It is common knowledge that ladybugs are “good insects.” They prey upon garden pests, especially aphids and scale insects. They are said to be bringers of good luck! And ladybugs are pretty!
So imagine how betrayed you would feel if a ladybug bit you! But this is exactly what is being reported around the country. You can be sure gardeners will take notice.
The last time the Garden Club worked at the Flournoy Butterfly Garden, it was a sunny and warm winter’s day. We were seeing lots of ladybugs. I found a red one with no spots. Nancy Lawson found an orange one with many spots. Becky Campbell saw many yellow-green ones that kept running down into the mulch. As we weeded away, we discussed ladybugs. It was Susan Fields who dropped the “bombshell.” Had any of us heard of ladybugs that bite?
What? No way! It would seem to be a crime against nature for a sweet little ladybug to bite!
Unfortunately, I had heard of such traitorous ladybugs. They are called Asian ladybugs. And they do have a propensity to bite.
I understand that they were imported from Japan and eastern Asia to control pecan tree aphids in the 1980s. This species of ladybug, Harmonia axyridis, was released mostly in the southeastern United States. The USDA eventually decided that the introduction of these Asian ladybugs was unsuccessful. However, in 1988 a bunch of these beetles was found near New Orleans. Whether this population was the result of the original, planned introductions is unknown. Nonetheless, this new ladybug was here and has since spread throughout North America.
In fact, the Asian ladybug, has become worldwide in its distribution. Some introductions have been accidental, but most have been on purpose. Why? It’s because this species, like nearly all ladybug species, does control serious infestations of aphids.
The lady beetle family consists of about 5,000 species worldwide. In England they are called ladybirds. Americans dubbed them “ladybugs.” But since they are not birds and not “true bugs” either, most scientists prefer to call them lady beetles.
You may wonder where they got the lady part of their name. It seems that in the Middle Ages, most farmers considered them a blessing from the Virgin Mary. They referred to the beetle as “Our Lady’s bird” and modern names reflect that.
The poor Asian lady beetle has other strikes against it. Like most species of lady beetles, it tends spend the winter in crevices, such as in tree bark. The Asian lady beetle, however, collects in large numbers inside the walls of houses. On warmer days, thousands of lady beetles climb up to the upper corners of window frames. They can invade the inner part of the homes. Trying to capture them stresses the beetles. The stress causes reflex bleeding from the leg joints, and the liquid smells bad. Imagine a thousand or so stressed lady beetles in your home. Besides the foul smell, the exuded liquid stains clothing and carpet. Yuck!
Since not all lady beetles have so many detrimental traits, it is important to know how to distinguish the Asian lady beetle from the more pleasing native ones. You can’t rely on the number of spots: the Asian species has variable numbers of spots. The most useful clue is to look at the head. White on the sides and top of the head delineate a black letter “W” as you look from the front towards the back of the animal. (If you are looking from the back towards the front, the letter becomes an “M”.)
Or you could just let the lady beetle crawl along your hand. If it bites or stinks, it is probably an Asian lady beetle. But don’t smash it! Crushed, they smell even worse.
Besides, Asian lady beetles do as good a job of eating aphids as most of the native species. And about that biting business: They don’t break the skin and have no toxins. In fact, some writers call you a whiner if you complain about the lady beetle’s nibbling. It is just pinching you a little to see if you are juicy, they say.
More important than identifying the different adult lady beetles, is being able to recognize the larval form of a lady beetle. All lady beetle larvae look like tiny, spiky alligators. They are rather ugly, the poor things. However, the larvae are voracious predators, perhaps even more so than the adults! They can wipe out an aphid infestation in no time. They don’t look so pretty, but they are highly beneficial in our gardens.
The next time you see a lady beetle, try to examine it closely. There are over 400 species in North America, most of them nicely mannered and beneficial. Even if you do find an Asian lady beetle, weigh its value against its flaws. I hope you will let it go.