The biological bases of wanting have been characterized in mammals, but whether an equivalent wanting system exists in insects remains unknown. In this study, we focused on honey bees, which perform intensive foraging activities to satisfy colony needs, and sought to determine whether foragers leave the hive driven by specific expectations about reward and whether they recollect these expectations during their waggle dances. We monitored foraging and dance behavior and simultaneously quantified and interfered with biogenic amine signaling in the bee brain. We show that a dopamine-dependent wanting system is activated transiently in the bee brain by increased appetite and individual recollection of profitable food sources, both en route to the goal and during waggle dances. Our results show that insects share with mammals common neural mechanisms for encoding wanting of stimuli with positive hedonic value.

The ethological study of dance behaviour has yielded some findings since Karl Von Frisch discovered and interpreted the ‘dance language’ in the honey bee. However, the function and role of long non-coding RNAs on dance behaviour are hardly known until now. In this study, the differential expression patterns of lncRNAs in the brains of waggling dancers and non-dancing bees were analysed by RNA sequencing. Furthermore, lncRNA-mRNA association analysis was constructed to decipher the waggle dance. The results of RNA sequencing indicated that a total of 2877 lncRNAs and 9647 mRNAs were detected from honey bee brains. Further comparison analysis displayed that two lncRNAs, MSTRG.6803.3 and XR_003305156.1, may be involved in the waggle dance. The lncRNA-mRNA association analysis showed that target genes of differentially expressed lncRNAs in the brains between waggling dancers and non-dancing bees were mainly annotated in biological processes related to metabolic process, signalling and response to stimulus and in molecular function associated with signal transducer activity, molecular transducer activity and binding. Nitrogen metabolism was likely implicated in the modulation of the waggle dance. Our findings contribute to further understanding the occurrence and development of waggle dance.

Growing evidence indicates that host behaviors are regulated by the gut-brain interaction. In honeybees (Apis mellifera), a critical defensive behavior is the sting extension reflex. However, it remains unclear how the gut microbiota affects aversive learning and memory of this behavior. Here we demonstrate that the normal gut microbiota contributes to aversive learning and memory of the sting extension reflex in honeybees. Metabolomics analysis reveals that the gut microbiota affects tyrosine metabolism of the gut and hemolymph. Oral reintroduction of Enterococcus faecium or Enterococcus faecalis restores aversive learning and memory of microbiota-free honeybees, with an increase in their brain dopamine levels by supplying exogenous tyrosine. Conversely, applying fluphenazine, which decreases brain dopamine levels, weakens aversive learning and memory of honeybees in normal hives. These findings provide insights into the role of gut bacteria in regulating aversive learning and memory in honeybees, highlighting beneficial effects of the gut microbiota on the cognitive behaviors of social insects.

Sacbrood virus (SBV) is a significant problem that impedes brood development in both eastern and western honeybees. Whole-genome sequencing has become an important tool in researching population genetic variations. Numerous studies have been conducted using multiple techniques to suppress SBV infection in honeybees, but the genetic markers and molecular mechanisms underlying SBV resistance have not been identified. To explore single nucleotide polymorphisms (SNPs), insertions, deletions (Indels), and genes at the DNA level related to SBV resistance, we conducted whole-genome resequencing on 90 Apis cerana cerana larvae raised in vitro and challenged with SBV. After filtering, a total of 337.47 gigabytes of clean data and 31,000,613 high-quality SNP loci were detected in three populations. We used ten databases to annotate 9359 predicted genes. By combining population differentiation index (F_ST) and nucleotide polymorphisms (π), we examined genome variants between resistant (R) and susceptible (S) larvae, focusing on site integrity (INT < 0.5) and minor allele frequency (MAF < 0.05). A selective sweep analysis with the top 1% and top 5% was used to identify significant regions. Two SNPs on the 15th chromosome with GenBank KZ288474.1_322717 (Guanine > Cytosine) and KZ288479.1_95621 (Cytosine > Thiamine) were found to be significantly associated with SBV resistance based on their associated allele frequencies after SNP validation. Each SNP was authenticated in 926 and 1022 samples, respectively. The enrichment and functional annotation pathways from significantly predicted genes to SBV resistance revealed immune response processes, signal transduction mechanisms, endocytosis, peroxisomes, phagosomes, and regulation of autophagy, which may be significant in SBV resistance. This study presents novel and useful SNP molecular markers that can be utilized as assisted molecular markers to select honeybees resistant to SBV for breeding and that can be used as a biocontrol technique to protect honeybees from SBV.

Nano-La ₂ O ₃ invades honeybee brains and increases neuronal apoptosis, resulting in impaired olfactory reward learning and memory.