Cremastocheilus
Knoch, 1801
Anteater Scarabs
A of myrmecophilous containing approximately 35-40 described in North America. are specialized of and , living within ant colonies. The genus exhibits remarkable morphological and behavioral for integration with aggressive host ants, including death-feigning to gain nest entry and chemical to avoid .
Pronunciation
How to pronounce Cremastocheilus: /krɛˌmæstoʊˈkaɪləs/
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Identification
Small, flattened approximately 10 mm in length with dull black coloration. Body strongly angular with exceedingly dense, heavily armored bearing pits or wrinkles. normally concealed in grooves beneath the . Hind angle of bears distinctive —brushes of glandular hairs of unknown function. enlarged and shield-like, covering modified adapted into piercing structures for feeding on .
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Habitat
Found within nests of , particularly mound-building Formica (thatching ants). Also associated with honeypot ants (Myrmecocystus), cornfield ants (Lasius), (), (, Veromessor), and -waisted ants (Aphaenogaster). Greatest diversity in desert southwest, but occurs across North America.
Distribution
Nearctic region; North America north of Mexico. Records from Vermont and throughout United States.
Seasonality
disperse to find new in spring. New adults emerge from pupal in late summer or fall, integrate into nest centers during winter dormancy, and begin feeding on ant the following spring.
Diet
feed as on and of . modified into piercing structures to penetrate soft of ant ; reduced, functioning only to transport liquefied food. Larvae feed on decaying vegetation composted by ants within nest periphery.
Host Associations
- Formica - primary mound-building thatching
- Myrmecocystus - honeypot
- Lasius - cornfield
- Camponotus -
- Pogonomyrmex - ; southwestern US
- Veromessor - ; southwestern US
- Aphaenogaster - -waisted ; southwestern US
Life Cycle
Females lay singly in soil around nest periphery. through three , feeding on decaying vegetation, capable of defensive striking with and secreting repulsive liquids from mandibular and glands. occurs in oval chambers constructed from soil particles. Complete cycle from egg to requires approximately four months. Newly emerged adults migrate to nest center, accumulating colony scent for chemical .
Behavior
Employs death-feigning () to gain nest entry: remains motionless with legs outstretched in areas trafficked by , which carry the apparently dead into the nest. fast-moving fliers that crash-land near ant foraging areas. Chemical of facilitates integration and reduces aggression.
Ecological Role
Myrmecophilous ; within colonies. can reach 20-30 individuals per excavated nest, with some nests hosting up to 200 or .
Similar Taxa
- other Scarabaeidaedistinguished by extreme body flattening, antennal grooves, pronotal , and myrmecophilous lifestyle
- other myrmecophilous beetlesseparated by combination of death-feigning entry , modifications for on , and specific associations with mound-building ants