INFLUENCE OF HOST PHEROMONE ON EGG PARASITISM BY SCELIONID WASPS; COMPARISON OF PHORETIC AND NON-PHORETIC PARASITOIDS

Authors: BRUNI, R - UNIVERISTY OF PERUGIA,IT; SANT'ANA, J - UNIVERSIDADE FEDERAL,BR; ALDRICH, JEFFREY; BIN, F - UNIVERSITY PERUGIA, IT

Submitted to: Journal of Insect Behavior
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/13/2000
Publication Date: N/A
Citation: N/A

Interpretive Summary: Parasitoids and predators are important biological control agents of agricultural pests. The present study investigated how certain parasites of stink bug eggs (Hemiptera: Pentatomidae) find eggs of their host species. One parasite species (Telenomus calvus) was found to parasitize only eggs of a predaceous stink bug (Podisus maculiventris) when give a choice in the field between eggs of this bug and eggs of another plant-feeding species of stink bug (Euschistus obscurus). This parasite was also shown to use the pheromone of the predatory bug to find the eggs of this host. A second species of parasite (Telenomus podisi) parasitized the eggs of both the predaceous and phytophagous stink bugs, but was indifferent to the presence of the pheromone of the predaceous bug. This information will be useful to researchers designing strategies to use the P. maculiventris for biological control without disrupting the egg parasites of pest species of stink bugs.

Technical Abstract: The kairomonal activity of the attractant pheromone for the "spined soldier bug", Podisus maculiventris (Hemiptera: Pentatomidae), was investigated by exposing fresh pentatomid egg masses in field traps with or without synthetic pheromone. Predominantly two parasitoids were recovered from exposed eggs of P. maculiventris and Euschistus obscurus: Telenomus podisi Ashmead (a generalist pentatomid egg parasitoid) and Telenomus calvus Johnson (a phoretic specialist on Podisus eggs) (Hymenoptera: Scelionidae). The incidences of T. podisi from P. maculiventris and Euschistus obscurus eggs placed in pheromone-baited and non-baited traps were not significantly different, suggesting that this oophagous wasp does not use the spined soldier bug attractant pheromone as a kairomone. However, T. calvus was reared almost exclusively from egg masses of P. maculiventris placed inside pheromone-baited traps. These results suggest that T. calvus females orient to volatile chemicals emitted by spined soldier bug males as a searching strategy to find areas likely to contain host eggs, in addition to the previously discovered strategy of using the pheromone to guide their phoretic behavior. The data also indicate that T. calvus can distinguish between the egg masses of these pentatomid hosts at close range.