In a honey bee colony, worker bees rear a new queen by providing her with a larger cell in which to develop and a
large amount of richer food (royal jelly). Royal jelly and worker jelly (fed to developing worker larvae) differ in
terms of sugar, vitamin, protein and nucleotide composition. Here we examined whether workers attending
queen and worker larvae are separate specialized sub-castes of the nurse bees. We collected nurse bees attending
queen larvae (AQL) and worker larvae (AWL) and compared gene expression profiles of hypopharyngeal gland
tissues, using Solexa/Illumina digital gene expression tag profiling (DGE). Significant differences in gene expression
were found that included a disproportionate number of genes involved in glandular secretion and royal jelly
synthesis. However behavioral observations showed that these were not two entirely distinct populations. Nurse
workers were observed attending both worker larvae and queen larvae, and there was no evidence of a specialized
group of workers that preferentially or exclusively attended developing queens. Nevertheless, AQL attended
larvae more frequently compared to AWL, suggesting that nurses sampled attending queen larvae may have been
the most active nurses. This study serves as another example of the relationship between differences in gene expression
and behavioral specialisation in honey bees