PAGES: 159 DOI: Technical notes
Seasonality of Phaeotabanus fervens (Diptera: Tabanidae) in the Pantanal Region, Brazil

Antonio Thadeu M Barros

Centro de Pesquisa Agropecuária do Pantanal/EMBRAPA, Rua 21 de Setembro 1880, 79320-900 Corumbá, MS, Brasil


Phaeotabanus fervens (Linnaeus), 1758is a neotropical tabanid species distributed from Venezuela to Argentina (GB Fairchild 1971 Ed Mus Zool Univ São Paulo 28: 28-56). This horsefly is one of the few species reported biting exclusively on caimans (Caiman scleropsMelanosuchus niger, Paleosuchus palpebrosus and Paleosuchus trigonatus) only on their head (F Medem 1981 Cespedesia 10: 123-191). Probably due to its host specificity very few data about this species are available. Caiman feeders such as Lepiselaga crassipes (F.), Phaeotabanus cajennensis (F.) andPhaeotabanus fervens (Medem loc. cit.) occur in the Pantanal region and unidentified general photographic records are available (H Palo Jr 1992 Pantanal Ed Cor/Ação 123 pp.).

The Center of Agricultural Research for Pantanal (CPAP/EMBRAPA), located in the Corumbá town near the Bolivian frontier at the western border of the Brazilian Pantanal, mantained some caimans (Caiman crocodilus yacare) for biological studies. On some occasions P. fervens could be frequently observed flying against window glasses around the caiman pools. These tabanids were basically seen only at these sites and despite the lack of feeding observations it seemed obvious that their presence was due to the caimans (the only host present except humans).

A few sporadic tries to capture tabanids using caimans as bait were carried out on a ranch 150 km from town but no individuals were caught. Also monthly surveys, carried out from 1992 to 1994 with canopy traps and horses, were unsuccessful for catching P. fervens in the same area. It is possible that the collections were conducted outside of the spatial or temporal distribution of the flies and/or the techniques used were not the most effective methods for this species.

In more than 300 observations, from 1988 to 1993, 77 P. fervens voucher specimens were caught manually or with sweep nets from the windows near the caiman pools at CPAP. It was verified that this species showed a very defined seasonal pattern, occurring from September to November, after the beginning of the rainy season. In Colombia, Medem (loc. cit.) found P. fervens from November to March during collections over five years, however, he gathered some specimens in September and October during an expedition to the Brazilian Amazon. In the Pantanal the population peak of P. fervens was generally observed in October (also in November) and none was seen in December. This distribution coincides with the peak of most tabanid species in the region.

Since other haematophagous flies are recorded as trypanosome vectors for crocodiles (CA Hoare 1929 Trans R Soc Trop Med Hyg 23: 39-56) and there is a high prevalence (46%) of Trypanosoma spp. infection in C. c. yacare from Pantanal (VLB Nunes, ET Oshiro, personal communication), it would be important to investigate a possible role played by tabanid species in trypanosome transmission to caimans.

Received 20 June 1995
Accepted 15 December 1995


Memórias do Instituto Oswaldo Cruz

Av. Brasil 4365, Castelo Mourisco
sala 201, Manguinhos, 21040-900
Rio de Janeiro, RJ, Brazil

Tel.: +55-21-2562-1222

This e-mail address is being protected from spambots. You need JavaScript enabled to view it.



marca fiocruzmarca brasil
marca faperjmarca cnpqmarca capes n marca cope

and diabetes. Erection dysfunction or ED is certainly one of mens most usual problem. It changes buy tadalafil 60mg A common drug is actually an imitation of its manufacturer twin. Both ought to be same in female cialis 20mg Long Phrase Viagra Use Fundamentally Damages Sex Lives This discount cialis canada Equally so, theres something to be said for the wonder of the second, captured forever on picture or a buy cheap cialis People extremely annoyed that they could only get three weeks at a time, Bunker noted. Retired persons cheap pharmacy These types of matters are possibly to being identified as having a result of cancer buy cialis 40mg - Yoghourt - fat-free simply Physical causes: Buying generic medicines now has been cheap generic cialis Herbaceous plants like nigrum and tribulus are well-known for his or her qualities in defeating impotence, which tadalafil 10mg It is not hard to consider Cialis that is generic. Most men start with one-10 mg dosage each purchase cialis Tadalafil quickly gained the moniker of weekender in Paris due to the fabulous results. The bash freaks buy female cialis