Over 2,500 cases flowed through the doors of the UW Insect Diagnostic Lab last year, ranging from the typical June beetles through bizarre creatures that most humans will never see in their entire lives (like the itch-inducing pyemotes grain mite). Perhaps Forrest Gump said it best when he quipped, “life was like a box of chocolates—you never know what you’re gonna get.” A distinction amongst insects, however, is that the “box” contains 20,000+ possibilities in Wisconsin alone and over well 1,000,000 globally. With that said, a year at the UW Insect Diagnostic Lab is like having one humongous, box of really awesome chocolates, without all the calories.
With insects and related creatures, the weather can of course have a big impact and there definitely were examples of this in 2017. The current cold winter aside, the last two winters had been otherwise mild, giving a few insects suited for warmer conditions a chance to inch their way northward. Last spring and summer, this meant a bunch of sightings of an otherwise uncommon bee for our area known as the carpenter bee due to its habit of tunneling into unpainted cedar trim and other wood. In a typical year, I might see a few cases out of the southeastern corner of Wisconsin, but 2017 had regular reports of these bumble bee look-alikes during the spring and summer months. Similarly, praying mantids often meet their maker at the hands of a cold winter, but were surprisingly abundant in late summer and fall of last year. Ticks were also extremely abundant last spring and with the rainy start to the summer, mosquito numbers were at an all-time high in some traps. Mosquitoes were also a big deal in the news, with Wisconsin’s first confirmed reports of the Asian Tiger Mosquito last July.
The creature that amassed the most phone calls and emails in 2017 was the notorious Japanese beetle, which likely also benefited from the warmer than average winters these past few years. For Wisconsin gardeners and farmers, the Japanese beetle is certainly a formidable foe, but at least there are ways to mitigate the damage. In contrast, there’s another destructive pest wiggling its way into the spotlight in the state, which is much more difficult to control—an invasive earthworm commonly known as the jumping worm. While they may not be insects, these earthworms are creepy-crawly and can wreak havoc in gardens and flower beds, so I received a fair number of reports and questions. What stood out to me in last year was the rapidity with which these destructive worms have been moved around the state (moved—as in humans have moved soil, plants, mulch, and similar materials). Jumping worms were first found in the state in 2013 (in Madison), but have now been spotted in roughly half of the counties in Wisconsin. To make matters worse, we don’t have any highly effective tactics to prevent these worms from turning rich garden soil into the consistency of dry, crusted coffee grounds—gardeners beware!
Speaking of invasive species, the emerald ash borer has continued its march through the state and now has footholds in some of our northern counties including Chippewa, Douglas, Eau Claire, Marathon, Marinette, Oneida, and Sawyer counties. Unfortunately, our greatest concentrations of ash trees are in the northern part of the state (e.g. black ash in swampy areas), and the loss of ash from northern wetland areas could result in significant ecosystem effects. Other recent invaders like the spotted wing drosophila and the brown marmorated stink bug had busy years as well.
In other insect news, it seemed to be a good year for monarch butterflies in 2017, and the rusty-patched bumble bee finally made it onto the federal endangered species list. I was pleasantly surprised by a number of confirmed sightings of the rusty-patched bumble bee in the state as well. Perhaps my favorite “bug” story for the year involved black widow spiders. It’s not common knowledge, but we do technically have a native black widow species in the state (Northern Black Widow, Latrodectus variolus). It’s a reclusive species and is rarely encountered in Wisconsin, but reports trickled in once or twice a week at some points during the summer months (details to follow in a future blog post).
With so many cases last year, we’re really only touching the tips of the antennae. If you’re interested in hearing more of the unusual stories from the UW Insect Diagnostic Lab, I’ll be giving a “highlight” talk on May 4th on the UW campus.