The evolution, ecology and conservation of honeyguide-human mutualism
This project focusses on a unique mutualism: the foraging partnership between the Greater Honeyguide Indicator indicator and human honey-hunters whom it guides to bees’ nests. Honeyguides know where bees’ nests are located and like to eat beeswax; humans know how to subdue the bees using fire, and open nests using axes. By working together, the two species can overcome the bees’ defences, with benefits to both. Remarkably, this relationship has evolved through natural selection, rather than through training or domestication which underpins cooperation by other human foraging partners such as dogs or falcons. The honeyguide-human system provides a wonderful opportunity to study the ecology and evolution of mutualisms in nature, because local human and honeyguide populations vary strikingly in whether and how they interact, and because we can readily manipulate these interactions experimentally.
Claire Spottiswoode and her team have been studying human-honeyguide interactions since 2013 in the Niassa National Reserve of northern Mozambique, collaborating with the honey-hunting community of Mbamba village, and receiving crucial support from the Mariri Environmental Centre led by Dr Colleen Begg and Keith Begg of the Niassa Carnivore Project. A key focus so far has been investigating reciprocal communication between the two parties: not only do honeyguide signal to humans, but in many different cultures humans signal back to honeyguides, giving special calls to attract honeyguides and maintain their attention while following them. Among the Yao honey-hunters of northern Mozambique, this call is a loud trill followed by a grunt: “brrrr-hm!”. In 2016, using a field experiment, we showed that honeyguides were twice as likely to initiate a cooperative interaction with humans who made this sound compared to humans giving control human and animal sounds, and three times as likely to successfully lead such humans to honey. So honeyguides use these specialised signals to choose partners who are likely to be good collaborators, in a two-way conversation between our own species and a wild animal, from which both partners benefit.
Supported by a Consolidator Grant from the European Research Council, we are now asking whether learning is involved in maintaining a geographical mosaic of honeyguide adaptation to local human cultures; how such reciprocal communication between humans and honey- guides mediates their interactions; what the effects of cultural co-extinctions may be on each partner and their ecosystems; and ultimately, we hope, how quickly such cultures can be re-ignited following their loss. In so doing we hope to test for the first time the hypothesis that reciprocal learning can give rise to matching cultural traits between interacting species. Understanding the role of such phenotypic plasticity is crucial to explain how and why the outcome of species interactions varies in space and time, and to predict how they will respond to a rapidly changing world.
Our research is conducted primarily in the Niassa National Reserve in Mozambique, with the support and cooperation of the Mariri Environmental Centre, and the community and traditional chiefs of Mbamba and Nkuti Villages. Here our research project is known as ‘Projecto Sego’ (sego is greater honeyguide in the Yao language), and heavily involves the local community in independent data collection as well as assistance with our field sampling and experiments.
Activities in 2018
- From May to October, David Lloyd-Jones and local data manager Orlando Ncuela managed and provided ongoing training and support to 20 honey-hunters collecting data on their own activities. This has been enabled by a custom app we developed together with the company HabitatInfo.
- From May to June, David Lloyd-Jones and Claire Spottiswoode carried out behavioural experiments designed to test whether young honeyguides refine their guiding behaviour through learning.
- During October, Dominic Cram, Jessica van der Wal, David Lloyd-Jones and Claire Spottiswoode captured and colour-marked honeyguides in our study area, to establish a marked population for future experimental work, and trialled methods for experiments that which will continue on a larger scale in 2020.
- UCT collaborator Prof. Timm Hoffman joined us in the field to advise on methods for the vegetation and landscape ecological components of the project.
- Twenty honey-hunters have already collected high-quality data on hundreds of honey-hunting trips, involving thousands of interactions with honeyguides. This directly involves Niassa’s community in our data collection, providing them with additional sources of income and allowing us to cooperate in scientific research.
- We celebrated our first year of honey-hunter data-collection with a ‘Festa’ at Mariri Environmental Centre in May 2018, honouring the teamwork and attention to detail of the honey-hunter team, and awarding prizes for data and photo quality and care of equipment.
- We have established a colour-ringed population of over 100 greater honeyguides, plus smaller numbers of lesser and scaly-throated honeyguides (which eat wax but do not guide humans) in our study area.
- The research team continue to carry out regular outreach activities in Mozambique, giving presentations to groups of school learners, visiting the Mariri Environmental Centre from various towns and villages in Niassa Province. Claire also contributed a week-long module on research design and scientific writing to the Masters course at the Edward O. Wilson Biodiversity Laboratory, Gorongosa National Park which trains young conservation biologists from all over Mozambique (a joint initiative between Lúrio University, Zambeze University, and Manica Higher Polytechnic Institute).
- Claire presented findings from the project in research talks in Mozambique, the USA, UK, and Switzerland, including the 2018 Stamford Raffles Lecture of the Zoological Society of London.
Impact of the project
This project is allowing us to involve rural communities in understanding a unique human-animal relationship. We hope this study will further our understanding of how mutualisms evolve, and specifically how learnt traits mediating mutualisms may coevolve with one another. Understanding mutualisms is broadly relevant because they help to shed light on the Understanding the evolution of mutualisms is important because it sheds light on the mechanisms that can maintain cooperation among unrelated individuals. It is also important for effective conservation, because mutualisms can have a wide reach in ecological communities. The honeyguide-human mutualism has already died out from large parts of Africa, as the continent develops. It would be a tragedy if it vanished altogether before we fully understood this part of our own evolutionary history.
European Research Council; National Geographic Society; Max Planck Institute for Evolutionary Anthropology; DST-NRF CoE grant.
Prof. Claire Spottiswoode (FIAO, UCT and, U. Cambridge)
David Lloyd-Jones (FIAO, UCT)
Dr Jessica van der Wal (FIAO, UCT)
Orlando Ncuela (Niassa Carnivore Project)
Dr Dominic Cram (U. Cambridge)
Dr Brian Wood (U. California Los Angeles)
Prof. Timm Hoffman (Biological Sciences, UCT)
Dr Colleen Begg (Niassa Carnivore Project)
Keith Begg (Niassa Carnivore Project)