Australian Native Bee Library
Australian native bees
In 2024, there were 1,649 described species of Australian native bee. This number is constantly changing as bees are discovered, described or redescribed. It is estimated that there are about 2,000 species, many of which are yet to be discovered.
Natural history and life cycle
About 125 million years ago, meat-eating wasps began to evolve with the new, flowering plants, angiosperms. This evolution saw the development of vegetarian bees, who feed their offspring pollen, as a protein source.
Over millions of years, most bees developed branched body hairs, to more effectively collect the tiny, dry pollen grains.
Generally, when a female solitary bee ecloses, emerges from the brood cell, she mates and then feeds. Once she has found ample floral resources, she locates or creates a nesting site, either in a woody cavity or in the ground. She then collects pollen, a protein, and nectar a carbohydrate, returns to the nest and creates a brood cell, by kneading pollen and nectar into bee bread. She lays an egg on top and closes the brood cell. She will never meet her offspring.
Some bees don’t have hairy bodies or scopa. Masked bees, and some other species, are pollen swallowers and transport both nectar and pollen in their crop, nectar stomach. These species provide their brood cells with a nutritious soup, upon which the larva floats.
Pollination services
Pollination is the first step in plant reproduction, which is essential for food production and ecosystem health.
Any animal, insect or larger, that visits a flower, and touches its reproductive parts, is a potential pollinator.
Pollination is the transfer of pollen, containing the male gamete, to the stigmatic surface. There, the pollen germinates, and the pollen tube grows down the pistil, carrying the male gametes to unite with the female gametes, within the ovule.
This is fertilisation, which leads to seed set and fruit tissue development. Social bees, such as stingless bees, need to feed many offspring within the colony, so foragers require an efficient method of transporting large amounts of pollen back to the nest. Pollen grains are constantly groomed from the body hairs into specialised pollen baskets, known as corbiculae.
Solitary bees generally only collect enough pollen and nectar to provide for one brood cell at a time. So, females don’t need to carry large pollen loads. Most solitary bees have scopal hairs, into which they pack dry pollen. The scopa is located on the underside of the abdomen or hind legs. As the bee moves over the flower, collecting pollen and nectar, the dry pollen grains are easily transferred to the stigmatic surface. Thus, enhancing cross pollination.
Pollen swallowers are not the best pollinators due to their lack of body hair, but small amounts of pollen will adhere to their bodies as they scrabble pollen from flowers. Thus, like many other scantly haired, flower-visiting insects, they do contribute to flower pollination and plant reproduction.
Sociality – diversity in nesting behaviour
Less than 5 per cent of the world’s bees are highly social, like European honey bees. Australian stingless bees are in this category, but only 11 species have a single, reproductive queen, hundreds to thousands of sterile, female worker bees and a few dozen males at various times of the year. These colonies will collect and store pollen and honey for use throughout the year. Some species can be domesticated and a small amount of honey, no more than 1 kg per year, can be harvested in the northern bee keeping regions.
Sub-social species form very small colonies, with the founding female being the egg-layer. Her daughters defend and clean the nest, as well as feeding and caring for offspring, until adulthood. Males leave the nest once sexually mature, and young females leave some time later to establish their own nests. Allodapine bees, such as reed bees, are in this category.
Most bees are solitary – living, rearing their young and completing their life cycle without the assistance of nest mates. Some species may nest communally, where they share a nest entrance, but mate and produce their own offspring.
Ground nesting bees
About 70 per cent of bees nest in the ground, digging burrows from a few centimetres up to 3m deep, depending on the species. These burrows will often have an elaborate array of branches, which terminate in a finely constructed brood cell.
Many ground dwellers prefer the company of others and nest in aggregations of hundreds to thousands of burrows within a few square metres.
Cavity nesting bees
The remaining 30 per cent of bees nest in pre-existing cavities or excavatable wood. In nature, cavity nesting bees will utilise old borer holes, hollow plant stems, under bark or they will excavate pithy stems or rotten wood. While not as architecturally elaborate as ground nests, brood cells may be lined with cellophane-like secretions for waterproofing or sealed with external resources including soil, plant resin or leaf fragments.
Role of the sexes
The females’ egg-laying ovipositor is also part of the stinger, meaning most native bees are capable of stinging. However, as they are solitary, they are not aggressive and will only sting in self-defence.
Males play no role in rearing offspring but can be effective pollinators as they patrol flowers in search of potential mates.
With written contribution from Megan Halcroft