TY - JOUR

T1 - Evidence for loss of nepotism in the evolution of permanent sociality

AU - Berger-Tal, Reut

AU - Lubin, Yael

AU - Settepani, Virginia

AU - Majer, Marija

AU - Bilde, Trine

AU - Tuni, Cristina

PY - 2015/9/3

Y1 - 2015/9/3

N2 - Kin selected benefits of cooperation result in pronounced kin discrimination and nepotism in many social species and favour the evolution of sociality. However, low variability in relatedness among group members, infrequent competitive interactions with non-relatives, and direct benefits of cooperation may relax selection for nepotism. We tested this prediction in a permanently social spider, Stegodyphus dumicola that appears to fulfil these conditions. Sociality is a derived trait, and kin discrimination exists in sub-social closely related congeners and is likely a selective force in the sub-social route to permanent sociality in spiders. We examined whether social spiders show nepotism in cooperative feeding when genetic relatedness among group members was experimentally varied. We found no effect of relatedness on feeding efficiency, growth rate or participation in feeding events. Previous studies on sub-social species showed benefits of communal feeding with kin, indicating nepotistic cooperation. The lack of evidence for nepotism in the social species suggests that kin discrimination has been lost or is irrelevant in communal feeding. Our results are consistent with the hypothesis that the role of nepotism is diminished when cooperation evolves in certain genetic and ecological contexts, e.g. when intra-group genetic relatedness is homogeneous and encounters with competitors are rare.

AB - Kin selected benefits of cooperation result in pronounced kin discrimination and nepotism in many social species and favour the evolution of sociality. However, low variability in relatedness among group members, infrequent competitive interactions with non-relatives, and direct benefits of cooperation may relax selection for nepotism. We tested this prediction in a permanently social spider, Stegodyphus dumicola that appears to fulfil these conditions. Sociality is a derived trait, and kin discrimination exists in sub-social closely related congeners and is likely a selective force in the sub-social route to permanent sociality in spiders. We examined whether social spiders show nepotism in cooperative feeding when genetic relatedness among group members was experimentally varied. We found no effect of relatedness on feeding efficiency, growth rate or participation in feeding events. Previous studies on sub-social species showed benefits of communal feeding with kin, indicating nepotistic cooperation. The lack of evidence for nepotism in the social species suggests that kin discrimination has been lost or is irrelevant in communal feeding. Our results are consistent with the hypothesis that the role of nepotism is diminished when cooperation evolves in certain genetic and ecological contexts, e.g. when intra-group genetic relatedness is homogeneous and encounters with competitors are rare.

KW - SPIDER STEGODYPHUS-DUMICOLA

KW - ANELOSIMUS-EXIMIUS ARANEAE

KW - KIN RECOGNITION

KW - SUBSOCIAL SPIDER

KW - GENETICAL EVOLUTION

KW - COOPERATION

KW - ERESIDAE

KW - SOCIETIES

KW - THERIDIIDAE

KW - DISPERSAL

U2 - 10.1038/srep13284

DO - 10.1038/srep13284

M3 - Journal article

C2 - 26333675

VL - 5

JO - Scientific Reports

JF - Scientific Reports

SN - 2045-2322

M1 - 13284

ER -