Monday, September 24, 2018

Hide Beetle

Hide beetles in the family Trogidae are unusual looking beetles with warty bodies covered in dried mud. They are brown, black or grayish-brown in color with a flat abdomen. They are related to scarabs and are often mistaken for one. There seems to be much debate among scientists as to whether they should be classified in their own family or as a subfamily of Scarabaediae. Apparently the confusion has something to do with the eye structure. Ommatidium of the eye are the structures that act like lenses and are made up of photoreceptor cells. The more ommatidium an insect or arthropod has, the more advanced it is considered to be. For instance isopods may only have a half dozen ommatidium, whereas dragonflies have  30,000 or more. Hide beetles differ enough in their eye structure from Scarabaeidae that many feel they warrant their own family.

More than 300 species make up the Trogidae family and they are found Worldwide with more living in drier or temperate climates than in moist or wet climates. They are a relatively small family of beetles and very little is known about them. Many species live solely in mammal burrows or birds nests and have not been studied adequately. These nest dwellers feed on feathers, fur, skin and feces. Typically they will be the last beetles to show up at a carcass to feed on feathers, fur and skin....the things other carrion feeders tend to ignore. The only exception seems to be if the dead body has been burned, then these beetles are the first to arrive. They will eat the charred outside of the unfortunate victim, leaving the softer, fleshy parts for other carrion feeders to consume.

Mating takes place near a piece of carrion, the female will dig a burrow underneath the carcass to act as a nursery. After laying eggs within the burrow she moves on and the newly hatched larvae will have a ready food supply in the form of bits and pieces of dried skin, feathers, fur or other tidbits they can scavenge. Typically it takes them 4 or 5 molts (instars) to reach adulthood, and will measure up to 20 mm (1 inch) when fully grown.

Sometimes these beetles are referred to as Skin Beetles, but this description is usually used for Dermestid beetles. Although, just like dermestid beetles, many museums will use hide beetles to clean specimens of fur, feathers and skin to ready them for displays or education props.

The one pictured here was found in late spring at a mercury vapor light I had out to attract insects. Over the course of several nights I found numerous hide beetles, their dirt covered bodies hiding among the vegetation. They are relatively difficult to see and when they've been disturbed, or discovered they will sit completely motionless, feigning death. Pretty good ruse if you have a hungry predator after you. Don't move and don't be seen.

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