Effects of cold storage on some biological characteristics of a predatory coccinellid, Oenopia conglobata contaminata reared on non-prey food

The most important coccinellid predator in pistachio orchards, feeding on aphids and psyllids, is Oenopia conglobata contaminata L. (Coleoptera: Coccinellidae). The aim of the present research was to evaluate the effects of a range of cold storage temperatures (4, 8 and 12ºC) in a seven-day cold storage period on some biological parameters of the newly emerged adults of O. conglobata contaminata reared on non-prey food. The replicates were 100, 32 and 30 one-day old adults for 4, 8 and 12ºC, respectively. Each couple of the coccinellids was put into an experimental unit and incubated at 26±1, 60±5% RH and a photoperiod of 16L:8D till death and some biological parameters of the beetle were estimated. The results elucidated that the percent vitality and longevity of the adults markedly increased at 12 and 8°C, respectively. In addition, the longest oviposition and post-oviposition periods were observed at 8°C. The total fecundity and fertility of females significantly had the maximum values at 8°C. Moreover, the number of egg clusters and days in which the oviposition happened significantly elevated at 8°C. The survival rate of the adult coccinellids declined after a seven-day cold storage at 4 and 12°C compared to that obtained at 8°C. The results highlighted the positive effects of the suitable cold temperature (8°C) on the storage of the efficient predator to improve long distance shipment. It could help to enhance the cold storage efficacy and quality of the predator reared to release for biological control programs.