No reason to carp about helpful Asian ladybugs
They don't pack the wallop, figuratively or literally, of the Asian carp, but Asian ladybugs can fuel a frightening buzz.
Hundreds, maybe thousands, of the ladybugs line the window sills of the relative's home where I spent Easter. The bugs crawl into our wine glasses. They fall from the ceiling and plunk guests in our sleep. We vacuum up the ladybugs and the next morning they are back. It looks so much like the start of a bad horror movie that I am scared to go into the attic for fear I'll discover all the little beetles are coming from an alien queen ladybug the size of a Volkswagen with an appetite for human brains.
"There's an awful lot of misinformation about the Asian ladybugs," begins Jim Louderman, a collections assistant in the insect division of The Field Museum in Chicago. For starters, he says the real name is Asian lady beetles.
The scene I witnessed is typical.
"It was more typical a few years ago than it is now," Louderman says, noting a long stretch of milder winters in the early part of the last decade was great for ladybugs. "In these warm winters there was less winter kill of the ladybugs and the aphids and other plant-sucking bugs they eat. That's what caused the explosion."
But seeing that many ladybugs at once can freak folks.
"We get lots and lots of calls," says Barbara Bates, horticultural educator with the University of Illinois extension office in Kane County. Most of those phone calls come in the fall, when the farm crops are harvested and the ladybugs are looking for a place to go into diapause (bug hibernation) for the winter.
"The reason you are seeing them now is they are coming out of diapause and they can't find their way out. They can't find the cracks and crevices where they came in," says Louderman, who speaks from personal experience. "There's been years where, on the front of the museum here, there's been thousands and thousands."
While native ladybugs usually spend their diapause curled up under leaves and twigs and such, Louderman says the Asian variety likes to winter in caves, with something solid touching its shell.
"There are no cliffs around here, so the houses are serving as cliffs," Louderman says.
While it seems creepy to think your home might suddenly be overrun by ravenous, post-diapausal ladybugs, there is nothing to worry about.
"They don't eat wood. They don't spread disease like flies. They are not like mosquitoes that spread West Nile virus," Bates says.
The Asian ladybug is a welcomed immigrant and hasn't caused any problems associated with invasive species such as the Asian carp, Asian long-horned beetles, the emerald ash-borer or the speeding Toyota.
"Asian ladybugs are not really an invasive species because they are beneficial. They do what they were brought here to do," Louderman says. "Nobody's trying to get rid of it because it's beneficial. It's very good for crops."
The insect, which was imported to this country from Asia before the first Toyota, established itself in the United States in the 1950s as a way to help native ladybugs eat the aphids, scales, mites and other "plant-sucking" pests that damage crops, vegetable plants and even garden flowers. The Asian ladybug is the Buffy the Aphid-slayer of horticulture.
"They are just better competitors than the native ladybugs" Louderman says. "They really are great at what they do. That's why they take over a little bit, because they are so good at it."
The pest-removal business has enough work to keep the other 60 species of native ladybugs in our area busy, Louderman adds. Ladybugs make all our plants - from tomatoes to geraniums - healthier.
The only discouraging word about Asian ladybugs is that they can deliver a harmless, but slightly painful, pinch and that they can emit a stink when threatened or squashed.
"We usually take the pacifist approach, just vacuum them up and take them outside," Bates says.
If you do have them inside, that's just another free service ladybugs provide - an energy audit to let you know which doors, windows and cracks need caulking.