For want of a fig wasp

This week, we stayed for three days in Lamington National Park, and it was not what I expected.

The rainforest was huge, lush, and intimidating. I thought I would love it, but I didn’t feel love so much as awe. For a rural Texas girl used to open pastures and expanses of flat plain, I almost felt claustrophobic as I walked along the tight, overgrown trails, dodging mossy fallen trees and pushing past thick hanging vines. It was amazing, awe-inspiring, beautiful, but I don’t know if I could stay there for very long.

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A view of forest foliage from the track

On our first hike, we zig-zagged over forested hills and crossed trickling streams as we made our way to Coomera Falls. The rocks in the water were carpeted in red algae which almost looked like blood spatters. Thick, gorgeous moss covered almost every exposed surface, and from the forest we could hear the piercing calls of the whip birds. The forest felt prehistoric, primal.

The hike to the falls was like nothing I have ever experienced. As soon as we turned one corner, the rest of the group was lost from sight and hearing. The ground was permanently damp, and I never felt quite dry. As we climbed higher and higher in elevation, the vegetation changed abruptly, fading from thick rainforest to eucalyptus glades to scraggly patches of birch.

We arrived at the falls after a two-hour hike, during which our guide, Barry Davies, fed us a constant stream of information about the plants and animals we saw and heard. My favorite plant he pointed out was the strangler fig, a towering tree with a touching dependence on an unlikely partner—a 3 millimeter long wasp.

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Coomera Falls (the picture doesn’t do it justice)

The strangler figs were impressive to look at. The body of the tree was a meshwork of sinuous trunks, which wove in and among each other until a point about 50 feet up, where they seamlessly merged to form a single trunk. This top trunk pushed its way up into the canopy, where it branched out in search of sunlight. The base of the tree was full of nooks and crannies that undoubtedly housed innumerable animals.

Barry explained the mechanism behind this odd growth pattern: instead of growing up from the ground, strangler figs can cheat the system. If their seeds are deposited in another tree by birds or other animals, the fig can grow down from the tree. The roots wind their way to the ground, engulfing and “strangling” the host tree, which usually dies.

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The roots of a strangler fig engulfing its host tree. Photo credit: Wikimedia Commons

These rainforest giants don’t just look impressive. They ­­play a key role in the ecosystem. Barry told us that fig trees produce fruit virtually all year round—they are the rainforest equivalent of a 24/7, all-you-can-eat buffet for fig-eating animals. Up to 70 percent of rainforest creatures depend on figs as their primary food source for at least part of the year.

The figs themselves are odd, like normal fruits turned inside out. The flowers are on the inside of the fruit—there is no point of access to pollen without boring into the fruit. And that’s where the wasps come in.

The female fig wasp is tiny, only 3 millimeters long, and her mission in life is to lay her eggs inside the fruit of the fig. To get to prime egg-laying territory, she embarks on a harrowing journey to the center of the fig, during which both her wings and most of her antennae are often torn off. When she reaches her destination, she deposits her eggs along the wall of the fruit, then dies.

The fig wasp eggs develop within the fruit, and when they reach the pupal stage, the male mates with the female straight away. Once mature, the male and female wasps tunnel their way out of the fig, collecting pollen as they go. Outside the fig, the male dies quickly, but the female goes on to another fig to lay her eggs, and in the process pollinates the next fig. It is an odd, complex process, and the whole forest ecosystem depends on it.

When I was younger I had a huge ugly journal which I decorated liberally with glitter glue, and on the inside front cover I wrote the poem proverb “For want of a nail.”

For want of a nail the shoe was lost.
For want of a shoe the horse was lost.
For want of a horse the rider was lost.
For want of a rider the message was lost.
For want of a message the battle was lost.
For want of a battle the kingdom was lost.
And all for the want of a horseshoe nail.

I’m not really sure why I chose that particular poem, but I think what fascinated me about it was the interdependence. A whole war, lost by one nail.

Just as the fate of the entire war depended on one horseshoe nail, the health of the entire rainforest—and rainforests all over the world—depends on one kind of wasp. It’s a beautiful example of the intricacy of nature, but also a reminder of the fragile complexity of our ecosystems. The fig wasps and trees coevolved over millions of years, and to me, the scale of their evolution dwarfs any short-term human decisions that can be made.

Thinking about the fig wasps really drove home the idea that we, as humans, can never know every consequence of our actions. The world is a tenuous interconnected web, and we will never know the interactions of every part of it. The best we can do is to make decisions based on the knowledge we have, and be aware that we can never be fully aware.

This idea of awareness applies to all decisions surrounding the issue of climate change. The continued release of greenhouse gases and incremental warming of the atmosphere will cause changes with their own ripple effects, and although we can make reasonable predictions, there is no we way can foresee every outcome. Likewise, efforts at mitigation and adaptation also come with consequences. Decisions still have to be made, but it is important to consider what outcomes we can foresee—and the possibility of outcomes we cannot foresee.

Thankfully, despite the millions of decisions that are being made every day and the drastic changes our environment has seen, rainforests are not wanting for fig wasps.

Extra Photos

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Flowers outside the cabin

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Moss hanging from trees in the forest

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Barry showing us a trapdoor spider

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Crazy twisty trunks

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A view from an overlook in the forest

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Some sort of palm roots

 

 

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