EMISIÓN, PERCEPCIÓN Y RESPUESTAS CONDUCTUALES DE LOS NEMATODOS ENTOMOPATÓGENOS A SEMIOQUÍMICOS

Abstract

Reyes-Vidal, Y. and M. de la Torre. 2009. Emission, perception, and behavioral responses of entomopathogenic nematodes to semiochemicals. Nematropica 39:213-223. Entomopathogenic nematodes of Heterorhabditidae and Steinernematidae families are the most used for biological control of insect pests. Recognition of one member of a species by another member of the same species and recognition of the natural host, as well as the recognition of the specific symbiotic bacteria, are due to the capacity of nematodes to perceive, respond to, and emit chemical cues. Semiochemicals mediate interactions between organisms. Those emitted and affecting members of the same species are named pheromones, while the signals called allelochemicals are involved in interspecific interactions. The occurrence of both types of semiochemicals has been demonstrated in entomopathogenic nematodes, although alarm pheromones and apneumones (chemicals derived from a non-living source that benefit the receiver) have not yet been demonstrated. Even herbivore-damaged plants emit volatile organic compounds that attract nematodes. The physicochemical characteristics of the cues, as well as the nematodes responses, are associated with the ecology and behavior of the nematode species, i.e. with habitat, reproductive behavior, foraging strategies and pre- ferred penetration route of host, but also with the habitat and behavior of the host. Therefore, cues and emitted responses are quite diverse. Furthermore, the same chemical compound can elucidate positive and negative behaviors in different species. Unfortunately, only very few reports have an ecological holistic approach of the very complex system nematode-bacteria-host-plant-soil and the chemical nature of most cues is unknown, especially sexual pheromones. A better understanding of this complex system, the signals, and the nematode ecological behavior will help to enhance the efficacy of entomopathogenic nematodes in the field, as well as the process for mass production of these biological control agents in vivo and in vitro.