Onitis phartopus

Beneficial

Common name(s)

none known

Taxonomy

Family: Scarabaeidae Subfamily: Scarabaeinae Genus: Onitis Species: Onitis phartopus Lansberge, 1875

Adult diagnosis

Total body length 18.0–26.0 cm (0.71–1.02 in). Body shape subquadrate posteriorly; may be caked in dried dung. Color dull black. Clypeus rounded to weakly sinuate. Frons with weak, central tubercle. Front tibia of male elongate, curving ventrally and inward at apex; female tibia less elongate and less curved than male; tarsi lacking in both sexes. Middle leg with tibia of male abruptly expanded to a trapezoidal apex, female tibia less clearly trapezoidal. Hind trochanter with spine on posterior margin in male (lacking in female). Hind femur lacking spine-like process on posterior margin in both sexes.

Larval diagnosis

Undescribed. For Scarabaeinae (Ritcher, 1966): Grub C-shaped and hump-backed, cylindrical, cream-colored. Maxilla with galea and lacinia distinctly separate. Antennae with 4 or 5 apparent segments. Distal segment of antenna much reduced in size. Epipharynx with tormae united mesally, anterior phoba present. Anal opening surrounded by fleshy lobes. Legs 2-segmented.

Native range

Philippines. This species is known from the islands of the Philippines (Fullaway, 1921).

Plant host(s)

None. Onitis spp. feed on dung as both adults and larvae (Edwards and Aschenborn, 1987).

Life history

Poorly known. (Edwards and Aschenborn, 1987): Related species of Onitis burrow under fresh dung and create a vertical tunnel lined with dung. Male and female beetles cooperate to transport dung pieces down the burrow where they are shaped into sausage-like masses. An egg (or eggs) is deposited into each of the dung sausages, and larval development occurs within the brood mass.

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

Recorded, not established. This species was brought to Hawaii for evaluation of its potential for biocontrol of the horn fly (Haematobia irritans), a biting pest of livestock. However, imported specimens failed to thrive and were not released (Fullaway, 1921).

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

Three species of Onitis are recorded from Hawaii (none are known from Guam). Onitis phartopus can be separated from the other Onitis species by examination of the middle tibia (O. phartopus male with an abruptly expanded, trapezoidal apex versus a gradually expanded, triangulate apex in O. alexis and O. vanderkelleni), hind trochanter (with a spine in Onitis phartopus versus O. alexis and O. vanderkelleni that lack a spine), hind femur (O. phartopus lacking femoral spine versus O. alexis and O. vanderkelleni males with spine on the posterior margin), and color (O. phartopus is dull black versus dark greenish with brown elytra in O. alexis).

Other names (synonyms)

Onitis sphinx Illiger

Report your observation

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Onitis phartopus male; photo by E.L. Engasser

Onitis phartopus male; photo by E.L. Engasser

Onitis phartopus male; photo by E.L. Engasser

Onitis phartopus male; photo by E.L. Engasser

Onitis phartopus male foretibia; photo by E.L. Engasser

Onitis phartopus male foretibia; photo by E.L. Engasser

Onitis phartopus male foretibia; photo by E.L. Engasser

Onitis phartopus male foretibia; photo by E.L. Engasser

Onitis phartopus female foretibia; photo by E.L. Engasser

Onitis phartopus female foretibia; photo by E.L. Engasser

Onitis phartopus male hind legs, ventral view; photo by E.L. Engasser

Onitis phartopus male hind legs, ventral view; photo by E.L. Engasser

Onitis phartopus male genitalia, dorsal view; photo by E.L. Engasser

Onitis phartopus male genitalia, dorsal view; photo by E.L. Engasser

Onitis phartopus male genitalia, lateral view; photo by E.L. Engasser

Onitis phartopus male genitalia, lateral view; photo by E.L. Engasser