Dynastes neptunus (Quensel, 1817) male, dorsal view	Dynastes neptunus (Quensel, 1817) female, dorsal view
male, lateral view
female, lateral view Photos by Mathew R. Moore

Distribution: Northwestern South America: Colombia, Ecuador, Peru, and Venezuela.

 

Description: Pronotal horn in males with two short horns either side of large horn. Protarsomere 5 thickened in males, venter of protarsomere 5 with stout spinules in both sexes. Pronotum and elytra black in both sexes. Clypeus in females acuminate, subtuberculate at apex.

Biological Data: Adults in captivity will feed readily on soft fruits such as bananas and papaya (Onore 2004). Larvae have been found in various tree species including achotillo (Alchornea sp., Euphorbiaceae), canelo or cashiacara (Ocotea sp., Lauraceae), and ortiguillo (Urera sp., Urticaceae). Larvae occupy tree hollows in standing trunks from the soil up to the canopy (Onore 2004). Larvae feed on reddish, rotten wood. Third instar larvae build pupal chambers of woody debris and fecal pellets. In captivity, the entire life cycle of D. neptunus lasts 443-724 days. In nature, the life cycle is probably two years (Onore 2004).

Temporal Distribution: Adults are most commonly collected at light just before dawn during the rainy season (Onore 2004).

Larvae: Onore (2004) described the third instar larvae.

References:
Endrödi, S. 1985. The Dynastinae of the World. Series Entomologica, Volume 28, W. Junk, Dordrecht. 800 pp., 46 plates.

Onore, G. and M. Morón. 2004. Dynastes neptunus Quensel (Coleoptera: Scarabaeidae: Dynastinae); Descriptions of the third instar larva and pupa, with notes on biology. Coleopterists Bulletin 58: 103-110.