Queen bee or worker bee? New insights into famous honeybee society caste system

September 21, 2011
Queen bee or worker bee? New insights into famous honeybee society caste system

Scientists are reporting deep new insights into whys and hows of the famous caste system that dominates honey bee societies, with a select few bee larvae destined for royalty and the masses for worker status. Their study probing the innermost biological makings of queen bees and worker bees appears in ACS's Journal of Proteome Research.

Jianke Li and colleagues (The joint work of scientists from China and Ethiopia) note that despite more than a century of research, mysteries remain about the biochemical factors at the basis of the fascinating caste system in . Schoolchildren learn that the (usually) one in a colony develops from larvae fed royal jelly, a protein-rich secretion from glands on the heads of worker bees. Other larvae develop into female workers or male drones. Although queen and share almost identical genes, their destinies could be more different.

"The female queen is large in size and specializes in reproduction," the scientists explain, "whereas workers are small and engage in colony-maintaining activities. Their life spans also vary, with the queen living for 1 to 2 years and the workers living only 6 to 7 weeks. To gain further information, the scientists looked at proteins inside the cells of larvae destined for queen and worker status.

Their findings reveal major differences, during early stages of life, in the activity of proteins in the mitochondria, structures that produce energy for cells. The differences include changes in the amounts of protein produced in cells and the activity of those proteins. In pre-queen larvae, proteins involved in carbohydrate and , for instance, are much more active than in workers. "This suggests proteins with metabolic enhancing activities generally appear to have significant roles in the process of caste determination," the researchers conclude.

Explore further: Wood ant queen has no egg-laying monopoly

More information: Mitochondrial Proteins Differential Expression during Honeybee (Apis mellifera L.) Queen and Worker Larvae Caste Determination, J. Proteome Res., 2011, 10 (9), pp 4263–4280. DOI: 10.1021/pr200473a

Abstract
Despite their similar genetic makeup, honeybee (A. mellifera) queens and workers show alternative morphologies driven by nutritional difference during the larval stage. Although much research have been done to investigate the causes of honeybee caste polymorphism, information at subcellular protein levels is limited. We analyzed queen- and worker-destined larvae mitochondrial proteome at three early developmental stages using combinations of differential centrifugation, two-dimensional electrophoresis, mass spectrometry, bioinformatics, and quantitative real time PCR. In total, 67, 69, and 97 protein spots were reproducibly identified as mitochondrial proteins at 72, 96, and 120 h, respectively. There were significant qualitative and quantitative protein expression differences between the two castes at three developmental stages. In general, the queen-destined larvae up-regulated large proportions of proteins at all of the developmental stages and, in particular, 95% at 72 h. An overwhelming majority of the queen larvae up-regulated proteins were physiometabolic-enriched proteins (metabolism of carbohydrate and energy, amino acid, and fatty acid) and involved in protein folding, and this was further verified by functional enrichment and biological interaction network analyses as a direct link with metabolic rates and cellular responses to hormones. Although wide-ranging mitochondrial proteomes participate to shape the metabolic, physiologic, and anatomic differences between the two castes at 72 h, physiometabolic-enriched proteins were found as the major modulators of the profound marking of this caste differentiation. Owing to nutritional difference, prospective queen larvae showed enhanced growth, and this was manifested through the overexpression of metabolic enzymes. Differently from similar studies targeting the causes of honeybee caste polymorphism, this subcellular level study provides an in-depth insight into mitochondrial proteins-mediated caste polymorphism and greatly improves protein coverage involved during honeybee caste determination. Hence, it is a major step forward in the analysis of the fundamental causes of honeybee caste pathway decision and greatly contributes to the knowledge of honeybee biology. In particular, the consistency between the 22 proteins and mRNA expressions provides us important target genes for the reverse genetic analysis of caste pathway modulation through RNA interference.

Related Stories

Wood ant queen has no egg-laying monopoly

June 28, 2007

The reproductive monopoly of the ant queen is not as strong as is often thought. Dr. Heikki Helanterä and Prof. Lotta Sundström, biologists working at the University of Helsinki, Finland, investigated worker ovary development ...

Royal jelly makes bee queens, boosts nurture case

March 14, 2008

New Australian National University research may explain why eating royal jelly destines honeybee larvae to become queens instead of workers – and in the process adds new weight to the role of environmental factors in the ...

Insulin signaling key to caste development in bees

July 14, 2010

What makes a bee grow up to be a queen? Scientists have long pondered this mystery. Now, researchers in the School of Life Sciences at Arizona State University have fit a new piece into the puzzle of bee development. Their ...

Honey bees: Genetic labeling decides about blue blood

November 3, 2010

Queen bees and worker bees share the same genome, but they are different in the chemical labeling of about 550 genes. This has been discovered by scientists of the German Cancer Research Center jointly with colleagues in ...

Recommended for you

Secrets of a heat-loving microbe unlocked

September 4, 2015

Scientists studying how a heat-loving microbe transfers its DNA from one generation to the next say it could further our understanding of an extraordinary superbug.

Plants also suffer from stress

September 4, 2015

High salt in soil dramatically stresses plant biology and reduces the growth and yield of crops. Now researchers have found specific proteins that allow plants to grow better under salt stress, and may help breed future generations ...

Ancient walnut forests linked to languages, trade routes

September 4, 2015

If Persian walnut trees could talk, they might tell of the numerous traders who moved along the Silk Roads' thousands of miles over thousands of years, carrying among their valuable merchandise the seeds that would turn into ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.