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Thursday, September 20, 2012

Life, Death, Cooperation, & Coevolution... in a beetle

While out on a stroll yesterday afternoon, a group of parents and kids went across the fields of NBNC in search of Monarchs as part of our weekly Monarch Tagging Program.  A large insect flew across the trail.  For a moment, a dull-yellow glow made the creature appear as a bumblebee, but I quickly netted it and discovered it to be a very special beetle: the Sexton Beetle.

Burying Beetle (probably N. tomentosus) found at NBNC

Sexton Beetles (Nicrophorus sp.) are also known as burying beetles for a very important and unique ecological role they fill: burying dead things.  After finding a small carcass, the beetles begin to dig out a hole underneath it, allowing the body to sink into the hole and eventually be completely covered in soil.  The reason the burying beetle fulfills this ritual is to protect the carcass from other scavengers that could compete for the meat.  The beetle then strips the carcass of fur or feathers, lays eggs nearby, and nurtures its young as they feed on the rotting flesh, protecting them as they grow.  

Photo of mite by Tom Murray,
courtesy of bugguide
If this incredible life history wasn’t fascinating enough, the beetle we found was covered in mites.  While it would seem that mites could be harmful to the beetle, they actually have a symbiotic relationship.  These mites (Poecilochirus sp.) also feed on carcasses, but are unable to successfully travel from one carcass to another on their own.  Instead, they hitch a ride on the burying beetle!  In exchange for the transportation, the mites perform a cleaning service (a car wash, we could say) by removing any remaining meat on the beetle that could harbor bacteria.  (close-up picture of mite on the right)

Just in this one beetle that happened to fly across the trail, we can find death, birth, cooperation, and co-evolution.  Nature is always full of surprises and there is always more to learn, even from the tiniest of creatures.

Text and Burying Beetle photo by Larry Clarfeld


  1. So cool. I found fungus beetles this summer, also covered in mites --

  2. Nice post! Bernd Heinrich's latest book, Life Everlasting, has some excellent descriptions of his experiments with these guys. Always enjoy your work Larry. Thanks.