Of the eight species of baobab in the world, six are confined to Madagascar, one to northern Australia and one species, Adansonia digitata, is found across the savannah regions of continental Africa.
They’re more than striking trees; they are cornerstones of African ecosystems and livelihoods. They provide fruit, fibre, medicine and shelter for both people and wildlife. But it’s their night-blooming flowers and partnership with tiny nocturnal visitors, like bats and moths, that hold the secrets of their evolution and future survival.
Baobabs have huge white flowers that are visited at night by bats and moths to drink their sweet-tasting nectar. While feeding on the nectar, the flower covers its nocturnal visitors with pollen which they carry to the next flower they visit. This transfers pollen from the male part of one flower to the female part of the next flower. Without this pollination, the trees would not be able to produce nutritious fruit, which African people have eaten for thousands of years, or seeds to grow the next generation of baobabs.
I’m a baobab ecologist who has studied these trees for 18 years.
In my latest research, my team studied 284 baobabs across west (Ghana), east (Kenya), and southern Africa (South Africa, Namibia, Botswana) to see which animals pollinated their flowers.
Our study found that the baobabs have different pollinators in different regions and have each adapted their flowers to suit those pollinators.
The baobabs are all genetically the same species, but their floral traits, shape, scent and nectar have evolved to suit the different pollinators in each region.
It takes thousands of years for these changes to happen. This also means the trees are deeply dependent on their relationships with either bats or moths. If these creatures go into a decline because of climate change, the trees might not reproduce. This would endanger not just the baobab species but the web of life that depends on it.
More research is needed about the animals that are pollinating baobab flowers and how important they are to the survival of baobabs in future….'
While baobab trees in West and East Africa are pollinated by different types of bats, in the Southern African region, no bats visit baobab trees. Instead, a variety of moths fill the role of pollinators. Some hover delicately; others land on the flowers themselves. The flowers here are smaller, with drooping petals and wider stigmas. These subtle adaptations nudge moths into direct contact with pollen-bearing parts.
Shape is important: In bat regions, petals fold back. This makes space for the bats to land or hang on the flowers. In moth regions, petals droop, encouraging close contact and effective pollen transfer.
Stigma position: In Southern Africa, some flowers have short and wide stigmas—the part of the female reproductive organ which receives the pollen before it is transferred to the ovary buried below the stamen ball. This is unlike the fully protruding stigmas of west and east African baobab flowers that are visited by bats. For moths, this positioning increases the chance that they brush against the flower's reproductive parts, forcing them to pollinate the flower.
Nectar: Large bats encouraged the development of nectar-rich flowers in West Africa. East African flowers produce less nectar for smaller bats, and Southern African baobab flowers provide only drops of nectar, just enough for moths.
Scent: Baobabs across Africa release unusual sulfur-like compounds that draw bats, but Southern African flowers emit sweeter-smelling scent, making them appealing to moths instead...
Our future rests on wings
Birds, bees and beetles do not pollinate baobab flowers, so baobabs rely on moths and bats for survival. Baobab trees can cope with a wide range of environmental and climatic conditions. But bats and moths may be more susceptible to climate change.
Our research shows that even giants depend on delicate partnerships, in this case, with the smallest of night-time visitors. Protecting these pollinators means protecting the baobabs themselves, and with them, the communities and ecosystems that depend on them.
Sarah Venter is a baobab ecologist at the University of the Witwatersrand. You can read her full article in The Conversation here: The secret life of baobabs - how bats and moths keep Africa's giant trees alive.