Small milkweed bugs are one of the most commonly mistaken for boxelder bugs. There are however some identifying characteristics to know the difference between the two. Boxelder bugs have a characteristic V shaped reddish-orange pattern to their wings while small milkweed bugs appear to have an X that does not quite intersect at the center point. Western species of the small milkweed bug tend to have two small white spots on the rear portion of their wing covers. Both the boxelder and small milkweed bugs are black with reddish-orange markings on their wing covers as adults. In both species nymphs that start off wingless with bright reddish-orange abdomens. Small milkweed bug nymphs vary at times and may have a more brownish-grey appearance. Small milkweed bugs feed primarily on the seeds of milkweed; however, in spring when seeds are not plentiful, this species has been known to exhibit predaceous habits, feeding on monarch butterfly caterpillars and other available insects. These insects are considered beneficial due to their assistance in controlling milkweed as they are one of the few insects that can tolerate the toxins contained within the milkweed plants. The same toxins cause the small milkweed bug to have a foul taste, which deters predators from wanting to consume them. Their bright colored markings serve as a warning to potential predators that they have a foul taste.
Although not common as invaders of homes and structures, they do occasionally find their way inside during cooler weather. Sealing gaps, cracks and crevices as well as checking threshold areas for weather stripping that needs replaced will decrease activity in residential and commercial locations.