TY - JOUR
T1 - Evolutionary drivers of group foraging
T2 - a new framework for investigating variance in food intake and reproduction
AU - Grinsted, Lena
AU - Deutsch, Ella K.
AU - Jimenez-Tenorio, Manuel
AU - Lubin, Yael
PY - 2019/10/1
Y1 - 2019/10/1
N2 - A proposed fundamental driver of group living is more reliable, predictable foraging and reproduction, i.e., reduced variance in food intake and reproductive output. However, existing theories on variance reduction in group foraging are simplistic, refer to variance at the level of individuals and groups without linking the two, and do not spell out crucial underlying assumptions. We provide a new, widely applicable framework for identifying when variance reduction conveys fitness benefits of group foraging in a wide range of organisms. We discuss critical limitations of established theories, the Central Limit Theorem and Risk-Sensitive Foraging Theory applied to group foraging, and incorporate them into our framework while addressing the confusion over the levels of variance and identifying previously unaddressed assumptions. Through a field study on colonial spiders, Cyrtophora citricola, we demonstrate the importance of evaluating the level of food sharing as a critical first step, previously overlooked in the literature. We conclude that variance reduction provides selective advantages only under narrow conditions and does not provide a universal benefit to group foraging as previously proposed. Our framework provides an important tool for identifying evolutionary drivers of group foraging and understanding the role of fitness variance in the evolution of group living.
AB - A proposed fundamental driver of group living is more reliable, predictable foraging and reproduction, i.e., reduced variance in food intake and reproductive output. However, existing theories on variance reduction in group foraging are simplistic, refer to variance at the level of individuals and groups without linking the two, and do not spell out crucial underlying assumptions. We provide a new, widely applicable framework for identifying when variance reduction conveys fitness benefits of group foraging in a wide range of organisms. We discuss critical limitations of established theories, the Central Limit Theorem and Risk-Sensitive Foraging Theory applied to group foraging, and incorporate them into our framework while addressing the confusion over the levels of variance and identifying previously unaddressed assumptions. Through a field study on colonial spiders, Cyrtophora citricola, we demonstrate the importance of evaluating the level of food sharing as a critical first step, previously overlooked in the literature. We conclude that variance reduction provides selective advantages only under narrow conditions and does not provide a universal benefit to group foraging as previously proposed. Our framework provides an important tool for identifying evolutionary drivers of group foraging and understanding the role of fitness variance in the evolution of group living.
KW - Cooperation
KW - feeding strategies
KW - inequality
KW - sociality
KW - stochastic environments
KW - uncertainty
KW - RCUK
KW - BBSRC
KW - BB/M008770/1
UR - http://www.scopus.com/inward/record.url?scp=85071879962&partnerID=8YFLogxK
UR - https://pure.royalholloway.ac.uk/portal/en/publications/evolutionary-drivers-of-group-foraging(31581f7a-7f23-4205-9134-2c37523cebb9).html
U2 - 10.1111/evo.13826
DO - 10.1111/evo.13826
M3 - Article
C2 - 31420977
AN - SCOPUS:85071879962
SN - 0014-3820
VL - 73
SP - 2106
EP - 2121
JO - Evolution
JF - Evolution
IS - 10
ER -