Number 45 • August 2, 2006 • Jeffrey K. Barnes

Large milkweed bug
Order: Hemiptera: Heteroptera
Family: Lygaeidae
Genus and species: Oncopeltus fasciatus (Dallas)

Large milkweed bug Large milkweed bug

Although they might be considered a nuisance by gardeners trying to propagate milkweeds, and they sometimes congregate in large numbers on or near buildings like the boxelder and golden raintree bugs, large milkweed bugs are not usually accorded pest status. However, they have been widely used as research animals because they are easy to rear in large numbers in the laboratory throughout the year, they have a short life cycle, and they are relatively large and easy to manipulate. This North American native ranges from Massachusetts to Florida in the East, westward to Texas, the Rocky Mountains, and California, and southward to Texas and Brazil. The aposomatically colored bugs warn potential predators that they are unpalatable. In the process of feeding of milkweed seeds they sequester toxins from the host plant. Females lay eggs in crevices between milkweed pods, producing as many as 2000 each. Individuals develop from egg to adult in about one month at 85ºF, and adults live for about one month.