Human-induced pheromone pollution leads to changes in alternative mating tactics of moths.

Abstract

Environmental changes driven by anthropogenic activities often disrupt animal communication and mating behavior. Consequently, these changes may force animals to adopt alternative mating tactics and strategies to find a mate. The mating disruption technique is an environmentally friendly tactic often used to control the pink-bollworm moth population in cotton fields. Though mating disruption is eco-friendly, it represents a Human-Induced Rapid Environmental Change for the targeted moths. Mating disruption involves spreading a synthetic version of the species-specific sex pheromone in the field, creating a pheromone-polluted environment, making it difficult for male moths to locate females and thereby reducing mating rates. We hypothesized that the intense sexual selection and environmental changes affecting communication would lead moths to increase their use of alternative mating strategies. An observed alternative mating behavior in male pink bollworm moths is disturbing mating pairs to displace the male and mate with the female. We compared this behavior between two populations and found that males long exposed to mating disruption disturbed mating pairs more frequently than those never exposed to it. In addition, males with a prolonged history of exposure to mating disruption showed reduced choosiness of females and increased their mating rate with small females of lower reproductive potential. The success rate of the observed couple disturbance was low. Nonetheless, this strategy, alongside other strategies, may contribute to the males' reproductive success when facing the additional challenge of locating females due to the pheromone-polluted environment.