Female Mate Choice and No Detected Predation Risk in Relation to the Calling Song of <I>Oecanthus niveus</I> (Gryllidae: Oecanthinae)

Abstract

Oecanthus niveus (Gryllidae: Oecanthinae), a tree cricket species, inhabits the Tehuacan Valley, Mexico, year-round. Solitary males radiate calling songs that attract receptive females. The calling song is composed of discrete trains of five pulses with regular intertrain intervals. The courtship and mating behaviors are similar to other tree cricket species. In this study, we evaluated 1) the relationship between male body size and train duration, and the train period of its calling song; 2) female choice by exposing females to contrasting trains and train periods of the calling songs; and 3) the predation risk associated with the song patterns preferred by females. We hypothesized that 1) there is a significant relationship between male body size with train duration and the train period of calling songs, 2) females prefer song patterns associated with larger males, and 3) that a high predation risk is associated with these patterns. In line with our hypotheses, we found a significant relationship between male body size and song patterns. Females preferred calls with a train duration corresponding to a male 11% larger than an average male of the population. Nevertheless, no increase in invertebrate predation was detected in a field experiment for this song pattern. The train duration of the song is a reliable indicator of male size that does not have associated predation costs. Females may obtain direct or indirect benefits, or both, as a result of their mate choice preferences.