Nebraskaland

36 NEBRASKAland • AUGUST-SEPTEMBER 2015 Story and photos by Eric Fowler S omewhere in Nebraska right now, a beetle is emerging from its natal den, which just happens to be what's left of a dead bird, or maybe a dead baby bunny, buried a few inches under the ground. The beetle's parents located and buried the carcass in June, laying eggs that hatched into larvae that fed on the carcass until it was time to pupate and turn into an adult insect. While it is one of many carrion beetles – insects that feed on nearly anything dead – this one is special. The American burying beetle was the first insect in Nebraska to be listed as an endangered species by the U.S. Fish and Wildlife Service. It has become the poster insect for some who would rather not see pipelines and power lines built in Nebraska. But when the black and orange insect was listed as an endangered species in 1989, we barely knew it still existed in Nebraska. As it turns out, that was because no one had really looked. The listing and some accidental discoveries prompted more searches, and we now know Nebraska may have more of the colorful insect than any of the six states where it can still be found. And thanks to research spawned by pipelines and other projects of the sort, we know more than ever about the American burying beetle. And we're learning more each year, knowledge that will help sustain and even expand populations here and elsewhere. Clean-up Crew The American burying beetle (Nicrophorus americanus) is one of about 570 species of carrion beetles found worldwide, and at 1½ inches long, it is the largest of the 31 found in North America. Nebraska is home to 18. Carrion beetles are part of nature's clean-up crew, which has a roster that includes turkey vultures, raccoons, ants, flies, bacteria and fungi. Using specialized organs on the tips of their antennae, these insects can smell a dead mouse within an hour of death from up to two miles away. Strong fliers, carrion beetles are active in their search, following the scent trail to their prize, and are among the first of the scavengers to arrive. They feed on whatever they find – dead birds, mammals, fish and even other insects – wherever they find it. By doing this they help recycle nutrients into the soil and remove a possible breeding ground for flies that are not only annoying, but also spread diseases, a direct benefit to everyone from cattlemen and their livestock to picnickers. There are two subfamilies of carrion beetles that differ primarily in their breeding habits. Silphinae lay their eggs near a carcass, and when they hatch, beetle larvae feed on fly larvae. The American burying beetle is part of a smaller group called Nicrophorinae that takes a much more unique approach, burying a carcass on which its young will feed. During the breeding season in late- May through June, American burying beetles search for just the right size corpse, preferring dead birds and mammals weighing 3 to 7 ounces. Quail, meadowlarks, 13-lined ground squirrels, pocket gophers, young pheasants and rabbits, and other species, young and old, fit this bill. A male that finds such a carcass will broadcast pheromones to attract a female. If more than one pair is present, a fight ensues that is usually won by the largest individuals. The winning pair works together to remove soil from beneath the carcass, plowing through it like a bulldozer until it is below ground level and then pushing soil over it. If the soil where the animal died is too hard and the prize small enough, the beetles turn on their backs, crawl under it, lift it with their legs and methodically move it to a spot where the soil is softer. They can move a mouse up to six feet. Burying their food reduces the chance they will have to share it with others, be it vertebrates or insects, especially other carrion beetles and flies. Flies quickly lay eggs, which soon hatch into maggots, a direct competitor with beetle larvae. But because flies are active during the day and most burying beetles are diurnal, the nocturnal American burying beetle has the advantage and often wins the race by having the The male and female American burying beetles are easily identified by the orange patch above their jaws: the female's is a triangle and the male's a larger rectangle.

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