100 species #4: Asian ladybug

[urbpan]

Asian ladybug Harmonia axyridis

I struggled a bit with this identification, since the "M" on this beetle's pronotum is filled in and indistinct. But, if I am correct (and I'll issue a prompt correction if you can convince me I'm not), this is the creature known as the "Variable Multicolored Asian Lady Beetle," and so a slight variation shouldn't be too unexpected. Indeed, over at bugguide.net, there are 26 pages of variation.

The habitat cue is appropriate, too: inside a house in the middle of winter. Harmonia is well-known for getting indoors to avoid the cold, sometimes in huge numbers. For this reason, and also because it has been "implicated in adverse ecological impacts involving changes in invaded communities through interspecific competition and intraguild predation," this species is considered by some to be a pest and/or an invasive species. Indeed, near human impacted environments in North America, one might have a hard time finding other species of ladybird beetles. This species is spreading across Europe and has been recently discovered in South Africa.

I don't know if their presence in a garden is more positive (they eat aphids, and were in fact deliberately introduced to do so) or more negative (as an indicator of reduced biodiversity).

Surprisingly, this is the first of the 100 species that was also one of my 365 urban species.

Comments

[ndozo.livejournal.com]

Is this the kind you get if you send away for ladybugs to put in your garden to eat aphids?

[urbpan.livejournal.com]

I think they used to be, but now it looks like most companies use Hippodamia convergens, a native species. If you are ordering, check to make sure. I wouldn't order anything that didn't identify the product with a scientific name.

[ndozo.livejournal.com]

People interested in ladybugs might like to participate in this project: http://www.lostladybug.org/index.php

[(Anonymous)]

One thing I've noticed about these lady beetles: when they first appeared in our area (upper peninsula of Michigan) they were fantastically common, getting into our house in great numbers and being about the only ones that we found in the yard. This lasted about four or five years.

Now they are practically gone.

I think that either something local developed a taste for them, or one or more diseases from the Old Country caught up with them over here. In any case, their local dominance over the other lady beetles seems to have been a fleeting thing. Of course, mileage may vary elsewhere.

[tceisele.livejournal.com]

Whoops, forgot to log in. That "anonymous" was me.

[copperwolf.livejournal.com]

Years ago my parents' house had wintertime ladybug invasions, too. I remember in the early 90s seeing lots of ladybugs around in autumn. I had no idea there are problematic nonnative ladybugs. The genus name is pretty, and the beetle is pretty too.

[phlogiston-5.livejournal.com]

Just wait until the brown marmorated stink bug gets to your neck of the woods! People will be wishing it was just asian ladybugs getting into their houses.