Researchers identify how queen bees repress workers' fertility

August 3, 2016

Researchers from New Zealand's University of Otago have discovered the molecular mechanism by which queen honeybees carefully control worker bees' fertility.

It has long been known that worker bees have a very limited ability to reproduce in a hive with a queen and brood present, but in their absence, a third of them will activate their ovaries and lay eggs that hatch into fertile male drones.

It is queen pheromone that represses worker bee fertility, but how it achieves this has remained unclear.

Now, Otago genetics researchers have identified that an ancient cell-signalling pathway called Notch, which plays a major role in regulating embryonic development in all animals, has been co-opted to also constrain reproduction in worker bees.

In research newly published in the prestigious journal Nature Communications, Professor Peter Dearden and colleagues Drs Elizabeth Duncan and Otto Hyink demonstrated that chemically inhibiting Notch signalling can overcome the effect of queen mandibular pheromone (QMP) and promote ovary activity in adult worker bees.

Professor Dearden says they were surprised to find that Notch signalling acts on the earliest stages of egg development in the ovary, perhaps even on the stem cells that make the ovary, and that in the absence of QMP the Notch receptor in a key region of worker bee ovaries becomes degraded.

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Queen bees reign again on Dungeness reserve

Published by surfbirds on August 12, 2015 courtesy of RSPB, surfbirds archive

Sightings of three short-haired bumblebee workers on an RSPB nature reserve mark a new milestone for a reintroduction project aimed at bringing this native species back to the UK.

The bumblebees were spotted on four consecutive days on RSPB’s Dungeness reserve in Kent, which is a first for the project.

Short-haired bumblebees were declared extinct in the UK in 2000, almost certainly due to the loss of 97% of ancient wild flower meadows on which they depend. They were last recorded in Dungeness in 1988.

Each year since 2012 around 50 queen bees from Sweden have been released on the Dungeness reserve as part of this pioneering project, led by the Bumblebee Conservation Trust (BBCT), RSPB, Natural England and Hymettus.

Consistent sightings of worker bees over the last three years reveals that the queens have successfully nested and produced young, a strong indication that the bees are finding sufficient food to build colonies.

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How Queen Bees Reign Over Reproduction

By Tanya Lewis, Staff Writer | January 16, 2014 02:29pm ET

When it comes to reproduction in social insects, nobody competes with the queen.

For some time, scientists have known that queen insects give off chemical signals that prevent workers from reproducing. When a queen kicks the bucket, the signals wear off, and the workers become fertile again. Now, researchers have found that queen ants, wasps and bumblebees all use a similar type of chemical to signal fertility, which their ancestors evolved millions of years ago.

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Promiscuous Queen Bees Maintain Genetic Diversity

ScienceDaily (Apr. 16, 2012) — By mating with nearly 100 males, queen bees on isolated islands avoid inbreeding and keep colonies healthy. The results, published in the current issue of PLoS ONE, focused on giant honey bee colonies on Hainan Island, off the coast of China. Since these bees have long been separated from their continental cousins, it was thought that the island bees would be prime candidates for inbreeding as well as having very different genes, said Zachary Huang, Michigan State University entomologist.

"We believed that the island bees would show evidence of the founder effect, or random genetic changes in an isolated population, on a unique sex determination gene from the mainland bees," he said. "At first we were surprised when we couldn't document this effect. Looking at it further, I asked myself, 'Why didn't I think of this before?'"

When compared to bees, humans have a rather simplistic sex-determination process. In females, the two sex-determination chromosomes are the same, and in males the two chromosomes are different. With bees, however, the combinations of complementary sex determination genes, or CSDs, determine the sex and the societal role of the bees.

One particular gene can have alleles -- the "flavor" of genes. In humans, they dictate hair and eye color. In bees, though, they are responsible for creating females (worker bees), fertile males (that mate with the queen) or infertile males (diploid males which serve no purpose).

Continued:  http://www.sciencedaily.com/releases/2012/04/120416150403.htm