The Wild Cycad Conservancy

It also affects species in other parts of Africa such as Encephalartos equatorialis in Uganda. Loss of pollinators would be expected in species that are Extinct in the Wild (EW), or very close to EW, but has now been documented in larger populations comprising several hundred plants. 

What can be done about it? 

As part of a postdoctoral project, Paul Janse van Rensburg is working with John Donaldson and other colleagues to identify possible solutions. In essence, we need to determine how specific the pollinators are, what drives host specialisation, and if it is possible to re-introduce pollinator populations from other related cycads. 

The first step has been to consolidate all the known information on host records and to complement this with additional surveys of poorly sampled species. We now have reasonable data for pollinators from 25 of the 37 South African species, meaning that we still need information on five remaining species. However, we note that we cannot sample the four EW species and we don’t expect to find anything on the three additional species that are known from fewer than five plants in the wild. 

Sorting out the taxonomy of the beetle pollinators is a challenge, but we are working with colleagues locally and overseas to sort out the identification and incorporate genetic information to better understand the relationships between beetles from different cycad hosts.

Smelly cycads that lure beetles

Another key part of the puzzle is to figure out host relationships, basically how many different hosts can a pollinator successfully colonise. Using host records, we can map the relationships between beetles and cycad populations and identify those pollinators that seem able to colonise different host plants. 

We also need to dig deeper into what drives host specialisation. We know from previous research that cycad cones release volatile odours, which mediate their interactions with insect pollinators. Mapping the relationships between different beetles and the odour profiles of their cycad hosts can point to pollinators that are attracted to specific compounds and identify those that could possibly move between cycad species with  similar cone odours. 

Finding the solutions

The ultimate test will be if pollinators associated with any of the more common cycads can be reintroduced to populations where pollinators are extinct. We can get some idea from host shifts occurring in gardens – and we are documenting these relationships – but this will need to be complemented by experiments in wild populations where all the complexities associated with attraction, host recognition, breeding and survival of pollinators on their host plants will come into play. Restoring pollinators isn’t just about putting some beetles back into a cycad population, it’s about ensuring they will thrive in the long term. 

By using science to inform conservation action, we hope to ensure the future of self-sustaining cycad populations with effective pollinator interactions. 

Left: Four species of pollinator beetles collected from Encephalatos lehmannii (a&b – species of Elaterid beetles; (c) Metacucujus sp., and (d) Porthetes sp.)

Right: Paul Janse van Rensburg collecting pollinators from Encephalartos lehmannii