Biased sex ratio and niche restriction in Baruscapillaria obsignata (Madsen 1945) (Nematoda, Capillariidae) from Columba livia (Aves, Columbidae).

In the present study populations of the avian nematode species Baruscapillaria obsignata are described from Columba livia. Male and female individuals were obtained from 27 birds, fixed in alcohol/formalin/acetic acid (AFA) and preserved in 70% ethanol. Nematodes were identified and then counted under a stereoscopic microscope. Baruscapillaria obsignata were much more frequent in the anterior third of the small intestine, and females were more abundant than males in all infra populations. The prevalence was 55.6%, mean intensity was 11.8 (median 11.0; range 1-31) and abundance 6.56. In the present study, we observed an aggregated distribution of parasite infrapopulations, as demonstrated by the value of the exponent of the negative binomial distribution, K = 0.2773; by the discrepancy index, D = 0.656 and by the variance/mean ratio, 12.44. The female/male sex ratios found in all infrapopulations were always greater than 1, showing a bias in favour of female abundance. This tendency was especially marked in infrapopulations containing fewer individuals. The sizes of infrapopulations ranged from 5 to 31 individuals. The mean sex ratio observed was 2.69 ± 3.28 (median 1.83; range 0-11). In infrapopulations with 5-15 individuals, the sex ratios observed varied from 2.6 to 11, while in those with 17-31 individuals, the sex ratios were lower, ranging from 1.7 to 2.4. There was a negative correlation between the intensity of infection and the sex ratio of infrapopulations. Results are discussed in terms of possible factors influencing the processes that lead to niche restriction and biased sex ratios in parasite infrapopulations.

Atividade anti-helmíntica de plantas em frangos de corte naturalmente infectados com Ascaridia galli / Anthelminthic activity of plants in broiler chickens naturally infected with Ascaridia galli

The anthelminthic activity of four plants - Allium sativum (garlic), Punica granatum (pomegranate), Tynnanthus labiatus (liana-carnation) and Cocus nucifera (coconut) with the activity of mebendazole was compared. Seventy Hubbard chickens, naturally infected with Ascarídia galli, divided in 5 groups of 10 chichens plus a control group (not treated, n=20) were used in the experiment. The vegetable matter was used in the forms of aqueous extract, juice and triturated, administered by probe or incorporated to the diet, in the doses of 2, 3 and 10glkg/day, for three days. A non parametric test was used to evaluate the anthelminthic effect of the plants. The eliminations of A galli for the garlic, pomegranate, lianacarnation, coconut and mebendazole were: 9.7; 6.6, 16.7; 19. 0 and 99. 0, respectively. The results showed that those plants do not have anthelminthic activity.

Structure of the community of the Strongylidae nematodes in the dorsal colon of Equus caballus from Rio de Janeiro state--Brazil.

The structure of the community of Strongylidae nematodes in the dorsal colon of naturally infected horses from the metropolitan region of Rio de Janeiro State was evaluated in 33 samples. Twenty-three species were found: Cylicostephanus longibursatus, Cylicostephanus goldi, Cylicocyclus nassatus and Cyathostomum tetracanthum were the central ones; Cylicostephanus minutus, Cylicostephanus calicatus, Cylicocyclus leptostomus, Cylicodontophorus bicoronatus and Parapoteriostomum euproctus were secondary, and there were 14 satellite species. The community was considered stable, with positive associations and correlations, no significant negative associations and correlations, suggesting little competition among species.