School seminar series: The coevolution of fig trees, pollinators and parasitoids
17 May 2013
Presented by Prof. James Cook, Hawkesbury Institute for the Environment, UWS (Host: A/Prof. Dieter Hochuli).
Symbiosis - the intimate ‘living together’ of different species - plays a huge role in both evolutionary innovation (e.g. the origin of plants) and ecosystem function (e.g. nitrogen fixation). Symbiosis is very common in nature and intimately interacting species are likely to influence each other strongly in terms of both adaptation and speciation. Many host-symbiont interactions are antagonistic, but others are mutualisms in which both partners derive benefits. A classic case involves fig trees, which provide a year-round supply of fruit to diverse animals, from tiny insects to bats, birds and elephants. This ecosystem function relies on an obligate pollination mutualism between fig plants and tiny fig wasps. I will discuss the origin and patterns of speciation in figs and fig wasps during their radiation to produce >750 species pairs spread across all tropical continents. This research supports substantial long-term co-speciation, but also additional modes of speciation in the wasps. I will also describe how the intricate symbiosis with fig trees has influenced genome evolution in the pollinators. I will then present a striking pattern of coadaptation between the pollination behavior of the wasps and floral sex ratio in the figs. Finally, I will consider how climate change impacts upon this intricate symbiosis, both in terms of immediate ecological population dynamics, and longer-term adaptation and speciation.
Location: DT Anderson Lecture Theatre, A08