Although many people call all land arthropods, from spiders to moths, “bugs,” one of the large groups of insects is the “true bugs” — its own group. (Sorry, “ladybugs” are actually beetles and “sowbugs” are crustaceans.)
True bugs have long, needle-like mouthparts and a backwards-pointing triangle on their backs (called a “scutellum”) that’s generally very noticeable, among other distinguishing characteristics. Most true bugs feed on plants, some feed on animals.
With their piercing mouthparts, true bugs poke deep into their food source to sip. They can also inject an enzyme into sturdy food to dissolve it so they can suck up.
While most insects hatch into a larval form that looks unlike the adult — think caterpillar/butterfly — the eggs of true bugs and a few other groups (grasshoppers, for example) hatch into nymphs that look like tiny versions of the parents.
True bugs show up in the fossil record about 300 million years ago. There are now about 75,000 described species of true bugs, including the familiar cicadas, aphids, water striders, giant water bugs, and lice. (Perhaps the use of “bug” to mean pester or annoy is the fault of the lice!)
“Stink bugs” are a classic true bug, with an obvious scutellum in the upper-middle of the back, between the wings. Stink bugs are usually rather flat and shield-shaped overall. And they stink. Off-putting to humans, stink bug odor apparently also fends off potential predators.
There’s a new bug in our region: the brown marmorated stink bug. Part of the name comes from the Latin word, marmoratus, that means “to adorn with marble” — which gives a clue about the markings on the upper side. Brown marmorated stink bugs have rough-textured backs and smooth leading edges on their “shoulders,” and they’re well marbled in browns, beige, black, and grays. A clear identification feature are the broad white bands on the antennae and alternating brown/white bands around the upper, outside edge of the body.
Native to eastern China, Korea, and Japan, the brown marmorated stink bug apparently landed in North America in Pennsylvania about 20 years ago. They’ve been spreading across the continent since and were first reported in Oregon’s Willamette Valley in 2004; the first official report of one in Coos County was made last week.
Brown marmorated stink bugs dine on apples, pears, and filberts, as well as peppers, tomatoes, berries, and more–over 170 species of plants, according to the Oregon Department of Agriculture.
The “Samurai wasp,” also from east Asia, is currently being evaluated as a possible predator control of brown marmorated stink bugs. These tiny wasps lay their eggs in the eggs of stink bugs, and the wasp larvae devour the unborn bugs. In some areas, including Portland, Oregon, some Samurai wasps are already volunteering for the job.
Like many other overwintering insects, brown marmorated stink bugs seek shelter when it gets cold. Cozy retreats include loose flaps and crevasses in tree bark and human homes. Stink bugs may secretly sneak into your house when it starts to get cold, then become more active as they warm up inside. Squishing stink bugs can have undesirable odiferous effects, so vacuuming or flicking into a container of soapy water are more pleasant ways to evict them. (Don’t spray, though: brown marmorated stink bugs tend to be resistant to pesticides and you might harm less-onerous natives in the meantime.)
Merriam-Webster’s online dictionary indicates “bug” comes from Middle English “bugge,” which means “hobgoblin.” In the case of the invasive brown marmorated stink bug, that seems rather apt.
Think you might have one of these unwanted guests in your home or garden? Visit the Oregon Department of Agriculture webpage for more information: