Catharsius molossus

Beneficial

Common name(s)

none known

Taxonomy

Family: Scarabaeidae Subfamily: Scarabaeinae Genus: Catharsius Species: Catharsius molossus (Linnaeus, 1789)

Adult diagnosis

Total body length 25.0–45.0 mm (0.98–1.80 in). Body shape elongate-oval; may be caked with dung. Color dull black. Clypeus broadly rounded. Head of male with clypeal horn; female lacking clypeal horn. Frons lacking horns or tubercles in both sexes. Pronotum with well-developed tumosity and distinct horizontal ridge in both sexes; lateral margins with distinct horns in major male (reduced or lacking in minor males, lacking in female). Elytra with indistinct striae.

Larval diagnosis

Undescribed. For Scarabaeinae (Ritcher, 1966): Grub C-shaped, 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

Southeastern Asia. This species is distributed widely through southeastern Asia, including India, southern China, Thailand, Vietnam, and Indonesia (Xu et al., 2002). Recently, this species was rediscovered in Singapore after nearly 40 years of searching (Ong et al. 2013).

Plant host(s)

None. This species feeds on dung as both an adult and larva (Ong et al. 2013).

Life history

Unlike many of the more familiar dung beetles that can occur in livestock pastures, this species is dependent upon primary and late-stage secondary rain forests (Ong et al. 2013). In Borneo, this species has declined in concert with the loss of primary forests (Davis, 2001). Catharsius molossus prefers the dung of large herbivores, constructing a brood burrow near fresh dung at night. Dung is then deposited in the burrow and impregnated with an egg (Ong 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

Recorded, not established. This species was imported into Hawaii in 1921 for evaluation as a biocontrol agent to help control populations of the horn fly (Haematobia irritans), a biting pest of livestock. However imported specimens failed to thrive, and none were released (Fullaway, 1921).

Status in Guam

Not established or recorded. This species has not been recorded in Guam.

Potential distribution and dispersal pathway

This species was intentionally imported into Hawaii.

Similar species

This species is somewhat like the similarly colored and sized Dichotomius carolinus. These two species are separated by examining the head (C. molossus with a single clypeal horn in males with females lacking a horn versus D. carolinus with paired clypeal tubercles in males and females with a tubercle on the frons), pronotum (C. molossus major males with pronotal horns with minor males and females lacking horns versus D. carolinus always lacking pronotal horns), and elytra (C. molossus with indistinct striae versus D. carolinus with distinct striae).

Other names (synonyms)

Sacrabaeus molossus Linnaeus, Catharsius abbrevatius Herbst in Jablonsky, Catharsius berbicaeus Herbst in Jablonsky, Catharsius janus Olivier, Catharsius ursus Fabricius

Report your observation

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

Catharsius molossus major male; photo by E.L. Engasser

Catharsius molossus major male; photo by E.L. Engasser

Catharsius molossus major male; photo by E.L. Engasser

Catharsius molossus major male; photo by E.L. Engasser

Catharsius molossus major male; photo by E.L. Engasser

Catharsius molossus major male; photo by E.L. Engasser

Catharsius molossus major male; photo by E.L. Engasser

Catharsius molossus major male; photo by E.L. Engasser

Catharsius molossus minor male; photo by E.L. Engasser

Catharsius molossus minor male; photo by E.L. Engasser

Catharsius molossus minor male; photo by E.L. Engasser

Catharsius molossus minor male; photo by E.L. Engasser

Catharsius molossus female; photo by E.L. Engasser

Catharsius molossus female; photo by E.L. Engasser

Catharsius molossus female; photo by E.L. Engasser

Catharsius molossus female; photo by E.L. Engasser

Catharsius molossus male genitalia, dorsal view; photo by E.L. Engasser

Catharsius molossus male genitalia, dorsal view; photo by E.L. Engasser

Catharsius molossus male genitalia, lateral view; photo by E.L. Engasser

Catharsius molossus male genitalia, lateral view; photo by E.L. Engasser