Figulus integricollis


Common name(s)

none known


Family: Lucanidae Subfamily: Lucaninae Genus: Figulus Species: Figulus integricollis Thomson, 1862

Adult diagnosis

Total body length 11.0–22.0 mm (0.43–0.87 in) including mandibles. Body shape elongate oval; dorsoventrally flattened. Color shiny black. Ocular canthus completely dividing eye. Mandibles prominent; not sexually dimorphic. Pronotum smooth; often with tubercle at anterior border at middle. Elytra with prominent striae.

Larval diagnosis

Undescribed. For Lucanidae (Ritcher, 1966): Grub C-shaped, not hump-backed, cylindrical, whitish. Antenna 3 or 4 segmented. Last antennal segment much reduced in size. Maxilla with galea and lacinia distinctly separated; maxillary stridulatory teeth absent. Epipharynx with united tormae. Anal opening Y-shaped.

Native range

Guam and the Marianas: This species is recorded from Guam and the Northern Marianas Islands of Farallon de Medinilla, Rota, and Alamagan (Bourquin, 2002).

Life history

Poorly known. Larvae and adults of the related Australian species Figulus regularis are known to tunnel in dead tree trunks. Dispersing adults may exhibit some host preferences when selecting new logs to colonize, and they have been recorded from trunks of Angophora bakeri (Hawkeswood, 2014) and Xanthorrhoea johnsonii (Hawkeswood, 1985). Larvae likely feed on rotting wood. Adults are probably predacious, feeding on small invertebrates similar to the related Figulus binodulus (Mori and Chiba, 2009). Limited parental care (observed in F. binodulis) may occur in this species, and significant larval mortality may be due to filial cannibalism (Mori and Chiba, 2009).

Pest potential

None. Adult Figulus spp. are predators and larvae feed upon dead wood. No associations with living plants are known (Mori and Chiba, 2009).

Status in Hawaii

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

Status in Guam

Native. This species is a native species in Guam, and it is endemic to the Marianas Archipelago (Bourquin, 2002).

Potential distribution and dispersal pathway

This uncommon species does not appear likely to spread beyond its natural range.

Similar species

This species is unlikely to be confused with other scarab beetles of Guam or Hawaii. The possibility exists that this species might be confused with exotic bess beetles (Passalidae). They are separated based on head armature (Figulus integricollis lacking horns versus passalids with horn or tubercle on the central, anterior portion of the head).

Other names (synonyms)

None known

Report your observation

Report your observation of this rare and native Guamanian species at our iNaturalist project.

Figulus integricollis female; photo by E.L. Engasser

Figulus integricollis female; photo by E.L. Engasser

Figulus integricollis female; photo by E.L. Engasser

Figulus integricollis female; photo by E.L. Engasser

distribution map for Figulus integricollis

distribution map for Figulus integricollis