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For Insects, Spiders & Their Kin
For the United States & Canada

Species Oncopeltus fasciatus - Large Milkweed Bug

Unknown nymph - Oncopeltus fasciatus BG2320 E4254 - Oncopeltus fasciatus Milkweed Bug - Oncopeltus fasciatus Large Milkweed bug - Oncopeltus fasciatus Large Milkweed Bug - Oncopeltus fasciatus Large Milkweed Bug - Oncopeltus fasciatus Some kind of Milkweed bug - Oncopeltus fasciatus Oncopeltus fasciatus moult from 4th to 5th instar - Oncopeltus fasciatus
Classification
Kingdom Animalia (Animals)
Phylum Arthropoda (Arthropods)
Subphylum Hexapoda (Hexapods)
Class Insecta (Insects)
Order Hemiptera (True Bugs, Cicadas, Hoppers, Aphids and Allies)
Suborder Heteroptera (True Bugs)
Infraorder Pentatomomorpha
Superfamily Lygaeoidea
Family Lygaeidae (Seed Bugs)
Subfamily Lygaeinae
Genus Oncopeltus
No Taxon (subgenus Erythrischius)
Species fasciatus (Large Milkweed Bug)
Explanation of Names
Oncopeltus fasciatus (Dallas 1852)
Size
adult 10-18 mm
Identification
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
Habitat
Fields and meadows containing milkweed or dogbane
Food
Seeds of milkweed plants. They can be reared and fed other seeds such as sunflower, watermelon, cashew, etc. Illinois.edu.
Life Cycle
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.
Remarks
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.
See Also
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
Print References
Rea et al., pp. 35-36 (1)
Slater, (2)
Internet References
Migratory behavior. Roy L. Caldwell Mary Ann Rankin. Journal of comparative physiology. Separation of migratory from feeding and reproductive behavior in Oncopeltus fasciatus
Works Cited
1.Milkweed, Monarchs and More: A Field Guide to the Invertebrate Community in the Milkweed Patch
Ba Rea, Karen Oberhauser, Michael Quinn. 2003. Bas Relief Publishing Group.
2.How to Know the True Bugs
Slater, James A., and Baranowski, Richard M. 1978. Wm. C. Brown Company.