An ecological and biological study was carried out on the preda-ceous soil mite Holaspina soften( (Metwals), (Parholaspidae : Gamasida). Seven types of diets were used. Results showed that developmental du‌ration between female and male did not vary much. Female life cycle ranged between 11.9 and 15.7 days, while it was 11 to 14 days for male. Rhabditis scanica was the most suitable diet, as it gave the highest fecundity of 41 eggs / female. Increase of temperature from 20 to 30°C reduced developmental duration of all stages and the life cycle as well. Total egg deposition and daily rate were higher at 25°C than at 20 or 30°C, while longevity and life span were shorter at 25°C than the other two aforementioned de-grees. Exposure to alternating temperature 10 / 20 and 15 / 20 was studied. Life cycle increased by 64 % and 47 % when the 2 regimes were used, respectively, compared with obtained values at only 20°C. Life span prolonged by 29 % and 17 %. Fecundity per female was re-duced to 47 % and 61 % under the two regimes. Exposing eggs to the same alternating temperature degrees increased gradually the incubation period, while hatchability decreased from 96.9 to 26.7 %. Presence of males did not affect longevity, while absence of males resulted in pro‌duction of only males and lowest fecundity (16.4 eggs / female). Pres‌ence of the male (once every 5 days) or allover female longevity gave high fecundity and female sex ratio.