Developmental Temperature Responses of the Sibling Species Phaenicia sericata and Phaenicia pallescens1

Abstract

The influence of temperature on the developmental rates of eggs, larvae, and pupae of Phoenicia sericata (Meigen) and Phoenicia pallescens (Shannon) was examined at 19°, 27°, and 35°C. The median time from egg to adult for sericata was 53.9 days at 19°C, 13.5 days at 27°C, and 11.3 days at 35°C; for pallescens it was 30.3 days at 19°C, 12.8 days at 27°C, and 10.4 days at 35°C. Phaenicia sericata sericata developed at a slower rate with more variability at each stage and tended to diapause at both low and high temperatures. These eurythermal features and ability to diapause have probably enabled sericata to become established in cooler temperate regions, while stenothermal pallescens which does not diapause has remained essentially sub-tropical.