title: [The development of the larvae of the sheep nasopharyngeal botfly, oestrus ovis l. (diptera, oestridae)].
abstract: In order to find out factors affecting the presence of two generations of O. ovis in the southern parts of its distribution area there were conducted regular measurements of the body length of the Ist instar (3718 specimens) and weight of the IInd and IIId instar larvae (1460 specimens). These observations were carried out in two herds of sheep in low-lying and foothill zones of Aserbaijan. Statistical analysis has shown the following: a) the growth inhibition, which is especially distinct in autumn-spring generation, takes place in the Ist instar larvae 1.76-2.20 mm long inhabiting the walls of the nasal cavity and concha (their average body length at hatching is 1.08 plus or minus 0.004 mm); the inhibition is associated with interpopulation relations and apparently does not depend on the date of its beginning and can last from 6 to 7 months; c) after the growth resumption the development continues uninterruptedly up to the moulting; the inhibition is also possible at the beginning of the 2nd instar and then the development proceeds without any intervals up to the complete maturation of larvae. The total number of the Ist instar larvae in the bot fly populations is two times higher than that of the IInd and III-instars. This points to a high mortality of larvae during the Ist instar developmental period.
mesh_terms: D000818:Animals; D001382:Azerbaijan; D004175:Diptera / Q000254:growth & development*; D005260:Female; D005843:Geography; D007814:Larva; D008297:Male; D009305:Nasopharynx / Q000469:parasitology; D012621:Seasons; D012756:Sheep / Q000469:parasitology*
vernacular_title: O nekotorykh osobennostiakh razvitiia lichinok nosoglotochnogo ovoda ovets oestrus ovis l. (diptera, oestridae)