Invasive Species Compendium

Detailed coverage of invasive species threatening livelihoods and the environment worldwide

Abstract

Intimacies of a forest pest: inter- and intrasexual behavioral interactions in Thaumastocoris peregrinus.

Abstract

Knowledge of the reproductive ecology of insect pests is important for the development of sustainable pest control strategies. Mating behavior studies can provide insights about relevant aspects of intra- or intersexual communication processes, which may lead to sustainable control strategies based on behavioral disruption. The bronze bug, Thaumastocoris peregrinus (Hemiptera: Thaumastocoridae), is an invasive eucalypt specialist that feeds and reproduces in aggregations on eucalypt leaves, causing defoliation and branch dieback in severe infestations. Scant information is available on its mating behavior, so we here report a systematic study of male-female and male-male interactions under controlled experimental conditions. Unmated, sexually mature naive males and females were paired and videotaped from two angles to describe and quantify their behavioral interactions and transitions. Intersexual interactions included mounting, rejection, copulation, antennation and a post-copulatory behavior that we termed smearing and consisted of a rapid backward and forward movement by the male while still on top female. Antennation occurred during copulation, and it may be interpreted as copulatory courtship. Smearing occurred after copulation and positively correlates with total mating time, likely involving mate guarding. Behavioral correlations with size and age showed that female rejection is not affected by male size or age. Intrasexual interactions included two agonistic behaviors that we called sparring and riding, both likely involved in male-male competition and the establishment of male dominance in natural aggregations. Male intrasexual aggressiveness was not related to male size or age either. The results are discussed in relation to the potential functions of these behaviors in the mating system of T. peregrinus.