Meeting Abstract

P2.12  Wednesday, Jan. 5  Behavioral test of complex signal rules and novel appendage attractiveness in gray treefrogs, Hyla versicolor HENDERSON, J.J.*; GERHARDT, H.C.; University of Missouri-Columbia; University of Missouri-Columbia jhenderson@mail.mizzou.edu

Acoustic signals vary from simple, repeated elements to a combination of diverse elements that create a complex signal. Sexual selection theory predicts that complex signals will be more attractive than simple elements, because it is generally assumed that females favor signals that provide more sensory stimulation. Understanding the mechanisms of sensory bias will help establish “rules” affecting the attractiveness of novel complex signals. The gray treefrog (Hyla versicolor) serves as a powerful model system for examining the rules that determine the effectiveness of novel complex signals. Temporal order is an important factor in novel call attractiveness as females of both species often preferred complex calls consisting of the pulsed advertisement call of the species followed by a novel acoustic appendage. This may be explained by a class of interval-counting neurons that are selective for interpulse interval. These neurons fire after a number of intervals with correct duration. The most selective of these neurons can be reset after one incorrect interval. The results of this preliminary study show that calls with one or more inappropriate intervals or pulses with short duration are discriminated against when presented with normal advertisement calls. However, when a call with inappropriate intervals had a following appendage, the complex call was no longer discriminated against. These results suggest that the interval-counting neurons do affect call attractiveness and that appendages may lessen discrimination of an unattractive call.