The co-evolution and maintenance of obligate pollination mutualisms in the Australian Phyllantheae
Mutualisms account for much of the diversity of life that we see in the natural world. They often involve very different organisms (e.g. animals and plants, or plants and fungi) swapping resources for services or other resources. Obligate pollination mutualisms (OPMs) are highly specialised interactions in which plants and pollinators are entirely dependent upon each other for reproduction. OPM pollinators provide a service by transporting pollen between the male and female flowers of a single host species. The pollinators then lay eggs within the flowers that they fertilise. Pollinator offspring develop by feeding on a proportion of the seeds fertilised by their mother, at the expense of the plant seeds (resource).
Natural selection will act on mutualists to maximise their own benefits from the interaction and minimise the costs. Selection could therefore result in "cheating", where services and resources are not "fairly" traded and interacting results in net loss of fitness to a partner. Mechanisms must therefore exist to prevent partners in a mutualism from overexploiting each other. Identifying these mechanisms is fundamental to understanding the evolution, stability and proliferation of mutualisms.
In 2003 a new pollination mutualism was described between moths in the genus Epicephala (Gracillariidae) and three species of plant in the genus Glochidion (Phyllanthaceae). OPMs involving Epicephala moths are estimated to occur in approximately 500 species of Phyllantheae, making it the second largest group of OPMs. The vast majority of the OPMs within Phyllanthaceae, however, have yet to be described or studied.
Breynia oblongifolia is a common and widespread native Australian bush within the Phyllanthaceae, occurring from as far north as Papua New Guinea to southern New South Wales. It is known to be involved in an OPM with Epicephala sp. moths. My project will involve the description and study of the OPM occurring between B. oblongifolia and Epicephala sp. moths across it's range. My research will provide us with increased knowledge of Australian native species and their interactions and generate new insights into the costs and benefits of mutualisms and the co-evolutionary processes that promote and maintain them.
Finch JTD, Power SA, Welbergen JA, Cook JM, (2018) 'Two's company, three's a crowd: Co-occurring pollinators and parasite species in Breynia oblongifolia (Phyllanthaceae)', BMC Evolutionary Biology, vol.18, no.1, Article no.193
Professor James Cook, Professor Sally Power and Dr Justin Welbergen