Pollen‐feeding in hover‐flies (Diptera: Syrphidae)

Abstract

Analyses of the pollen contents of the crop and intestine of 11 species of New Zealand Syrphidae . showed that small, sparsely haired hover‐flies with unbranched hairs, short, simple bristles, and a short proboscis had ingested at least 99% anemophilous pollens, and that larger, more hairy hover‐flies with pollen‐collecting hairs, long, spirally grooved bristles, and elongate mouthparts had ingested pollens almost exclusively from nectar‐bearing flowers. Pollen‐feeding behaviour was studied in one hairy species, the drone‐fly Eristalis tenax, and in one sparsely‐haired species, Melanostoma fasciatum. Using granulated charcoal as a substitute for pollen, it was found that in E. tenax particles trapped among the body hairs are combed off by the front and hind tibiae and transferred to pollen‐retaining bristles on the front and hind tarsi respectively. Particles retained among the front tarsal bristles are ingested directly from the bristles. Those retained by the hind tarsi are transferred in flight by leg‐...