Possible interactions between gut microbiome and division of labor in honey bees

Abstract

Recent studies have provided new insights into the role of the microbiome in shaping host behavior. However, the relationship between the temporal division of labor among honey bees (Apis mellifera) and their gut microbial community has not been widely studied. Therefore, we aimed to evaluate the link between the gut microbiome and division of labor in honey bees by examining the microbial absolute abundance and relative composition of 7-day-old nurse bees and 28-day-old forager bees from a natural hive, as well as those of worker bees of the same 14-day-old age showing different behaviors in a manipulated hive. We found that forager bees had fewer core bacteria, particularly gram-positive fermentative genera such as Lactobacillus and Bifidobacterium, with Bifidobacterium asteroides being the most sensitive to host behavioral tasks. Our results showed that forager bees have lower gut community stability compared to nurse bees, suggesting that their gut community is more susceptible to invasion by non-core members. Furthermore, a pollen limitation experiment using caged honey bees indicated that dietary changes during behavioral shifts may be a driving factor in honey bee microbial diversity. This study contributes to a greater understanding of the interaction between the gut microbiome and behavioral tasks and provides a foundation for future assays.

Keywords: division of labor; gut microbiome; honey bee; pollen.

FIGURE 1

Honey bee gut microbiome abundance in natural nurse and forager bees. (a) and (b) Total 16S rRNA gene copies from all bacteria. N_7d: 7‐day‐old nurse bees; F_28d: 28‐day‐old forager bees. (c) Absolute copy numbers of five core bacterial species. Forager bees had lower total and core bacterial abundances. Significance was set at **p < .01.

FIGURE 2

Honey bee gut microbiome composition in natural nurse and forager bees. (a) Relative abundances of the five core bacterial species. (b) Differences in alpha and beta diversities between the gut microbiomes of the two types of honey bees. (c) Principal coordinate analysis (PCoA) using weighted UniFrac distances. Significance was set at *p < .05, **p < .01.

FIGURE 3

Honey bee gut microbiome composition in 14‐day‐old manipulated nurse (N_14d) and forager (F_14d) bees. Absolute (a, c) and relative (b, d) abundance of total and affected core bacterial members. Forager bees had lower total and core bacterial abundances. Significance was set at **p < .01, ***p < .001.

FIGURE 4

Honey bee gut microbiome composition in 14‐day‐old manipulated nurse (N_14d) and forager (F_14d) bees.

FIGURE 5

(a) Absolute and (b) relative abundance of the gut microbiome in honey bees fed varying amounts of pollen. Significance was set at *p < .05, **p < .01.

FIGURE 6

Absolute and relative abundance of all core bacterial species in the gut community of bees fed varying amounts of pollen. Significance was set at *p < .05, **p < .01, ***p < .001.