The Effects of Food Availability on the Sexual Behavior of Meadow Voles.

Two competing hypotheses have been used to explain species and sex differences in the effects of food availability on the sexual behavior of mammals. One hypothesis, the metabolic fuels hypothesis, posits that individuals, primarily females, forgo reproduction when faced with food deprivation and invest their limited resources in behaviors not associated with reproduction. The other hypothesis, the reproduction at all costs hypothesis, states that individuals, males and females, continue to reproduce or increase their reproductive behavior when faced with food deprivation. Results show female voles followed the predictions of the metabolic fuels hypothesis. That is, food-deprived female meadow voles were less attractive, proceptive, and receptive toward males than were female voles that had continuous access to food. Dams that were food deprived late in lactation failed to enter postpartum estrus, a period of heightened sexual receptivity that occurs immediately after parturition. Females that were food deprived during the first or second week of lactation spent less time involved in maternal care compared to dams that were not food deprived. In contrast, male voles mainly followed the reproduction at all costs hypothesis. Food-deprived male voles were as attractive, as proceptive, and as sexually receptive toward females as were males that had continuous access to food.