Cremastocheilus puncticollis

Distinguished from other Cremastocheilus species by specific punctation patterns on the pronotum (collar region), as indicated by the species epithet "puncticollis" (spotted/punctured neck). The combination of small size (~10 mm), flattened angular body, dull black coloration with pitted exoskeleton, and pronotal trichomes separates this genus from other scarab beetles. Species-level identification requires examination of punctation density and pattern on the pronotum. Distinguished from Epicauta puncticollis (a blister beetle) by family-level characters: Cremastocheilus has lamellate (plate-like) antennal clubs and lacks the soft, flexible elytra characteristic of Meloidae.

Associated with ant nest mounds, particularly those of mound-building Formica species (thatching ants). Found in areas with well-drained soils where host ants construct above-ground nest mounds incorporating vegetation. Habitats include open woodlands, grasslands, and desert edge environments in the southwestern United States where host ant species are abundant.

Southwestern United States: Arizona and California. Records indicate presence in Nearctic desert and semi-arid regions where suitable host ant populations occur.

Adults most commonly encountered during spring dispersal period when they fly to locate new host colonies. New adults emerge from pupal cells in late summer or fall, then migrate to ant nest centers where they remain dormant through winter. Active feeding on ant brood occurs primarily in spring.

Adults are specialized predators of ant larvae and pupae. Larvae feed on decaying vegetation that ants have composted within their nest mounds.

• Formica - predatorprimary host; mound-building thatching ants
• Myrmecocystus - predatorhoneypot ants
• Lasius - predatorcornfield ants
• Camponotus - predatorcarpenter ants
• Pogonomyrmex - predatorharvester ants
• Veromessor - predatorharvester ants
• Aphaenogaster - predatorspine-waisted ants

Females lay eggs singly in soil around ant nest mound periphery. Larvae pass through three instars, feeding on composted vegetation within the ant nest. Pupation occurs in oval chambers constructed from soil particles. Development from egg to adult requires approximately four months. Adults emerge in late summer or fall, migrate to nest center to acquire colony scent, and remain dormant through winter. Spring brings active feeding on ant brood.

Adults employ death-feigning (thanatosis) to gain entry to ant nests: they remain motionless with legs outstretched in areas trafficked by worker ants, which carry the apparent carcass into the nest. Once inside, adults accumulate colony-specific chemical cues during slow movement toward the nest center, rendering them chemically camouflaged. Adults are capable of rapid, sustained flight for dispersal but crash-land in areas frequented by scouting ants. Larvae defend against ant attack by striking with mandibles and secreting repellent compounds from mandibular and anal glands.

Specialized predator within ant colonies, exerting top-down pressure on brood populations of host species. Larval stages contribute to decomposition processes by consuming composted vegetation in ant mounds. As a myrmecophile, represents an evolutionary example of exploitation of socially complex insect societies.

No direct economic significance. Occasionally encountered by entomologists and naturalists investigating ant colonies. Provides research interest as a model for studying myrmecophily, chemical camouflage, and behavioral adaptations for social insect exploitation. Not considered a pest species.

• Epicauta puncticollisSimilar species epithet but belongs to family Meloidae (blister beetles), not Scarabaeidae. Distinguished by soft, flexible elytra, thread-like antennae without lamellate clubs, and different body form. Not myrmecophilous.
• Other Cremastocheilus speciesApproximately 35 North American species, many requiring examination of pronotal punctation patterns, body proportions, and male genitalia for definitive identification. C. puncticollis specifically characterized by punctate pronotum.
• Other Cetoniinae scarabsNon-myrmecophilous flower chafers and fruit beetles lack the flattened angular body form, pronotal trichomes, and specialized mouthpart modifications of Cremastocheilus.

• myrmecophile
• predator
• scarab beetle
• ant associate
• death-feigning
• thanatosis
• desert fauna
• specialized predator

• BugGuide
• GBIF taxonomy match
• iNaturalist taxon
• Meloidae Holdings | Entomology Research Museum
• Bug Eric: Anteater Scarab Beetles
• Ants invade Beetles in the Bush! | Beetles In The Bush