Dichotomius carolinus

Beneficial

Common name(s)

Carolina dung beetle, Carolina copris

Taxonomy

Family: Scarabaeidae Subfamily: Scarabaeinae Genus: Dichotomius Species: Dichotomius carolinus (Linnaeus, 1767)

Adult diagnosis

Total body length 20.0–30.0 mm (0.78–1.18 in). Body shape distinctly round when viewed from above; may be caked with dung. Color dull black. Clypeus broadly rounded. Head of major male with paired tubercles on clypeus; clypeal tubercles reduced in minor male; lacking clypeal tubercles in female. Head of female with single tubercle on frons; tubercle on frons lacking in male. Pronotum with well-developed tumosity (male and female); lacking horns. Elytra with distinct striae.

Larval diagnosis

(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, tormae symmetrical; anterior phoba present. Chaetopariae each consisting of 15–20 setae. Prothoracic shield with an anteriorly projecting, angular process on each side. Venter of last abdominal segment with polystichous palidia. Anal opening surrounded by fleshy lobes. Legs 2-segmented; with paired terminal setae; claws lacking.

Native range

Eastern United States. This is a common dung beetle species in many pastures of the eastern U.S., where it is known from southeastern South Dakota southward to eastern Texas and east to southern Florida and New England (Woodruff, 1973).

Plant host(s)

None. This species feeds on dung as both an adult and larva (Woodruff, 1973).

Life history

Dichotomius carolinus is a nocturnal species and often is attracted to lights (Woodruff, 1973). Male-female pairs excavate a brood burrow near dung, often leaving a large mound of dirt near the entrance. Such burrows can contain multiple tunnels and are constructed at night near fresh dung in meadows and grasslands. A mass of dung is placed at the end of a tunnel, and an egg is laid within. In Nebraska, adults have been found in June and August (Ratcliffe and Paulsen, 2008). In Florida, however, adults are found throughout the year (Woodruff, 1973).

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 intentionally released from Florida to the Big Island at Parker Ranch in 1954 (Weber, 1955) to help control populations of the horn fly (Haematobia irritans), a biting pest of livestock. Despite this effort Dichotomius carolinus 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 released but did not establish.

Similar species

The only dung beetle recorded from Hawaii that reaches the size of Dichotomius carolinus is the similarly colored Catharsius molossus. These species are separated by examining the head (D. carolinus with paired clypeal tubercles in males and females with a tubercle on the frons versus C. molossus with a single clypeal horn in males and females lacking a horn), pronotum (D. carolinus always lacking pronotal horns versus C. molossus major males with pronotal horns), and elytra (D. carolinus with distinct striae versus C. molossus with indistinct striae).

Other names (synonyms)

Copris carolinus Linnaeus, Copris colonicus Say, Dichotomius colonicus Say, Pinotus bituberculatus Harold, Pinotus carolinus Linnaeus

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Dichotomius carolinus male; photo by E.L. Engasser

Dichotomius carolinus male; photo by E.L. Engasser

Dichotomius carolinus male; photo by E.L. Engasser

Dichotomius carolinus male; photo by E.L. Engasser

Dichotomius carolinus male; photo by E.L. Engasser

Dichotomius carolinus male; photo by E.L. Engasser

Dichotomius carolinus male; photo by E.L. Engasser

Dichotomius carolinus male; photo by E.L. Engasser

Dichotomius carolinus female; photo by E.L. Engasser

Dichotomius carolinus female; photo by E.L. Engasser

Dichotomius carolinus female; photo by E.L. Engasser

Dichotomius carolinus female; photo by E.L. Engasser

Dichotomius carolinus male genitalia, dorsal view; photo by E.L. Engasser

Dichotomius carolinus male genitalia, dorsal view; photo by E.L. Engasser

Dichotomius carolinus male genitalia, lateral view; photo by E.L. Engasser

Dichotomius carolinus male genitalia, lateral view; photo by E.L. Engasser

distribution map for Dichotomius carolinus

distribution map for Dichotomius carolinus