Entomologist Dr. Art Evans and WCVE producer Steve Clarke discuss the latest developments with the brown marmorated stink bug.
SC: I'm Steve Clark with Dr. Art Evans, entomologist, and this is What’s Bugging You. I don't know whether to remain hopeful.
AE: That's not like you. (laughing)
SC: I know. It seems to me that multicolored Asian lady beetles are trending down in my house.
AE: Really.
SC: So far this season I think only two have flown into the halogen lamp and immolated themselves, and I just haven't seen any around. I've seen some outside the house. I've seen them try to get in, so maybe they're still in the walls; I don't know. But I hope that this is a downward trend, and I hear that there's also a downward trend with the brown marmorated stink bug.
AE: Yeah, I heard the same thing about the brown marmorated stink bug, and it's possible that the wasp parasitoid that was released to help keep it in check is doing its job. And there's also word that some native predators, birds and rodents, are also developing a taste for brown marmorated stink bugs. But it's hard to say, you know, when we're seeing a general downward trend in all insects. It may be that these pests are succumbing to those downward pressures as well.
SC: So brown marmorated stink bugs became a pest here back in the nineties.
AE: They were first discovered in the mid-, late-nineties, and they were thought to be just a nuisance at first because they were entering homes in the fall and the winter. And then they'd keep working their way indoors, and they would die by the dozens or hundreds in window sills and light fixtures, very similar fashion to the multicolored Asian lady beetle. But then they soon developed a taste for several crops - fruits, yeah, and posed a real problem. And all along they are spreading across North America. They’re, well, all the way over to the Pacific Coast now. But there was an aggressive effort to introduce parasitoids, these wasps from Asia that evolved with the stink bugs, and it seems to be they're doing their job and keeping the numbers down. And also a lot of people have been pursuing ways of trapping distinct bugs using pheromones, their natural sense that they use to attract one another, and developing traps to capture them. And all these things may have played a role in knocking the numbers down. I'm still thinking that it may be their decrease in numbers may be part of an overall trend of insects decreasing in numbers as well, so again, there's not going to be much of an outcry for these two species if they start dwindling in numbers. But again, insect populations are always going up and down. I mean that's just the way nature works, and we don't always understand what causes those fluctuations in population numbers. And we really have to look at them over the long period of time to even hope to begin to see patterns and understand what influences those population numbers.
SC: Just don't kill off any of the predators, known predators, of the brown marmorated stink bug.
AE: Well, see, this is what happens. You know, you can't always be selective in your control measures. There's always collateral damage, you know, these non-target species as they say in the business. So again, it just points to how little we know about the largest group of animals on this planet.
SC: Dr. Art Evans is a Research Associate at the Virginia Museum of Natural History. You’ll find photos, audio, and links to the museum and Art’s Facebook page at ideastations.org/radio/bugs.
Photo: Brown marmorated stink bug, Halyomorpha halys (Hemiptera: Pentatomidae).
