Genome‐wide analysis of genes related to ovary activation in worker honey bees

Abstract

A defining characteristic of eusocial animals is their division of labour into reproductive and nonreproductive specialists. Here, we used a microarray study to identify genes associated with functional sterility in the worker honey bee Apis mellifera. We contrasted gene expression in workers from a functionally sterile wild-type strain with that in a mutant (anarchist) strain selected for high rates of ovary activation. We identified a small set of genes from the brain (n = 7) and from the abdomen (n = 5) that are correlated in their expression with early stages of ovary activation. Sterile wild-type workers up-regulated two unknown genes and a homologue of Drosophila CG6004. By contrast, reproductive anarchist workers up-regulated genes for the yolk protein vitellogenin, venom peptides and a member of the AdoHycase superfamily, among others. The differentially expressed genes identified are likely to be involved in early differentiation into sterile and reproductive worker phenotypes and may therefore form part of the gene networks associated with the regulation of honey bee worker sterility. Our study may have lacked sufficient power to detect all but a minority of biologically relevant changes taking place; however, the differential expression of vitellogenin and a putative AdoHycase suggests that our screen has captured core reproductive genes and that ovary activation may involve an epigenetic mechanism.

The transcriptomic and evolutionary signature of social interactions regulating honey bee caste development

“…Over longer periods of time following queen loss and unsuccessful queen rearing, additional sets of genes change expression patterns in a subset of workers that activate their ovaries and begin laying unfertilized drone eggs (Thompson et al. 2008; Cardoen et al. 2011).…”

Factors affecting ovary activation in honey bee workers: a meta-analysis

“…Likewise, genetic factors included natural mutants or strains (e.g. Thompson et al, 2008), response to selection experiments (e.g. Amdam et al, 2007;Wang et al, 2009) and pedigree analysis (e.g.…”

Queen mandibular pheromone modulates hemolymph ecdysteroid titers in adult Apis mellifera workers

“…Because we work with commercially available lines that are not heavily selected for specific traits, we suggest our results reflect a more typical condition for ovaries in worker honey bees. Genetic sources of variation, such as directional behavioral selection for pollen hoarding (Amdam et al 2010) or patriline selection for traits such as anarchy (Thompson et al 2008), have been shown to increase the tendency of workers to activate their ovaries (Backx et al 2012). Heavy selection for behavioral traits may result in loss or masking of subtle aspects of physiological regulation.…”