Oniticellus cinctus

Beneficial

Common name(s)

bordered dung beetle

Taxonomy

Family: Scarabaeidae Subfamily: Scarabaeinae Genus: Oniticellus Species: Oniticellus cinctus (Fabricius, 1775)

Adult diagnosis

Total body length 9.0–13.0 cm (0.35–0.51 in). Body ovate, oblong, somewhat dorsoventrally compressed; make be caked in dung. Color shiny black; outer margins of elytra bordered with tan. Head smooth, lacking distinct transverse ridge or horn in both sexes. Pronotum with distinct, impressed, medio-longitudinal line at posterior margin; anterior margin smooth, lacking excisions or tubercles. Front tibia of male gracile, apex with inner spur; female tibia more robust, apex with a broad, downward curving, inner tooth (spur lacking).

Larval diagnosis

Undescribed in English. For Oniticellus spp. (Ritcher, 1966): Grub C-shaped, with projecting hump, cylindrical, whitish. Maxilla with galea and lacinia distinctly separated. Epipharynx with tormae united mesally, anterior phoba present. Antennae with 4 segments; distal segment of antenna much reduced in size. Legs 2-segmented. Prothoracic shield without anteriorly projecting processes. Third abdominal segment without a prominent, conical, dorsal gibbosity. Venter of last abdominal segment with 2 patches of short, spine-like setae.

Native range

Tropical Asia. This species is found across a broad area of southern and eastern Asia with records from Burma, southern China, India, Indonesia, Malaysia, Thailand, and Vietnam (Karimbumkara, 2013).

Plant host(s)

None. This species feeds on dung as both adult and larva (Klemperer, 1983).

Life history

(Klemperer, 1983): Adults of this diurnal scarab are active throughout the year (Venugopal et al., 2012), and may show some preference for forested habitat. Females create a brood chamber within a dung pat and create brood balls from the surrounding feces. An egg is implanted within each brood ball, with approximately 20 brood balls created in total. While the larvae grow and feed within the dung balls, the maternal female remains in the brood chamber and continues to apply dung to the surface of the ball. She will drive other female dung beetles from her chamber (though males may be tolerated) and will kill larvae of other dung beetle species. As the larvae develop, their brood balls become both more hollowed and more dry. By the time pupation occurs, the brood ball is a dry, hollow chamber. The maternal female remains in the brood chamber until the larvae emerge as adults.

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. There is conflicting information regarding the arrival of this species to Hawaii. Markin and Yoshioka (1998) reported that this species was intentionally introduced to Big Island in 1956 and Oahu in 1957-1958 to help control populations of the horn fly (Haematobia irritans), a biting pest of livestock. However, it has also been reported that specimens collected on Oahu in 1965 represent the first record of this species in Hawaii (Hawaiian Entomological Society, 1967), and that the species is adventive to the state (Harris et al., 1982). It does appear that this beetle is established on both islands, though it is rare on Oahu (Toyama and Ikeda, 1976).

Status in Guam

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

Potential distribution and dispersal pathway

It is unclear how this species arrived to Hawaii. It was probably intentionally introduced. It is possible that adults or larvae were transported on farm or ranching supplies or in natural, manure-based fertilizers.

Similar species

Oniticellus cinctus is one of two Oniticellus species known from Hawaii, the other being Oniticellus militaris. These two scarabs are separated by examining the head armature (O. cinctus lacking horns or distinct ridges in both males and females versus O. militaris with a short horn in males and a transverse ridge in females), elytral color (O. cinctus with elytra black bordered with tan versus O. militaris which is dark brown with broken, tan stripes), and the form of the pronotum (O. cinctus lacking sinuate excisions versus anterior margin with sinuate excisions in O. militaris).

Other names (synonyms)

Oniticellus diadema Wiedemann, Oniticellus serratipes Drury, Scarabaeus cinctus Fabricius

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Oniticellus cinctus; photo by E.L. Engasser

Oniticellus cinctus; photo by E.L. Engasser

Oniticellus cinctus; photo by E.L. Engasser

Oniticellus cinctus; photo by E.L. Engasser

Oniticellus cinctus male foretibia; photo by E.L. Engasser

Oniticellus cinctus male foretibia; photo by E.L. Engasser

Oniticellus cinctus female foretibia; photo by E.L. Engasser

Oniticellus cinctus female foretibia; photo by E.L. Engasser

Oniticellus cinctus male genitalia, caudal view; photo by E.L. Engasser

Oniticellus cinctus male genitalia, caudal view; photo by E.L. Engasser

Oniticellus cinctus male genitalia, lateral view; photo by E.L. Engasser

Oniticellus cinctus male genitalia, lateral view; photo by E.L. Engasser

distribution map for Oniticellus cinctus

distribution map for Oniticellus cinctus