Wild Thing: Parenting, Beetle Style
Burying beetles go to horrifying lengths to make their own baby food.
By Ben Hutchins
When we think of devoted animal parents, our thoughts usually go to mammals like elephants, bravely guarding their young in the center of the herd, or birds like emperor penguins, stoically incubating eggs through the Antarctic winter.
However, a number of invertebrates engage in spectacular feats of parental care, though the care rarely takes the shape of a cuddly cub curled up next to a loving mom.
The American burying beetle, Nicrophorus americanus, goes to great lengths to provide for its young, and it does so in an interesting, albeit unsavory fashion. (A warning to the weak-stomached: This article gets into the gooey details of carrion consumption.)
Together, a new beetle couple constructs a nursery by excavating a small chamber for a bird or small mammal carcass. The beetles cover the carcass with several inches of soil. A small cavity around the carcass is maintained by the parents, giving them room to work. The parents use their powerful jaws to strip fur or feathers and skin from the carcass before working it into a compact ball of meat. To prevent mold from ruining the carcass, the beetles coat the carcass in oral and anal secretions.
Once the eggs hatch in a chamber above the carcass, both mom and dad continue to provide care for the young throughout their development. Both parents regurgitate partly digested carrion into a cavity dug into the top of the carrion ball. This serves as a kind of baby food on which the larvae feed. Like birds, the adults regurgitate directly into a begging larva’s mouth when prompted. As the larvae grow, they begin to feed directly on the carrion ball.
Throughout larval growth, ever-vigilant parents maintain the carrion ball and groom their nursery, removing mold, flies and even intruding burying beetles. When only bones are left on the carcass, the larvae are ready to leave the nursery. The parents dig out and fly off like empty-nesters on vacation while the larvae dig into the surrounding soil to pupate and emerge about a month later.
A number of burying beetle species are involved in parental care like that described above. The American burying beetle, however, is unique. It is the largest of the carrion beetles, reaching lengths up to 1.5 inches, and also the rarest. For reasons not entirely clear, the species’s range, which once spanned most of the eastern U.S., has been reduced to noncontiguous patches in Nebraska, Oklahoma, Arkansas and Rhode Island. The drastic decline may be the result of changes in land use or a reduction in bird or mammal populations that serve as an adequate food source, but no one knows for sure. The species was listed as endangered by the U.S. Fish and Wildlife Service in 1989.
In the mid-2000s, American burying beetles were discovered in Lamar and Red River counties in Northeast Texas. However, subsequent attempts to relocate individuals have failed, and the species’s persistence in Texas is uncertain.
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Common Name: American burying beetle Scientific Name:Nicrophorus americanus Habitat:Grassland, scrubland, forest edges Diet:Small mammal and bird carcasses Did You Know? The odor of a fresh carcass attracts a male burying beetle, which then attracts a female beetle with pheromones, announcing the newly found assets that he’d like to share with a female. |
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