THE EFFECT OF RELATEDNESS ON SPACING BEHAVIOR AND FITNESS OF FEMALE PRAIRIE VOLES

Numerous behavioral hypotheses have been suggested to explain populati on cycles in microtine rodents. Charnov and Finerty (1980) proposed th at preferential behavior toward relatives drives population cycles thr ough kin selection. Their hypothesis makes three assumptions: (1) indi viduals behaviorally discriminate kin from non-kin, (2) kin associate, and (3) kin benefit from this association. These assumptions were tes ted in female prairie voles (Microtus ochrogaster) in eastern Kansas. An equal number of laboratory-born females and males were released int o 12 fenced enclosures; 6 enclosures contained groups of littermate si sters and 6 contained groups of unrelated females. Space use, reproduc tive success, and survival were monitored during two replications of t he experiment (Fall 1989 and Spring 1990). Female survival and reprodu ctive success were not affected by relatedness, although more young we re born in the Spring than in the Fall. Home range size and overlap we re greater for females in related groups than those in unrelated group s. Home range size also was larger in the Fall than in the Spring. Pra irie vole sisters associated spatially, but our measurements showed no fitness benefits conferred by these associations. Although the kin-se lection hypothesis could not be demonstrated in this experimental popu lation, relatedness in local neighborhoods may have consequences for s mall mammal population ecology.