Development, Longevity and Fecundity of the False Wireworms Pterohelaeus Darlingensis and P. Alternatus (Coleoptera: Tenebrionidae). I. Effect of Constant Temperature.

Abstract

All stages of P. darlingensis and P, alternatus were reared on wheat sprouts under constant temperatures ranging from 11.1 to 37.5°C. Eggs and larvae of both species developed between 15.8 and 33.1°C. Threshold temperatures for P. darlingensis and P. alternatus eggs were 13.8°C and 13.2°C respectively; 77.6 and 81.5 day-degrees above the threshold, respectively, were required for development. Larvae required 676.6 day-degrees above a threshold of 14.6°C, and 636.3 day-degrees above a threshold of 16.8°C, for development. Pupae developed between 11.1 and 37.5°C. P. darlingensis requiring 138.9 day-degrees above l3.6"C and P. alternatus 146.2 day-degrees above 13.4°C. Weekly fecundity and survival of adults were monitored; the optimal temperature for ovarian development was approximately 24.4°C. Survival of both sexes was similar at each temperature but longevity generally increased with decreasing temperatures. Parameters describing the biotic potential of both species were calculated; the capacities for increase were optimal at 28.6°C. The applicability of linear and curvilinear models for simulating development rates is discussed.