Constraints on Adaptive Evolution: The Functional Trade‐Off between Reproduction and Fast‐Start Swimming Performance in the Trinidadian Guppy (Poecilia reticulata)

AbstractIn many animal species, individuals with certain morphological, physiological, or behavioural traits may have a disproportionately large role in determining group behaviour. While most empirical studies of leadership have focused on behaviour of individuals exploring new environments or foraging, little is known about leading behaviour in other ecological contexts. Here, we use a selective breeding design in the Trinidadian guppy (Poecilia reticulata) to quantify the heritability of leadership in a cooperative context, and determine the behavioural traits associated with it. Firstly we found that phenotypic selection for high and low leadership (HL and LL, respectively) over three filial generations resulted in pronounced differences in leadership tendency with a moderate degree of heritability. In our assay of other social traits, LL males were more aggressive and sampled their social environment less than HL males, but HL and LL females did not differ in either aggressiveness or sociability. Traits such as boldness and exploratory tendency did not diverge between the two lines. Leading behaviour was thus associated with social traits in males, but not females; suggesting that there may be sex-specific mechanisms driving the emergence of leadership in this context. We discuss our findings in the context of the evolution of cooperation.

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Selection for brain size impairs innate, but not adaptive immune responses

Proceedings of The Royal Society B Biological Sciences ◽

10.1098/rspb.2015.2857 ◽

2016 ◽

Vol 283 (1826) ◽

pp. 20152857 ◽

Cited By ~ 26

Author(s):

Alexander Kotrschal ◽

Niclas Kolm ◽

Dustin J. Penn

Keyword(s):

Immune Responses ◽

Poecilia Reticulata ◽

Brain Size ◽

Innate Immune Responses ◽

Rejection Reaction ◽

Trade Off ◽

Large Brain ◽

Rejection Response ◽

Selection For ◽

Acquired Immune Responses

Both the brain and the immune system are energetically demanding organs, and when natural selection favours increased investment into one, then the size or performance of the other should be reduced. While comparative analyses have attempted to test this potential evolutionary trade-off, the results remain inconclusive. To test this hypothesis, we compared the tissue graft rejection (an assay for measuring innate and acquired immune responses) in guppies ( Poecilia reticulata ) artificially selected for large and small relative brain size. Individual scales were transplanted between pairs of fish, creating reciprocal allografts, and the rejection reaction was scored over 8 days (before acquired immunity develops). Acquired immune responses were tested two weeks later, when the same pairs of fish received a second set of allografts and were scored again. Compared with large-brained animals, small-brained animals of both sexes mounted a significantly stronger rejection response to the first allograft. The rejection response to the second set of allografts did not differ between large- and small-brained fish. Our results show that selection for large brain size reduced innate immune responses to an allograft, which supports the hypothesis that there is a selective trade-off between investing into brain size and innate immunity.

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Ontogenetic changes in chemical alarm cue recognition and fast-start performance in guppies (Poecilia reticulata )

Ethology ◽

10.1111/eth.12691 ◽

2017 ◽

Vol 123 (12) ◽

pp. 916-923 ◽

Cited By ~ 4

Author(s):

Jigang Xia ◽

Meiling Cheng ◽

Ruiyu Cai ◽

Shijian Fu ◽

Steven J. Cooke ◽

...

Keyword(s):

Poecilia Reticulata ◽

Ontogenetic Changes ◽

Chemical Alarm Cue ◽

Alarm Cue ◽

Fast Start ◽

Cue Recognition

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