Meeting Abstract
Sexual signals are spectacular behaviors. Reproductive rewards for successful display are great, but must be balanced against the many potential costs. To maximize payoff, individuals must monitor both internal and external cues and use that information to adjust display investment. Leptin, a hormone secreted by adipose tissue, is a promising index of body condition that regulates energy allocation to functions as diverse as feeding, sleep, reproductive effort, and immune response. Despite evidence that leptin influences reproductive trade-offs, its role as a putative regulator of courtship display is poorly understood. Here we examine the integration of interoceptive and exteroceptive cues into allocations of display effort using Alston’s singing mouse (Scotinomys teguina). We first manipulate individuals’ perception of energy balance through intraperitoneal injection of exogenous leptin, and alter social context through playback of conspecific song using a repeated-measures design. Mice injected with leptin sing back more frequently and more quickly than mice injected with saline. Leptin also improved measures based on acoustic parameters thought to be indications of song effort, but not those thought to be markers of identity. In a follow-up experiment using a design that avoided some confounds of our repeated-measures design, we again found that animals injected with leptin sang at a high rate. We are currently examining the acoustic structure of evoked song, and the induction of immediate early genes in brain regions we hypothesize are responsible for integrating social context and body condition.
