Emeritus Professor Robin Crewe from the University of Pretoria (UP) has been awarded the John F.W. Herschel Medal for 2026 by the Royal Society of South Africa (RSSAf). This is the highest award bestowed by the RSSAf – the country’s premier multi disciplinary scientific organisation, founded in 1908. The Society’s mission is to foster a national culture of science excellence and to recognise eminent scientists who have contributed significantly to science in southern Africa.

“My response on hearing I had been awarded this great honour was initially disbelief, as there are many extremely strong and deserving candidates – but I am delighted,” says Prof Crewe, whose extraordinary body of research focuses on honey bee behavioural ecology and chemical communication systems. He is currently a senior research fellow in UP’s Centre for the Advancement of Scholarship, where he was formerly the Director.

 Honey bees, he explains, provide a critical ecosystem service as flagship pollinators. “It is crucial for us to understand bees – and in particular honey bees – because our fate as humans and their fate as bees are inextricably intertwined. The immediate effect of the loss of honey bees would be a dramatic decline in food production and hence large-scale food shortages that would likely lead to famine.”

His interest in chemistry and biochemistry dates back to when he was a student at what was then the University of Natal (now the University of KwaZulu-Natal). “The study of the highly developed chemical communication systems in honey bees was in its infancy then, in the early 1970s. It intrigued me, and it led to my life-long research,” says Prof Crewe, who did his PhD at the University of Georgia in Athens, Georgia, USA.

He returned to South Africa in 1971 and was a lecturer and researcher in the Entomology Department at the University of Natal until 1975, when he moved to the Zoology Department at University of the Witwatersrand (Wits). He established the Communication Biology Research Group at Wits and served as its Director from 1988 to 1996. I

n 1997 Prof Crewe joined UP as Dean of Natural and Agricultural Sciences. He served as a Vice-Principal of UP from 2003 to 2013, was a past president of the Academy of Science of South Africa, and established the Social Insects Research Group (SIRG) at UP.

He explains that honey bee societies consist almost exclusively of females: the queen being the reproductive individual and the large number of female workers that are non-reproductive. The drones (males) are purely for mating with virgin queens.

“Social interactions in the colonies are controlled by a set of chemical signals mainly produced by the queen to, for example, indicate her general state of health,” Prof Crewe explains. “In certain situations, such as when the colony is swarming, the worker bees also release chemical signals into the air to attract other workers to come and join the swarm. The signals are detected via the bees’ antennae. We use electro-physiology to insert very fine electrodes into the nerves of the antennae of the bee in order to detect their responses to the chemical signals they are smelling and the way in which this affects the physiology and behaviour of the colony.”

The SIRG studies honey bee colonies on the hillside above Future Africa, UP’s pan-African platform for collaborative research, and they have observation hives in a building at UP’s Experimental Farm on its Hillcrest Campus.

Prof Crewe says wild honey bee colonies vary enormously in size. “I’ve seen massive colonies with honeycomb spanning over two metres long, but many are much smaller, such as in termite mounds. The wild colonies range from 10 000 to 70 000 worker bees per colony, while managed colonies, which are transported to different agricultural sites to pollinate fruit trees and crops, range from 20 000 to 50 000 worker bees per colony.”

All worker bees have an average lifespan of four to five weeks, while the queens live for about four years. The queen only mates once – early in life she takes a mating flight and mates with up to 70 drones which die as soon as they mate. Prof Crewe flies quadcopter drones to study this mating behaviour. Once she has mated, the queen then returns to the colony and produces up to 2 000 eggs per day.

“The queen is replaced when chemical signals show signs of her becoming less reproductive, at which point the worker bees raise a new queen by feeding worker bee larvae with royal jelly so that they develop into queens. The virgin queens then either fight it out for control of the colony or they will leave with a swarm of their own. Every new queen then takes her mating flight before returning to the colony for her egg-laying years.”

Interestingly, Prof Crewe says not all bees are busy. “As with humans, some of the worker bees are very busy, some are lazy, and some even cheat on the job. Studies have shown that some bees can spend up to 40% of their time in a hive doing nothing. Some are purely part of a hive’s reserve force, and put to work only when there is lots of nectar to be collected and processed.” 

The flight range of female forager bees is about 21.9km, and they have a top speed of 28km/h. When they return to the colony, they dance to indicate the direction and distance of a source of flowers or blossoms; to signal a suitable new home if they need to migrate for better food conditions, or if the colony gets too big and part of it needs to swarm off; or if there is a fire or infection in the colony.

“With the threats to the survival of managed honey bee colonies, we are doing research into bee diseases and the potential threats they pose to honey bee health and sustainable apiculture. Our group is also part of global initiatives such as COLOSS (Prevention of honey bee Colony LOSSes) and SUPER-B networks that focus on research and improving the well-being of pollinators at the global level.”

Prof Crewe is currently working on a book that explores the unique biology of the Cape honey bee, which he aims to complete by the end of 2026.