Meeting Abstract
Multimodal communication often requires coordination of multiple signaling systems, which may be subject to divergent selection pressures. Physical gestures are prominent in many species’ multimodal displays. We have shown that selection for “foot flagging,” a novel gestural signal in frogs, is associated with increased sensitivity to androgenic hormones in the spinal cord and hind limb muscles, similar to that found in the larynx of vocalizing frogs. Staurois parvus sexually displays with foot flags and vocalizations, therefore we tested whether peripheral androgens modulate both signals. We injected males with testosterone (T) plus Flutamide, a drug that blocks all androgen receptors (ARs), or T plus Bicalutamide, which blocks only peripheral ARs, and recorded the frequency of foot flagging and vocalizations. We found that both drugs inhibit foot flagging, which suggests that ARs in the peripheral muscles primarily influence this behavior. Surprisingly, and in contrast to many other anurans, we found that vocalizations do not appear to be androgen-dependent in male S. parvus. This result suggests that sexual selection may differentially influence the nervous and muscular tissues underlying different components of multimodal displays.
