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Brain size affects female but not male survival under predation threat
Author(s) -
Kotrschal Alexander,
Buechel Séverine D.,
Zala Sarah M.,
CorralLopez Alberto,
Penn Dustin J.,
Kolm Niclas
Publication year - 2015
Publication title -
ecology letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.852
H-Index - 265
eISSN - 1461-0248
pISSN - 1461-023X
DOI - 10.1111/ele.12441
Subject(s) - predation , brain size , biology , pike , cichlid , trophic level , guppy , ecology , predator , brain morphometry , affect (linguistics) , zoology , fish <actinopterygii> , fishery , psychology , medicine , communication , magnetic resonance imaging , radiology
There is remarkable diversity in brain size among vertebrates, but surprisingly little is known about how ecological species interactions impact the evolution of brain size. Using guppies, artificially selected for large and small brains, we determined how brain size affects survival under predation threat in a naturalistic environment. We cohoused mixed groups of small‐ and large‐brained individuals in six semi‐natural streams with their natural predator, the pike cichlid, and monitored survival in weekly censuses over 5 months. We found that large‐brained females had 13.5% higher survival compared to small‐brained females, whereas the brain size had no discernible effect on male survival. We suggest that large‐brained females have a cognitive advantage that allows them to better evade predation, whereas large‐brained males are more colourful, which may counteract any potential benefits of brain size. Our study provides the first experimental evidence that trophic interactions can affect the evolution of brain size.