Family: Trogidae Subfamily: Troginae Genus: Trox Species: Trox scaber (Linnaeus, 1767)
DNA barcode available: specimen information; sequence data
Total body length 5.0–7.0 mm (0.19–0.28 in). Body shape oval (dorsal view), surface rough and warty, often dirt encrusted. Venter flat, dorsum convex (lateral view). Color dark grey-brown. Pronotum with base weakly sinuate, basal angle quadrate. Scutellum rounded, never hastate. Elytra with patches of short, reddish-brown hairs. Middle tibia lacking numerous fine teeth along outer margin.
Undescribed. For Trox (Ritcher, 1966): Grub C-shaped, not hump-backed, cylindrical, whitish. Maxilla with galea and lacinia distinctly separated. Antennae with 3 segments, with 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 of thorax and abdomen biforous.
Holarctic, Australia, southern South America. Trox scaber is widely distributed across the temperate Northern and Southern Hemispheres (Zidek, 2013). It is widely distributed in the Palearctic, from the Canary Islands and North Africa eastward to Siberia. In North America, this species occurs from southern Canada through the northern half of the contiguous U.S. (Ratcliffe and Paulsen, 2008). In the Southern Hemisphere, the species is known from Australia and Argentina, and recorded (but not thought established) in Chile (Zidek, 2013).
None. Both adults and larvae of this species feed on late stage carrion and other dry animal remains, thus posing no threat to crops or ornamental plants.
Both adults and larvae of this species feed on feathers, hair, and other dry animal remains. These remains may consist of debris in mammal burrows, bird nest debris, dry carrion, or regurgitated owl pellets (Ratcliffe and Paulsen, 2008). Females lay eggs in batches of 3 or 4, burying them 1–3 mm (0.4–1.2 in) beneath an animal carcass. Larvae emerge from eggs after 8 or 9 days and begin feeding. Pupation occurs in a cell beneath the feeding site. It appears that only a single generation is produced per year, with overwintering occurring in the adult stage (Baker, 1966), though it is unclear that this is true of Hawaiian populations. In Nebraska, adults of this species have been found from April through September (Ratcliffe and Paulsen, 2008). This species is known to be attracted to lights at night (Hawaiian Entomological Society, 1977) and is likely nocturnal.
None. This species recycles carrion and poses no threat to crop or ornamental plants.
Established. Trox scaber first arrived to Hawaii around 1900, first being recorded near Hilo on Big Island. To date, this species appears confined to Big Island, with most specimens found at lights (Hawaiian Entomological Society, 1977; Nishida, 2002).
Not established or recorded. There are no records of this species from Guam.
In Hawaii, this species may have first arrived in marine cargo, though this is speculation This species is native to the U.S. (Ratcliffe and Paulsen, 2008), thus it does not pose a threat in the contiguous U.S.
Trox scaber is one of three hide beetles (Trogidae) known from Hawaii and Guam. The other two species are Omorgus procerus and O. suberosus. These species are separated by size (T. scaber at 5.0–7.0 mm [0.19–0.28 in] versus O. suberosus and O. procerus both over 10.0 mm [0.39 in]) and by examining the pronotum (T. scaber with the pronotal base weakly sinuate and basal angle quadrate versus O. suberosus and O. procerus with pronotal base scalloped and the basal angle obtuse), scutellum (T. scaber with scutellum rounded versus O. suberosus and O. procerus both with scutellum hastate), and middle tibia (T. scaber without middle tibia lacking numerous fine teeth along lateral margin versus O. procerus with numerous, fine teeth).
Silpha scabra Linnaeus, Trox barbosus von Laicharting, Trox arenarius Fabricius, Trox hispidus von Paykull, Trox trisulcatus Curtis, Trox niponensis Lewis
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