Abstract
AbstractThe optimum temperature for rate of development and survival of immature stages of Coccinella novemnotata Herbst was found to lie between 70° and 80°F. Different photoperiods between 10 and 18 hours per day did not influence rate of development or survival. With a 16-hour photoperiod the mean number of eggs laid per female and mean longevity of females were greater at 70° than at 80°F, but not significantly so. At 90°F egg production was sharply curtailed and most eggs produced were infertile, probably due to inactivation of sperm in the male. Photoperiods of 10, 12, and 18 hours per day induced diapause in a large percentage of adult females; intermediate photoperiods of 14 and 16 hours per day were much less effective. Low temperature and lesser amounts of food available to adult females increased the effectiveness of the short and the long photoperiods for inducing diapause. The stage susceptible to induction of diapause, or conversely the initiation of gonad maturation, was determined to be the young adult from emergence to 7 days of age. The results of experimental data are related to a field study of the biology of this insect in California.
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