Lipopolysaccharide facilitates partner preference behaviors in female prairie voles

Exposure to proinflammatory cytokines (e.g., IL-1 beta) or lipopolysacchari de (LPS) produces an acute activation of the immune response and results in a repertoire of behavioral patterns collectively termed sickness behaviors . Although nonspecific responses to pathogenic infection have traditionally been viewed as maladaptive effects of infection, sickness behaviors may ha ve significant, adaptive value for the host. One set of adaptive behaviors affected by infection among mammals and birds is mate choice. In Experiment 1, female prairie voles exhibited the expected increase in blood corticost erone concentrations in response to a 0.1 cc i.p. LPS injection (50 mu g), indicating activation of the endocrine system. A separate cohort of females was injected with LPS or saline and paired for 6 h with a novel, previousl y unpaired male. Following the cohabitation period, LPS-injected females sp ent significantly more time (p < 0.05) with the familiar partner when given a choice between familiar and unfamiliar males in a three-chamber apparatu s designed to test partner preferences. Saline-injected females spent signi ficantly more time with the unfamiliar male. In Experiment 2, males injecte d with LPS or saline spent equal amounts of time with familiar and unfamili ar females following a 6 h cohabitation with a naive female, and therefore, did not exhibit preferences. From a proximate perspective, this study prov ides evidence that sickness behaviors influence female, but not male, partn er preference in prairie voles. (C) 1999 Elsevier Science Inc. All rights r eserved.