Euoniticellus intermedius

Beneficial

Common name(s)

intermediate sandy dung beetle

Taxonomy

Family: Scarabaeidae Subfamily: Scarabaeinae Genus: Euoniticellus Species: Euoniticellus intermedius (Reiche, 1849)

Adult diagnosis

Total body length 6.5–9.5 cm (0.26–0.37 in). Body oblong, somewhat dorsoventrally compressed; make be caked in dung. Color tan to grayish-brown with dark brown markings. Clypeus of male with distinct anterior ridge; female lacking ridge. Frontoclypeal suture of female quadrate, male suture indistinct. Frons of male with peg-like horn; female lacking horn. Canthus quadrately produced. Pronotum of male somewhat hump-like when viewed laterally. Tibia of female robust; male tibia comparatively gracile.

Larval diagnosis

(Blume, 1984): Grub C-shaped, hump-backed, cylindrical, and cream-colored. Maxilla with galea and lacinia distinctly separate. Lacinia with uncus lacking proximal teeth. Frons with both sides bearing single posterior frontal seta. Chaetoparia composed of 12 or 13 setae. Tormae symmetrical. Mesophoba monostichous. Haptolachus with 4 macrosensillae at center. Mandible with 2 lateral setae; left mandible with 3 scissorial teeth, right mandible with 2 scissorial teeth. Maxillary stridulatory area with 11 or 12 anteriorly pointing teeth. Glossa with transverse row of setae anterior to the oncyli. Legs 2-segmented; with terminal papilla bearing a single seta. Prothoracic shield lacking anterior projections. Raster with tenth sternum bearing a central undivided patch of short, stout setae.

Native range

Africa and Arabia. This species is native to Africa from South Africa north to the Sahel. It is also known from the Arabian peninsula (Tyndale-Biscoe, 1990). In the mainland U.S., this species was intentionally released in California, Texas, and Florida (Wood and Kaufman, 2008). It was also released in Australia (Tyndale-Biscoe, 1990).

Plant host(s)

None. Euoniticellus spp. feed on dung as both adults and larvae (Hull et al., 2013).

Life history

Adults are found in variety of moist and semi-arid habitat types (Edwards, 2007), although they show some preference for open areas with clay-loam soils (Blume, 1984). Adults are diurnal with flight activity peaking between 2–5 pm. Adults are readily attracted to cattle dung but avoid pig feces (Blume, 1984). Working together, a male and female dig a 7–15 cm (2.7–5.9 in) deep burrow beneath a dung source. Dung is used to line the burrow and create a 3.0–3.5 gram brood ball. The brood ball is created at the end of the burrow and impregnated with a single egg. Multiple brood masses, each with its own egg, can occupy the same burrow. The number of masses is dependent upon food availability, soil moisture, and temperature. Development from egg to adult takes five or six weeks. Adults live up to two months (Hull et al., 2013).

Pest potential

None. This species recycles dung and is beneficial for ranching and farming in Hawaii. Being a dung feeder, this species poses no threat to crop or ornamental plants. Additionally, this species is not a threat to native dung beetles because none are known from Hawaii or Guam.

Status in Hawaii

Established. This dung beetle was intentionally released in 1974 at Parker Ranch on Big Island to help control populations of the horn fly (Haematobia irritans), a biting pest of livestock (Nakao and Funasaki, 1976).

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 introduced.

Similar species

Euoniticellus intermedius is one of two Euoniticellus species known from Hawaii, the other recorded species being the very similar Euoniticellus africanus. The two scarabs can be separated by examination of the frons (E. intermedius male with horn on the frons versus E. africanus male lacking a horn, instead with a v-shaped ridge) and frontoclypeal suture (E. intermedius female with suture quadrate and male suture indistinct versus E. africanus female suture triangulate and male suture crescent shaped).

Other names (synonyms)

Oniticellus intermedius Reiche, Euoniticellus clavatus Roth, Euoniticellus nasicornis Peringuey, Euoniticellus pallens Laporte (Comte de Castelau), Euoniticellus speciosus Costa

Report your observation

Report your observation of this beneficial species at our iNaturalist project.

Euoniticellus intermedius male; photo by E.L. Engasser

Euoniticellus intermedius male; photo by E.L. Engasser

Euoniticellus intermedius male; photo by E.L. Engasser

Euoniticellus intermedius male; photo by E.L. Engasser

Euoniticellus intermedius male; photo by E.L. Engasser

Euoniticellus intermedius male; photo by E.L. Engasser

Euoniticellus intermedius male; photo by E.L. Engasser

Euoniticellus intermedius male; photo by E.L. Engasser

Euoniticellus intermedius female; photo by E.L. Engasser

Euoniticellus intermedius female; photo by E.L. Engasser

Euoniticellus intermedius female; photo by E.L. Engasser

Euoniticellus intermedius female; photo by E.L. Engasser

Euoniticellus intermedius male genitalia, lateral view; photo by E.L. Engasser

Euoniticellus intermedius male genitalia, lateral view; photo by E.L. Engasser

distribution map for Euoniticellus intermedius

distribution map for Euoniticellus intermedius