Bust out your vacuum cleaners and hand vacs, folks—it’s beetle season! Autumn is typically greeted with cheers at the colorful foliage and cooler weather but it’s also met with a collective moan of irritation because we know that the local wild’s cool-weather nuisance, the Asian Lady Beetle, is not far behind.
When I refer to these non-native insects as ladybugs many folks are quick correct me with a “They aren’t ladybugs. They’re Asian beetles.” Perhaps they feel as if the term I use is putting them in the wrong? The trouble is they aren’t wrong… but neither am I. This is one of those rare instances where both parties are correct! How? Let me explain by offering a quick refresher course in basic taxonomy, the science dedicated to the classification of organisms.
Scientists classify organisms according to named groupings that cascade from general to specific: Kingdom, Phylum, Class, Order, Family, Genus, Species, Subspecies, with some trickling and even more precise categories beneath. We’ll use man’s best friend to illustrate how this categorizing system works.
Wolves, coyotes, and domestic dogs all belong to the kingdom canis, which translates simply to “dog” from the Latin. As you travel further down the taxonomic ladder the animals split off from one another. Coyotes branch away first into their own species, latrans (the scientific name canis latrans translates to “barking dog”, an ode to the wide variety of sounds coyotes make), while wolves and domestic dogs are together in the species lupus (“wolf”). Domestic dogs go a step further into the subspecies familaris, which scientifically categorizes them as canis lupus familiaris or, translated, “the family wolf”.
When it comes to Asian beetles, calling them ladybugs is not incorrect, it’s just less specific. All ladybugs belong to Coccinellidae (say “cox-in-elly-die” and you’ve got the pronunciation right), the widespread family of beetles ranging in size from 0.8 to 18mm that are most easily identified by their smooth, spotted, domed shells. Asian beetles split from other ladybugs down the line into Harmonia (genus) and Axyridis (species). Taxologically they’re referred to as harmonia axyridis. “Asian lady beetle” is the common name people use around this local wild, even though the insect also goes by these other names: Harlequin ladybug, multicolored Asian ladybug, Japanese lady beetle (not to be confused with the Japanese beetle, a different pest entirely), and even Halloween beetle due to their October swarming habits.
Asian beetles have a signature M-shaped black marking on the protonum, the exoskeleton plate covering its thorax, and they can have anywhere from 2 to 22 spots with colors that vary from yellow to red. Asian beetles are generally considered beneficial since they are voracious predators of garden- and crop-harming pests, and indeed that’s why they were brought to North America in the first place in 1978: to get rid of crop pests in place of harmful pesticides. Asian beetles go from helpful to harmful when they swarm, seeking a safe and warm hibernating space, and often move in such numbers that they negatively affect humans’ quality of life. Some individuals experience allergic reactions—ranging from eye irritation to asthma—to the noxious yellow secretion the beetles let loose in self-defense or upon death.
If residents wish to deter these beetles without using artificial pesticides, consider mixing together 2 cups water, 5 drops dish detergent, and 10-15 drops of Tea Tree oil in a spray bottle and spraying around doors, windows, or other places Asian beetles like to gather and enter the home. (Beware: Tea Tree oil is toxic to cats. If you keep or have cats that wander around your home, consider a citrus essential oil instead.) I have personally found this Tea Tree oil mixture to be effective.
In closing, if anyone insists our pesky non-native coccinellidae be called Asian beetles instead of just ladybugs, perhaps, in the name of fairness, they should also insist dog owners refer to their canines not merely by kingdom but by most specific subspecies. In which case, congratulations to all you folks with domestic dogs: You can now tell people you don’t have a dog, but a Family Wolf.
This is one in a series of articles written for The Local Wild, a bi-monthly column in the Cannon Falls Beacon.