The Multicolored Asian Lady Beetle: Not So Harmonious --- by Daniel Kraft --- Muhlenberg College Class of 2014

I loathe Lady Beetles. While they bug me, they are not even technically bugs but rather beetles. Years ago, I played host to one of these unharmonious creatures when it decided to take up residence inside my head. I probably would not have felt so bothered if it had called ahead, but being as it just decided to show up and live inside my ear I was less than thrilled at having a boarder. It happened in the night, as my uninvited guest made itself at home. I cannot tell you how long it was in my head, months at a minimum. While inside my ear, it died after it became lodged in earwax. Here is as a fun fact: human earwax is made from cholesterol not actual wax.

When I was growing up in the Pocono Mountains I had insects for neighbors, and Lady Beetles as house guests. Every year in the spring, once the Lady Beetles emerge, they come out by the hundreds if not thousands inside the house. To their defense, I cannot particularly blame them for it. As winter begins to set in Lady Beetles look for somewhere to hibernate, as this is the case they will frequently overwinter in the siding of houses. When spring comes and they begin to emerge the Lady Beetle will be attracted to the warmer interior of the house rather than the cold exterior.

In the end, the ultimate reason for my distain. It’s the smell. So many people I talk to do not even know that they have a have a smell but believe me they do. They secrete a chemical called Pyrazine. This chemical is an obnoxious compound in the same class as chloroform. While it will not kill you, long term exposure in high amounts can cause negative side effects.

With my bitterness towards these animals aside, I should highlight some of their good qualities. The Multicolored Asian Lady Beetle, Harmonia axyridis was introduced to North America from Asia in 1916 to help control aphids. I am a lover of fruit, and I know aphids are a pest of fruit trees. I do not really believe in bringing in a foreign species to take care of a problem and the harlequin is an invasive species.

Lady Beetles will also eat more than just aphids. According to research done by Edward W Evans and a few of his colleagues at the University of Utah, these invasive insects may be causing harm to native Lady Beetle populations as well as populations of other animals such as the Monarch Butterfly.

Unlike many other insects, Lady Beetles will not eat your couch, clothes, food or just about anything else around your home. What they will eat however is a tetranychus, which is more commonly known as a spider mite. Spider mites are a major threat to US agriculture, and they will destroy many crops including among other things potatoes, and I love French fries, a lot. Despite everything I said before, if Lady Beetles keep my potatoes readily available to be sliced diced and deep fried, I may be able to put up with them.

The Multicolored Asian Lady Beetle is a threat to the wine industry. While they are not destroying the grape vines should the insect be present at a rate of more than one per three kilograms (about six and a half pounds) when they are processed into wine it will taint the wine and make it unsellable. The taint comes from 2-isopropyl-3-methoxypyrazine (IPMP), which is the odor compound produced by the harlequin as a defense.

The Multicolored Asian Lady Beetle is showing itself to be a useful biological control. As a huge positive, using this insect is a natural control as opposed to having to use pesticides. This way a lot of crops and the surrounding land can be kept pesticide free. Being as we do not really know what other animals and plants the pesticides are going to be harming or how far reaching such harm could be, maybe having ladybugs around is not such a terrible thing. However, we do need to consider how we want to handle the issue of the invasive harlequin and from personal experience, I highly recommend keeping them out of our ears.

The Multicolored Asian Lady Beetle, Harmonia axyridis: It may not be so harmonious. by Daniel Kraft is licensed under a Creative Commons Attribution-ShareAlike 4.0 International License.