著者

福島 正三 宮藤 守雄

出版者

北日本病害虫研究会

雑誌

北日本病害虫研究会報 (ISSN:0368623X)

巻号頁・発行日

vol.1970, no.21, pp.5-12, 1970-11-20 (Released:2011-08-11)

参考文献数

18

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Ten years ago, about 40 species of spiders were recorded from the apple or chard by the senior author, while engaged in a study of the effects of spray programs on pest population and beneficial organisms (HUKUSIMA, 1961). Of these collections Misumenops tricuspidatuswas considered first as an important predator of orchard pests, because of its universal occurrence and frequent abundance. But almost nothing is known of the bionomics of this species up to date. From an economic side, at present, the first thing to do in analysing the property of the hunting spider as regulating agents in orchards is to know some aspects of life histories and habits.Based on the field survey, M. tricuspidatus hibernates in various instars of nymphal period and adult stage from November among the ground cover of fallen leaves and dead herbaceous plants, but adults or larger immature stages are the most case which is frequently observed during winter in orchards. As the season advanced, overwintered adults and immatures leave their hibernation qua ters on warm days in following early March, and rest on the trunks and branches of fruit tree. Meanwhile, the peaks of seasonal occurrences were formed over 3 times, on mid-April, early July early August and mid-October.According to the observations in a insectary, the mating takes place mostly in the daytime without food intake except particular case. At the time of oviposition, the female builds a crude nest by tying two or more overlapping leaves together and constructs the lenticular egg-sac within it. Thus the 1st egg-sacs were produced on late May early July, and next during the period from late August to early October. In this case, the number of eggs per egg-sac varied with different seasons, and an average of 163.1 and 87.7 eggs per egg-sac was counted corresponding with above seasons respectively.M. tricuspidatus mostly feed on living organisms like other spider species, but under the fasting condition they sometimes utilize the dead arthropods. Such a habit would servefor the recovery from exhaustion by hunger. In contrast to male behavior, the feeding activity of females does not become weak after they reached adulthood, but 7 times of male meal per day were consumed when prey was supplied in suitable number. The daily food consumption of immature stages, as a rule, increases keenly about 2 days after moulting, and also adult females tend to increase their foods just after the final moulting and mating.With regard to the number of moults, all individuals reared did not moult in the same number, but they moulted 5 to 9 times after leaving the egg-sac. In this context, it is well known fact that the number of moults necessary for maturity in many species of spiders is somewhat variable, and may be increased under unfavorable conditions. This assumption would seem easily to admit in the present case. Namely the phenomenon that the number of moults in M. tricuspidatus increases under the lower rearing temperature and with the decrease of food supply, was clearly evidenced. Further this tendency strongly appeared in the females than in the males.Already as a few case was mentioned, a considerable variation of life histories and habits under different temperature conditions is thought to be worthy of notice. As might be expected, within 25-30°C the duration of each instar shortened with increasing temperature, and at the same time much more foods were consumed at higher temperature condition, though the feeding intensity was not necessarily indicated in the same pattern between males and females. On the other hand, the number of egg-sacs per female was somewhat more under 25°C, and the rate of hatching was also higher than that under 30°C.