Dawson's Burrowing Bees in Australia
Our blog post last Friday was about the amazing Museum of the Earth online bee exhibit which you can visit in the comfort of your home. Bees that live in different parts of the world are right there for you to observe, close up and in full color.
One of the fascinating bees you’ll meet there is the Dawson’s burrowing bee, or Amegilla dawsoni, of the Anthophorini tribe and the Amegilla genus. This unique bee lives only in the hard-baked claypans of the Outback in Western Australia, and nests there by the thousands.
One of Australia’s largest bees, it grows to 0.91 inches (23 millimeters) long, with a 1.8-inch (45 millimeter) wingspan and is similar in coloring and size to the Xylocopa, or Australian carpenter bee. Males are covered in brown fur, females in white and brown fur, except on their lower faces which are bare and light yellow to dark brown in color. They have long tongues and are big and noisy, but usually harmless unless you pick up a female bee, in which case she may sting you.
This 4:15-minute BBC video has excellent footage of Dawson's burrowing bees in the Australian Outback:
Dawson’s burrowing bees are solitary nesting bees that live in large communities with as many as 10,000 burrows, which makes it seem like they live in colonies. Each female breeds only once during the breeding season, and builds her own nest by digging into the ground. Each brood cell is an individualized capsule.
These nomadic bees live in a vast arid area that can be as much as 700 kilometers or 435 miles from the northernmost to southernmost areas of their nesting and mating grounds. If it is extremely dry and there is a shortage of flowering plants in their area, they are known to migrate north or south within their larger area to source their foraging needs.
Females indicate if they are receptive to mating by the mix of chemical signals they emit. This also reveals whether they have already mated.
Males are dimorphic. Larger males are called majors and make up about 20% of the male population, while smaller males are minors and represent 80% of the male population.
Mating habits can be brutal, a fight to the death that sometimes even accidentally kills the female. Majors are aggressive and patrol the emergence areas, ready to get into physical fights to mate with recently mated females or virgins. Minors hover at the edges of the emergence area and only mate with females that are able to fly away unmated from the vicinity of their natal nests.
These are not honey producing bees. Pollen and nectar are collected for their young and deposited around the eggs they lay.
Female bees collect nectar by inserting their long proboscis into the flower, so they do not need to enter the flower corolla to collect nectar. They favor four main genera of plants that grow in the deserts of Western Australia, foraging on these 4 plants even if other types of nectar and pollen are available.
Their favorite flowers are: Cassia, Eremophila, Solanum and Trichodesma.
As with all bees, there are parasite troubles. Cleptoparasitic Miltogrammine fly parasites break into brood cells and eat the provisions the female bee arranged for her developing brood.
Dawson's burrowing bees are real survivors, living in extremely harsh conditions but surviving since ancient times.
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