Abstract
Endoparasitic mites on anatid birds were investigated. The survey was carried out in Shinhama, Chiba prefecture and in Koshigaya, Saitama prefecture during the period from November, 1967 to February, 1968. The total of 489 anatid birds consisted of 6 species were examined. 1) Two species of nasal mites, which have not been reported in Japan, were collected from the anatid birds. These were Rhinonyssus rhinolethrum (Trouessart, 1895) and Trispeleognathus womersleyi (Fain, 1955). 2) The six species of host birds examined were pintail, Anas acuta acuta Linne, 1758; teal, Anas crecca crecca Linne, 1758; wigeon, Anas penelope Linne, 1758; shoveller, Anas clypeata Linne, 1758; spot-billed duck, Anas poecilorhyncha zonorhyncha Swinhoe, 1866 and mallard, Anas platyrhynchos platyrhynchos, Linne, 1758. In addition, domestic ducks were examined in the two different places of the survey. 3) Rhinonyssus rhinolethrum was collected from 169 birds of 489 examined (34.6% of infestation rate), which were distributed to all 6 species in the survey. The infestation rate of wigeon by this mite was highest (73.5%). These of pintail, teal, shoveller, spot-billed duck, and mallard were 40.5%, 20.6%, 17.6%, 11.1% and 2.2% respectively. Trispeleognathus womersleyi was collected only from pintail and mallard. Their infestation rates were 16.4% and 4.4% respectively. 4) Majority of pintail and wigeon were found to be infested by less than 5 mites of Rhinonyssus rhinolethrum or Trispeleognathus womersleyi if infested. 5) Of the 171 domestic ducks examined, 84 were used as decoy birds, among which 8 were found to be infested by nasal mites. The rest of the domestic ducks were found not to be infested by them.
