Box Elder Bug (Family Rhopalidae)

Greetings, BugFans,

Box Elder Bugs

This week’s BOTW is the really spiffy Box elder bug. All bugs are insects, but not all insects are bugs. These guys and gals are true bugs—Hemiptera (which means half-wing and refers to front wings that are membranous on the tip half and opaque and leathery on the half closest to the body). They are in the family Rhopalidae, the Scentless Plant Bugs, which indicates a trend toward BO among their non-Rhopalid relatives.

Some autumns they are present in dense windrows in the grass near box elder trees. They feed on a variety of plants, not just box elders, and can cause cosmetic damage on fruits. They look a lot like milkweed bugs (also of BOTW fame).


Eggs are hidden in crevices in the spring. Box elder bugs have simple or incomplete metamorphosis, so the young are born looking similar to the adults. They add a few adult structures like reproductive organs and wing buds over a few weeks as they molt. The younger nymphs are all red; they add black markings as they age. You can see a variety of ages in the picture.

Females gather in swarms in fall, looking for warmer places to overwinter—like houses. The BugLady’s offspring (grubs?) used to get alarmed when box elder bugs migrated inside in fall and lurked at the edges of their vision throughout winter. We renamed them “Kate’s friends” in order to cast them in a better light. The Bug Lady is uncertain whether her non-arthropod friends would be charmed, but the tactic got her children over their initial heebie-jeebies.

Happy trails,

The BugLady