REARING BLACK FLIES (DIPTERA, SIMULIIDAE) IN A CLOSED SYSTEM OF WATER CIRCULATION

Abstract

A method of rearing large numbers of black flies was devised using a closed system of water circulation. The subsystems used for hatching, feeding, filtration and adult trapping are labor efficient and flexible for rearing most species of temperate and tropical black flies. The filtration subsystem permits daily assessment of larval growth rate, drift and mortality so that life table statistics can be derived for populations of immatures. Black flies, Simulium pictipes, S. vittatum, S. decorum and Cnephia dacotensis were used in developing this rearing system. Percentage survival varied with species and may be a function of food quantity within discrete particle-size intervals. Over 28,000 larvae of C. dacotensis were reared in a single unit with 89.3% surviving to the adult stage. In each of 2 rearings of S. pictipes, conducted under different nutritional regimens, .apprx. 60% survived to the imaginal stage. Over 9500 adults of S. vittatum were reared from 12,127 eggs. An F1 generation of S. decorum was produced from parental stock that originated as field-collected larvae. Combined survivorship of this species approached 94% with the production of 5847 adults.