Abstract

Ecological peculiarities in development of exogenous stages of Nematodirus nematodes include some important aspects of their survival and distribution at different abiotic factors. The aim of this work was laboratory study of some biological peculiarities of Nematodirus spathiger exogenous stages (Railliet, 1896) taken from cattle and grown at different temperatures (+20°C, 23°C, 26°C, 29°C and 32°C). The temperature was found significantly affects the period of exogenous development of N. spathiger eggs, both until L3 and on individual stages. Temperature also effects nematodes survival both eggs and hatched L3. At 32°C, the survival rates of eggs and hatched L3 were the highest, with the shortest period of development. At this temperature, L3 hatching was completed by day 10, and their survival was 94.3%. As temperature decreased, the time of L3 exogenous development prolonged, and survival rates were less: at 29°C – 12 days and 91.9%, at 26°C – 18 days and 86.7%, at 23°C – 22 days and 80.0%, at 20°C – 30 days and 56.7%, respectively. During the development of N. spathiger eggs, their length and shell thickness decreased by 10.6 and 22.6%, respectively, and their width increased by 10.5%. Also, changes in morphometric parameters during L3 maturation were observed, length and percent of filament to STE increased by 7.1 and 7.8%, and body width, thickness of sheath, and STE length decreased by 40.4%, 37.9%, and 8.8%, respectively.