Rearing indicates life cycles of 2–5 years for coastal sand scarab beetles Pericoptus punctatus and P. truncatus (Coleoptera: Scarabaeidae)

Abstract

ABSTRACTLarvae of the endemic dynastine scarabs Pericoptus truncatus and P. punctatus (Coleoptera: Scarabaeidae) occur in coastal sand dunes. Life cycles from egg to egg-laying adults were determined by rearing for the first time. They were 3–5 years (mean ± SD = 3.41 ± 0.53 years, n = 172) and 2–4 years (2.90 ± 0.45 years, n = 53) for P. truncatus and P. punctatus, respectively. The modal life cycle length was three years for both species. In the first year of development, survival of P. truncatus and P. punctatus was superior when larvae were provided with driftwood than with grass (Spinifex sericeus or Stenotaphrum secundatum). Head-capsule width could be used to reliably differentiate between instars of P. punctatus and P. truncatus except for second instar P. truncatus and third instar P. punctatus. These data may inform planning to protect sand scarabs and associated fauna of coastal sand dunes.