By Mary Free, Extension Master Gardener
This post has been updated from the original posted on February 24, 2012.
If you think that this red-orange and black insect is a large milkweed bug (Oncopeltus fasciatus), then you would be correct. But surely those are not milkweed flowers. No, milkweed plants die back in the fall. These half-inch long blossoms belong to Lonicera fragrantissima (winter honeysuckle), a semi-evergreen shrub that blooms in winter.
You may know that large milkweed bug females lay eggs on milkweed plants spring into fall. The eggs hatch into nymphs or “instars” that are immature, wingless versions of the adults. It takes about a month (or more depending on the temperature) for them to undergo five growth stages, gradually developing wings. After each stage, they molt. After the 5th instar and fifth molt, they become a winged adult. Newly molted adults have whitish wings, which will turn black as they harden. This life cycle, called incomplete metamorphosis, usually is spent entirely on milkweed plants, like natives Asclepias syriaca (common milkweed) and Asclepias tuberosa (butterfly-weed).
The bugs suck juice from the seeds inside milkweed follicles and from the plant tissue. Although all parts of the milkweed plant are poisonous (except for the pollen and nectar), milkweed bugs are able to absorb the toxin in their bodies. Their aposematic coloration warns predators to stay away because they have become poisonous too. Since they are relatively easy to breed, large milkweed bugs often are used for elementary/middle school projects and scientific research. When raised in captivity, if the bugs eat raw, cracked sunflower seeds instead of milkweed, then they do not become toxic.
Two other “milkweed bugs” may be mistaken for O. fasciatus, although they are more often confused with each other: small milkweed bug (Lygaeus kalmii) and false milkweed bug (Lygaeus turcicus). In fact, at one time these two bugs were thought to be the same species. Both sport a reddish band on their forewing forming an “X,” but L. kalmii distinguishes itself with a large black “heart” on its back and occasional white markings on its wings. L. turcicus has two smaller black hearts (or triangles)–one on top of the other. Also, as inferred by its common name, adult false milkweed bugs are not likely to favor milkweed; they prefer yellow flowers in the aster family, such as false sunflower (Heliopsis helianthoides).
Large and small milkweed bugs have similar life cycles. Usually adult milkweed bugs live only about one to two months. So what was that adult bug doing on winter honeysuckle in early February?
If adult milkweed bugs have not reproduced before winter, then they hibernate and wait until spring to mate and lay their eggs when the milkweed plants are growing again. On a temperate winter day, they may roam about, especially the more cold-tolerant small milkweed bugs. Adult milkweed bugs (notably small milkweed bugs that reportedly also eat other insects) sometimes drink nectar and suck juices from plants other than milkweed. Apparently this time, a large milkweed bug found Lonicera a suitable substitute for milkweed in winter. Who knew? Did you?
References
Cresswell S. American Insects. (accessed November 11, 2021).
Raupp MJ. 2021. False Milkweed Bug, a.k.a. False Sunflower bug: Lygaeus turcicus. University of Maryland Extension.
The BugLady. 2015. Milkweed Bugs, Large and Small (Family Lygaedidae). College of Letters & Science Field Station. University of Wisconsin-Milwaukee.