Necrobia violacea
(Linnaeus, 1758)
blacklegged ham beetle, blue ham beetle, cosmopolitan blue bone beetle, Violet Checkered Beetle
Necrobia violacea is a small clerid , 4–5 mm in length, with uniformly metallic blue-green to green coloration including its legs. The occurs in the Palearctic region and has been introduced to North America. are long-lived and associated with dried animal products, including cured meats, dried fish, aged cheeses, oilseeds, and desiccated carcasses. Larvae are predatory, feeding on other insect larvae found on carrion rather than consuming the carrion directly. The species has limited forensic relevance due to its preference for corpses in advanced decomposition stages.
Pronunciation
How to pronounce Necrobia violacea: /nɛˈkroʊbiə vaɪəˈleɪʃiə/
These audio files are automatically generated. While they are not always 100% accurate, they are a good starting point.
Identification
Distinguished from congeneric by uniformly blue-black legs (vs. red legs in N. rufipes, red pronotum in N. ruficollis). Distinguished from Korynetes violaceus by spindle-shaped (not axe-shaped) terminal maxillary palp segment, more condensed antennal club with larger terminal segment, and pronotum shape (widening in straight line posteriorly with pointed angles vs. evenly curved). The coarser pronotal punctuation and more condensed antennal club also separate it from Korynetes.
Images
Habitat
Found in forest and woodland environments, particularly where carrion remnants occur. Regularly associated with stored food products including dried, cured, or smoked meats, bacon, aged cheeses, dried fish, rawhide, and oilseeds. Occurs on desiccated carcasses and insect- or mite-infested carcasses. In forensic contexts, found on older bodies exposed to elements, typically during ammoniacal decay stage (fourth stage of decomposition).
Distribution
Native to Palearctic region; introduced and established in North America. Present in Europe and northern Asia (excluding China). Specific country records include Austria.
Seasonality
active year-round under warm conditions, with activity in search of food. In Switzerland, imagines observed during fourth stage of body decomposition (ammoniacal decay), corresponding to 5–9 months postmortem. Larval development period estimated at 25–35 days.
Diet
feed on dried animal products including cured meats, aged cheeses, dried fish, oilseeds, and desiccated carcass material. Larvae are predatory, consuming larvae of other insects found on carcasses, particularly Dermestes (skin beetles); laboratory observations confirm feeding inside pupae of Sarcophaga flies. Larvae do not consume carrion directly.
Host Associations
- Dermestes - preyLarvae prey on skin beetle larvae found on carcasses
- Sarcophaga - preyLaboratory confirmed feeding inside fly pupae
Life Cycle
laid on commodity surface. Larvae burrow into substrate material. Larvae possess three pairs of jointed legs, sclerotized and first thoracic segment, soft-skinned marbled , and pincer-shaped urogomph at abdominal apex. occurs within cocoon constructed either in infested commodity or in self-bored tunnel. Development from egg to estimated at 25–35 days under favorable conditions. Adults long-lived and capable of when warm.
Behavior
fly in search of food under warm conditions. Larvae burrow into substrate material and construct cocoons for . When disturbed, adults run rapidly over surfaces. Associated with same food preferences as Piophila casei fly.
Ecological Role
of other insects in carrion and stored product ; contributes to decomposition of dried animal materials. Limited forensic indicator value due to preference for advanced decomposition stages.
Human Relevance
Pest of stored food products, particularly dried and cured meats, cheeses, and oilseeds. Minor pest in museums and taxidermy contexts. Limited utility in due to preference for advanced decomposition; rarely relevant for postmortem interval estimation. Historical significance in entomology: name commemorates discovery of N. ruficollis by Latreille while imprisoned during French Revolution, leading to his recognition and release.
Similar Taxa
- Necrobia rufipesRed legs vs. blue-black legs in N. violacea; both occur on cured meats
- Necrobia ruficollisRed pronotum vs. uniformly blue-green in N. violacea
- Korynetes violaceusSimilar metallic coloration but distinguished by axe-shaped maxillary palp terminal segment, less condensed antennal club, and evenly curved pronotum
More Details
Etymology
name violacea from Latin 'violaceus' meaning violet, referring to blue coloration. name Necrobia from Greek 'nekrós' (dead) and 'bíos' (life/place of residence), indicating association with dead animal matter.
Historical note
The name was established to commemorate Latreille's discovery of N. ruficollis while imprisoned in Bordeaux during the French Revolution; this discovery led to his recognition by a fellow prisoner and subsequent release.