Submitted to: Entomologica Experimentalis et Applicata
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/14/1997
Publication Date: N/A
Interpretive Summary: There are more than 4000 species of so-called "seed bugs" in the world (Heteroptera: Lygaeidae) and, as the common name suggests, some lygaeid bugs are grain pests. However, the group also includes several important predatory members, and certain poisonous members of the group have been model insects in the study of migration and colonization. We report identification of the first attractant pheromones for lygaeids. In addition, we present evidence indicating that the pheromones of these species are produced in the gland usually thought to be solely responsible for chemical defense in Heteroptera. This research provides a chemical basis to study the migration and colonization, and may lead to identification of attractants for beneficial and pest species in the lygaeid family.
Technical Abstract: (E)-2,7-Octadienyl acetate and (E)-2-octenyl acetate (1:10 by volume) were identified as a pheromone attractive to both sexes of the lygaeid bug, Tropidothorax belogolowi. In a parallel investigation of Neacoryphus bicrucis (Lygaeidae), (E,E)-2,4-hexadienyl acetate and phenethyl acetate (9:1) were identified from males, and found attractive to both sexes of adults in the field plus a tachinid fly parasitoid of the bugs. In N. bicrucis, the pheromone was clearly shown to come from the tubular accessory glands of the metathoracic scent gland; this evidence, plus earlier literature reports for other species, indicate that male lygaeids are the pheromone emitters. In another lygaeid, Oncopeltus fasciatus, 2-isobutyl-3-methoxypyrazine was identified in the cardiac glycoside-laden fluid sequestered from milkweed hosts and expelled by these bugs when they are attacked. Alkyl methoxypyrazines are warning odorants associated with poisonous insect secretions, and their presence in O. fasciatus indicates that the plant-derived chemical defense of lygaeines is more elaborate than previously appreciated