So this week I was going to write about the amazing wildlife I saw while on vacation last week in Wisconsin’s Northwoods葉ales of places where grouse hunters roam, and deer and otters play耀hoot, there was even a bear in a grocery store’s beer cooler. But those stories will have to wait, because here on the home front we have a much more immediate concern: The bugs are back in town.
Make that the ladybugs. Or, to be more correct, the multicolored Asian lady beetles, Harmonia axyridis. Pretty from a distance, yet teeming in numbers, stinky when disturbed and sometimes bitey, these imported insects ain’t no ladies. Or are they?
Although ill-mannered by our human standards, the multicolored Asian lady beetle’s habits do make sense when taken in context. Their peculiar smell is related to a defense behavior called reflex bleeding; they release a small amount of stinky “blood” to deter predators. And their “bites” aren’t meant to be aggressive; they’re simply one way an MALB explores its environment. Lastly, their great numbers can be attributed to their status as a beneficial insect; in both their larval and adult stages, these insects consume large quantities of garden and crop pests.
The insect’s “official” history here in the United States dates back to 1916, when the federal government released a shipment of beetles in California as part of an effort to control aphids and scale insects on nut trees. Subsequent releases around the country, combined with assorted accidental introductions, have led to one undeniable fact: MALBs are here to stay. Although, if you’re reading this in your home in the TriCities, you probably don’t need me to tell you that.
According to Asian entomologists, MALBs are programmed to migrate toward “prominent, isolated objects on the horizon” as temperatures cool in the fall. (Our native species head for the safety of loose bark and leaf litter) In the MALB’s homeland, those “prominent, isolated objects” typically are mountains and cliffs lined with cracks and crevices容xcellent places to crawl in and take a long winter’s nap.
But here in the TriCities, our “prominent, isolated objects” are houses, apartments and offices buildings. And, unless you’re really good with a caulking gun, your “object” probably has at least a few cracks and crevices, especially around doors and windows. You may have found you have more than a few multicolored visitors on your windows, curtains and walls.
Why have so many shown up this week? According to research conducted in Ohio, MALB migration as a rule begins the first day temperatures surpass 18C (64F) after a period of cooler, near-freezing temps. Guess what we had on Monday? A high of 66F, after several days with lows in the 30s.
I happened to be at the natural area at St. Charles’ West Side Community Park that day, in the afternoon, just as temperatures were peaking. It didn’t take long to notice what was up. Within seconds I had bugs on my shirt, pants and shoes, in my hair and on my cheek.
Unfortunately, I forgot to roll up the truck window, so when I got in to leave I also had MALBs on the dashboard, the inside of the windshield, the seats and the rearview mirror. Driving a few miles with the windows down seemed to thin their numbers a bit; a stop at Jiffy Lube for an oil change, which included a thorough vacuuming of the truck’s interior, took care of the rest.
You can use a similar strategy要acuuming葉o mitigate MALB numbers in your own home. Be careful not to squish them, though葉he stain and stink they leave behind is tough to get rid of.
Are you wondering what MALB’s effects on native ladybug species have been? I am. The thing is, it looks like nobody’s quite certain. Monitoring efforts have begun, though, and Cornell University’s Lost Ladybug Project is a good place to get involved. Visit their web site, www.lostladybug.org, for more info.
Pam Otto is the manager of nature programs and interpretive services for the St. Charles Park District. She can be reached at potto@stcparks.org or 630-513-4346.