Other Common Names
Red-legged Ham Beetle, Copra Beetle (N. rufipes)
Red-necked Necrobia (N. ruficollis)
Blue Corynetes (N. violacea)
Numbers
3 species in North America (
nearctica.com)
Identification
Adult: superficial resemblance to dermestid beetles (N. ruficollis and N. violacea were originally placed in the genus Dermestes); antennae clubbed or expanded distally, with 9th and 10th segments narrowly transverse; elytra and pronotum metallic greenish, bluish, or blackish with or without colored markings
N. rufipes: head, thorax, elytra shiny metallic bluish-green; underside of abdomen dark blue; legs bright reddish-brown or orange; antennae mainly reddish-brown but with dark brown or black club at tip; sides of thorax and elytra with stiff bristle-like hairs
N. violacea: similar to rufipes but antennae and legs entirely dark
N. ruficollis: legs, pronotum, and base of elytra red or reddish-brown; remainder of elytra bluish; head and antennae entirely dark
Larva: body creamy-gray with mottled violet-gray markings on upper surface; head and upper surface of first thoracic segment and last (ninth) abdominal segment with brown hardened plates; 2nd and 3rd thoracic segments also with tiny brownish plates; plate on last abdominal segment with two horn-like protuberances which curve strongly upwards
Range
cosmopolitan (except Antarctica)
in North America - from Alaska to Newfoundland, south to Mexico
Habitat
found on dried fish, skins and bones of dead animals, and other carrion; also found on museum specimens
Season
summer in the far north; most of the year in the south; year-round indoors; optimum temperature for development indoors is in the range 30-34°C, and the minimum temperature is 22°C
Food
adults feed on the surface of dried fish, skins and bones of dead animals, and museum specimens
larvae feed on the same material as adults, plus they prey on larvae of some flies, and on eggs and larvae of Dermestes spp. beetles
Life Cycle
Eggs are laid on the food material; larvae pass through three or four instars; the last instar spins a cocoon in which pupation occurs; life-cycle takes 6 weeks or longer depending on food type and physical conditions. Under optimum conditions, the rate of population increase is about 25 times per month. The adults fly actively and can thus easily disperse to new sources of food.
Remarks
considered a pest in museums containing specimens of vertebrate animals, as well as in places where dried fish is stored
Internet References
live adult image of
N. rufipes (Finland)
preserved adult image of
N. rufipes (Kasetsart U., Bangkok, Thailand)
preserved adult image of
N. ruficollis (CSIRO, Australia)
preserved adult image of
N. ruficollis (Galician Entomological Association, Spain)
preserved adult images of
N. rufipes, violacea plus description, habitat, food, distribution (A Guide to the Cleridae of Atlantic Canada)
drawings of adults of
N. violacea, ruficollis, plus common name references [Blue Corynetes, Red-necked Necrobia] (L. Watson and M.J. Dallwitz, British Insects: the Families of Coleoptera, UK)
drawings of adult and larva of
N. rufipes, plus common name references [Copra Beetle, Red-legged Ham Beetle], description, biology, damage to fish (Food and Agriculture Organization of the United Nations)
distribution in Canada and Alaska; PDF doc (Cleridae; Checklist of Beetles of Canada and Alaska)
