Monday, October 18, 2010

Home invasion

I found these weevils a few days ago, in a bag of bird seed.

They're really tiny, barely 3.5 mm, 1 3/8 in., snout to tail. The bag was swarming with them, which I didn't notice until I had poured out a bowlful for my juncos. By then, many had escaped and were scattering across my kitchen counter.

I got rid of all I could catch (they run pretty fast for such tiny critters), but I was too late. Now, every evening a few come out from some hideout, and head across the kitchen floor.

Two in a plastic lid.

There was a pinhole in the bag. I began to wonder if they made it, and which way they were going; in or out?

I sent their photos in to BugGuide for ID, and heard back within the hour. Yay BugGuide! It's a granary beetle, one of the Sitophilus (grain loving) species. And my question is answered already; they were leaving the bag.
The adults, which are unable to fly, live for 7 to 8 months and during this period each female lays about 150 eggs. In egg-laying, the female drills a small hole in the kernel, deposits an egg in the cavity and seals the hole with a gelatinous secretion. There is only one larva in each infested kernel. The white, legless grub completes its growth, pupates and develops into an adult weevil within the kernel. After reaching the adult stage, it eats its way out of the kernel. (From Canadian Grain Commission)
And after eating their way out of the kernel, they kept on going, out of the bag. So they're somewhere in hiding, and for at least 8 months, I'll have to make sure all grains are in bug-proof containers, not plastic bags. As for the weevil-infested seed, it's now stored in the freezer.

At least the birds will like the extra protein.


  1. Oh my - you know you're a naturalist when weevils come crawling out of your birdseed and your response is to photograph them and identify the species! The snouts remind me of a little beetle-ish insect I found dead on the sidewalk yesterday, I wonder if that was a weevil of some sort as well.

  2. Oh, what a worry for you! I wish you could have opened the bag outside...then the birds would have had all the weevils. I think I will do that now, after hearing this!

    It's a constant war against these bugs here, because of the arid conditions. They love to come in thru crack, to find water and grains.And this is the time of year for it!

  3. Oh, wow! I didn't know any of this about weevils. How interesting!

  4. Rebecca, Lol!

    Marion, No worry; they're harmless, and I'll manage to get them all, eventually.

    You're right about opening the bags outside. I'll do that next time.

    JayLeigh, they're funny critters, with the long snout and all. Most of the ones around here have been a different species, about 4 times as big. Also very interesting. They play dead when they're disturbed, and very convincingly, too.

  5. thanks for the info on what to do to identify a bug. I've a small blue fly in swarms in my yard with a fuzzy blue bottom. So cute but too small to photograph


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