Chill sensitivity and cryopreservation of eggs of the greater wax moth Galleria mellonella (Lepidoptera: Pyralidae)

Abstract

There is an increasing need for methods of cryopreservation of arthropods. In particular, Lepidoptera are extremely important in entomological applications for the protection of agricultural crops and forest ecosystems and also in many aspects of biodiversity conservation. Yet, few studies have dealt with cryopreservation techniques in species of this insect order. The aim of this study was to examine the chill sensitivity of eggs of the greater wax moth Galleria mellonella (L.) and the possibility to cryopreserve the eggs by vitrification methods. One day-old eggs were dechorionated with water solutions of 1.25% sodium hypochlorite and 0.04% Tween 80, treated with cryoprotective agents in two steps, subjected to rapid cooling by immersion in LN and stored in a mechanical freezer for 48 h at −140 °C. They exhibited survival rates of 1.6 ± 0.5% after being cooled in LN and 0.6 ± 0.2% after being stored in the mechanical freezer. 92.9% of the larvae that hatched from cryopreserved eggs completed development regularly, producing adults that bred and laid fertile eggs. The hatching rate of eggs in the F1 and F2 generations was higher than 90%. Adult emergences of the progeny of eggs stored at ultra-low temperatures allowed us to establish a laboratory colony.