Adaptive changes in pheromone production and release under rearing conditions in stink bugs

Abstract

BackgroundHealthy cultures of arthropods are important for pest management programs (e.g., bio‐control). Little is known about how rearing conditions may affect pheromonal interactions. We investigated how rearing histories and densities affect the pheromone emission/production in two stinkbug species (Hemiptera: Heteroptera), the predatory bug Arma custos, a biocontrol agent and the bean bug Riptortus pedestris, a pest on legume crops.ResultsNymphs of newly‐established laboratory colonies of both species produced higher amounts of the defense (dispersal) compound, 4‐oxo‐(E)‐hexenal (OHE), in the presence of conspecific nymphs. Also, when two or more A. custos males were placed together, the dorsal abdominal glands (DAGs) ceased the release of their aggregation pheromone, while the metathoracic glands (MTGs) increased the emission of defensive odors. These changes resulted from exposure to conspecific pheromone odors as confirmed by exposing bugs to pheromone standards. Hence, pheromone emissions in these stinkbugs readily change in response to odors of conspecifics, which may become a problem after long‐term rearing. Indeed, an old lab colony of A. custos (ca. 30 generations) exhibited less‐developed DAGs and reduced pheromone production. Instead, males released significantly more defensive odors from the enlarged MTGs. Furthermore, long‐term rearing conditions appeared to favor nymphs that were able to share space with conspecifics by releasing less OHE, which has not yet occurred in the new lab colonies.ConclusionRearing density affects the pheromone release in newly established lab colonies of stinkbug species, while long‐term rearing results in new pheromonal compositions coinciding with the adaptive changes in gland development.This article is protected by copyright. All rights reserved.