A study of the interaction of photoperiod and temperature on the biology of the black-margined aphid, Monellia caryella (Fitch)

Abstract

The present study is concerned with the role of photo-period and temperature on the biology of the black-margined aphid. The four principle areas of investigation are duration of life stages, size of individual aphids, fecundity and artificial inducement of sexual forms. Production of sexual forms are blocked by exposing the aphids to a constant environment of 27 [plus or minus] 1°C and 16 hrs light. Sexuals (females) are produced by holding the aphids under short photophase (10 hrs L) and low temperatures (20°C). Nymphal developmental time ranges from 6.85 to 21.86 days when held at 14L:10D-30°C and 10L:14D-20°C, respectively. Mean length of adult life is 13.68 days at 14L:10 D-30°C and as long as a mean of 36.84 at 14L:10D-25°C. The mean number of reproductive days per female is 11.08 at 14 L:10D under 25°C and shortest (3.40 days) at 14L:10D under 30°C. The mean number of offspring per female is highest (107.48) at 14L:10D under 25°C and lowest (11.98) at 10L:14D under 30°C. The size of the body and the fecundity of the aphid is greatly reduced by high temperature (30°C). Optimum temperature and photoperiod regime for body development and fecundity for the regimes studied is 25°C and 14L:10D. Temperatures of 15° and 35°C cause extremely long developmental times or death, respectively. A mathematical model for predicting possible aphid populations is constructed. The resultant model is presented as a Temperature-Photoperiod Index.