Factors influencing the selection of larviposition sites in the laboratory by Glossina morsitans morsitans Westwood (Diptera: Glossinidae)

Abstract

AbstractPregnant females of Glossina morsitans morsitans Westw. were offered choices of larviposition sites in the vicinity of various models and patterns. Ground-level surfaces of black, green, white or red were not attractive. Vertical surfaces did not attract a majority of flies, but 50% of those that settled on them gave birth in that region of the chamber. Shade cast by horizontal surfaces was attractive, but shade cast by vertical objects was not. Models with an enclosed space were attractive, but larviposition rarely occurred within the model, probably because flies do not readily enter cavities unless the temperature is very high. Among patterns presented at a distance, a simple unbroken area of black was more attractive than equivalent areas in the form of stripes, etc. No distinction was made between stripes presented vertically, horizontally and at an angle. Models representing logs or trees with rot holes were not attractive. Models with subterranean cavities, even a simple trench, were attractive. Loose sand was not more attractive than sand glued to a substrate, but there was an indication of a preference for larger particles. No evidence was obtained for the hypothesis of Nash et al. (1976) that a larval pheromone attracts gravid females to larviposition sites.