Response of the Egg Parasitoids Trissolcus basalis and Telenomus podisi to Compounds from Defensive Secretions of Stink Bugs

Abstract

We tested the hypotheses that host-searching behavior of the egg parasitoids Telenomus podisi and Trissolcus basalis may be differentially influenced by the different blends of volatiles released from the metathoracic glands of adult stink bug host species. We further studied whether such a differential response is due to different individual components of these glands and whether these responses reflect host preferences. Y-tube olfactometer bioassays were carried out with crude extracts of metathoracic glands of five different host species of neotropical stink bugs. Additionally, we tested the parasitoids' responses to synthetic standards of individual compounds identified in these stink bug glands. Results showed that females of T. basalis and T. podisi responded differentially to crude gland extracts of the different species of host stink bugs and to the compounds tested. The parasitoid T. basalis showed a positive taxic behavior to Nezara viridula methathoracxic gland extracts of a host species preferred in the field, i.e., N. viridula. Furthermore, T. basalis responded positively to 4-oxo-(E)-2-hexenal and (E)-2-decenal, two components of N. viridula glandular secretion. Higher residence time, reduced linear velocity, and higher tortuosity in the arm of the olfactometer supplied with 4-oxo-(E)-2-hexenal showed that this compound modifies the kinetics of some traits of T. basalis walking pattern and suggests that it might stimulate the searching behavior of this parasitoid. The parasitoid T. podisi was attracted to crude gland extracts of the preferred host (Euschistus heros) and also to 4-oxo-(E)-2-hexenal. Additionally, this parasitoid responded positively to (E)-2-hexenal and to the hydrocarbon tridecane, both of which are defensive compounds released from the metathoracic glands by several stink bugs. The results indicate some degree of specialization in the response of two generalist parasitoid species toward defensive secretions of stink bugs.

Egg parasitoid wasps as natural enemies of the neotropical stink bug Dichelops melacanthus

“…podisi (Moraes et al, 2005(Moraes et al, , 2008. In addition, there is also some evidence that these parasitoids may selectively respond to semiochemicals from stink bugs (Borges et al, 2003;Conti et al, 2004;Salerno et al, 2006;Silva et al, 2006;Laumann et al, 2009) or substrate-borne vibratory signals used in the stink bug sexual communication (Laumann et al, 2007 complexes in tri-trophic interactions, as well as other relevant biological and ecological aspects need to be established.…”

Defesas induzidas por herbivoria e interações específicas no sistema tritrófico soja-percevejos-parasitoides de ovos

“…Já os parasitoides de ovos de T. podisi e T. basalis, foram criados conforme Laumann et al (2009). As colônias foram acondicionadas em salas climatizadas, a 26±1 o C, 65±10% de umidade relativa e 14:10 L:D (light:dark) de fotoperíodo.…”

“…A influência dos voláteis liberados pelas plantas danificadas pelos percevejos no comportamento dos parasitoides foi analisada em bioensaios de olfatometria, tendo-se utilizado fêmeas acasaladas de T. podisi e T. basalis com 24-48 horas de idade adulta, sem experiência de oviposição (Moraes et al, 2005;Laumann et al, 2009). Para os bioensaios, foram utilizadas plantas de soja (cultivar Conquista) no estádio fisiológico V5.…”

“…Após a passagem pelas câmaras, o ar foi transportado, em mangueiras de silicone, até os braços do olfatômetro. Para o escoamento do ar, uma bomba de sucção foi ligada no extremo oposto à entrada do olfatômetro (0,6 L min -1 ) (Moraes et al, 2005;Laumann et al, 2009).…”

“…Moraes et al (2005) observaram que fêmeas de T. podisi respondem a compostos voláteis liberados por soja danificada por E. heros, mas não são atraídas pelos voláteis liberados pelo dano alimentar da lagarta Anticarsia gemmatalis (Hübner, 1818). Além disso, T. podisi também mostra resposta seletiva a compostos de alarme encontrados na glândula metatorácica do seu hospedeiro preferencial, E. heros (Laumann et al, 2009).…”