Insects in the true bug class, Hemiptera, are a wildly diverse group. It’s hard to imagine that cicadas, water striders, tree hoppers and this column’s subject: lace bugs are as related to each other as butterflies and moths, but they are. What ties them together is a juice-sucking bodily straw, or rostrum, which usually folds under their thorax.
Lace bugs are in the Tingidae family, which is one of those words you want to say a few times just for fun. They are tiny insects, at most 1/8th of an inch long, as you can see from the image with my index finger. They have intricate, raised filigree patterns on their wings and on the hood and “shoulders” section of their body. The transparent panes in the “lace” can refract and reflect light to create colorful sheens, like stained glass. If you can find a way to focus on them, you’ll see they are stunning creatures.
I saw these Corythucha genus bugs on the underside of Indian plum, or osoberry, leaves at the margin of a wooded area at Mt. Pisgah. Lace bugs are picky eaters, and their common names reflect the foods they exclusively eat. So, there’s a sycamore lace bug, birch lace bug, willow lace bug, and on and on for about 165 species in North America.
Corythucha bugs spend the winter as adults, and emerge in spring to eat freshly-grown leaves. They are cold tolerant to below 15 degrees. One study from China found that if temperatures fall slowly, Tingidae are more resilient than if there’s a sudden chill… such as, for example, stuffing them in a freezer. Not much of a surprise there, but they are resilient little creatures, as more than 20% of the shocked ones survived.
I’m not sure why a group of three lace bugs chose to hang out on top of each other (see image). I don’t think they were mating. However, these bugs will be doing so soon, and then it’ll be time to look for the nymphs. They go through five stages. The first one is nearly see-through and the next older ones have spines but no wings. I’ll probably return to this location in a couple weeks to see if they’re there.
If you research Tingidae, you’ll see lots of alarm bells and red flags about the azalea lace bug, which was recently introduced to Oregon and eats and uglifies azalea leaves. I’m not yet sure which species I found, but I do know it’s in a different genus than the azalea lace bug. Regardless, even though azalea lace bugs harm the leaves, the plants usually recover. Also, Tingidae have natural enemies like ladybugs and carnivorous wasps, both of which I saw on this osoberry as I was taking pictures. Nature keeps its own balance if we allow it.
Stay curious!
Karen Richards
Sources:
Lace bug overview at the Missouri Department of Conservation: https://nature.mdc.mo.gov/discover-nature/field-guide/lace-bugs Accessed 3/19/21.
Research paper on “rapid cold hardening” of lace bugs: https://www.sciencedirect.com/science/article/abs/pii/S0022191011002472 Accessed 3/19/21.
