Carrion Beetles in Grand Canyon
by Sharon Hester
Who knew that sitting on the groover (a river trip’s camp toilet) is one of the best places to observe nature on a river trip? Wildlife is most active during the cool early mornings and late evenings. That’s also often the exact times you might find yourself taking care of business at the quiet “groover” locations a little way from camp. Daytime creatures wake up, and nighttime creatures head home to their hidden places in the morning. Birds sing and flit about, and the white footed mice and ring-tailed cats scurry off to bed at those hours. In the evening, the reverse happens. And opportunities to observe this “changing of the guard” abound when sitting quietly taking care of business.
During these getting back to nature moments, you might find yourself looking at the groover locations “moving views,” enjoying the birds in the trees serenading your efforts, and the lazy lizards, slyly observing you from their favorite rocks. But while sitting there, you might also want to carefully look down and around in this most hallowed, if not odiferous location. Not for the rattlesnakes slithering after those mice, (although it is good to be on the lookout for these shy and rarely observed creatures), but for insects attracted to this stinky location. No, NOT the flies either! But rather be on the lookout for beetles! Carrion beetles to be exact, looking for a nursery for their children.
The groover has a smell shall we say, similar to carrion, and the beetles can pick up this fine chemical scent with their highly specialized antennae from long distances away. You may discover them furiously trying to dig under the metal groover box (or hidden beneath if the box is moved). Normally the male and female work together to bury a carcass, in which to bury safely underground and lay their eggs. They do this surprisingly fast, and to an observer, it may look like the body of a mouse or bird is sinking into a miniature bed of quicksand. Fortunately for you, the groover box is too large for these industrious creatures to bury with you sitting upon it.
These large brightly colored orange and black beetles are not often seen by the average person. This is because carrion beetles are mostly nocturnal, and they do their jobs so well that carcasses are buried quickly. Once buried, in about a week, all that will be left is fur and bones. And carrion beetles are excellent parents! Once the carcass is secure underground, the female lays her eggs, and in a couple of days, they hatch. Together, for the next week, the parents help to feed and defend their newly hatched offspring.
There are two types of carrion beetles you are likely to see at groover locations in Grand Canyon. The colorful blocky orange and black Hairy Burying Carrion Beetles (Nicrophorus guttula and N. mexicanus whose ranges overlap in GCNP), described in this post, as well as the Hairy Rove Carrion Beetle (Creophilus maxilosus) which are slimmer and have black and white stripes. These look a little like a large earwig. Hairy Rove beetles do not bury carcasses, but feed instead on fly maggots on carcasses above ground.
Studies have shown that carrion beetles are also key drivers of soil biology and help to control ecosystem respiration, nutrients, and carbon cycling by controlling soil biology. See more on this here.
So, enjoy watching these important little creatures, while you take care of important business, as they diligently work to keep our beaches, waters, deserts, forests, roads, etc clean and healthy. If they were not out there disposing of the bodies of the deceased, diseases might run rampant, or, at the very least, the world would be a smellier place!