Difference between uncapping and removal behaviors in Apis cerana from the perspective of long non-coding RNAs

Abstract Background Hygienic behavior has been identified as a specific type of immune response that has evolved in social insects, in which it contributes to preventing the spread of diseases throughout insect colonies. In bee colonies, such hygienic behavior entails the dual steps of uncapping and removal of dead and diseased larvae and pupae. Although in recent years, numerous studies have examined the development of hygienic behavior among bees, the mechanisms underlying the division in the performance of uncapping and removal have yet to be sufficiently elucidated. In this regard, long non-coding RNAs (lncRNAs) have been evidenced to be engaged in regulating the physiological activities of honeybees; however, whether lncRNAs are similarly involved in the uncapping and removal behaviors of these bees has not been clarified. Results In this study, the strong hygienic Apis cerana worker bees were used and the processes of uncapping and removal behaviors in three colonies were assayed with freeze-killed brood in the field. We then sequenced the antennal RNAs of honeybees to identify differentially expressed lncRNAs and performed lncRNA–mRNA association analysis to establish the differences between uncapping and removal. We detected 1323 differentially expressed lncRNAs in the antennae, and the findings of lncRNA–mRNA association analyses revealed that the target genes of differentially expressed lncRNAs between uncapping and removal worker bees were mainly annotated to response to stimulus, receptor activity, and synapse. Among the lncRNAs enriched in cellular response to stimulus, XR_001766094.2 was identified to be uniquely expressed in the uncapping workers bees. We accordingly speculate that by responding to external stimuli, XR_001766094.2 may play a key role in the distinction between uncapping and removal, thereby indicating that the division of hygienic behaviors is determined by a differential response to environmental stimuli. Conclusion We characterized differences in the uncapping and removal behaviors of worker bees from perspectives of lncRNAs. The uncapping bees may equip with a more rapid stimulatory response and more acute olfactory sensitivity, contributing to the rapid hygienic behavior in honeybee colonies. Our study thus laid the foundation for the potential lncRNA-mediated expression regulation of genes in hygienic behavior.