results suggest that, while the majority of variation in the size of various expensive organs in this species likely reflects that individuals in good condition can afford to allocate resources to several organs, the cost of the expensive brain was visible in the visceral fat content of females, possibly due to the high costs associated with female egg production.

Keywords
Brain size evolution, sex-role reversal, Syngnathidae, the expensive tissue hypothesis, trade-off
National Category
Ecology
Identifiers
urn:nbn:se:uu:diva-280263 (URN)10.1002/ece3.1873 (DOI)000369974900002 ()26865955 (PubMedID)
Funder
Helge Ax:son Johnsons stiftelse Swedish Research Council, 621-2012-3624
Note

Data available from the Dryad Digital Repository: http://dx.doi.org/10.5061/dryad.t25d2

Available from: 2016-03-09 Created: 2016-03-09 Last updated: 2017-11-30Bibliographically approved
Goncalves, I. B., Mobley, K. B., Ahnesjo, I., Sagebakken, G., Jones, A. G. & Kvarnemo, C. (2015). Effects of mating order and male size on embryo survival in a pipefish. Biological Journal of the Linnean Society, 114(3), 639-645
Open this publication in new window or tab >>Effects of mating order and male size on embryo survival in a pipefish
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2015 (English)In: Biological Journal of the Linnean Society, ISSN 0024-4066, E-ISSN 1095-8312, Vol. 114, no 3, p. 639-645Article in journal (Refereed) Published
Abstract [en]

In species that provide parental care, individuals should invest adaptively in their offspring in relation to the pre- and post-zygotic care provided by their partners. In the broad-nosed pipefish, Syngnathus typhleL., females transfer large, nutrient-rich eggs into the male brood pouch during mating. The male broods and nourishes the embryos for several weeks before independent juveniles emerge at parturition. Given a choice, females clearly prefer large partners. Yet, females provide protein-richer eggs when the same individual mates with a smaller than a larger male. In the present study, we allowed each female to mate with one small and one large male, in alternated order. We found a strong effect of female mating order, with larger clutches and higher embryo mortality in first- than second-laid broods, which may suggest that eggs over-ripen in the ovaries or reflect the negative effects of high embryo density in the brood pouch. In either case, this effect should put constraints on the possibility of a female being selective in mate choice. We also found that small and large males produced embryos of similar size and survival, consistent with the reproductive compensation hypothesis, suggesting that, in this species, larger males provide better nourishment to the embryos than smaller males.(c) 2014 The Linnean Society of London, Biological Journal of the Linnean Society, 2015, 114, 639-645.

Keywords
differential allocation, mating constraints, parental investment, paternal care, reproductive compensation hypothesis, sex role-reversal
National Category
Biological Sciences
Identifiers
urn:nbn:se:uu:diva-248436 (URN)10.1111/bij.12441 (DOI)000349749100012 ()
Available from: 2015-04-02 Created: 2015-03-30 Last updated: 2017-12-04Bibliographically approved
Goncalves, I. B., Ahnesjo, I. & Kvarnemo, C. (2015). Embryo oxygenation in pipefish brood pouches: novel insights. Journal of Experimental Biology, 218(11), 1639-1646
Open this publication in new window or tab >>Embryo oxygenation in pipefish brood pouches: novel insights
2015 (English)In: Journal of Experimental Biology, ISSN 0022-0949, E-ISSN 1477-9145, Vol. 218, no 11, p. 1639-1646Article in journal (Refereed) Published
Abstract [en]

The pipefish brood pouch presents a unique mode of parental care that enables males to protect, osmoregulate, nourish and oxygenate the developing young. Using a very fine O-2 probe, we assessed the extent to which males of the broad-nosed pipefish (Syngnathus typhle) oxygenate the developing embryos and are able to maintain pouch fluid O-2 levels when brooding in normoxia (100% O-2 saturation) and hypoxia (40% O-2 saturation) for 24 days. In both treatments, pouch fluid-O-2 saturation levels were lower compared with the surrounding water and decreased throughout the brooding period, reflecting greater offspring demand for O-2 during development and/or decreasing paternal ability to provide O-2 to the embryos. Male condition (hepatosomatic index) was negatively affected by hypoxia. Larger males had higher pouch fluid O-2 saturation levels compared with smaller males, and levels were higher in the bottom section of the pouch compared with other sections. Embryo size was positively correlated with O-2 availability, irrespective of their position in the pouch. Two important conclusions can be drawn from our findings. First, our results highlight a potential limitation to brooding within the pouch and dismiss the notion of closed brood pouches as well-oxygenated structures promoting the evolution of larger eggs in syngnathids. Second, we provide direct evidence that paternal care improves with male size in this species. This finding offers an explanation for the documented strong female preference for larger partners because, in terms of oxygenation, the brood pouch can restrict embryo growth.

Keywords
Embryo development, Fish, Hypoxia, Male size, Normoxia, Paternal care, Syngnathidae
National Category
Biological Sciences
Identifiers
urn:nbn:se:uu:diva-257012 (URN)10.1242/jeb.120907 (DOI)000355602000011 ()26041030 (PubMedID)
Available from: 2015-06-29 Created: 2015-06-29 Last updated: 2017-12-04Bibliographically approved
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