Collection of viable honey bee (Apis mellifera) larvae after hatching in vitro

Many techniques currently under development in bee research, including the cloning, genetic manipulation and cryopreservation of embryos, require the rearing of larvae and adults from eggs that may have a reduced chance of survival if introduced into colonies. Obtaining viable larvae from in vitro-rearing of eggs is work intensive, because the duration of embryonic development is highly variable and neonate larvae only survive for a short time without food. We therefore developed and tested 14 protocols to prolong the survival of larvae after hatching in an incubator. The common goal of these techniques was to install the eggs in a way that enabled the larvae to reach food at the moment they hatched. Larvae obtained with the most successful protocol were then reared into queens, in order to evaluate their capacity to continue development. With the best protocol tested, 74.6% of eggs could be retrieved as living larvae when collected at intervals of 12 h, and 56.7% of eggs could be reared into queens. Three different methods to prolong the survival of hatching larvae are described in detail, and their relative usefulness is discussed.