Will the Hot, Dry Weather Cause a Boom in Insects?

By Chris Williams on January 29, 2013.

June 2011 to June 2012 was the warmest 12 month period in the U.S. since record keeping began in 1895, according to the National Oceanic and Atmospheric Administration. In general, the winter was unusually mild with little snow, spring was early, and summer so far has been extra hot and dry. How is this extreme weather affecting pests? Ask 10 pest experts and you’ll probably get 10 different answers to that question. There are so many different variables that affect an insect’s life cycle, that it’s hard to isolate just one factor, temperature for example, and predict how that will affect certain insect populations.

We do know a few things about how insects react to temperature. Since insects are cold-blooded, their body temperatures are directly related to what’s happening in their environment. In cold weather, insects slow down, and in hot weather, they become more active. During a warmer-than-normal winter, fewer insects die as a result of extreme cold. That means more insects are available come spring. In hot weather, insects’ reproduction rates increase and they grow faster. Cockroaches, for example, develop a lot more rapidly at 85°F. than at 65°F.

This increase in reproduction has some experts worried because the extra warm winter, followed by an early warm spring, means many outdoor insects got an early start on feeding and egg laying. Insects that emerge too early from their winter hibernation run the risk that their plant or insect foods are not yet available. But insects that emerge earlier in the spring and are successful may be able to produce an extra generation. Instead of producing just two broods of young before fall, for example, they may be able to fit in a third generation. An extra brood of crop pests could be especially devastating for farmers whose crops are already suffering from drought. The drought is helping the insects and hurting the farmers in another way. The bacteria and fungi that provide natural controls for some insects like grasshoppers are not as abundant in hot, dry conditions.

The extended drought in many areas should mean a decrease in mosquito problems. Less rain and less snow melt = less standing water = fewer mosquito larvae. However, if you have had rain along with your heat, you could be in for a worse than normal mosquito season. In some coastal areas, experts predict that the warm winter combined with last year’s tropical storms could mean even more mosquitoes.

Although insects like heat, in general they don’t like drought. Most insects are susceptible to drying out and like damp areas. The plants that insects feed on don’t do as well during a drought, and that in turn affects insect numbers.

When temperatures are too extreme, even insects seek shelter in shady spots. Drought causes many outdoor insects and arthropods to migrate, looking for shelter and moisture. Often that means they head indoors. You may be having more of a problem indoors with pests that normally live outdoors around the foundation of your home like ants, millipedes, sowbugs, pillbugs, and crickets. If so, give Colonial a call. We can’t do anything about the weather, but we can do something about the pests!



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