Dermestid Beetle


ORDER: Coleoptera

FAMILY: Dermestidae

GENUS: Dermestes

SPECIES: marmoratus

DESCRIPTION:
This is the largest dermestid in California with a length of 9 to 14 mm. Adult has an slightly flattened elongate oval carapace. It is black with gray scales forming spots and a broad band across the base of the wing covers. The underside is mostly whitish. Larvae are elongate and reddish brown with a pale stripe down the back. They are covered with long reddish brown hairs.

GEOGRAPHICAL RANGE AND HABITAT:
Throughout California at low to middle elevations. Found elsewhere in North America as well.

DIET:
Carrion.

LIFE CYCLE/SOCIAL STRUCTURE:
Beetles lay eggs which produce larvae quite different in form from the adult. When full-size, such larvae undergo a further change of form to become a pupa which is inert and does not feed. The pupa undergoes metamorphosis and emerges as the adult. Adult female insects emerge from the pupa with a full complement of eggs retained in the ovaries. Sperm introduced by the male is stored and released as the eggs pass out through the ovipositor. This beetle's eggs are usually deposited in carrion.

SPECIAL ADAPTATIONS:
The hair of the larvae break off readily and cause irritation of tender skin (e.g. in a bird's mouth), thus acting as a defense mechanism. Coleoptera means sheathed wing. Beetles have their forewings strengthened and chitinized as protective covers for the operative under pair.

INTERPRETIVE INFORMATION:
Also known as Common Carrion Beetles since they are found around animal carcasses in the later stages of decomposition. It is thought they were introduced into California by hide traders in the early days. Beetles of the Dermestidae family feed on a great many things such as cereal products, grains, rugs and carpets, various stored foods, upholstery, fur coats, etc. and thus most are considered destructive pests. Some dermestids are harmful in museums since they may feed on mounted birds or mammals and specimens of plants and insects while other dermestids are employed by museums to clean skeletons for exhibits. Beetles typify the success of insects. This order contains not only the most numerous species (over 330,000 worldwide) of the insects, but also of the animal kingdom.

OUR ANIMALS:
Several in the Children's Zoo.

STATUS IN WILD:
Not endangered.

BIBLIOGRAPHY:

  1. Internet: umich.edu/mammals/dermestid.html
  2. Borror, Donald and Richard White. Field Guide to the Insects. 1970
  3. Powell, Jerry & Charles Hogue. California Insects. 1979. Univ.of California Press.
  4. Wootton, Anthony. Insects of the World. 1984. Facts on File Publications, New York, NY. CL:05

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