It's been a particularly wet summer in the Green Mountain State. Torrential downpours contributed to historic flooding across Vermont last month, and all this rain is impacting mosquito populations statewide.
Vermont Public's Jenn Jarecki recently spoke with Patti Casey, the environmental surveillance program director at the Vermont Agency of Agriculture, Food and Markets. Casey leads the state's efforts to monitor mosquito populations. Their conversation is below and has been edited and condensed for clarity.
Jenn Jarecki: Is Vermont dealing with more mosquitoes than usual because of how wet this summer has been?
Patti Casey: Well, it appears to be the case, yes. So our numbers this year before the flood are up about 50% over last year's mosquito collections, and up about twice as much as over our historic numbers, which date back to 2009. And our collection techniques have changed a little bit over the years, so that it's that's not a hard and fast assessment, but it gives us a pretty good idea that this year is a really successful year for mosquitoes.
That data that you mentioned, does any of it point to those flood incidents directly contributing to the increases in Vermont's mosquito populations?
Yes, we were able to get out to our collection sites, not the week of the flood — we got out to a few of them — but within the two weeks following the flood, we were able to get to about 30% of our traps. And we were still up about one-third over our averages. So yeah, the flood appears to have made things worse.
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I was just at our lab yesterday. I don't usually need to actually go in and identify mosquitoes, but because we've had such big numbers in our traps, it was kind of an all-hands-on-deck situation. So I went down, and our collections are up a lot since the flood.
Patti, are there dangers associated with a jump in mosquito populations like we're seeing? I mean, for example, are Vermonters more likely to contract diseases?
Well, first of all, the disease has to be present in the mosquito population, and that takes a little while to sort of ... we consider it sort of heating up. So the disease happens in a cycle between birds and mosquitoes for the most part. So West Nile virus, and Eastern Equine Encephalitis, or EEE, are the two mosquito-borne diseases that we test for in the specimens that we collect.
If there are more mosquitoes in the environment, as the summer goes on, there's a greater likelihood that the viruses can amplify in the mosquito population.
Read our newsletterOut There: Mosquito season
So I'm curious, Patti, what function or functions do mosquitoes perform in nature, other than feeding on our blood?
That's a great question, and it's one that a lot of people forget to ask because mosquitoes are just so annoying, and potentially a health risk.
But they actually do have a function in nature — several functions, really. They're on the food chain like all of us. Their larva which can be very, very prolific in standing water, they feed other small organisms. So dragonfly larvae are particularly fond of mosquito larvae. And in fact, there are mosquito larvae that that don't bite human beings that are voracious feeders on other mosquito larvae that do bite humans. So they kind of help us out. And then go on up the food chain — tadpoles — and so any small microorganisms in an environment like that will feed larger ones. So that's an important service that they provide. Adult mosquitoes also feed birds and bats.
One thing that most folks don't maybe don't know is that male mosquitoes don't bite humans or anybody.Patti Casey, environmental surveillance program director at the Vermont Agency of Agriculture, Food and Markets
And surprisingly, the male mosquitoes are pollinators — and they're little tiny pollinators, but it all adds up. If you think about millions of mosquitoes acting as little pollinators, they actually do provide that service. One thing that most folks don't maybe don't know is that male mosquitoes don't bite humans or anybody. It's called taking a blood meal, which is kind of unattractive way of thinking of it, but that's what the females are doing. They're taking a blood meal so that they can produce eggs.
But the males feed on nectar. So they're sticking their little proboscis into flowers and sipping nectar and getting pollen on their legs and their wings and their feet and moving it to the next plant — so they do provide a service.
You recently told Seven Days, "Nothing is going to keep me from going outdoors and enjoying Vermont. So it's just a matter of doing what we have to do to protect ourselves to be able to be outdoors." So, what can listeners do to prevent mosquito bites and stay safe?
I go outdoors all the time. I do go outdoors for work a lot. I look for mosquitoes; I look for ticks. I put myself out in the environment, but when I'm not doing that, I'm trail running and hiking and riding my bike. I grew up in Vermont and there's no way that I'm going to stay inside.
So what I do, I put on long pants. I wear long sleeves that can be really hot. I look for stuff that's lightweight. If I'm going to be walking around in potential tick habitat, which is everywhere, or a lot of places, I'll tuck my pants into my socks, which can also keep you from getting mosquito bites. I do use DEET. I know a lot of people don't care for it. There are other products out there.
I also treat a set of clothes early on in the season with permethrin, which you put on your clothes and let them dry. You don't ever apply it to your skin. It's a repellent [that lasts] for several washes. So depending on how often you wash your field clothes, you know, it could last you most of the summer.
I usually have a wide brim hat on. I apply the repellent to my exposed skin. I don't particularly like it — I don't know if anybody likes putting it on their skin but, you know, it's a risk-benefit ratio that I'm willing to engage in.
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