The Diversity of Call Recognition: Selective Phonotaxis in Neoconocephalus ensiger

Abstract

In many insect and anuran species, the temporal pattern of male calls encodes the species identity of the signaler and females use the temporal pattern to identify and approach conspecific mates. We studied the call recognition mechanism of Neoconocephalus ensiger in phonotaxis experiments conducted on a walking compensator. Stimuli were presented in a no-choice paradigm and female response strength quantified. The calls of N. ensiger have an unusually slow pulse rate (approximately 12 Hz) for this genus, which is a derived trait. Call models were attractive when pulse durations were between 25 and 55 ms and interval durations were between 19 and 99 ms. An amplitude attenuation depth of 6 dB was sufficient for females to detect the conspecific temporal pattern. The call recognition mechanism of N. ensiger differs strikingly from four other temporal recognition mechanisms previously described in Neoconocephalus, but is similar to call recognition in more distantly related taxa (including anurans) that have male calls with similar pulse period. This suggests that the evolution of call recognition mechanisms is more strongly influenced by signal parameters and/or neural constraints than by phylogenetic constraints.