Thursday, September 25, 2008

Better Know an Insect: Just a Little Weevil

I love whole grains, so I keep a variety of them in miscellaneous jars and other storage vessels in a cabinet in my kitchen. I like barley in my soup, curried quinoa, fresh popcorn (no microwave needed!), steel cut oats, and other tasty grains.

Unfortunately, I'm not the only one.

While restocking our popcorn jar, I picked up a bag of barley that I had opened some weeks ago and had rolled and clipped shut. I noticed that some of the barley was... moving. Crawling, really.

This was how we found out that we had an infestation of weevils. More specifically, they were probably wheat weevils, also known as granary weevils, which are a common pest of grain. They look like this:

Unlike the giant water bugs a few months back, however, what you're seeing on your screen is far larger than lifesize. If you check out the post on Wikipedia, you'll see the length given as 3-4 mm from snout-tip to end. These are tiny little critters; they burrow into seeds, very tiny indeed!

They might be tiny, but they don't lack ambition. We found the majority in the barley, but they'd also made it into the wild rice and the oat bran. (Actually, we caught a mating pair in the act nestled in the oat bran. I'm just glad we found them before it was full of their offspring.) It's not entirely clear -- they may have simply navigated the folds of the bag -- but they may have actually chewed through the plastic to get to the barley. (It was one of those flimsy two-pound bags.)

Anyway, we transferred everything to weevil-proof glass jars and threw the infested materials in the trash.

I don't know how accurate the Wikipedia article is, although the description is true enough. (It's completely lacking in citations.) The page about the weevils as a group is fairly interesting, if brief. It's too bad that the article is so short. There are 60,000 species of weevils in the world, so such a short entry really doesn't do them justice.

Weevils are in Curculionoidea, a superfamily of Coleoptera, or beetles; there are approximately 350,000 described species of beetles total, although there may be as many as 5 million in the world. (This might sound familiar -- frustration with mammal-centrism is part of the reason I do these "Better Know an Insect" posts.) As the visualization goes, if you lined up every known species of animal at random, every fifth one would be a beetle. By comparison, there are fewer than 6000 species of mammal in the world. There are not quite 60,000 species of vertebrates. Yet the gallery for weevils has just a handful of pictures, including the very pretty palmetto weevil.

Even the Encyclopedia of Life has no information about the little granary weevil. The best you can do is the snout beetles page, which has a few nice pictures and a phylogeny but not much besides.

I'm tired and it's nearly Friday, so I'm going to end there for now... but there will be more about other kinds of beetles in the future! There are so many, I could just blog about beetles and have several years' worth of material!


Margaret said...

Your blog just gets better and better; those weevils and your musings about food, all good stuff. Keep it up, there may be a book in it one day.


Anonymous said...

I know of only 4 Beatles (not including Pete Best), but I have gone on with only those for years also!


Sharon said...

This one time, our parents went out and left us this soup to eat. It was good soup, until we figured out that there were insects in it. So uh, glad we had that experience, I'm gonna go check the pantry now...