Autumn arrivals: No worries, but Asian stink bugs, lady beetles on the way

The brown marmorated stink bug, an inadvertent Chinese import, could start showing up in numbers around our dwellings any day now. The multi-colored Asian lady beetle, when seeking winter shelter, sometimes collects with its kin in swarms on the sunny side of man-made structures.

Now that autumn is here officially, we can look forward to greeting a couple of our seasonal pester bugs.

They are no big deal, wreaking no significant havoc nor inflicting any real suffering on us. Yet, many folks find it distasteful that we are coming upon those fall days of overly abundant stink bugs and lady beetles.

These two exotic species of Asian origin tend to show up in unusual numbers, maybe even modest swarms during the fall season. These two insect varieties are here year-round now, but we typically don’t notice them during spring and summer months when they are dispersed in the environment, working their day jobs.

Come fall, however, these two bugs start showing up in numbers. We begin seeing them around our homes when they begin to look for nooks and crannies where they might seek shelter from the coming cold season.

The players here are brown marmorated stink bugs, Halyomorpha halys, and multi-colored Asian lady beetles, Harmonia axyridis. Both of these insects at a glance appear to be like native species of stink bugs and ladybugs. But our native species do not show up in large numbers around our domiciles seeking winter accommodations like these Asian varmints do.

It varies according to the weather conditions, but it seems the first of these exotics to begin gathering around us are the stink bugs.

The brown marmorated stink bugs, China natives, are practically the same size (about ½-inch long) and very similar to our locals, brown stink bugs and dusky stink bugs.

In appearance, the brown marmorated has a standard shield-like stink bug body shape and is colored with multiple shades of brown in a mottled pattern. It is a six-legged flying bug, but at rest or walking its folded wings are hidden.

Keys to identification of this exotic stinker are rounded “shoulders” on its abdomen (not pointy, like some natives) and its legs and antennae are banded in white.

Stink bugs don’t sting or bite, but as a defense they can excrete from thorax glands a fluid that doesn’t seem toxic to humans, but it is smelly. The marmorated insect’s self-protective juice is said to smell like dirty socks, helping it live up to the name stink bug.

It’s my experience that people are generally afraid of stink bugs of all sorts because they are, I don’t know, menacing looking.

These harmless-but-intimidating bugs may start appearing any day now on the windows, doors and walls of our residences, on vehicles, and, if you stand in one place long enough, maybe you, too.

You might find dozens where you seldom saw one just days earlier.

It seems that well in advance of the first frost, the Asian stink bugs begin to mass instinctively around structures mostly, especially on south-facing surfaces that tend to be warmer in cooling conditions. They don’t anticipate warmer conditions inside structures, but instead they seek cracks and crevices of sun-facing surfaces where they can get out of the worst temperatures to come.

That’s much the way it is with multi-colored Asian lady beetles. They tend to appear later in the season than the exotic stink bugs, but their motivation is the same. They are small enough that they often find their way into the walls of homes, some inadvertently making passage all the way to the interior.

Lady beetles in the house is no emergency, although possibly annoying. These little bugs can show up in greater numbers than shelter-seeking Asian stink bugs. There are accounts of swarms of hundreds or even thousands of the beetle bugs massing on houses.

People tend to be less spooked by a few Asian lady beetles because, well, they’re cute.

And they look much like a native ladybug.

These are flying bugs of about 1/3-inch long that, when they light, tuck their wings under solid-looking wing covers.

Most are pumpkin orange, but colors range from yellow to red.

Most are black spotted, as many as 19 spots, but the spots are sometimes faint or absent.

Unnoticed most of the time, in the fall the little beetles in nature collect along sun-exposed bluffs or rock outcroppings as they seek out cracks and crevices. They find similar attraction around sunny sides of buildings like your home.

Lady beetles cannot sting and although some claim they can inflict a tiny, pinch-like bite, I’ve had bunches of them on me and never had them misbehave.

There could be a slight problem with Asian lady beetles indoors. They can exude a slightly stinky fluid if jostled around, much like the smelly defense juice that stink bugs release.

Supposedly, lady beetles hassled indoors have deposited enough of the trauma liquid to stain furniture and curtains.

I’ve caught and released them and hardly noticed that stuff if at all. Regardless, if you get either Asian lady beetles or brown marmorated stink bugs inside, you probably shouldn’t squash or agitate them and risk staining anything nice.

A few can be caught by hand and removed. If there is a bunch, the recommended tactic is to get a vacuum sweeper after them, suck them up and then do what your conscience advises. If I had to do that, I’d just release them outside.

Multi-colored Asian lady beetles and brown marmorated stink bugs are not going to hurt us or anything of ours.

They’re just looking for a hidey hole from the frigid future.

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