Plant biodiversity and adaptation in a changing world: the effects of animal pollinators

A project undertaken at the School of Biosciences, University of Melbourne, and supervised by Dr Michael Whitehead

Animals play a vital role in the reproduction, evolution, and ecology of plants, with an estimated 90% of flowering plant species relying on animals for pollination. The range of animal species involved in pollination is broad, encompassing birds, bats, non-flying mammals, and a wide swathe of insect diversity from the smallest of flies to very large moths. Given the sometimes radically different morphology, behaviour and ecology of these varied pollinator groups, it would be incredibly unlikely that contrasting pollinator types will move pollen in the same manner. More likely is that different pollinators’ behaviour will result in different patterns of pollen movement. Over evolutionary timescales, any potential differences in pollen movement will exert profound influences on the evolution and adaptation of plant lineages. Despite this, we lack a fundamental understanding about how different animal pollinators influence the movement of pollen in the plants they service.

This project uses Australia’s unique biodiversity to answer the question: “What’s the difference between a bird and bee as a pollinator?”. The study examines rare occurrences of closely related plant species, inhabiting the same area, but employing distinct kinds of pollinators. For example, in East Gippsland (Victoria), the Monkey Mint Bush (Prostanthera walteri) grows with its relative, the Christmas Mint Bush (Prostanthera lasianthos). The former is bird-pollinated, while the latter is pollinated by flies and beetles. By examining the population genetic structure of these two species, and in two other species-pairs, this study aims to uncover differences that have accumulated as a result of differing pollen transport by contrasting pollen vectors.

These results will be essential for a general understanding about how different groups of animals move pollen. Ultimately, this information can be used to manage and conserve our natural capital, as well as interpreting evolutionary patterns

Figure 1. The Monkey Mint Bush (Prostanthera walteri) is a bird-pollinated shrub restricted to far South-East Australia

Figure 2. The Christmas Mint Bush (Prostanthera lasianthos) is predominantly pollinated by flies and beetles.