Australia’s sexual swindlers.

Seduction. Pollination. Deception.

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I recently wrote an article for Wildlife Australia about Australian sexually deceptive orchids, their evolutionary biology, and historical and current research about them. You can download and read the article here: PDF. Thanks to Carol Booth for her collaboration and editorial guidance.

The latest of Australia’s sexually deceptive orchids that I have seen (below) are Caleana major, the Flying Duck orchid (left), and a spider orchid Caladenia clavigera (right). Both were photographed last week in Brisbane Ranges NP, Victoria.

Flowering this year is one of the best seasons of recent times both east and west of the country. So if you’re in Australia, don’t miss the chance to get out bush and enjoy it.

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Sex, Lies and Nectar: Evolutionary Biology as Written by Flowers

I spoke to the Canberra Skeptics group earlier this week, on a subject most near to my heart. The abstract appears below. It is my aim to soon turn elements of this into a video for online audiences.

In the eyes of evolution, finding a suitable mate for reproduction is one of the most critical stages in any organism’s life. The great majority of flowering plants have outsourced this essential service to animals, giving rise to a fascinating evolutionary dance between plants and pollinators.

Charles Darwin was the first to recognize that flowers were superb teachers of evolution. I will touch on his classic work and explain what we have since learned about remarkable flowers who smell like dung and death, flowers who attract insects with the false promise of sex and a fly with a ridiculously long tongue.

These and other awesome examples of floral evolution would surely have thrilled Darwin, and may even solve his “abominable mystery”: the rapid rise of the spectacular diversity of flowering plants.

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Male thynnid wasp gripping tightly to the lure of the hammer orchid (Drakaea glyptodon).

Plant pollinator interactions in the South African flora

The slides from my recent departmental seminar at the ANU are below.

The first half of the talk concentrates on plant-pollinator interactions, floral guilds and floral evolution. The second half is a slideshow of vistas, creatures and plants I encountered in my work.

Die Selfish Gene, Die.

I was recently asked by a friend for my opinion on David Dobbs’ piece “Die Selfish Gene, Die.” The article spins a yarn on why Richard Dawkins’ “Selfish Gene” thesis is sunk and the battle for updating it with a new theory of “genetic accommodation”.

It has attracted much attention as a great piece of science writing popularising the battle for a paradigm shift in genetics and evolution. Unfortunately its inaccurate and a bit too puffed up on its own bravado. My brief statement is below, however Jerry Coyne, Richard Dawkins and PZ Myers provide a more thorough commentary.

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Dobbs’ article describes a battle of two straw men. 

The term “genetic accommodation” is a new one to me, but the description of it sounds like phenotypic plasticity together with pleiotropy and epigenetics in a fancy jacket, but maybe we needed a word for that. Nonetheless, contrasting it with the selfish gene hypothesis is a false dichotomy. The messy truth for many traits lies somewhere in between, where the convoluted cascade of genetic-epigenetic-genetic interactions involved in “expression” will face selection as soon as its resultant phenotype hits the environment. 

The complexity of gene expression via interactions between genes and epigenetics (non-DNA inheritance) is blowing a lot of our heads off right now. It’s chaotically complex in there. I think the article therefore makes a mistake in referring to “gene expression” as a singular process.

Work I saw presented by John Mattick from the Garvan Institute provides a good example. Gene expression in human neurons can be governed by the interaction of RNAs, binding to “non-coding” DNA and interacting in 3 dimensions with complex protein molecules. In other words, it starts with a gene, which makes an RNA. That RNA’s action depends on the interaction between its sequence and where it binds on the genome. The sequence of DNA to which it binds, governs how it binds; simple like a zip, or more complex and looped up. Along comes a protein molecule (encoded earlier, elsewhere, by another gene) and the molecular properties of that gargantuan tangle of amino acids determine how it interacts with that looped up bit of RNA stuck to the DNA. This binding provides but a step in some long chain of protein interactions in a biological pathway. 

This kind of combinatorial complexity of interactions provides huge plasticity of action for a single set of tools (the genome).

One could argue that the first step of environmental interaction of any gene is the “environment” of the genome and epigenome it inhabits. This could still be squared with the selfish gene thesis.