Development of larvae of Chrysops nigripes Zetterstedt and Chrysops probably zinzalus Philip (Diptera: Tabanidae) in a subarctic Labrador peatland

Abstract

A total of 476 tabanid larvae, including 108 Chrysops nigripes and 145 Chrysops probably zinzalus, were obtained from regular collections made from early June through late August 1990–1991 in Iron Arm Fen, a minerotrophic peatland located in subarctic Labrador near Schefferville, Quebec. Changes in head capsule and total body length-frequency distributions among successive sampling periods and years suggest very slow growth rates for Chrysops species at subarctic latitudes; life cycles may require 7–8 years to complete.