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Colony Member Discrimination by Juvenile Columbian Ground Squirrels ( Spermophilus columbianus )
Author(s) -
Hare James F.
Publication year - 1992
Publication title -
ethology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.739
H-Index - 74
eISSN - 1439-0310
pISSN - 0179-1613
DOI - 10.1111/j.1439-0310.1992.tb00968.x
Subject(s) - kin recognition , inclusive fitness , kin selection , agonistic behaviour , biology , juvenile , reciprocal altruism , altruism (biology) , helping behavior , aggression , ecology , zoology , social psychology , psychology , evolutionary biology
Kin discrimination mechanisms allow the maximization of inclusive fitness via kin‐differential behaviour. Previous studies of kin discrimination in ground squirrels ( Spermophilus spp.) have concentrated on the proximate mechanisms by which kin are discriminated from non‐kin. Few studies have examined the extent to which kin discrimination is expressed among free‐living squirrels, and none have examined the relative strength of potential alternative levels of social discrimination (i.e. kin, neighbour, group member). To elucidate the level at which juvenile Columbian ground squirrels ( Spermophilus columbianus ) discriminate among conspecifics, dyadic interactions between otherwise free‐living littermates, neighbours, non‐neighbouring members of the same colony, and individuals from two different colonies were staged in a neutral arena. Similar levels of cohesive and agonistic behaviour, and similar inter‐individual distances were recorded for all intra‐colony dyads while interactions between non‐colony members were characterized by decreased cohesion, increased agonism, and greater inter‐individual distances. The results suggest that siblings are not discriminated from nonsiblings, but that colony members are discriminated from members of other colonies. Although the functional significance of colony member discrimination is unclear, such discrimination produces amicable relationships among local group members and ensures xenophobic responses to non‐group members. Colony member discrimination may reduce costs of intra‐colony aggression, ensure the appropriate distribution of cooperation and reciprocal altruism to enhance direct fitness benefits that accrue via social grouping, and ultimately promote outbreeding among sexually mature individuals. Finally, the discrimination of colony members from non‐colony members could appear as an incidental byproduct of the operation of a mechanism promoting species recognition.