Out in the paddock last night, Andrew was mowing and noticed these little guys (yes, they are guys) on several grass stems. They were very placid, despite the vibrations of the ride-on mower. Each bee was less than 1 cm in length.
Native bees, Lipotriches sp.
They seemed to be settling in for the night – as the light faded, they became less and less active. They are of the species Lipotriches, one of about 2000 species of native Australian bees. They are solitary bees – they do not build a communal nest like European honeybees.
According to Terry Houston (Guide to Native Bees of Australia, CSIRO Publishing, 2018; also a useful fact sheet at Western Australian Museum):
Male bees have a sole purpose: to ensure that females are fertilised. They do not engage in nest construction, provisioning or brood care, but that is not to say they are of no special interest. They can engage in a range of behaviours (sometimes bizarre) and often display unusual structural features, many of which assist them to locate and mate with females.
As a rule, males of solitary bees emerge ahead of females in any particular population. Early in the flight season, males may be found flying about or perched on fresh or even unopened flowers of the preferred forage plants days before the first young females arrive. After leaving the nests in which they developed, males of solitary bees tend not to return. Males of social and colonial bees, by contrast, often shelter overnight or during inclement weather in active nests. This is the case in the weakly social Amphylaeus morosus and various Meroglossa species.
Males of many solitary bees roost overnight in exposed situations, commonly on dead twigs, thin stems, leaves or flowers. Depending on the particular species, they may roost solitarily or in the company of others. In the latter case, individuals may be sparsely distributed on the same bush or branch or they may form ‘sleeping aggregations’ of varying size, shape and density. Usually, males return to the same roost each night, showing that they possess a well-developed homing ability.
The largest roosting aggregations can contain thousands of males.
If you are wondering about the females:
Australia’s bees are predominantly solitary, each female building one or more nests in which to rear her offspring without the aid of ‘workers’. Many burrow in the ground though a few bore in dead, rotting wood or pithy stems. Most others are ‘lodgers’, utilizing existing hollows such as borer holes in dead wood, hollow stems and abandoned burrows of other bees and wasps. Lodger bees will also utilize man-made cavities such as nail and bolt holes, pipes and cut bamboo. A few species build free-standing nests on stems or rocks. A variety of materials may be used in nest construction including soil, plant fibre, leaf pieces, leaf pulp, resin and secretions such as wax and silk. Typically, each brood cell is an urn-shaped cavity providing a protective environment for the development of a single individual; it is stocked with sufficient food to enable development from egg to adult and is sealed once it receives an egg. (Western Australian Museum)
Apparently, most native bees are capable of stinging, but will do so only under extreme provocation. The European honeybee is more enthusiastic in this regard.
Eleven native bee species are social and produce small amounts of honey (‘sugarbag’, bush tucker). They are stingless.
Another unexpected find on the property!