1.4.1. Freezing

Freezing at -80ºC is the gold-standard for long-term storage of bee samples intended for RNA analysis. Freezing at -20ºC also provides good storage for preserving the quality of bee samples. However, significant to complete degradation of RNA can occur within days in dead bees kept at 4°C (Chen et al., 2007; Dainat et al., 2011). It is therefore strongly recommended to transfer frozen bees to the -80°C freezer immediately after samples are brought back from the field to the laboratory, if analysis is not initiated immediately.