Written by Joe Ballenger

Photo of household casebearer, from AaE inbox.

We get a lot of questions about household pests, and the biology of these pests can be a bit…weird. Most live in dry areas, and have a lot of adaptations to deal with it. It’s also a good way to be preadapted to human habitation, because our dwellings tend to be very dry and typically don’t have a lot of food.

One of the more common insects we get in our inbox is the insect above, the household casebearer. It’s often confused with clothes moths, although it doesn’t feed on fabrics. It’s a different critter altogether.

The early literature on this species is actually full of misidentifications, and it’s biology isn’t very well known. However, as far as entomologists can tell, it appears this species originated in either Africa or Australia and has hopped around the globe with people. Outside of it’s habitat, wherever it’s found, it’s usually found in association with people…and it doesn’t typically dwell far outside human habitations.

In it’s native habitat-or at least what we think it’s native habitat is-it’s found in conjunction with spiders. The caterpillars tend to live under spider webs, eating the leftovers the spider tosses out when it’s done. In addition to dead insects, it also eats silk from abandoned spiderwebs, webspinners, and other silk producing insects.

From here, it’s pretty easy to understand how this insect could get into houses. There’s a number of spiders which live in houses, which include cobweb builders like Pholcus and Steatoda. In addition, most houses contain some amount of dead bugs which come in from outside and can’t quite gain a foothold.

As a result, control is pretty simple…find and get rid of any cobweb building spiders, and do some deep cleaning in those forgotten recesses. However, it’s also a pretty cool bug. It feeds off the traces other bugs leave behind, and has spread all over the world because of it’s unique lifestyle.

Works Cited

Written by Joe Ballenger

So…this is a correction of a previous post I wrote on Facebook, back in March.

In the comments under the article, I may have gotten myself into a bit of trouble because I made some comments which implied some things which weren’t quite correct:

Everything here is factually correct. Ladybugs bought online don’t really help with pest control, unless they’re contained inside the garden with something like netting. Invasive ladybugs do carry parasites, whose roles in ladybug ecology are uncertain overall. They also do eat ladybug eggs and larvae, and it’s that last point which I’ve decided to explore a little bit further.

When I made these comments, the implication…and what I thought was true at the time, was that Asian ladybeetles were a major cause of ladybug species changes in North America. However, it seems that I wasn’t current in my research because these questions have begun to be answered by our colleagues.

So…this week, let’s explore ladybug declines in the US.

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Written by Joe Ballenger

I work in industry, so it’s not often that I can talk about what I do. The reason for this is that I work in a group called discovery, which means that I look for new proteins which we can use against crop pests. The majority of what I find doesn’t work, which is kind of par for the course. However, when we find something that only works against certain insects, we slap it in a plant and then wait a decade for it to come on the market after a whole host of safety tests. In agricultural biotechnology, our goal is to find things that are specific. That is, we want to use stuff that only targets insects…and specific groups of insects at that.

Double-stranded RNA is perfect for that. Critters use dsRNA to do a whole lot of things, from fighting infections to turning specific genes on and off while they’re growing up. It’s purpose is to be very specific, and only act on certain genes. It’s the perfect tool for agriculture, because if we find the right gene sequence, we can make a pesticide that is species specific.

Beyond that we also need things that are durable; that are resistant to evolution so they’ll be on the market for awhile. Some animals are so well known for what they do, that we can associate them with a certain lifestyle. Fish live in the water, so they swim. Birds get around by flying, so they’re associated with flight. Well, insects evolve resistance to everything we’ve ever used to control them. So birds fly, fish swim, and insects evolve.

dsRNA was supposed to be a perfect tool. It was species specific, safe for use in food plants. Hypothetically it was supposed to be durable, as well. This is a pretty important pathway, because bugs need it to fight diseases and work their genes. The idea was that if insects became resistant to one gene, that gene could be swapped out with something else pretty easily.

Well…even seemingly obvious hypothesis need to be tested, because nature doesn’t always work like we think it should.

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