Things would be one smelly mess around forest and field without the undertakers. Turkey vultures start the process of cleaning up larger dead animals, then the coyotes get their share, followed by weasels, mice and even our favorite campground pests, golden mantle ground squirrels. Anything smaller or left over is usually taken care of by the little-known burying beetles, aka undertaker beetles, and they are true to their name whether it be a stinky shrew, frog or a dead sparrow. If it smells bad, it's just what they're looking for.
The role of antennae on insects can never be overstated - their function is remarkable. In the case of the burying beetle, the antennae detect the beetle's gory glop. No one needs to tell you that dead animals stink, and it's that rich odor drifting through the sensitive nerve endings of the beetle's antennae that gets the insect's attention. A dead mouse or bird even a half mile away will attract a burying beetle. There is only one place a mother-to-be undertaker beetle can lay its eggs and hope for them to hatch and that's beneath the body of a dead animal.
Here's how it works: A mouse dies and then begins to decay. The biology of decay starts a process of degeneration of tissues that in turn produces methane gases. Those gases drift downwind in the breeze, and the poppa-to-be burying beetle sniffs it with his incredible antenna loaded with chemoreceptors and away he goes, right to the source.
The first thing daddy-to-be does is release a special scent (pheromones) from his abdomen, a perfume that gets a female burying beetle's attention. To her it shouts, "Yoo-hoo! Here I am!"
If two males arrive at the macabre site at the same time, a battle breaks out. When females arrive, they, in turn, fight other females. Usually it's the more robust pair that comes out on top. Actually the phrase, "comes out on the bottom," might prove more accurate in this case as that's where all the action is.
As soon as the winning pair has run off the competitors, they bury the body as quickly as possible, not completely, but deep enough to cut off the odor of decay from drifting away and attracting potential competition. Once the animal is in the ground, the prospective parents begin to dig a hole beneath the corpse. If a female cannot find a male, and has mated previously, she doesn't need him as she is capable of fertilizing the new batch of eggs with sperm she's stored for that "just in case" moment.
Both beetles cover the corpse with antibacterial and anti-fungal secretions issued from the mouth and anus. These chemicals slow down decomposition and also hide the scent from other beetles. (DuPont once had a slogan: "America is a better America though chemistry." If you substitute "nature" for "America" and add "organic," it's still a true statement.) Then the parents build a crypt, a chore that can take up to eight hours.
The females then lay their eggs around the wall of the crypt, the larvae hatch in a matter of days and then the orgy begins. Even though the larvae are capable of eating on the ball of decaying flesh on their own, mom and pop beetle help them by regurgitating food to speed up the growing process.
If you think this is the action of "loving parents," forget it. Mom or dad will take up the practice of infanticide to match the number of babies with the balance of food left to raise them to the pupating stage. However, the parents also stand guard over the surviving larvae, protecting them from ants, parasites, the grubs of bluebottle flies and other adult burying beetles.
It might be safe to say the parents heave a great sigh of relief when their pudgy white larvae crawl off into the soil and metamorphose into adult beetles.
I don't know about you, but if I had it to do all over again, I'd observe insects for a living. I'd never get bored.
