O'Malley: Surprising answers to questions about Alaska bugs

jomalley@adn.comJuly 24, 2013 

First there were the plagues of mosquitoes. Then came the legion of grasshoppers thumping into the office window. Next: the wasp nest in the shed, big as a softball, nestled into a canvas bag (which, luckily, I didn't pick up). And then, earlier this week, a hummingbird moth as big as my palm came fluttering through the garden.

Maybe it's because I've been spending more time outside, but this bright, record-warm summer has been my summer of bugs. Readers on Facebook and Twitter said pretty much the same thing. And they had lots of questions about what they were seeing out there. So I talked to bug experts to get them some answers.

Q: What the heck is up with all of the grasshoppers this year? I've seen more this summer than I have in my whole life here!

A: The answer to this question was a little tricky, because no one has been documenting the number of grasshoppers in Anchorage this summer. Janice Chumley with the Cooperative Extension Service on the Kenai Peninsula told me that this year's grasshoppers are a result of eggs laid not last summer, but the summer before. The eggs overwinter in the soil and when they hatch, those baby grasshoppers, or nymphs, overwinter again. It also doesn't hurt that temperatures have been warm, and the climate when the eggs were laid must also have been favorable. Other players in grasshopper populations are predators, like birds and other insects. When predators have a good year, grasshopper counts go down. Grasshoppers love gardens, grass and open fields, she said.

Q: Someone recently told me that Alaska's daddy longlegs are not actually spiders. Is that true? And as for daddy longlegs, I keep hearing the story about how poisonous they'd be if they could only pierce human skin.

A: Matt Bowser, an expert on daddy longlegs with the U.S. Fish and Wildlife Service told me that daddy longlegs, also know as "harvestmen," are arachnids, but not true spiders.

"They are as distinct as scorpions (also arachnids) are from spiders," he said.

The most obvious difference between daddy longlegs and spiders is their body form, he said. Spiders have a distinct head and abdomen. Daddy longlegs' bodies are one fused shape. And, daddy longlegs are not poisonous. "They don't have venom," Bowser said.

Some of them are predators, but most scavenge, he said. Some species are known to steal dead insects from spider webs. Alaska has a number of native species, but the largest, most common and visible is a type that came originally from Europe. The males of the species have what look like horns on their (here's a creepy word) pedipalps, the grasping organs on the front of their bodies.

Q: How can you make your house less attractive to wasps? Does anything repel them?

A: Most of the wasps homeowners are dealing with this time of year are yellow jackets and bald-faced hornets, which tend to make nests in the eaves of homes and sheds, said Jim Kruse, a forest entomologist with the U.S. Forest Service in Fairbanks. He didn't have suggestions about how to repel them, but said the best way to deal with them is to patrol the parts of your house where they are prone build nests and knock them down when they are small. About half the time a queen will come back and try to make a new nest in the same spot, he said. In that case, knock it down again. Kruse said he'd never seen a third attempt at nest-building in the same location.

Wasp traps, hung away from houses can also ease the problem. They can be homemade from a soda bottle

(Google offers plenty of how-tos on this). A chunk of fish is great bait, he said. He wasn't convinced that dummy nests that look like grey paper lanterns work to deter wasps.

Q: What are the giant insects that we call mosquito-eaters actually called? (Perhaps they are mosquitoes themselves?)

A: These are called crane flies, Kruse said. As mature insects, they don't eat mosquitoes (or bite humans). They do eat mosquito larvae when the crane flies are in the larval phase, Kruse said. Most don't feed as adults, though a few species drink nectar.

Q: Do all bees and wasps die after they sting you?

A: No. All bees and wasps, except for the domesticated honey bee, will sting multiple times and will not die after stinging you, Kruse said. That can make them very dangerous to people with allergies.

Q: Do dragonflies bite?

A: Dragonflies are physically capable of biting, but they are not aggressive insects, Kruse said. They can pinch skin when they are trapped up against it, but they aren't after humans, Kruse said. They eat other insects, including mosquitoes. They can eat mosquitoes and mosquito larvae, both as adult insects as larvae.

"Dragon flies are good to have around," he said.

Q: How can I keep leaf-roller caterpillars from eating my trees and garden?

A: Leaf-roller caterpillars in birch trees are different than the ones that attack gardens, Kruse said. To target birch leaf-rollers, apply bT pesticide in the spring.

Q: Is it true that some people attract mosquitoes and others don't?

A: I asked several insect experts this question, all but one said yes. Some people attract mosquitoes more than others. It isn't just a matter of perception.

The largest attractant for the insects is carbon dioxide output, they said. When the insects pierce the skin, some of their saliva mixes with human blood. The proteins in their saliva cause people to react with a raised bump. It's possible some people react more than others to the same proteins. That may also lend itself to the perception that some people are bit more than others.

Roger Burnside, a retired state entomologist, told me that in his time working in the field, he noticed that there were some people who just didn't get bit. His theory was that it had to do with skin chemistry. He once worked with a person who seemed to repel everything, even wasps. Once time they even got swarmed by yellow jackets, Burnside said, and the guy "just walked away" unscathed.

An article this month in Smithsonian Magazine backs up Burnside's theory. It says mosquitoes are attracted and repelled depending on carbon dioxide output, blood type (they like Type O and shun Type A. Type B fell in the middle), body temperature and acids in sweat and bacteria on the skin. Beer drinkers and pregnant women tend to attract them more than other people. Children were less likely to attract them than adults.

And I'll leave you with this: The article also said that some mosquitoes have become immune to repellent.

Julia O'Malley writes a regular opinion column. Reach her by phone at 257-4591, email her at jomalley@adn.com, follow her on Facebook or Twitter: @adn_jomalley.

 

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