Family: Lucanidae Subfamily: Lucaninae Genus: Figulus Species: Figulus integricollis Thomson, 1862
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.
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.
Guam and the Marianas: This species is recorded from Guam and the Northern Marianas Islands of Farallon de Medinilla, Rota, and Alamagan (Bourquin, 2002).
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).
Not established or recorded. There are no records of this species from Hawaii.
This uncommon species does not appear likely to spread beyond its natural range.
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).
Report your observation of this rare and native Guamanian species at our iNaturalist project.