Oncopeltus fasciatus

Large Milkweed Bug on milkweed @ Colonel Samuel Smith Park, Etobicoke (Afternoon, mid-October, overcast, just before rainfall).

The large milkweed bug, Oncopeltus fasciatus, is colored orange-red and black. It has a long proboscis and is a piercing sucking insect. It feeds on the seeds, leaves and stems of milkweed (Asclepias). It is found in small groups on milkweed often on the stems, leaves and on the seed pods. The bodies of milkweed bugs contain toxic compounds derived from the sap which they suck from milkweed. Milkweed bugs are true bugs (Hemiptera) . They are used as research insects because they are easy to use in the laboratory, have a short life cycle and are easy to manipulate.

Milkwood bugs (Oncopeltus fasciatus) on common milkweed seed pods (Asclepias syriaca), in Chesapeake, Virginia. 

One of my earliest jobs with the Virginia Tech Entomology Department was tending to the milkweed bug colonies used for genetics research in the labs of Drs. Mary Ross and Donald Cochran. They were much more pleasant to handle than the thousands of jars of live-specimen cockroach colonies we kept in the lab. 


Immature Milkweed Bugs on milkweed along Grenadier Pond @ High Park, Toronto (Afternoon, early October, sunny).

The milkweed bug, Oncopeltus fasciatus, is a medium–sized hemipteran (true bug) of the family Lygaeidae. It feeds mainly on grains, particularly those of the milkweed. Like all hemiptera, it feeds through a long mouthpart known as a rostrum.