Onthophagus cuniculus

Beneficial

Common name(s)

none known

Taxonomy

Family: Scarabaeidae Subfamily: Scarabaeinae Genus: Onthophagus Species: Onthophagus cuniculus MacLeay, 1864

Adult diagnosis

Total body length 7.0–12.0 mm (0.28–0.47 in). Body shape oval; may be covered in dung. Color of head and thorax bright metallic red-green; abdomen black. Small to medium-sized dung beetle, over 6 mm. Clypeal apex of major male produced, strongly recurved; minor male and female with apex rounded or feebly sinuate, not strongly recurved. Head of both sexes lacking horns; major male with paired tubercles near base; minor male and female with slightly curved ridge near base. Ocular canthus completely dividing eye. Pronotum of major male with horn-like process; minor male and female with bi-lobed process. Pronotum with anterior angles curved outward in both sexes. Front tibia of male slightly slender and elongate, female tibia somewhat more robust. Scutellum absent.

Larval diagnosis

Undescribed. For Onthophagus spp. (Ritcher, 1966): Grub C-shaped, hump-backed, cylindrical, and cream-colored. Maxilla with galea and lacinia distinctly separate. Epipharynx with tormae united mesally, anterior phoba present. 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 covered with numerous short, stout setae.

Native range

Australia. This species is known from Queensland Australia, where it occurs between the Atherton Tablelands and the Tropic of Capricorn (Matthews, 1972).

Plant host(s)

None. This species feeds on dung as both an adult and larva. There are no records of this beetle feeding on live plant tissues.

Life history

This diurnal species has been found on cattle and human dung, it is also known to feed on carrion (Matthews, 1972). It can be found in savannahs and open woodlands where annual rainfall exceedes 127 cm (50 in). Life history of the species is poorly known, but related Onthophagus species are dung tunnelers, with females creating a burrow under or near dung (Woodruff, 1973). 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.

Pest potential

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.

Status in Hawaii

Recorded, not established. This species was intentionally brought to Hawaii in 1921, though it is unclear if any individuals were released (Hawaii Division of Forestry, 1923). Similar dung beetle introductions were undertaken to help control populations of the horn fly (Haematobia irritans), a biting pest of livestock (Markin and Yoshioka, 1998). If this species was released, it failed to establish populations in the state (Nishida, 2002).

Status in Guam

Not established or recorded. There are no records of this species from Guam.

Potential distribution and dispersal pathway

In Hawaii, this species was intentionally imported.

Similar species

This dung beetle could be confused with similarly colored, small to medium-sized (more than 6 mm) Onthophagus species such as Onthophagus binodis, Onthophagus incensus, Onthophagus laminatus, Onthophagus armatus, and Onthophagus comperei.

Major males of these species can be distinguished by examining the head armature (O. cuniculus has paired tubercles versus O. incensus, O. laminatus, O. armatus, and O. comperei all with head horns versus O. binodis lacking horns).

Females are somewhat more difficult to distinguish, but nonetheless can be separated by examining the base of the head (O. cuniculus with a slightly curved ridge versus O. armatus with a feebly bisinuate ridge and O. comperei with 2 tubercles), pronotal process (O. cuniculus with a bi-lobed process versus O. binodis and O. laminatus with a small lobe-like process versus O. incensus, O. armatus, and O. comperei lacking a pronotal process) and anterior angle of the pronotum (O. cuniculus with anterior angles curved outward versus O. binodis, O. incensus, O. armatus, and O. comperei with anterior angles rounded).

Other names (synonyms)

none known

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Onthophagus cuniculus male; photo by E.L. Engasser

Onthophagus cuniculus male; photo by E.L. Engasser

Onthophagus cuniculus male; photo by E.L. Engasser

Onthophagus cuniculus male; photo by E.L. Engasser

Onthophagus cuniculus male; photo by E.L. Engasser

Onthophagus cuniculus male; photo by E.L. Engasser

Onthophagus cuniculus male; photo by E.L. Engasser

Onthophagus cuniculus male; photo by E.L. Engasser

Onthophagus cuniculus female; photo by E.L. Engasser

Onthophagus cuniculus female; photo by E.L. Engasser

Onthophagus cuniculus female; photo by E.L. Engasser

Onthophagus cuniculus female; photo by E.L. Engasser

Onthophagus cuniculus male genitalia, lateral view; photo by E.L. Engasser

Onthophagus cuniculus male genitalia, lateral view; photo by E.L. Engasser