Family: Scarabaeidae Subfamily: Scarabaeinae Genus: Onthophagus Species: Onthophagus tuberculifrons Harold, 1873
Total body length 3.5–5.0 mm (0.13–0.20 in). Body shape oval; may be caked in dung. Color dull black, sometimes with orange spots on abdomen. Size tiny, under 6 mm. Sexes noticeably dimorphic. Clypeal apex broadly emarginate in male; bifurcate in female. Head with 2 weak tubercles in both sexes. Ocular canthus not completely dividing eye. Scutellum absent.
(Brach, 1977): Grub C-shaped, hump-backed, cylindrical, and cream-colored. Maxilla with galea and lacinia distinctly separate. Mandible maxillary stridulatory area with a row of 5–7 short, conical teeth. Epicranial stem deeply forked basally on frons. Epipharynx with tormae united mesally. Epipharyngeal phoba with teeth small and conical. Antennae 4-segmented, distal segment much reduced. Legs 2-segmented. Prothoracic shield without anteriorly projecting processes. Third abdominal segment bearing a prominent conical, dorsal gibbosity with two patches of 45–52 weakly curved to straight, finely-pointed setae. Venter of last abdominal segment with two sparsely-set, irregular patches of 30–39 caudally oriented setae.
Eastern U.S. This species is native to the U.S. where it is found from eastern Texas and Kansas north to Wisconsin and eastward to Connecticut and southern Florida (Woodruff, 1973).
(Woodruff, 1973): This species is often associated with sandy habitats where adults feed on dung, rotting vegetation, carrion, and fungus. In South Carolina, adults are active throughout the year (Bertone, 2004). Life history is poorly known, but related Onthophagus species are dung tunnelers, and females create burrows under or near a dung source. The burrow is then provisioned with dung in the form of brood balls. Each ball is impregnated with an egg; larval development occurs within the brood ball.
None. This species recycles dung and is beneficial for ranching and farming in Hawaii. Primarily being a dung feeder, this species has never been recorded damaging crop or ornamental plants. Additionally, this species is not a threat to native dung beetles because none occur in Hawaii or Guam.
Established. In Hawaii, this species was imported to combat the horn fly (Haematobia irritans), a biting pest of livestock. Specimens were released in 1963 at Ewa and Kailua on Oahu (Davis and Krauss, 1964).
Not established or recorded. There are no records of this species from Guam.
In Hawaii, this species was intentionally imported.
This tiny scarab is extremely similar to the closely related Onthophagus oklahomensis and superficially similar to small specimens of Leconte's dung beetle (Ateuchus lecontei). These three species are separated by examining the clypeal apex (O. tuberculifrons with an emarginate or bidentate clypeus versus O. oklahomensis with an entirely rounded clypeus) and tubercles of the head (O. tuberculifrons with paired tubercles versus O. oklahomensis and A. lecontei lacking tubercles).
Onthophagus tuberculifrons Sturm (nomen nudum), Onthophagus tuberculatus Gemminger and Harold (nomen nudum)
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