Regulation of behaviorally associated gene networks in worker honey bee ovaries

Abstract

Fat body expression of hormone receptor-like in 46 (HR46) and phosphoinositide-dependent kinase-1 (PDK1) correlates with ovary size as well as worker division of labor (Wang et al., 2009). HR46 is a possible nuclear hormone receptor for ecdysteroid hormones Accepted 28 September 2011 SUMMARY Several lines of evidence support genetic links between ovary size and division of labor in worker honey bees. However, it is largely unknown how ovaries influence behavior. To address this question, we first performed transcriptional profiling on worker ovaries from two genotypes that differ in social behavior and ovary size. Then, we contrasted the differentially expressed ovarian genes with six sets of available brain transcriptomes. Finally, we probed behavior-related candidate gene networks in wild-type ovaries of different sizes. We found differential expression in 2151 ovarian transcripts in these artificially selected honey bee strains, corresponding to approximately 20.3% of the predicted gene set of honey bees. Differences in gene expression overlapped significantly with changes in the brain transcriptomes. Differentially expressed genes were associated with neural signal transmission (tyramine receptor, TYR) and ecdysteroid signaling; two independently tested nuclear hormone receptors (HR46 and ftz-f1) were also significantly correlated with ovary size in wild-type bees. We suggest that the correspondence between ovary and brain transcriptomes identified here indicates systemic regulatory networks among hormones (juvenile hormone and ecdysteroids), pheromones (queen mandibular pheromone), reproductive organs and nervous tissues in worker honey bees. Furthermore, robust correlations between ovary size and neural-and endocrine response genes are consistent with the hypothesized roles of the ovaries in honey bee behavioral regulation. Supplementary material available online at

The gene vitellogenin affects microRNA regulation in honey bee (Apis mellifera) fat body and brain

“…Our challenge is to understand how those remote signals are integrated. Recent work suggests that tissues as diverse as brain and ovary are regulated by the same systemic factors such as JH, ecdysteroids and Vg that form a global network that modulates individual behavior (Wang et al, 2012a;Wang et al, 2012b). Our findings suggest that microRNAs can be part of this network, potentially acting both within tissues as local signals and between tissues as remote signals.…”

“…New evidence makes it increasingly likely that ecdysteroids influence honey bee social behaviors (Velarde et al, 2009;Wang et al, 2009;Wang et al, 2012b), and we have identified microRNAs Table S1 for definitions and information on the gene symbols.…”

Starvation stress during larval development facilitates an adaptive response in adult worker honey bees (Apis mellifera L.)

“…Here, we were able to use a one-tailed test for TYR1 because we had a priori expectations of a reduction in TYR1 expression in the bees that experienced starvation during development. Previously, we found that the bees with fewer ovarioles had less TYR1 mRNA (Wang et al, 2012b; Y.W., G.V.A. and R.E.P., unpublished data).…”

“…We used a one-tailed test for TYR1. We expected a priori TYR1 down-regulation because of a consistent correlation between ovariole number and TYR1 mRNA levels in other studies (Wang et al, 2012b; Y.W., G.V.A. and R.E.P., unpublished data).…”

“…2). Although worker bees usually do not reproduce, their ovaries and ovariole number influence metabolic biology and food-related behavior (Wang et al, 2009(Wang et al, , 2010a(Wang et al, , 2012b.…”