Species Oncopeltus fasciatus - Large Milkweed Bug

Oncopeltus fasciatus (Dallas 1852)

adult 10-18 mm

Adult: overall black and orange - leathery portion of forewing with orange forward-pointing triangle anteriorly, and orange backward-pointing triangle posteriorly, separated by a black band in the middle; membranous portion of forewing black; pronotum black with orange lateral margins; freshly-molted young adults are very pale yellow, their color becoming darker and more orangish with age; adult males have a black band on the ventral side of the fourth abdominal segment; adult females have two black spots in that location

Nymph: early instars have a bright orange abdomen, developing black spots with age; later instars are more orangish-yellow; pronotum orange with black posterior margin; wingpads black, lengthening with age

Egg: oblong with three downcurved projections at tip; color initially yellow, changing to orange and then bright red before hatching

Fields and meadows containing milkweed or dogbane

Seeds of milkweed plants. They can be reared and fed other seeds such as sunflower, watermelon, cashew, etc. Illinois.edu.

Eggs are laid in milkweed seed pods or in crevices between pods. About 30 eggs are laid a day, and about 2,000 over a female's lifespan, which lasts about a month during the summer. One or more generations per year.

They overwinter as adults. They can't survive cold winters, so they migrate south in the fall. They overwinter in the southern Atlantic and Gulf coast states where they feed and breed and gradually migrate north again in the spring and summer.

Detailed life cycle and rearing information found here: Raising and Overwintering Oncopeltus

In the course of feeding these bugs accumulate toxins from the milkweed, which can potentially sicken any predators foolish enough to ignore the bright colors which warn of their toxicity.

Lygaeus kalmii adults have a red X-mark on the forewing and a red transverse band on the pronotum, and redder nymphs with two diagonal black markings on the pronotum

Rea et al., pp. 35-36 (1)

Slater, (2)

Migratory behavior. Roy L. Caldwell Mary Ann Rankin. Journal of comparative physiology. Separation of migratory from feeding and reproductive behavior in Oncopeltus fasciatus