News

Postgraduate Excellence Prize awarded for cheating bee research



13 November 2013

Robyn Overall and 2013 finalists Michael Holmes (winner), Oliver Griffith, Alex Little and Martyna Molak. Credit: M. Ricketts
Robyn Overall and 2013 finalists Michael Holmes (winner), Oliver Griffith, Alex Little and Martyna Molak. Credit: M. Ricketts

Michael Holmes has won the 2013 Postgraduate Excellence Prize for his presentation exploring sneaky (and well timed) worker bee behaviour.

The Postgraduate Excellence Prize was announced earlier this month with Michael Holmes, of the Social Insects Lab, taking the top prize for his work entitled 'Cheaters sometimes prosper'. He investigated how and why worker honeybees, which are usually sterile, sometimes become reproductively active. The other finalists for this prize were Oliver Griffith, Alex Little and Martyna Molak.

For his talk, Michael presented one of the major projects of his PhD. "I was quantifying the levels of worker reproduction in Western honeybee colonies (Apis mellifera)during reproductive swarming events," said Michael. To date, evidence had shown that honeybee workers rarely - if ever - reproduce in the presence of a queen. In addition, policing mechanisms in the hive prevent any worker-laid eggs from reaching maturity.

Michael Holmes, winner of the Postgraduate Excellence Prize, hard at work.
Michael Holmes, winner of the Postgraduate Excellence Prize, hard at work.

Michael's research has thrown new light onto the evolutionary conundrum of sterile workers. "Social insect researchers hadn't accounted for the effect of reproductive swarming," explained Michael. "This is important because reproductive swarming is the only time of year virgin queens are present." Queen bees mate only once in their lifetime, and store the sperm for later use. Meanwhile workers can only lay male eggs, so unless their sons mate with a queen, worker bee reproduction is an evolutionary dead-end. "In order to maximise their reproductive output the workers need to lay eggs at a time when virgin queens will be present."

The results of Michael's study turn the 'sterile worker' hypothesis on its head. "My research shows that the proportion of worker-laid drones (male bees) is significantly higher during reproductive swarming events." Michael dissected the ovaries of nearly 9000 individual workers to come to this conclusion about the timing of worker fecundity. He also genotyped thousands of individuals and found that the proportion of worker offspring in the hive was more than 40 times higher than generally reported. "Both genotyping and dissecting are quite repetitive procedures, and it can get a bit tedious. But as the data came together and I began to see that I had a pretty interesting story, it started to get a lot more exciting!"

The Postgraduate Excellence Prize is judged on an initial application, followed by a presentation from the four short-listed finalists. For the first time this year, the presentations were judged by popular vote from the academic staff and research students in the audience. "I feel really lucky to receive this prize," exclaimed Michael, "especially considering that the competition was so tough and the vote was so close. And it's the perfect way to finish my PhD!"

The other finalists presented talks on a diverse range of topics. In his research, Oliver Griffith asked the question "Is there more than one way to build a placenta?", Alex Little spoke about the role of thyroid hormone in cold acclimation of fish and Martyna Molak presented a talk entitled 'How wrong can your date go?', which investigated rate estimation across timescales. All finalists did an excellent job and it was a wonderful opportunity for the School to reward the top-quality research being carried out by our students.