摘要:

Summary.1. The influence of temperature, humidity, food, light, parentage, age, and sex on instar length and its variability inTegenaria atricawas investigated.2. Only one factor of the external environment was varied at a time. The factors were:–20oC, 25‐5oC, and 30oC.; 8‐25, 16‐36, and 23‐13 mm. saturation deficiency; two food levels in excess of the needs for an instar and one at the minimum amount; light and darkness.3. A threshold amount of food was required for completion of an instar, and this quantity was greater when the rate of feeding was lower. It also increased as temperature fell and saturation deficiency rose, but illumination had no effect.4. Instar length decreased as temperature rose, as saturation deficiency fell, and when the animals were illuminated.5. Different amounts of food, provided that they were more than the minimum needed for instar completion, had no effect on its length. An instar which had only the minimum amount was slightly lengthened and the following one, with excess food, was considerably shortened.6. Variance of instar length increased at the lowest humidity, with minimum feeding, and with age, decreased with rise of temperature, and was unaffected by illumination.7. In regard to internal environment, the offspring of various parents fell into three groups, each with its own inherent mean instar length; instar length always increased with age; and the sexes of the animals were indistinguishable.8. The above results and their relation to work on insects are discussed, and it appears that the moult cycle ofT. atricais controlled in a similar manner to that ofRhodnivsandCimex.However, this and other spiders show a striking variability in individual insta

ISSN:0370-2774    

DOI:10.1111/j.1469-7998.1942.tb08488.x

出版商:Blackwell Publishing Ltd    

年代:1942

数据来源: WILEY