Higher than average rainfall and growth of the bees’ two favourite flowers could account for the larger than usual colony

Dawson’s burrowing bees, or Amegilla dawsoni, emerge from the ground from a few weeks every spring to breed and dig new burrows, which they will line with wax and fill with pollen and eggs.

On Hamelin Station Reserve, a property managed by Bush Heritage Australia, more than 5,000 burrows have appeared in a long colony near Hamelin Pool, a marine reserve off Shark Bay about 400km north of Perth.

It’s the largest colony since the reserve managers, Michelle and Ken Judd, moved to the reserve three years ago.

Michelle Judd says the bees are so preoccupied with their breeding season that humans – including a school group – have been allowed to quietly and carefully wander into the swarm.

Images for story on Adrian Iodice, a beekeeper living on a property in Brogo on the south coast of New South Wales

“It’s fantastic, like it’s just humming,” she said. “The noise from these bees, because they are quite large too, the humming is very loud.”

Dawson’s burrowing bees grow to about three centimetres in length and are “so fluffy they are like teddy bears”, Judd said.

They are also gentle – only the females have stings, and if you stand quietly both male and female bees will come to perch.

“Last week we had our Malgana Aboriginal rangers coming out to do some training on the property, and they were absolutely fascinated,” Judd said.

“Two landed on the hand of one of the fellas. They were mating on his hand. He was just sitting really still and they just went about their business.”

Mating is the main objective. Male bees emerge from their burrows before the females and skim the surface of the clay flats in packs.

Female bees emit a pheromone before they emerge, attracting packs of males to their burrow.

“As soon as she comes out you can have this ball of 20 males, all tumbling along with this one female, everybody fighting for the one girl, and then as soon as she’s fertilised they’re not interested in her again,” Judd said.

“So she can go about totally un-annoyed by the males once she’s fertilised.”

Once fertilised, female Dawson’s burrowing bees begin digging out a tunnel which can be up to 2cm in diameter and 30cm long, with a turret up to 2cm high to protect the holes against any dirt falling in.

They then line the egg chambers with wax, fill them with pollen and nectar, and lay one egg in each before carefully closing up the tunnel so the eggs can grow and pupate over the next year.

Exhausted by her efforts, the female bee then dies.

It is a short and busy life cycle.

Judd says the higher than average rainfall, which allowed for the growth of the bees’ two favourite flowers, could account for the larger than usual colony.

“It could also be an indication of recovery because we’ve been removing hard-hoofed animals off the landscape,” she said. “There’s a lot less disturbance for them.”

Dr Terry Houston, a research associate and bee expert from the Western Australian Museum, described Dawson’s burrowing bees in an entry for the museum’s website “one of the largest and handsomest of Australia’s native bees”.

He said watching an active nesting colony was “One of the most exciting entomological experiences.”

“Well, I think they are handsome, don’t you?” Houston told Guardian Australia. “They are handsome in that they are so robust in their form, and they have the lovely furry thoraxes. Maybe it’s a term that not everyone would choose to use.”

In a dry year with fewer plants to forage on, Houston says, the pupa will stay in their burrows.

Most of Australia’s 2,000 species of native bees are burrowing bees, Houston said. It’s a product of evolving from wasps; and most of the “More primitive”, less social bees have kept it up.

It is the social nature of European honeybees, which form such large hives, that have made them such a successful and commercially popular species, to an extent that native bee populations around the world are threatened.

“Bees have been around since the time of the dinosaurs, and perhaps even longer, so they have had a long period of evolution,” Houston said. “So they have diversified across every continent except Antarctica.”

Source | The Guardian.