Follicular development in salt marsh Tabanidae (Diptera) and incidence of nectar feeding with relation to gonotrophic activity.

Yolk deposition commenced during pupation of Chrysops fuliginosus Wied. and C. atlanticus Pechuman but did not begin in Tabanus nigrovittatus Macq. until after the female emerged. C. fuliginosus and T. nigrovittatus females autogenously matured eggs in the laboratory without sugar meals during the first genotrophic cycle. Parous, fructose-positive C. fuliginosus were more abundant in a forest habitat (50%of the sample) than were blood-seeking females in the salt marsh (25%). There was little difference in the frequency of recent nectar feeding for C. atlanticus (20.9 and 21.0%) in the two habitats, and, in the marsh, comparatively fewer T. nigrovittatus contained detectable sugars (12.1%). Small amounts of fat-body were observed in anterior abdominal segments of parous, field-collected tabanids but, since no females completed a second ovarian cycle, it was believed nectar sugars are a main source of nutrient for female sustenance.