Saturday, May 21, 2011

Burying beetle wants to know: Are you gunna eat that or can I have it?

What does a burying beetle bury? Dead bodies, of course. These beetles are native throughout North America, but they're usually nocturnal and sometimes underground, so you may not have made their acquaintance. I've only seen one, toward dusk on a forested trail. Actually, at first all I saw was a dead shrew that was somehow twitching its way off trail. When the beetle crawled up from underneath the shrew, I had my first look at a margined burying beetle. I had no idea what it was, but later that evening some field guides clued me in to its disgustingly fascinating story.

Can't get enough of your love, babe. Photo from bugguide.net; photo by Andrew Williams
Sensitive chemical receptor on a beetle's antennae alert it to dead animals. It flies to the recently departed, ready to party. It has to act fast, though, because a dead thing is a pretty popular item in the wild. So it gets the body underground as quickly as possible. If the soil is compacted (like, say, on a trail), it might have to get underneath the creature, lie on its back and hook its leg claws into fur or feathers. Using its six legs as levers, the small beetle is gradually able to move the much larger animal to its final resting place.

As the beetle is working, chances are a suitable mate will show up to help, because there's nothing like a dead body to get burying beetles in the mood for love. The two beetles excavate the soil underneath the animal, which gradually sinks below the surface while the loosened soil rolls down to cover it. The beetles inter themselves with the deceased, and then they listen to some Barry White. No, actually, the act of examining and burying the dead causes the female's partially developed eggs to mature. The beetles mate and dig a brood chamber, and she lays her eggs.

Now the expectant couple further prepares the body. They remove fur or wings, and move them off to the side within the chamber, and then shape the denuded carcass into a ball. (If you happen to be eating anything right now, this might be a good time to stop.) By the time their eggs hatch, the parents have rendered the flesh edible for them by regurgitating it and depositing the resulting droplets into conical depressions in the body. The female calls her grubs to these soup bowls by rubbing a ridge on her wing covers against her abdomen. The adults tend their young for about two weeks, finally leaving the crypt when the young pupate. Ten days later, the young emerge as adult beetles, ready to sniff out another dead body and play some Barry White.

11 comments:

  1. When I worked in Saskatchewan we did pit trapping for beetles and caught tons of these. I didn't know what they were at the time, though. (We lowly technicians just collected the samples, which were then sent off to an expert for identification.)

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  2. Ooh, pit trapping. DId you use any kind of bait, or just waited to see who fell in by happenstance?

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  3. Wow. I have never heard of an insect that actually cares for its young for that long. (except maybe water beetles- how long do those nasty larvae stick around?)

    I've never heard of any of this... and I'm kind of glad about that. The way this blog is going, pat, you might want to make an affiliate deal with a brain bleach company.

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  4. No bait, just plastic containers of the sort you'd use for leftovers, buried up to their lips in the soil. Spending eight or ten hours a day burying the pit traps in the prairie soil with a trowel was one of the most exhausting things I've ever been paid to do, actually.

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  5. New diet: Read Pat's blog before dinner.

    Actually, I've heard of burying beetles, but had no idea of the whole routine. Was this in one of your books? And I missed it?

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  6. Hmmm, note to self for next nonfiction title: The Gross-Out Diet Book

    Yeah, I wrote about the whole sordid burying beetle story in "River-Walking Songbirds and Singing Coyotes." How very sweet of you to ask!

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  7. Gee - and I thought I'd been on some weird dates in my life. Never yet has a man said to me, "Hey baby, wanna bury a dead mouse, then do it?" I feel positively normal now!

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  8. The Germans call them Grave Diggers (Totengräber). I found a black burying beetle on the wall in my breezeway one night. Even more interesting were the dozen or so phoretic mites crawling on its back. Apparently they are just hitchhikers. I have yet to encounter a "grave site." Good post.

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  9. All I can say is: thank god I'm not a burying beetle. But now you've got me wondering what those scarab beetles do in Egypt. They're believed to know the secrets of the dead since they burrow deep into the sand and thus into tombs.

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  10. This sort of thing reminds me to stop being so darn anthropocentric - I love to be reminded that nature does not have our sensibilities and that we should respect that.

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  11. Ain't that the truth!

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