Phenotypic plasticity of acoustic traits in high-frequency lebinthine crickets (Orthoptera: Eneopterinae: Lebinthina).

Abstract

Driven by natural and sexual selection, calling behaviours and call parameters can vary within and between individuals. Phenotypic plasticity can be influenced by environmental conditions (e.g., temperature), size, body condition, and age. Crickets have been classic model organisms for studying the evolution of acoustic communication, but previous studies have focused on field crickets, for which males call at a low frequency, while females exhibit phonotaxis. This study holistically investigated the plasticity of calling behaviours and call parameters across a temperature gradient in a species of lebinthine crickets and examined plasticity between and within individuals. These crickets exhibit a unique communication system, including males calling at a near-ultrasonic frequency while actively searching for females. Ten recording assays at different temperatures were done on males of different sizes and body conditions, half of the assays when the males first became adults and another half 1 month later. Size, body condition, and age group of male crickets, as well as the ambient temperature, had different effects on different calling behaviours (e.g., number of songs produced) and call parameters (e.g., call duration, trill syllable period), even when the acoustic traits were correlated. The crickets also exhibited acclimatisation to the experimental conditions in their calling behaviours and acoustic traits to repeated assays. We also found that calling behaviours were less repeatable than temporal call parameters (e.g., call duration, trill duration), which in turn, were less repeatable than the spectral call parameter (dominant frequency).