Activities of tabanids (Diptera, Tabanidae) attacking domestic duck-Cairina moschata (Linnaeus) (Aves, Anatidae), introduced in a forest area in the Central Amazon, Manaus, Brazil

Presented here are the feeding habits, attack behavior, daily and annual activity of adult of Phorcotabanus cinereus (Wiedeman, 1821), Chrysops laetus (Fabricius, 1805) and Phaeotabanus cajennensis (Fabricius, 1787), while biting a domestic duck, Cairina moschata (Linnaeus, 1758). The last two species were recorded for the first time attacking birds. This study comprehended monthly observations of two consecutive days from April/97 to March/98 between 5:30 a.m. and 6:30 p.m. at the Army Instructional Base ((BI-2/CIGS) near Manaus. Annual occurrence of P. cinereus was from July to September, with a daily occurrence between 9:00 a.m. and 5:00 p.m. and highest activity at 12:00 a.m. and 2:00 p.m. C. laetus ocurred from June to October; with a daily occurrence between 8:00 a.m. and 3 p.m. and highest activity at 11:00 and 12:00 a.m. Occurrence of P. cajennensis with one specimen only, was in July between 10:00 and 11:00 a.m.

The life cycle of Dendritobilharzia anatinarum cheatum, 1941 (Trematoda, Schistosomatidae)

The life cycle of Dendritobilharzia anatinarum was completed experimentally in the laboratory. Cairina moschata domestica (domestic duck) and Biomphalaria straminea served respectively as definitive and intermediate hosts. Eggs passed in duck faeces hatch miracidia in 10 minutes when placed in water. Eight days after the snail infection, the mother sporocyst contains daughter sporocysts ready to migrate. Cercariae are present within the daughter sporocysts 23 days after infection and emerge from the snail on the 25th day. They actively penetrate the skin of the duck and after a prepatent of 39 days, sexually mature trematodes are present in the blood vessels of the bird. The adult parasite is predominantly in the renal-portal system and to a lesser degree in the lungs and mesentery. A detailed morphological description of the egg. miracidium, sporocyst and cercaria is presented.

Natural lectin activity in the haemolymph of Panstrogylus megistus (Heteroptera: Reduvidae)

The haemolymph of Panstrongylus megistus showed a natural lectin activity for a wide range of vertebrate erythocytes. Agglutination was observed against all vertebrate erythrocytes tested (human ABO, duck, rabbit, mouse, sheep, chicken and cow). Cow erythrocytes showed the lowest titre. Concerning human erythrocytes, the lectin activity was similar in the types A+,B+ and AB+ while the highest activity was observed in the type O+. Determination of minimal inhibitory concentrations was carried out with human erythrocytes type O+. Agglutination was inhibited by several carbohydrates (rhamnose. D-galatose, raffinose, D-lactose and D-fucose). Rhamnose wasreported as the strongest inhibitor (0.78mM). The results suggest the presence of more than one lection in the haemolymph of P. megistus.

Philophthalmus gralli (Digenea: Philophthalmidae) parasite of Anas bahamensis and Amazonetta brasiliensis, from Lagoons of Maricá county, Rio de Janeiro, Brazil

Forty ducks, 18 Anas bahamensis (white-cheecked pintail) and 22 Amaxonetta brasiliensis (Brazilian duck) from Maricá and Guarapina lagoons, Maricá, RJ, Brazil, were examined. The prevalence of Philophthalmus gralli in A. bahamensis was 22.2% ans in A. brasiliensis was 27.27%. This is the first record of P. gralli in the Neotropical region, and A. bahamensis and A. brasiliensis are new host records for P. gralli.

The interaction between Poultry and Triatoma infestans Klug, 1834 (Hemiptera: Reduviidae) in an experimental model

This paper compares the predation pressure that ducks and chickens exert on triatomines. For the tests, these birds were placed in individual boxes together with a known number of Triatoma infestans and left to interact from 6 p.m. till the next morning, involving a long lasting period of complete darkness limited by two short-term periods of semi-darkness. There was a shelter which could prevent the bugs from being predated. The number of live and dead triatomines was recorded, considering missing bugs as predated by the birds. Ducks exhibited a greater predatory activity than chickens, that could be due to a long term active period at night while chickens sleep motionless from sunset to dawn. Surviving triatomines that had fed on chickens outnumbered those fed on ducks suggesting that these were less accessible to the triatomine biting. If ducks are better than chickens to detect and eat bugs and to interfere with their feeding in the field, an increase in duck number might help to diminish triatomine density. Further research is needed to determine the feasibility of application of these experimental results.

Phorcotabanus cinereus (Wiedemann, 1821) (Diptera, Tabanidae), an ornithophilic species of Tabanid in Central Amazon, Brazil

In Central Amazon, Brazil, the tabanid Phorcotabanus cinereus (Wiedemann) was recorded attacking the native duck Cairina moschata (Linnaeus) (Anseriformes, Anatidae). The flight and behavior of the tabanid during the attacks and the host's defenses were videotaped and analyzed in slow motion. The tabanid was recorded flying rapidly around the heads of the ducks before landing. Landing always took place on the beak, and then the tabanid walked to the fleshy caruncle on the basal part of the beak to bite and feed. Firstly the duck defends itself through lateral harsh head movements, and then, when it is being bitten, it defends itself by rubbing its head on the body, or dipping the head into water, when swimming. If disturbed, the fly resumed the same pattern of flight as before and would generally try to land again on the same host and bite in the same place. This feeding activity was observed predominantly between 9:30 am and 4:30 pm and always in open areas, near aquatic environments, from June 1996 to January 1997, the dry season in Central Amazon. To test the attractiveness of other animals to P. cinereus, mammals, caimans and domestic and wild birds were placed in suitable habitat and the response of P. cinereus observed. P. cinereus did not attack these animals, suggesting that this species has a preference for ducks, which are plentiful in the region.

The prevalence of human immunodeficiency virus type 1 and hepatitis C virus among injection drug users who use high risk inner-city locales in Miami, Florida

In order to estimate the prevalence of human immunodeficiency virus type 1 (HIV-1) and hepatitis C virus (HCV) co-infection in hard-to-reach intravenous drug users, 199 subjects from high-risk inner-city locales, the so called "shooting galleries", were consented, interviewed, and tested in Miami, FL, US. Positive HIV-1 status was based on repeatedly reactive ELISA and confirmatory Western Blot. Positive HCV status was based on reactive ELISA and confirmatory polymerase chain reaction techniques. Overall, 50 (25%) were not infected with either virus, 61 (31%) were HIV-1/HCV co-infected, 17 (8%) infected by HIV-1 only, and 71 (36%) infected by HCV only. The results of the multivariable analyses showed that more years using heroin was the only significant risk factor for HCV only infection (odds ratio = 1.15; 95% confidence interval = 1.07, 1.24) and for HIV-1/HCV co-infection (odds ratio = 1.17; 95% confidence interval = 1.09, 1.26). This paper demonstrates that HIV-1/HCV co-infection is highly prevalent among so called "shooting galleries".

Identificação de resíduos de disparos de armas de fogo por meio da técnica de espectrometria de massas de alta resolução com fonte de plasma indutivo

The violence derived from crimes involving firearms represents one of the main concerns of society. For this reason modern techniques have emerged in forensic science to identify suspects at crime scenes. This work describes a methodology to identify residues present in the hands of suspect by using a high resolution inductively coupled plasma mass spectrometry and collection procedure based on ethylenediaminetetraacetic acid (EDTA) solution as a complexing agent in moistened swabs. In order to distinguish real gunshot residues from others types of residues present in the hand of suspect, ternary ratio per cent diagrams were developed for antimony (Sb), barium (Ba) and lead (Pb) detected on the hands of volunteers, before and immediately after shooting tests, revealing a remarkable difference in both situations.

Multispecies weed competition and their economic threshold on the wheat crop

Two field experiments were conducted to evaluate the effects of multispecies weed competition on wheat grain yield and to determine their economic threshold on the crop. The experiments were conducted in 2002, on two sites in Iran: at the Agricultural Research Station on Ferdowsi University of Mashhad (E1) and on the fields of Shirvan's Agricultural College (E2). A 15 x 50 m area of a 15 ha wheat field in E1 and a 15 x 50 m area of a 28 ha wheat field in E2 were selected as experimental sites. These areas were managed like other parts of the fields, except for the use of herbicides. At the beginning of the shooting stage, 30 points were randomly selected by dropping a 50 x 50 cm square marker on each site. The weeds present in E1 were: Avena ludoviciana, Chenopodium album, Solanum nigrum, Stellaria holostea, Convolvulus spp., Fumaria spp., Sonchus spp., and Polygonum aviculare. In E2 the weeds were A. ludoviciana, Erysimum sp., P. aviculare, Rapistrum rugosum, C. album, Salsola kali, and Sonchus sp. The data obtained within the sampled squares were submitted to regression equations and weeds densities were calculated in terms of TCL (Total Competitive Load). The regression analysis model indicated that only A. ludoviciana, Convolvulus spp. and C. album, in E1; and A. ludoviciana, S. kali, and R. rugosum, in E2 had a significant effect on the wheat yield reduction. Weed economic thresholds were 5.23 TCL in E1 and 6.16 TCL in E2; which were equivalent to 5 plants m-2 of A. ludoviciana or 12 plants m-2 of Convolvulus spp. or 19 plants m-2 of C. album in E1; and 6 plants m-2 A. ludoviciana, 13 plants m-2 S. kali and 27 plants m-2 R. rugosum in E2. Simulations of economic weed thresholds using several wheat grain prices and weed control costs allowed a better comparison of the experiments, suggesting that a more competitive crop at location E1 than at E2 was the cause of a lower weed competitive ability at the first location.

Water use efficiency of cassava plants under competition conditions

The objective of this work was to evaluate characteristics associated with the photosynthetic activity of cassava plants in competition with weeds or not. The trial was performed on open environment conditions, with experimental units consisting of fiber glass vases with 150 dm³ filled with Red Yellow Latosol, previously fertilized. Treatments consisted in the cultivation of cassava plants isolated and associated to three weed species (Bidens pilosa, Commelina benghalensis and Brachiaria plantaginea). After cassava shooting, 15 days after planting, a removal of the weeds excess was performed, sown at the time of cassava planting, leaving six plants m-2 of B. pilosa and four plants m-2 of C. benghalensis and B. plantaginea. At 60 days after emergence (DAE), stomatal conductance (Gs), vapor pressure in the substomatal cavity (Ean), temperature gradient between leaf and air (ΔT), transpiration rate (E) and water use efficiency (WUE) were evaluated. B. pilosa showed greater capacity to affect growth of cassava plants. B. plantaginea is very efficient in using water, especially by presenting C4 metabolism, and remains competitive with cassava even under temporarily low water status. C. benghalensis, in turn, is not a good competitor for light and apparently is not the primary cause of water depletion in the soil. The effects of weeds, in this case, were more associated with the competition. However, they were found between moderate to low. This implies that the competition established at experimental level was low.