The Reduviid, Agriosphodrus dohrni Signoret, has but one generation a year. The duration of each developmental period is : 40 days for the eggs, 24 days for the first stage nymphs, 18 days each for the second and third, 32 days for the fourth and about 7 months for the last stage nymphs. In the life-history studies conducted in the field, the entire developmental period (egg to adult) was never less than 11 months. Variations in the length of the developmental period appear to be due primarily to fluctuations in the length of the nymphal life which is very much influenced by the amount of food. This species spends the winter in the fifth nymphal stage. From December to February in the following year the nymphs do not take food. At room temperatnres the longevity of the adult stage ranged from 17 to 73 days. Copulation is performed in such a position as the male lying dorsally to the female. The male grips his mate with all of his legs, and his rostrum rests on the pronoturn of the female. Oviposition occurs in late May. The newly hatched nymphs do not move away from the ootheca for three to seven days. At night or on the rainy days the nymphs would aggregate themselves in a certain favourite habitat. This habitat is changed several times according to the different conditions of the season. The overwintering habitat is restricted to such a place as having the maximum high temperature at night. In all the nymphal stages this Reduviid has its favourite habitat, where a number of individuals are aggregating during night as given in my first report. This habit may be regarded as a peculiar and well developed one of the types among insect aggregations.
Mendeley出力
