Sternostoma tracheacolum was found to be ovoviviparous, laying eggs in the lung of the host.Larvae hatch shortly after oviposition and moult without feeding. Following a blood meal female protonymphs move to the posterior airsacs while male protonymphs tend to stay within the lung to complete development. Gravid females tend to occupy the airsacs, the syrinx and trachea of the host while adult non-gravid, non-gorged females are more commonly found in the upper respiratory system, particularly the buccal and nasal cavities. In vitro rearing experiments and other observations indicate that the life cycle (from egg to adult) is completed in less than 6 days. Transmission is accomplished by the adult non-gravid, non-gorged female and this stage is often encountered on the head plumage, bill and nares of infected birds. Observations on the behaviour and survival of the transmissible indicate a potential for direct transmission between hosts in close proximity and indirect transmission via water, perches or other surfaces. Adult male mites tend to be common in small infrapopulations but uncommon and often absent in large infrapopulations, supporting an argument for parthenogenesis and an arrhenotokous system of sex determination.

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The rhinonyssid and kytoditid mite fauna in the endangered finch E. gouldiae and 6 co-occurring species (long-tailed finches (Poephila acuticauda), masked finches (P. personata), pictorella manikins (Heteromunia pectoralis), zebra finches (Taeniopygia guttata), double-barred finches (T. bichenovii) and budgerigars (Melopsittacus undulatus)) in Northern Territory, Australia, were surveyed over a 3-year period to assess prevalence and intensity of infection and to determine the stability in these parameters over space and time. These data were used to examine the likelihood that prevalence and intensity of infection by the rhinonyssid mite Sternostoma tracheacolum in E. gouldiae are in any way aberrant. 12 new host records for rhinonyssid and kytoditid mites are reported from 2 localities in the Northern Territory. Kytonyssus andrei is a new genus record and S. paddae and Kytodites amandavae are new species records for Australia. S. tracheacolum was found to infect E. gouldiae, P. personata, M. undulatus and H. pectoralis. The other nasal mites found were Sternostoma sp., Ptilonyssus astrildae, P. neochmiae and P. emberizae. Prevalence and intensity of infection with S. tracheacolum were significantly higher in E. gouldiae than in Poephila personata and M. undulatus, but were not significantly higher than those found in H. pectoralis. The frequency distribution of infrapopulation sizes of S. tracheacolum in pooled E. gouldiae samples was significantly different from that found in pooled M. undulatus and P. personata samples but not from pooled H. pectoralis samples. Prevalence and intensity of infection by rhinonyssid mites in E. gouldiae were significantly higher than infection in all other host species examined, except H. pectoralis. Significant increases in the intensity of infection in H. pectoralis were detected between 1992-94, suggesting that this species may also be under threat from parasitism by S. tracheacolum.