Harmonia axyridis
The Multi-Colored Lady Beetle
The Multi-Colored Lady Beetle
It's that time of the season again! I was at the gym last night and every once in a while I would notice one of these flying past my head while I was working out.
As late Autumn approaches many people begin to complain about lady beetle infestations in their homes. H. axyridis is attracted to light colors and warmth and can find their way into people's homes since they get can fit though tiny cracks.
My first experience with H. axyridis was when I was a little kid...On the soccer field, when I was more interested in looking at bugs than looking out for the soccer ball, I found one of these little guys and was shocked when it bit me. I had always been taught that lady beetles are beneficial insects, and had the image of the happy little lady beetle in my head. Later I learned that this was not the lady beetle that I was used to. It was an invader! For years after that experience I was weary of picking up lady beetles until I learned how to tell the difference between the "nice" and the "mean" lady beetles. I never thought I would be working with the "mean" lady beetles every day!
For a portion of my research, I am investigating their effect on native lady beetle populations in Ohio. I am interested in studying the hypothesis of intraguild predation (when predators within the same guild eat eachother). We think that H. axyridis may be eating the eggs and larvae of native lady beetles in the wild. Laboratory studies have been done that show that H. axyridis can and does prey on native lady beetles, but we still need to find out if it happens in their habitat.
How do you tell the difference between the nice ones and the mean ones?
ReplyDeleteThe best way to identify H. axyridis is to look for a "W" or "M" shaped mark on their pronotum (which is segment right behind the head). It has difficult to identify them based off of their coloring or spots since they vary in color and number and size of the spots. They also tend to be larger than native species, or other exotic lady beetle species.
ReplyDeleteI hope that helps!
I didn't know there were mean ones! Thanks CHELS.
ReplyDeleteWell I wouldn't say they are "mean" anymore. That was just my first thought as a 10 year old, after getting bitten! Their bite is actually more of a pinch and it is nothing to worry about. Of course they are just insects like any other trying to survive and produce young. While they often cause problems here in peoples homes, and may be an important factor in the decline of native lady beetle species of North America. In Asia, where they originated, there is a good chance that they are considered to be very beneficial.
ReplyDeleteDo the native lady beetles come inside in the winter too?
ReplyDeleteI haven't seen or heard any reports of native lady beetles entering homes. So I don't think they do.
ReplyDeleteSo the ones who spend winters in our garage are not our friends and I shouldn't be thinking I'm doing a good thing by having them spend the winter with us?
ReplyDeleteThe ones in your garage are probably the Asian species, but the best way to find out is to look for that "W" or "M" (depending on the way you look at them) on their pronotum. You can always take a picture and email it to me if you would like!
ReplyDeletePerfect! My husband just got a new marco lens for this camera, so this will be a good job for him this weekend. I'll send it to you. Thank you!
ReplyDeleteAzijske pikapolonice so se prvič pojavile pri meni doma v Voličini v Sloveniji dne v petek, 28.oktobra 2011.
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