Differences in microRNAs and their expressions between foraging and dancing honey bees, Apis mellifera L.

Many studies have established that microRNAs (miRNAs) regulate gene expression in various biological processes in mammals and insects including honey bees. Dancing behavior is a form of communication unique to honey bees. However, it remains unclear which miRNAs regulate the dancing behavior in honey bees, and how. In the present study, total small RNAs (sRNAs) in Apis mellifera foragers and dancers were extracted and analyzed by a Solexa Sequencer to determine differentially expressed miRNAs. A small percentage (12.62%) of the unique sRNAs (the number of sequence types) were shared between foragers and dancers, but their expression accounted for 92.92% of the total sRNAs (the number of all sequence reads), and the length of them centered around 22 nt. Out of 58 previously identified miRNAs, 54 were present in both foragers and dancers and most of them were down-regulated in dancers. The fold-changes of ame-miR-34, ame-miR-210, ame-miR-278 and ame-miR-282 were higher than 2. 86 and 104 novel miRNAs were detected in foragers and dancers, respectively. Furthermore, two known miRNAs (ame-miR-278 and ame-miR-282) were confirmed, by qPCR, to have lower expressions in dancers. The target genes of ame-miR-278 and ame-miR-282 were associated with kinase, neural function, synaptotagmin and energy. These results indicate that miRNAs are substantially different between the foraging and dancing stages, and suggest that miRNAs might play important roles in regulating dancing behaviors in honey bees.

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► Total small RNAs in foragers and dancers were analyzed using new sequencing method.
► Eighty six and 104 novel miRNAs were detected in foragers and dancers, respectively.
► The expression of most known miRNAs in dancers were significantly lower than that in foragers.
► Ame-miR-278 and ame-miR-282 were confirmed to have lower expressions in dancers.
► Most targets of these two miRNAs were associated with kinase, neural function and synaptotagmin.