It sounds like a miracle: a honeybee that’s able to reproduce through virgin birth. But scientists have pinned down the gene that’s responsible for the Cape bee’s unique ability.
The Cape bee is a subspecies of honeybee that’s native only to the southern tip of South Africa.
What makes it unique is that the female worker bees are able to lay eggs that develop into other female bees. These eggs are not fertilised by a male (worker bees are unable to mate), so this is a form of asexual reproduction, known as ‘thelytoky’. The Cape bees are essentially creating a clone.
Cape bees only develop this ability once the colony’s queen bee dies. By producing female bees, they can give birth to the colony’s new queen, ensuring that the colony survives. In other honey bee subspecies, the worker bees only produce male bees (drones), which have to fly off in search of a queen bee in another colony.
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The Cape bee’s ability comes at a cost, though. “Instead of being a cooperative society, Cape honeybee colonies are riven with conflict because any worker can be genetically reincarnated as the next queen,” said study leader Prof Benjamin Oldroyd at the University of Sydney, Australia. “When a colony loses its queen, the workers fight and compete to be the mother of the next queen.”
By comparing the genetic sequences (‘genomes’) of Cape bees to those of other honeybee subspecies, Oldroyd and colleagues were able to identify the gene that causes these virgin births, called ‘GB45239’.
“It is extremely exciting,” said Oldroyd. “Scientists have been looking for this gene for the last 30 years. Now that we know it’s on chromosome 11, we have solved a mystery.”
It raises the possibility of a genetic ‘switch’ that could turn off this form of asexual reproduction in animals that are seen as pests.
“Many pest ant species like fire ants are thelytokous,” said Oldroyd, “though unfortunately, it seems to be a different gene to the one found in [Cape bees].”
Reader Q&A: Do bees have knees and, if so, what’s so special about them?
Asked by: Steve McCabe, Skye
Bees, like all insects, have six sections to their legs: the coxa, trochanter, femur, tibia, metatarsus and tarsus. Each is connected by a joint and the one most like a knee is between the femur and tibia. Bees have lots of other specialised structures on their legs to carry pollen, but the bee’s knee itself is no more remarkable than any of the other leg joints.
So with that in mind, what’s the origin of the phrase: “the bee’s knees”? Probably simply because “knees” rhymes with “bees”.
The phrase seems to have evolved in 1920s America, along with “the cat’s pyjamas”. Other seemingly arbitrary terms of distinction from that era that have since died out include “the snake’s hips”, “the kipper’s knickers” and “the sardine’s whiskers”. Of all of these, the only one actually found in nature is the bee’s knees, so perhaps that’s what’s so special.
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