For the first time, scientists have peered into the remarkable visual world of Australia’s native stingless bees, discovering that different species see their environment in dramatically different ways.
Distinct visual superpowers: The Australian native stingless bee Austroplebeia australis, pictured, can detect objects in low-light conditions, so it can forage under canopies and in overcast conditions. Image credit: Sue Jaggar, iNaturalist.
This new Macquarie-led research, published in the Journal of Comparative Physiology A, shows how two different species evolved distinct visual superpowers helping them excel as crop pollinators and navigate diverse Australian landscapes.
Both Australian native stingless bee species Tetragonula carbonaria and Austroplebeia australis can see detail equally well – but there are big differences in their visual capabilities.
“This is the first description of the eyes of Australian native bees,” says Associate Professor Ajay Narendra from Macquarie University's School of Natural Sciences, who supervised the research.
“This sets the scene to probe what bees can see that enables them to find flowers, return home and negotiate obstacles.”
Eyes for detail
The research team used a technique called pattern electroretinography to measure how well each species could detect contrast and see fine details.
While both species showed similar sharpness of vision, A. australis was much better at detecting contrast – they could pick out faint objects just 7.6 per cent brighter than their background. T. carbonaria however, could only distinguish objects 16.6 per cent brighter than their background.
Unlike the single-lens eyes of humans, bees have ‘compound eyes’ – made up of thousands of tiny visual units, each with a lens and photoreceptors.
Understanding these visual capabilities will become increasingly important, as Australian agriculture looks for sustainable pollination solutions and as conservation efforts focus on protecting native bee populations.
Even though both Australian stingless bee species have fewer lenses than European honeybees, they can still see detail just as well, suggesting both native bee species have efficient visual processing systems.
However, the researchers found the eye structures of each species were slightly different, with the larger bee, A. australis, having more and bigger lenses than T. carbonaria.
“Their eye structure gives A. australis higher contrast sensitivity, so these bees can discriminate many different shades and colours of petals,” says Associate Professor Narendra.
With better visual capability, A. australis can search for food when the light is dimmer - such as under tree canopies or in overcast conditions, explaining why these bees are spotted buzzing around in light that’s too low for their coastal relatives.
Hungry like the bees
The visual differences between the species match up with their differences in food gathering (foraging) behaviours. T. carbonaria is a generalist, collecting pollen from many different sources, while A. australis is choosier about where it goes.
Clear and bright: The coastal bee Tetragonula carbonaria, pictured, prefers brighter conditions and is found along Australia's eastern seaboard from NSW to northern Queensland. Credit: Tina Hanneman, iNaturalist.
“A. australis foragers spend proportionately less time hovering in front of flowers than T. carbonaria, so they are described as more efficient foragers in terms of their energy consumption,” says Associate Professor Narendra.
The research suggests these visual adaptations support different ecological strategies, with A. australis gathering pollen from a relatively narrow flower colour range compared to the less selective T. carbonaria.
Both species are important crop pollinators in Australia, with A. australis particularly valued for pollinating celery, capsicum and other commercial crops.
Distribution and habitat
The two species are found in different Australian locations. T. carbonaria lives along the east coast from northern Queensland down to Bega in New South Wales - the furthest south of any Australian stingless bee.
A. australis is found over a wider area, living in drier inland regions throughout northern New South Wales, Queensland, Northern Territory and parts of Western Australia, and lives in smaller colonies.
“Those different habitat ranges explain why we don’t hear much about A. australis in urban areas like Sydney,” says Associate Professor Narendra.
He says the study has advanced our understanding of Australia’s remarkable native bee species and that the findings will drive further investigation of their behaviours.
“These differences in visual physiology help us understand how native bees have adapted to their distinct foraging behaviours and environmental conditions,” he says.
The research, conducted with former PhD candidate Bhavana Penmetcha and Research Fellow Laura Ryan, also compared the Australian species with European honeybees.
Even with big differences in eye structure and body size, the researchers found sharpness of vision stayed surprisingly similar across all bee species.
Research first: Associate Professor Ajay Narendra, pictured, says the study is the first to describe the eyes of Australian native bees helping to understand how they find flowers and navigate different habitats.
“Understanding these visual capabilities will become increasingly important, as Australian agriculture looks for sustainable pollination solutions and as conservation efforts focus on protecting native bee populations,” Associate Professor Narendra says.
Associate Professor Ajay Narendra is Co-Director of Macquarie University Pollinator Futures Research Centre.
This research was supported by Australian Research Council Discovery Project grants and represents collaboration between researchers from different countries and career stages, reflecting the international nature of bee vision research.
