Effects of Two Prey Species Combinations on Larval Development of the Predatory Ladybird .

Feeding on mixed, alternating, or changing diets often favor insect development. With the aim to optimize mass rearing and use for the biological control of insect pests, we investigated the effects of various combinations of high-quality (the green peach aphid ) and low-quality (eggs of the grain moth ) foods on the larval development of a predatory ladybird In the first experiment, eggs and aphids were mixed in different proportions; in the second experiment, larvae switched from feeding on aphids to feeding on eggs. Although the beneficial additive effect of mixed foods was detected in some treatments with limited diets, feeding on various combinations of eggs with aphids never resulted in higher survival, faster development, or a larger size of emerging adults than those observed for feeding on unlimited amounts of aphids.

Signal and Nutritional Effects of Mixed Diets on Reproduction of a Predatory Ladybird, .

It is known that food has a double impact on females of predatory ladybirds: qualitative signal effect (the onset of oogenesis) and quantitative nutritional effect (the increase in oogenesis intensity). We compared the patterns of these effects by feeding females on mixed diets: unlimited low-quality prey (eggs of the grain moth ) and limited high-quality prey (the green peach aphid : 0, 2, 10, and 50 aphids per day). About half of the females fed only on the grain moth eggs oviposited and their fecundity was very low.

Storage Potential of the Predatory Ladybird in Relation to Temperature, Humidity, and Factitious Food.

The ability of the females of the predatory ladybird to survive and to retain reproductive potential in the absence of natural food (aphids) was estimated under various hydrothermal (temperatures of 7, 12, 17, 22, and 27 °C; air humidities of 50% and 80-90%) and trophic (starved vs. fed on the frozen eggs of the grain moth ) conditions. The post-storage reproductive potential was estimated using the mean number of eggs laid over 20 days.