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Intestinal nematodes of the Aythyini ducks in Western Pomerania. Biology, including ecology, of the Aythyini renders them particularly attractive subjects of parasitological studies. The tribe is represented in Poland by 4 nesting species; two of them, Aythya fuligula and A. ferina, are very abundant game birds. However, their helminth fauna, including nematodes, is stili very poorly known. This study was aimed at quantifying the structure of parasitic intestinal nematodes of the Westem Pomeranian Aythyini. The study, performed in 1999-2004, involved a total of 71 ducks representing 3 species: A. ferina, A. fuligula, and A. marila. The nematodes, isolated from the intestines, were fixed in 75% ethyl alcohol and cleared in lactic acid. Among the 9668 helminth individuals found, 589 (6.1 %) represented the phylum Nematoda. They were found in 57 ducks (80.3% of all the ducks examined). The nematodes - belonged to the following 4 families: Amidostomatidae, Tetrameridae, Acuariidae, and Trichuridae. They were identified as representing 8 species, 2 genera (Amidostomoides sp. and Tetrameres sp.), and 1 subfamily (Capillariinae gen. sp.); in addition, 1 damaged individual could be identified as a nematode only. The highest prevalence (57 .8%), at mean intensity ( 4.8 inds), was typical of Amidostomoides petrovi (Shakhtahtinskaya, 1956) Lomakin, 1991, while Tetrameres fissispina (Diesing, 1861) Travassos, 1914 occurred with the highest intensity (15.1 inds) and 12.7% prevalence. Nematodes of the subfamily Capillariinae occurred with a fairly high intensity (averaging 10.0 inds) as well, although their prevalence was not high, either (4.2% of all ducks were infected). The nematofauna studied was clearly dominated by A. petrovi, T. fissispina, and Capillaria anatis (Schrank, 1790). The total frequency of occurrence of those species was close to 80%; their dominance indices exceeded the threshold value of 0.1 and amounted to 1.6 (the dominant A. petrovi), 0.2, and 0.5 (the subdominants T.fissispina and C. anatis, respectively). The three species listed occurred with the highest mean density (2.8; 1.9; and 1.8 nematode per duck examined). No age- (adult vs. immature) or sex- (males vs. females) related differences in the quantitative structure of the parasitic Aythyini nematodes were observed.
The reproductive behaviour of brood parasitic birds has been of long-standing interest to evolutionary biologists, but some key features of this breeding tactic are largely unknown in particular species. Here we investigated antiparasitic tactics in ground nesting Common Pochard Aythya ferina females towards intraspecific brood parasitism. Using a conspecific female dummy we experimentally simulated a situation where a female returning to her own nest is confronted with a conspecific parasite. The behaviour of the tested females towards the experimental dummy was compared with their responses towards the stuffed female Ring-necked Pheasant Phasianus colchicus used as a control. The reactions towards both dummies were similar: Pochard females typically swam silently around their nests and observed the dummy. The lack of differences between the measured parameters recorded in the experiments with conspecific and pheasant dummies may indicate that female Pochards do not recognize the conspecific intruder as a specific threat. In addition, the responses of the incubating female towards the conspecific female on her nest were studied using continuous video recordings. The defence was not sufficient, since the intruders were never expelled from the nest. The only rejection technique recorded was that of the parasitic egg being removed from the nest with the aid of the bill. The data indicate that active sophisticated anti-parasitic tactics have not evolved in Pochards, although there is some level of defence towards intruding conspecific parasites.
Specimens previously identified as Fimbriaria fasciolaris or Fimbriaria sp. from Poland, Ukraine and the Czech Republic were re-examined. The revision revealed Fimbriaria czaplinskii from naturally-infected Anas platyrhynchos dom., Anas acuta and Aythya fuligula (new host records) in Poland, Tadorna tadorna from the Black Sea coast and Aythya ferina from the coast of the Sea of Azov, Ukraine (new host records), Anas platyrhynchos, Aythya fuligula and Aythya ferina (the latter two being new host records) from Moravia, Czech Republic (new geographical record). The diagnostic characters of F. czaplinskii are commented and updated from an original erroneous description. The most reliable distinguishing character is the structure of the copulatory part of the vagina, which is funnel-shaped and usually has smooth internal surface. The characters associated with the cirrus size and armament and the number of genital primordia per segment are not considered reliable differentiating characters. A lectotype and paralectotypes of F. czaplinskii are designated.
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