Increase of the Behavioral Response to Kairomones by the Parasitoid Wasp Leptopilina heterotoma Surviving Insecticides

Abstract

Hymenopterous parasitoids are key species involved in the regulation of insect populations. Kairomone perception is an important step leading to host parasitization. The massive use of insecticides induces environmental pollution that can interact with the reproduction of parasitoids. In this work, we have determined the sublethal effects of two insecticides, an organophosphorus (chlorpyrifos) and a pyrethroid (deltamethrin), on the arrestment, by host kairomones, of female parasitoids surviving an LD 20 for 24 h. The behavior of the parasitoids has been recorded with a video-computerized system. The analysis of the behaviors in control conditions versus exposed to an LD 20 have shown that both insecticides significantly increased the arrestment of parasitoids by kairomones. This increase was not followed up by a modification of the kinetics of the behavior. In both control and exposed conditions, parasitoids regularly increased their residence time on the kairomone patch indicating that no saturation to kairomones had occurred. In a field situation where hosts could be scarce, this increase in arrestment could be advantageous for parasitoids by increasing their host finding.

Sublethal effects of chlorantraniliprole and thiamethoxam seed treatments when Lysiphlebus testaceipes feed on sunflower extrafloral nectar

“…For example, Komeza et al (2001), studied Leptopilina boulardi (Hymenoptera: Figitidae) females exposed to the LD20 of the organophosphate chlorpyrifos and found them to be less efficient in finding host patches marked with kairomones, and exhibit longer patch residence times. In contrast, Delpuech et al (2005) found that the congeneric Leptopilina heterotoma Thomson females responded to kairomones of Drosophila with greater arrestment following contact with chlorpyrifos and deltamethrin at LD20. Thus, either inhibitive or stimulative (hormoligosis) effects of neurotoxic insecticides may be observed at sublethal doses, depending on the insecticide and species of insect.…”

Seletividade de inseticidas, recomendados para cucurbitáceas para Trichogramma atopovirilia Oatman & Platner (Hymenoptera: Trichogrammatidae) em condições de laboratório

“…Para o sucesso de um programa de manejo fitossanitário, a integração de produtos químicos com o controle biológico é necessária . Assim, estudar a seletividade dos agrotóxicos é importante, para que se tenha sucesso na sua associação com os inimigos naturais das pragas (Delpuech et al, 2005).…”

Sublethal Effects of Pyrethroids on Insect Parasitoids: What We Need to Further Know

“…In face of these results, the authors hypothesize that the sublethal effect of deltamethrin on host foraging may decrease T. basalis efficacy in controlling N. viridula. Delpuech et al (2005) also found that deltamethrin increased the arrestment response of Leptoplilina heterotoma (Hymenoptera: Figitidae) to host cues and reduced their linear speed. The authors explained that the observed increase in the arrestment response is coherent with pyrethroid intoxication, given that deltamethrin induces a prolongation of nervous stimulations each time neurons are stimulated by the perception of host cues.…”