Breev K A, Sultanov F R
Parazitologiia. 1975 Jan-Feb;09(1):47-56.
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.
为了找出在其分布区域南部影响羊狂蝇两代虫存在的因素，对一龄幼虫（3718个样本）的体长以及二龄和三龄幼虫（1460个样本）的体重进行了定期测量。这些观察是在阿塞拜疆低洼和山麓地带的两群绵羊中进行的。统计分析表明：a）在鼻腔和鼻甲壁上栖息的体长为1.76 - 2.20毫米的一龄幼虫出现生长抑制，这在秋 - 春季世代中尤为明显（它们孵化时的平均体长为1.08 ± 0.004毫米）；这种抑制与种群间关系有关，显然不取决于其开始时间，可持续6至7个月；c）生长恢复后，发育持续进行直至蜕皮；二龄幼虫开始时也可能出现抑制，然后发育无间断地进行直至幼虫完全成熟。羊狂蝇种群中一龄幼虫的总数比二龄和三龄幼虫的总数高出两倍。这表明一龄幼虫发育期间幼虫的死亡率很高。
