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

SIMPLE SUMMARY: Short- and long-term storage potential is an important feature of a biocontrol agent. We estimated survival during storage in the absence of natural food (aphids) and the post-storage fecundity of females of the predatory ladybird Cheilomenes propinqua in relation to temperature (from 7 to 27 °C), air humidity (from 50 to 80–90%), and feeding regime (starved or fed). The experiments showed that under the optimal conditions (temperatures of 15–17 °C and feeding on the grain moth eggs) C. propinqua females can be stored for up to 80 days for future use in mass rearing or the biological control of pests. Short-term storage or transportation (shipment) can occur at a much wider range of temperatures, i.e., from 12 to 27 °C. We conclude that C. propinqua can be successfully used for biological control in greenhouses by preventing colonization, although this would require the regular supplementation of food. Besides this, storage for more than 10 days at temperatures of 7 °C and lower results in 100% mortality; therefore, escaped individuals would not survive the winter even in the south of the temperate zone. ABSTRACT: The ability of the females of the predatory ladybird Cheilomenes propinqua 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 Sitotroga cerealella) conditions. The post-storage reproductive potential was estimated using the mean number of eggs laid over 20 days. The experiments showed that fed females can be stored at temperatures of 15–17 °C for 20 days with a rather low (about 20%) and for up to 80 days with an acceptable (not more than 50%) loss of the reproductive potential. The successful short-term (up to 3 days) storage or transportation of fed and starved females can occur at temperatures from 12 to 27 °C. However, storage for more than 10 days at temperatures of 7 °C and lower results in the 100% mortality of both the starved and fed beetles. These data suggest that (1) in greenhouses, C. propinqua can be used for the biological control of aphids by preventing colonization, although this would require the regular supplementation of factitious food, and (2) escaped individuals would not survive the winter even in the south of the temperate zone.