THE INFLUENCE OF PHOTOPERIOD ON DEVELOPMENT AND REPRODUCTIVE MATURATION OF MACROLOPHUS PYGMAEUS (HEMIPTERA, MIRIDAE)

摘要

The effects of day length on the development and reproductive maturation of the zoophytophagous bug, Macrolophus pygmaeus (= M. nubilis), were investigated in laboratory using two strains originated from the environs of Rome, Italy (41.75 degrees N, 12.30 degrees E and 41.95 degrees N., 12.80 degrees E) and Sochi, Krasnodar Krai, Russia (43.9 degrees N, 39.3 degrees E). The insects were kept under day length of either 10 or 16 h at the constant temperature of 20 degrees C. Nymphs and adults were fed with eggs of grain moth. The embryonic development lasted 18-20 days, the nymphal development - 25-30 days, and the reproductive maturation of females - 4-6 days. The short day length (10 h) resulted in the 1-2-day prolongation of nymphal development period and a longer maturation period in individuals from both strains, whereas the duration of the embryo developmental period was independent of photoperiod. Under both photoperiods, males developed faster than females. Under the short day length, females of the Rome strain matured markedly faster than those of the Sochi strain. The faster development under low temperature and a stronger tendency to delay the reproductive maturation observed in the Sochi strain could be explained by a relatively fast (when compared with Rome) autumnal decrease in temperature. The mechanism and adaptive value of the long-day acceleration of development are not yet clear.