Phorcotabanus Cinemus (Wiedemann) (Diptera, Tabanidae) Uma Espécie de Mutuca OrnitofíLica Na Amazônia Central, Brasil.

Abstract

In Central Amazon, Brazil, the tabanid Phorcotabanus cinereus (Wiedemann) was recorded attacking ducks of the species Cairina moschata (Linnaeus) (Aves, Anatidae). The flight and behavior of the tabanid whiie xttacking and the host's defences were videotaped and anaiysed in slow motion. The ~tabanid was recorded flying rapidiy around the heads of ducks before danding, -alternately flying around a head in a clockwise and anti-clockwise direction. Rarely a tabanid was captured by a duck, and on such occasions it was ~aaten. Landing always took place on the beak, with the tabanid walking to the fleshy caruncie on the basal part of the beak to bite and feed. Firstly, the duck defends itself through lateral brusque head movements, and then when it is being ,.bitten, it defends itself by rubbing its head on the body, either rubbing the nail on the tabanid or when swimming, the duck dips its head into the water. If disturbed, fhe fly resumed the same pattern of fiight as before and would generally Iand iagain on the same host and biting the same place. This feeding activity was .abserved predominantly between 09:30 and 16:30 hours and always in open -areas, near aquatic environments, from 27 june 1996 to 30 january 1997 (the iess -rainy season in Central Amazon). To test the attractiveness of other animals to P. cinereus, mammals (horse and cow), caymans and domestic and wild birds were placed in suitable habitat and the response of P. cinereus observed. These animals did not attract P. cinereus, suggesting that this species has a preference -for ducks, which are plentiful in the region. Females of another tabanid species, 'C?hrysops iaetus Fabricius, were observed fiying above and landing on ducks, but blood feeding apparently did not occur. C. iaetus was captured biting mammals (horse, tapir, man) and occasionally biting ducks in a different place. A way of reducing tabanid adult density around heavily affected flocks of ducks is the use of interception fly traps.