# Obscure darkling beetle (Eleodes obscura) > A common, flightless black darkling beetle of western and central North America that feeds on decaying plant material and can release a defensive odor when handled. Source: https://insectscanner.com/species/obscure-darkling-beetle/ (updated 2026-10-10) ## Is it dangerous? **Non-toxic.** Not venomous and do not bite as a normal defense. They can emit a strong, unpleasant-smelling defensive secretion that can irritate eyes or skin in sensitive individuals; avoid handling and wash skin if contacted. **Pets:** Generally harmless to pets. The odor may deter animals; ingestion of many beetles could cause mild stomach upset but serious poisoning is unlikely. ## Quick facts - Scientific name: Eleodes obscura - Also called: Pinacate beetle, Stink beetle - Order: Coleoptera (Beetles) - Family: Tenebrionidae (Darkling beetles) - Size: About 20-35 mm long (one of the larger Eleodes species) - Colours: Black, Very dark brown, Matte charcoal - Habitat: Dry open areas, grassland, scrub, agricultural margins, under rocks, logs, leaf litter and sometimes inside garages or buildings. - Range: Western North America, especially the Great Plains, Rocky Mountain region and the Southwest of the United States. - Active: Spring to fall; mainly nocturnal but sometimes active in cool daylight. - Lifespan: Adults live months to a few years depending on climate and food availability (typical for Tenebrionidae). - Effect on plants: Detritivore - Pest: no ## Overview Eleodes obscura is a medium-sized darkling beetle (family Tenebrionidae) often seen walking on soil, under rocks or in leaf litter. It is primarily a detritivore, feeding on decaying plant material, seeds and fungi. Adults are flightless and typically active at night or during cool parts of the day. When threatened they commonly raise their abdomen and may release a strong-smelling defensive secretion that deters predators. They are widespread and not dangerous to people, though they occasionally wander into garages and basements. ## How to identify it Adults are elongate, robust and somewhat flattened, uniformly dark (black to very dark brown). The pronotum (area just behind the head) is distinct and the elytra (hardened wing covers) are finely ridged or punctate and cover the abdomen completely. Legs are relatively short and adapted for walking; wings are absent or nonfunctional, so adults cannot fly. When disturbed many hold their abdomen up in a characteristic 'head-down, rear-up' posture before producing an odor. - Uniformly very dark (black to very dark brown), elongate and robust beetle about 20-35 mm long. - Elytra with fine longitudinal ridging or punctures and pronotum distinct from head; no obvious bright markings. - Flightless: wings absent or nonfunctional and beetle walks rather than flies. - When threatened often lifts the rear end and may emit a strong, unpleasant odor. ## Lookalikes - **Other pinacate / Eleodes darkling beetles** (Eleodes spp.): Many Eleodes species look similar (black, elongate). Identification to species often requires examination of subtle body shape differences or the beetle's sculpture under magnification; geographic range and size help narrow options. ## Life cycle - **Egg:** Laid in soil or hidden detritus; small and white. Development time varies with temperature and moisture. - **Larva (mealworm-like):** Soft-bodied, elongated larvae that feed on decaying organic matter in soil; look like traditional mealworms (tenebrionid larvae). - **Pupa:** Pupation occurs in the soil; the pupal stage lasts days to weeks depending on conditions. - **Adult:** Wingless or flightless beetle that forages on the surface at night and reproduces to continue the cycle. ## Diet and predators - Young eat: Decaying plant material, detritus, fungi and organic matter in soil. - Adults eat: Detritus, dead plant material, fungi and seeds. - Predators of the young: Ground-dwelling predators such as beetles, ants, spiders, small mammals and birds. - Predators of adults: Birds, small mammals, lizards and predatory insects; the defensive scent reduces predation by many animals. ## Effect on plants and gardens Adults feed mainly on decaying plant material, seeds and fungi. Eleodes larvae (false wireworms) live in soil and can occasionally damage germinating seeds and seedlings in dryland crops. ## Where and when to find it Search under stones, logs, leaf litter, at the edges of fields, in gardens and around foundations. Larvae are in soil and decaying material. - Best time: Spring to fall; mainly at night or during cool cloudy days. - Tips: Photograph from above to show body shape and elytra texture. Use a low-angle light at night to spot moving individuals. Do not handle directly to avoid the defensive odor. ## Fun facts - Many Eleodes species are called 'pinacate' or 'stink beetles' because of the defensive odor they produce. - Their characteristic head-down, rear-up posture is a warning display that often prevents predators from attacking. - Darkling beetle larvae (mealworms) are widely used as feeder insects and in research, though not all species are the same as the common mealworm (Tenebrio). ## Frequently asked questions ### Do obscure darkling beetles bite? No. They are not known to bite people; their main defense is a smelly chemical release, not biting or stinging. ### Do Eleodes obscura stink? Yes. When handled or threatened they can release a strong-smelling defensive secretion that many people find unpleasant. ### Why is this beetle in my house? They usually wander in by accident from nearby yards and fields, seeking shelter in cool, dark places like garages and basements. They do not infest homes. ### Are they dangerous to my family or pets? No serious risk. The secretion can irritate skin or eyes in sensitive individuals or pets, so avoid handling and wash affected areas. ### How do I get rid of them? Seal entry points, remove debris and food sources, store dry food in sealed containers, reduce outdoor lighting at night, and sweep or vacuum beetles found indoors. For large infestations in stored products follow integrated pest management steps or consult a pest professional. --- More about this species: [iNaturalist](https://www.inaturalist.org/taxa/790491), [Wikipedia](https://en.wikipedia.org/wiki/Eleodes_obscura). Identify insects and spiders from a photo with the Insect Scanner iPhone app: https://apps.apple.com/app/id1543946563?pt=126685406&ct=web-markdown&mt=8 Identification from photos is never certain: don't handle insects you can't identify, and get medical advice for bites, stings or allergic reactions.