DIURNAL NECTAR-FEEDING OF SALT-MARSH TABANIDAE (DIPTERA)

Chrysops fuliginosus Wiedemann adults visited Rosa palusths Marsh, and Achillea millefolium L. flowers primarily during the morning (0700-1100 h), but following a mid-day lull in their attraction to these plants, a small number of males and females resumed feeding on flowers between 1800 and 2000 h. Chrysops atlanticus Pechuman adults were sighted on these nectar sources sporadically throughout the diurnal period. Anthrone tests showed that C. fuliginosus, C. atlanticus, and Tabanus nigrovittatus Macquart females contained fructose throughout daylight h. Thin-layer chromatography detected glucose alone or a combination of glucose and fructose in more than 90% of the deer flies tested, whereas a mixture of glucose, fructose, and sucrose was found in 51.6% of the T. nigrovittatus females analyzed. Compositae, Rosaceae, Gramineae, Acer, Quercus, and/or Salix pollen grains were recovered from digestive tracts in 28% of the 150 flies examined. The presence of common nectar sugars and pollen grains in tabanids suggests an important association between these salt marsh insects and host plants. In addition to carbohydrates, proteins and amino acids (derived from pollen and nectar) may be important dietary components for adults. © 1979 Entomological Society of America.