Wheel Bug on the Window Sill in Westminster
I was cleaning off my second story windows and looked out on the stone ledge and saw this critter. It is known as the “Wheel Bug”, Arilus cristatus, a member of the Assassin Bug family and is considered to be a Beneficial. It’s one of the largest members of the true bugs; this particular one was huge, practically pinky sized and was easily visible from the parking pad to the attic eaves where it was seen the next day. It’s a greyish brown with the distinctive cog on its back.
Favored habitats for Wheel Bugs are arboreal- shade,fruit and nut trees and shrubs–and flowering plants like goldenrod or sunflowers. Wheel bugs aren’t often seen since they are shy and hidden but they are extremely effective predators. Like preying mantids, their nymphs are voracious eaters of aphids and small soft-bodied insects. Similarly, as adults they don’t discriminate between what we consider beneficial insects or harmful ones. They just grab and feed on grasshoppers, spiders, caterpillars, moths and bees. In trees, they are one of the few predators that help control hairy caterpillars that would otherwise wreak defoliating havoc.
Having read about Assassin Bugs, I was a little leary as I was taking the photo, ready to jerk my camera back in an instant. However, it appears that Wheel Bugs are slow moving and this one especially so in the cold weather. The adults are preparing to die off, leaving only brown bottle shaped egg masses, laid primarily on trees or shrubs, to overwinter. Still, one would not want to risk handling a Wheel Bug with bare hands.
Note the folded beak mouth part. It’s a straw-like appendage that stabs into prey (or an unlucky body part), delivering a paralyzing neurotoxin which quickly dissolves the prey’s innards to be sucked out. Yummy! People who have been stabbed by a Wheel Bug or had one fall on them don’t ever want to suffer that again. Descriptions of pain, even from those whose livelihood may involve handling many stinging, biting or venomous creatures, range from it feeling like “being shot”, worse than the worst sting you can imagine, wanting to chop off the body part or commit suicide. Apparently the excruciating pain lasts for several minutes and the “extreme pain” lasts for days, weeks, months… So, don’t mess around with Wheel Bugs!
