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Project: 281/2011

Title: Financial support to present the conference paper titled, “Total Evidence Phylogenetic Analysis of the Orchid Tribe Diurideae and What it Tells Us About the Evolution of Pollination Systems” at the International Botanical Congress held in Melbourne in July, 2011
Applicant: James Indsto
Institute: Royal Botanic Gardens and Domain Trust, Sydney, NSW

James Indsto, james.indsto@optusnet.com.au
Dr Peter Weston, Royal Botanic Gardens and Domain Trust, Sydney, NSW
Dr Andrew Perkins, Royal Botanic Gardens and Domain Trust, Sydney, NSW
Dr Mark Clements, Centre for Plant Biodiversity Research, CSIRO, Canberra, ACT

In this project phylogenetic methods were used as a research tool to investigate pollination systems in the orchid tribe Diurideae. Previously, two major studies of this orchid tribe have been undertaken using DNA sequence analysis. These studies have led to a revised understanding of relationships within Diurideae since the morphology-based system proposed by Robert Dressler. We have used a total evidence approach in which the data sets of previous DNA sequence-based studies were combined with a data matrix of 100 morphological characters. This analysis has produced the most robust phylogenetic tree for Diurideae obtained to date. Advances in knowledge of pollination biology have been mapped on to this tree to help elucidate the evolution of pollination in this large orchid group. Our findings:

• Demonstrate that the subtribe Diuridinae forms a sister relationship with the rest of Diurideae.
• The genera Pterostylis and Chloraea belong in the tribe Cranichidae, not Diurideae.
• Food source mimicry is an ancestral pollination system in Diurideae.
• Sexual deception has evolved at least 6 times in Diurideae.
• Nectar production has arisen secondarily in several Diuris lineages.
• An understanding of flower number and clonality gives further insights into evolutionary drivers of pollination systems in Diurideae.

This study has been presented as a conference paper for the Darwin’s Orchids Symposium at the International Botanical Congress held in Melbourne in July, 2011. The Australian Orchid Foundation has generously funded James Indsto to attend this conference to present an oral paper of this work and also the Orchid Workshop held at the Cranbourne Botanic Gardens outside Melbourne on Saturday, 30 July 2011. This project is also being written up as a book chapter in a conference proceedings publication commemorating Darwin’s contribution to our understanding of orchid pollination biology.