The influence of animal behaviour on plant adaptation and evolution.
McKenzie Postdoctoral Fellow, University of Melbourne, Victoria, Australia
The range of animal species involved in pollination is broad, encompassing birds, bats, non-flying mammals and a large swathe of insect diversity. Despite this and the importance of animal pollination for sustaining natural and agroeconomic systems, we lack fundamental knowledge about how different animal pollinators influence the ability of plant species to adapt to global change. Specifically, our understanding of the way different pollinators influence patterns of plant gene flow remains poor. Gene flow controls the distribution of genetic diversity across the landscape and therefore determines how populations adapt to selection pressures in a changing world. In animal-pollinated plants, gene flow is influenced by the behaviour of their pollinators. It is therefore likely that different guilds of pollinators (e.g. birds, bees, butterflies) will impose distinct patterns of gene flow in the plants they service.
This project seeks to uncover generalities in the way different classes of pollinator move genes within and between individual plants and plant populations.
Collaborators: Mike Bayly, Ary Hoffman (University of Melbourne)
Are pollinators of rewardless orchids betrayed by learning or instinct?
Postdoctoral scholar, University of KwaZulu-Natal, Pietermaritzburg, South Africa
The subjects of this study are the ‘food deceptive’ orchids of South Africa – species that lack nectar rewards yet attract foraging insects through mimicry of common nectar-bearing flowers. Specifically, I will be studying the species Disa nivea which attracts a particular long-tongue fly by close visual mimicry of the nectar-bearing flower Zaluzianskya microsiphon. The successful deception of long-tongue flies by D. nivea mimicry of Z. microsiphon could potentially work in one of two ways:
– Long-tongue flies are conditioned from emergence to associate the flowers of Z. microsiphon with a nectar reward.
– Long-tongue flies have an innate instinctual attraction to the floral signals (colour/shape/smell) of Z. microsiphon.
This study aims to test which of these scenarios is important for D. nivea mimicry.
By telling us to what extent flowers are shaped by either learned or innate pollinator biases we gain fundamental insight into the reciprocity of plant-pollinator evolution.
Collaborators: Steve Johnson (UKZN)
Diversification of south-west Australian spider orchids.
Research Fellow, Australian National University, Canberra and King’s Park Botanic Garden, Perth, Australia.
The south west of Australia is famous as a biodiversity hotspot and the spider orchids are no exception to this phenomenon. With a rich diversity of species, form and pollination strategy they provide an excellent group in which to test a range of hypotheses concerning the evolution of floral diversity. My work here is as part of a team dedicated to unravelling the above and below ground relationships of a group of sexually deceptive spider orchids. Specifically, I am using seed baiting techniques, fungal isolation and DNA sequencing to elucidate the relationships between orchids and their mycorrhizal fungi. As a strict requirement for germination, obligate mycorrhizal fungi play a key role in the orchid life-cycle. But can specialization on fungal symbionts drive speciation? Does higher fungal diversity at a site promote higher floral diversity? These are the sorts of questions I am tackling in this project.
Collaborators: Celeste Linde (ANU), Rod Peakall (ANU), Ryan Phillips (KP), Kingsley Dixon (KP).
Gene flow in sympatric sexually deceptive orchids.
This work formed the basis of my PhD research at the ANU where I was supervised by Professor Rod Peakall.
Work generously funded by the Australia-Pacific Science Foundation
The project focuses on sexually deceptive orchids in the genus Chiloglottis. These orchids attract their wasp pollinators through a remarkable chemical mimicry of the female wasp sex pheromone. By employing a multidisciplinary approach including molecular genetics, experimental studies of pollinator behaviour and analytical chemistry I explored a range of questions concerning the reproduction and evolution of these plants.
The two taxa under study occur sympatrically and attract distinct pollinators through the emission of distinct floral volatile profiles. I explored questions about hybridization and reproductive isolation through gas-chromatography and mass-spectrometry of floral volatile emissions coupled with population genetic analysis of variation at microsatellite loci.
I also carried out mating system and paternity analysis to investigate what gene flow can tell us about the evolutionary implications of sexual deception as a pollination strategy. As an additional approach to studying gene flow I conducted mark-recapture studies of wasp pollinators to learn more about their behaviour and what that means for orchid populations.