Flowers high up in the
Maloti-Drakensberg World Heritage Site made world news when it was discovered that the Drakensberg Crag Lizard is their sole pollinator.
This first for continental Africa – a plant being pollinated by a lizard – is a discovery by a research group including
Dr Sandy-Lynn Steenhuisen, Senior Lecturer in the
Department of Plant Sciences and affiliate of the
Afromontane Research Unit (ARU) at the Qwaqwa Campus of the University of the Free State (UFS), in collaboration with Dr Timo van der Niet, Prof Steven Johnson, and project leader
Ruth Cozien, all from the
Pollination Ecology Research Laboratory and Centre for Functional Biodiversity at the
University of KwaZulu-Natal.
Besides their work being published in popular news here in South Africa (including an isiZulu article), it has also received coverage in, among others, Belgium, Canada, the Netherlands, and the United States of America.
Is it a bee, a bird, perhaps a mouse?‘Hidden Flower’, true to its name, is a plant species with flowers hidden at ground level, underneath the leaves of the plant. Like the leaves, the flowers are also green. With the flowers filled with nectar (up to 1 ml per plant) and strongly scented, one concludes that, just as with other flowers, these flowers must be visited by a pollinator. Is it a bee, is it a bird, perhaps a mouse/non-flying mammal?
According to Dr Steenhuisen, who was brought into the project because of her experience with rodents pollinating proteas, many plants are adapted to attract and be pollinated by a specific animal. They attract their pollinators using particular scents and colours and reward them for their service with, for example, nectar, oil, fragrance, and sometimes even shelter.
The ‘Hidden Flower’ initially had the group of researchers thinking that it was being pollinated by a non-flying mammal. “Everything about the plant made it look like it should be mammal-pollinated,” Dr Steenhuisen said.
They investigated all options, using several techniques to assess the contribution of different possible animals to set seed. To further assist them in their quest to find the true pollinator, the team put up motion cameras that recorded activity in the area of the ‘Hidden Flower’.
Great was their surprise when studying the video material after a week of fieldwork in the mountains, finding shy lizards dipping their snouts in the ‘Hidden Flower’ and lapping up the nectar.
Dr Steenhuisen described this discovery as completely bizarre, exciting, and fascinating.
To make 100% sure that lizards are pollinating the ‘Hidden Flower’, these animals were excluded from the plants. Results published in a paper in Ecology showed that when the lizards were experimentally excluded from the plants, the number of seeds produced dropped dramatically by almost 95%. This finding helped to further prove their discovery.
Strong scent and bright orange colour attractThe team researched the new phenomenon and found that although flower visitation by lizards is not unknown, it occurs almost exclusively on oceanic islands. Cozien says one should keep in mind that mountains are like sky islands and might therefore have similarities with oceanic islands in terms of their ecology.
The strong scent and the touch of orange at the base of the inside of the flowers is believed to play an important role in attracting lizards. The little lizard may recognise the spots of orange inside the flowers which resemble the orange colour of a male lizard in mating season, attracting females. Lured by the strong scent and the orange spots, the reptiles stick their snouts into the flower in search of nectar, pollinating the ‘Hidden Flower’; thus, making sure that this flower will continue to grow on the slopes of Sentinel Peak in the Maloti Drakensberg range.
This research finding on lizard pollination, which reads almost like a fairy tale with its islands, hidden flowers, nectar from the gods, and little dragons, shows that there are still many unknown and surprising interactions that need to be discovered and conserved to ensure a healthy ecological system.
The research findings of this study were published in April 2019.