Omorgus procerus

Beneficial

Common name(s)

none known

Taxonomy

Family: Trogidae Subfamily: Troginae Genus: Omorgus Species: Omorgus procerus (Harold, 1872)

Adult diagnosis

Total body length 10.0–15.0 mm (0.39–0.59 in). Body shape strongly convex dorsally, flattened ventrally; appearance warty; often encrusted with debris. Color dark gray to reddish-brown. Abdomen extremely flat when viewed laterally. Pronotum with base scalloped and basal angle obtuse. Scutellum hastate. Elytra with patches of short, reddish-brown hairs. Middle tibia with numerous fine teeth at outer margin.

Larval diagnosis

Undescribed. For Omorgus spp. (Ritcher, 1966): Grub C-shaped, not hump-backed, cylindrical, whitish. Maxilla with galea and lacinia distinctly separated. Antennae with 3 segments, lacking distal sensory cone on second segment. Distal segment of antennae much reduced in size. Epipharynx with tormae united mesally. Legs 4-segmented, never with stridulatory organ. Spiracles cribriform.

Native range

Northeastern Africa, western Asia. This species is broadly distributed across arid and semi-arid regions of Africa and western Asia, occurring from India through the Middle East, Egypt, and into the Horn of Africa and across the Sahel (Zidek, 2013).

Plant host(s)

None. Larvae of this species appear to be specialized egg predators of the desert locust (Schistocerca nitens [formerly S. gregaria]) (Roffey, 1958). The adult diet is unclear, but the related bark-like hide beetle (Omorgus suberosus) feeds upon late stage carrion and other animal debris as adults (Ratcliffe and Paulsen, 2008).

Life history

(Roffey, 1958): Eggs are deposited in loose soil near egg cases of the desert locust (Schistocerca nitens) and emerge after 2–3 days. Larvae grow rapidly with the final instar reached in an average of 14 days. During this time, grubs move through the soil feeding on the locust eggs, often leaving behind small mounds of dirt. The final adult form is reached after an average of 60 days.

Pest potential

None. This species feeds upon the eggs of the desert locust (Schistocerca nitens), a destructive pest in the Hawaiian Islands (Latchininsky, 2008).

Status in Hawaii

Recorded, not established. This species was intentionally released in Hawaii as a biocontrol agent. In 1966, specimens were released on Sand Island in Honolulu to combat the invasive desert locust (Schistocerca nitens) (Davis and Krauss, 1967), a generalist herbivore with periodic outbreaks that can cause serious ecological damage (Latchininsky, 2008). Omorgus procerus failed to establish in Hawaii (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 (Nishida, 2002).

Similar species

Omorgus procerus is one of three hide beetles (Trogidae) known from Hawaii and Guam. The other two species are Trox scaber and Omorgus suberosus. These species are separated based on examination of the scutellum (hastate in O. procerus versus parabolic in T. scaber), the pronotum (pronotal base scalloped and the basal angle obtuse in O. procerus versus pronotal base weakly sinuate and basal angle quadrate T. scaber), and the middle tibia (O. procerus with a row of fine teeth along outer margin versus teeth lacking in O. suberosus).

Other names (synonyms)

Afromorgus procerus (Harold), Trox procerus Harold

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Omorgus procerus female; photo by E.L. Engasser

Omorgus procerus female; photo by E.L. Engasser

Omorgus procerus female; photo by E.L. Engasser

Omorgus procerus female; photo by E.L. Engasser

distribution map for Omorgus procerus

distribution map for Omorgus procerus