Abundância e sazonalidade da mosca-dos-chifres: Haematobia irritans no Bioma Amazônia

Abstract

The horn fly is an ectoparasite that mainly affects cattle, continuously feeding on the blood of these animals through its bite, causing enormous losses in the production of meat and milk. The present work aims to understand the biological aspects of the fly -dos-horns in the Maranhão Amazon, providing the basis for strategic control. The experiment was carried out on a farm in the municipality of Buriticupu, Maranhão, Northeast Brazil. The study was carried out during the parasitic and non-parasitic phases. In the parasitic phase, 100 Nelore females (Bos indicus) were used, aged between 1.5 and 2 years, and were observed every 15 days to count horn flies. To do this, within the batch, 30 animals were chosen at random and the count was always done on one side of the animal, and the number of flies multiplied by 2x. The count followed the following pattern: ≤ 50 flies were counted individually, > 50 flies were counted in groups that were added together at the end of each individual's count. In the non-parasitic phase, 20 emergency traps were used on fresh feces of the animals, and the flies that emerged from the feces were counted monthly. During the parasitic phase, horn fly population density varied throughout the year. A first population peak was observed in November and a second starting in May with a peak in June. At the November peak, an average of 600 flies/animal were observed, while at the June peak ~500 flies/animal. During the non-parasitic phase, peaks were observed in November (~180 flies) and May (110 flies). Both peaks (parasitic and non-parasitic phases) coincided with the beginning of the rainy season (November- December) and the end of the rainy season (May-June). It is concluded that the horn fly in the Amazon biome tends to present a seasonal pattern, with peaks in the months of November-December and May-June, with precipitation being an important regulator, since there was little variation in temperature throughout of the study