How many native bees fit into six car parking spaces?

Two-fifths of a tennis court. About six car park spaces. Three-tenths of an IMAX screen.

That’s the size of my front yard. Yet despite its limited expanse, and its densely urban situation 10 km north of Melbourne CBD, my yard is habitat for at least five species of native bees.

I began watching the bees closely last year in lockdown. The tiny, faintly metallic Sweat Bees (Homalictus) are most common. They appear first in Spring, visiting the Wahlenbergia, the Oxalis weed in the lawn, the strawberry, and rocket flowers; anywhere there’s pollen.

Later, the bold and stripey Lipotriches turn up. Like rock-climbers gripping an overhang, they lock themselves upside down to the anthers of dangling Dianella flowers, emitting short zip-like buzzes as they work with methodical focus.

Then when Summer days begin to blaze, the hyperactive Resin Bees (Megachile) arrive, with that distinctive ember thumb print on their behinds. They fire around the yard like deranged bullets, collecting pollen and scouting for cracks to nest in.

That such biodiversity endures in this landscape—once grassy woodland, now houses, roads, and light industrial—is a testament to these species’ resilience. But their persistence also begs the question of which species might now be absent, less tolerant of such drastic change.

The White-headed Digger Bee (Amegilla albiceps) is one such bee. Large, rotund, and covered in a pelt of golden and white fuzz, one has not been recorded in Melbourne for at least 70 years, perhaps longer. In a Summer free of travel restrictions, I’ll leave town to seek the White-headed Digger. But for now, I’ll keep discovering the delightful locals. It’s Homalictus season now.

This mini essay was originally written for the Urban Field Naturalist Project

We don’t know what pollinates most Australian plants.

Australian flowering plant diversity is legendary. Within an hour trip outside of our major metro centres anyone can quite easily witness unique Australian plant diversity in subtropical forest (Brisbane), grassland (Melbourne), and sandstone heath (Sydney). The diversity close to home is fairly well catalogued, and while it is hard to discover a new plant species, merely spending time around our native plants is very likely to reveal something that has never before been documented.

Something like 90% of our native plants rely on animals for pollination in order to set seed. Despite this, we simply do not know what pollinates most of our Australian native plants. The fact that the private lives for many of our native plants remains mysterious is due to their great diversity and the limited time and resources available to document what’s going on every day in the bush.

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Two native bees (Hylaeus (Rhodohylaeus) sp.) visiting flowers of the Broom Bush (Eremophila scoparia) in Western Australia.

And these uncharted interactions are totally critical for the functioning of our native ecosystems. Pollination underpins production of seed for the next generation, builds seed banks for post-fire regeneration, and also produces fruits and seeds that are critical food resources for our native animals.

Our ignorance of native pollination networks is therefore vastly out of step with their importance. This is illustrated in the example of bee declines, where we have all heard about the threats impinging on honeybees and pollination service for food crops, yet when it comes to Australian native bees, we lack the basic benchmark data needed to make a solid judgment about whether they too are declining*. It is therefore imperative that we commit effort to recording native pollination networks now, before they are lost to us. While it is hard for long term ecological monitoring projects to attract funding, ongoing development of automated imaging of flower visitors and large scale citizen science projects offer some promise for increased capability in filling this ecological blind spot.

But our ignorance here can also be thrilling. This means that every time you are in the bush, and witness an insect or bird taking nectar or pollen from a flower, there is a reasonable chance it has never been documented before. In my work with University of Melbourne I have been studying several native shrubs to understand their pollination, and for many of these species, it is gratifying to know that my work will be the first documented evidence of what is visiting them. But you don’t have to be a trained scientist to do this, you just need some patience, luck, and some fine weather. And while discovering and photographing an unusual native bee pollinating one of our native flowers won’t win you a Nobel Prize, I guarantee it will provide any enquiring mind with a hit of electric discovery every single time.

 

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Photographed on Mount Buffalo, Ken Walker (Victoria Museum) later identified this bee as the very rare Lasioglossum (Callalictus) callomelittinum. Few photos of it exist. This individual is buzz-pollinating a Fringe Lily (Thysanotus tuberosus).

 

Links for pollinator observations:

Bowerbird: Nature observations database

Wild Pollinator Count

Government pollinators repository

*But given native bees need native habitat, and native habitat is being cleared at astonishing levels, we can, with a high degree of confidence, say that native bees are declining too.