TAXONOMY

Latin Name: Dynastes grantii Horn, 1870

English Name: Western Hercules Beetle

Size: 40-70mm (1.5" - 2.8")

Distribution: USA (Arizona and adjacent states)

Known Hosts: velvet ash (Fraxinus velutina)

Etymology: The species name grantii is derived from the original collection site, the Fort Grant in Arizona where the species is first encountered by original collector. The specimen then transferred to George Henry Horn, who described it in 1870.

Comment: Adult beetles attracted to lights. Although it is very abundant in Arizona, it is considered to be Species of Greatest Conservation Need (SGCN) in New Mexico. Also, there is a scientific research that D. grantii can be at a high risk of endangerment due to Emerald Ash Borer (EAB) which also occurs on velvet ash.

REARING/BREEDING

It is considered easy species overall to rear and breed. D. grantii is known to spend several months as eggs, however, with right temperature and humidity, larvae can hatch out of eggs within 2-3 weeks. One whole life cycle takes little over an year. 4-5 weeks as pupa, about 4+ months as adult. Using large substrate particles to house females for breeding (adding clean potting soil is recommended). Larvae feed on well-fermented substrate of white oak, hardwood, etc.