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.
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| 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.