Why are so many strangler figs home to ghosts and goblins?
Frying eggs, flying foxes, dying wasps, crying shame
Crack an egg in a pan, turn up the heat and you can witness a kind of magic. In just seconds the viscous egg solidifies. And despite the rising heat, it’s the opposite of melting that occurs. I was a teenager when I heard a biology teacher explain this paradox: “The egg is full of proteins and the heat has denatured them”. Denatured. The word was new to me. Twenty-five years later I find it is a fitting descriptor of more than just wayward proteins.
My teacher had explained that every protein has a temperature at which it will function best. Too hot or too cold and the protein’s shape can buckle or break. It will no longer be able to bond with other chemicals. It will cease to work. I think about that fried egg often when I consider what rising temperatures could mean for the planet.
We know that when people die of heat stroke, part of the problem is that some of their proteins have denatured. Could our cells become our jailors?
The proteins inside us and every other living thing vary greatly. Some tolerate heat better than others. Others begin to destabilise at just a couple of degrees warmer than normal. It is not the average protein that poses a problem, but the weaker links, those most liable to destabilise in extreme heat. We don’t know yet which of them are also critically important – to our food crops for instance.
As the world warms, what will happen to the millions of different proteins in the millions of different species, from spores to sperm whales, soil bacteria to sunflowers? These invisible structures are central to life itself. They give shape not only to hair and to horn but also to hormones and enzymes and DNA. They are the messengers and mechanics that control and correct processes in and between cells. Like the gaps in music that make the beats thrilling, these in-between places are where wonder is born.
It’s the same between species. Life is not a zoo of caged individuals living in isolation but a web of shared destiny. And while activists go on about polar bears or other creatures in danger, I am more curious about what climate change could mean for the way species interact and provide us gifts as a result. It’s been on my mind since the early years of my career when I lived in a rainforest in Borneo and studied the most fascinating of plants, the strangler figs.
Every one of the 750 or more species of fig trees depends for survival on its own species of tiny wasps to pollinate its flowers. The wasps in turn depend on the figs, the only places in which they can lay their eggs. This mutual reliance combines with the wasps’ short lifespans to ensure figs are available year-round, and because of this they sustain more species of birds and mammals than other plants. In return for the fig flesh those creatures disperse the trees’ seeds, and provide the same service to thousands of other rainforest plants. These interactions between fig trees and animals help to sustain the great rainforests of the world.
What does this have to do with climate change? Researchers have shown that just a small increase above current temperature levels will shorten a fig wasp’s life to just a couple of hours – not enough time to find a fig, pollinate its flowers and lay eggs. No pollination would mean no ripe figs for animals to eat, and this would mean fewer seeds get spread from place to place. Tree species that form a key part of the forest and its capability as an ensemble to lock away carbon are likely to suffer.
The tiny wasps are frail but some of the fig trees’ bigger partners are at risk too. They include fruit bats called flying foxes that can carry seeds 50 kilometres or more before pooping them out, making them some of the most effective seed dispersers around. Their vulnerability became clear early in 2014 when thousands of them fell dead from the sky during a blistering heat wave in Queensland, Australia. For both the bats and the fig wasps, the heat was too much. It will have interfered, at a cellular level, with proteins that cooked and then closed for business. These snapshots suggest trouble in store for the fig trees and the forests, whose fates entwine with our own.
Ecology teaches us that no species is an island. It’s a lesson our leaders seem to have skipped. It shows us we’re all in this together, the fig wasp and the fruit bat, the you and the me. That’s what makes the human fingerprints all over climate change all the more ironic. As we develop societies ever more distant from nature to protect ourselves from its wild whims, we risk unleashing upon these denatured societies powers we cannot hope to control or even predict.
This post reproduces my contribution to Culture and Climate Change: Narratives, which launched on 24 June at the Free Word Centre. The whole book is available for free and anyone can reproduces its articles under a Creative Commons Licence.