The Hippo


May 28, 2020








Swarming insects
Yellow jackets and seed bugs invade the state

By Ryan Lessard

 Two species of insects have made a big impression in recent weeks. Yellow jackets have appeared swarming in places where humans gather, causing a public park to close in one instance, and harmless western conifer seed bugs, often mistaken for “stink bugs,” have begun to gather in large numbers near human homes, seeking shelter. 

Seed bugs
UNH entomologist Alan Eaton says western conifer seed bugs are around in the summer but the nymphs are harder to spot for the untrained eye and most are way up at the tops of coniferous trees feeding on the seeds.
“And then, along about sometime in September, they start investigating places as candidates of sites to overwinter,” Eaton said.
They tend to appear in the fall as the temperature begins to drop, but Eaton said they don’t usually show up in such force.
“We see them on buildings and so forth and, man, we’ve seen lots of calls and lots of activity,” Eaton said.
He said he’s personally seen clusters of them walking all over his house, looking for openings. They tend to sneak into poorly fitting screens and door cracks.
Eaton said he was surprised there were so many this year, but they showed up a little later than usual because of the warmer season.
The bugs first showed up in New Hampshire in 1997 in western counties like Cheshire and Sullivan. Now they’re found statewide.
They prefer to eat the developing seeds and flowers of pines, white spruces and hemlocks. 
The western conifer seed bug is a close relative of the stinkbug; both make a stinky aroma with their secretions. They have similar abdomens to brown marmorated stink bugs, but they have longer hind legs that widen into a leaf shape at the end. 
While they may be showing up in greater numbers, they don’t pose any serious threat, Eaton said.
“Thank goodness they don’t bite or attack your drapes or chew on the woodwork or things like that,” Eaton said. “It’s just the yuck factor.”
He’s observed years where their numbers balloon and others where they shrink back down, so it’s unclear whether they will grow as a nuisance in the future. Little is still known about them because biologists don’t track them closely, but it’s believed they don’t have many serious predators, especially given their pungent natural defense mechanism. 
And it’s possible the warmer weather might give them an advantage.
Yellow jackets
Another nuisance insect that has apparently shown up in significant numbers these days is the yellow jacket, especially in October. Some have reported seeing them swarming around town dumps. And a yellow jacket infestation resulted in the temporary closure of the Portsmouth Plains Playground. 
The black and yellow stinging insects were crawling all over the playground equipment.
But, at least to Eaton, the strong presence of yellow jackets seems to conflict with his findings out in the field this year, since he hasn’t come across very many ground nests.
“Why we’ve had so many, it just seems out of proportion to the number of colonies I’ve seen,” Eaton said.
Around late October or so is when their populations are usually at their highest, Eaton said. But he’s observed they also seem to be more aggressive this year. 
Yellow jackets will remain active until the first hard frost. And it’s certainly possible the unusually warm fall extended their presence somewhat later than normal. 
They may also be getting closer to human population areas because food sources become scarce around the same time. They turn to carrion and caterpillars. But they’ll also be lured by odors that signal the presence of food and sugars such as apple cider presses or dumps.
Usually, Eaton said, the thing that determines their numbers each year is the amount of snow cover to help the mothers hibernate in the ground beneath leaf litter.
It’s possible last year’s winter provided that cover and the feeding season during the summer supplied them with more than enough food.
“Maybe they overwintered in good numbers,” Eaton said.
Unlike western conifer seed bugs, yellow jackets can be aggressive and sting when they feel threatened. And humans can be severely allergic to the venom. Eaton said that in many cases, one or more stings can send a person allergic to the venom to the hospital. 

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