TY - JOUR
T1 - Prey to predator body size ratio in the evolution of cooperative hunting—a social spider test case
AU - Grinsted, Lena
AU - Schou, Mads F.
AU - Settepani, Virginia
AU - Holm, Christina
AU - Bird, Tharina L.
AU - Bilde, Trine
PY - 2020/3/1
Y1 - 2020/3/1
N2 - One of the benefits of cooperative hunting may be that predators can subdue larger prey. In spiders, cooperative, social species can capture prey many times larger than an individual predator. However, we propose that cooperative prey capture does not have to be associated with larger caught prey per se, but with an increase in the ratio of prey to predator body size. This can be achieved either by catching larger prey while keeping predator body size constant, or by evolving a smaller predator body size while maintaining capture of large prey. We show that within a genus of relatively large spiders, Stegodyphus, subsocial spiders representing the ancestral state of social species are capable of catching the largest prey available in the environment. Hence, within this genus, the evolution of cooperation would not provide access to otherwise inaccessible, large prey. Instead, we show that social Stegodyphus spiders are smaller than their subsocial counterparts, while catching similar sized prey, leading to the predicted increase in prey-predator size ratio with sociality. We further show that in a genus of small spiders, Anelosimus, the level of sociality is associated with an increased size of prey caught while predator size is unaffected by sociality, leading to a similar, predicted increase in prey-predator size ratio. In summary, we find support for our proposed ‘prey to predator size ratio hypothesis’ and discuss how relaxed selection on large body size in the evolution of social, cooperative living may provide adaptive benefits for ancestrally relatively large predators.
AB - One of the benefits of cooperative hunting may be that predators can subdue larger prey. In spiders, cooperative, social species can capture prey many times larger than an individual predator. However, we propose that cooperative prey capture does not have to be associated with larger caught prey per se, but with an increase in the ratio of prey to predator body size. This can be achieved either by catching larger prey while keeping predator body size constant, or by evolving a smaller predator body size while maintaining capture of large prey. We show that within a genus of relatively large spiders, Stegodyphus, subsocial spiders representing the ancestral state of social species are capable of catching the largest prey available in the environment. Hence, within this genus, the evolution of cooperation would not provide access to otherwise inaccessible, large prey. Instead, we show that social Stegodyphus spiders are smaller than their subsocial counterparts, while catching similar sized prey, leading to the predicted increase in prey-predator size ratio with sociality. We further show that in a genus of small spiders, Anelosimus, the level of sociality is associated with an increased size of prey caught while predator size is unaffected by sociality, leading to a similar, predicted increase in prey-predator size ratio. In summary, we find support for our proposed ‘prey to predator size ratio hypothesis’ and discuss how relaxed selection on large body size in the evolution of social, cooperative living may provide adaptive benefits for ancestrally relatively large predators.
KW - Dietary niche
KW - Group living
KW - Phenotypic plasticity
KW - Predator-prey interactions
KW - Social evolution
UR - http://www.scopus.com/inward/record.url?scp=85076224997&partnerID=8YFLogxK
UR - https://pure.royalholloway.ac.uk/portal/en/publications/prey-to-predator-body-size-ratio-in-the-evolution-of-cooperative-huntinga-social-spider-test-case(a6cbc318-bed8-4404-8892-7d6fb5505981).html
U2 - 10.1007/s00427-019-00640-w
DO - 10.1007/s00427-019-00640-w
M3 - Article
C2 - 31768622
AN - SCOPUS:85076224997
SN - 0949-944X
VL - 230
SP - 173
EP - 184
JO - Development Genes and Evolution
JF - Development Genes and Evolution
IS - 2
ER -