Friday, June 28, 2013

The fig wasp's journey

Fig Wasps from my neighbors fig "fruit".

       I just finished reading Trees: Their Natural History by Peter Thomas. This book describes the lifespan of a tree, detailing what defines a tree from leaf to trunk, down to the roots below. Although a scientific book, Peter Thomas's descriptions become quite poetic when he takes time to reveal the small intricacies bound up in a tree's life. In his chapter, Towards the next generation: flowers, fruits and seeds he writes about the sheer brutality and complex beauty of the plant and pollinator in the fig wasp cycle.

       Here is my simplified explanation: When one cuts open a fig “fruit,” they will discover a bunch of stringy looking innards. These stringy forms are actually layers of different heights of flowers. Pollination of the fig happens when a female, bearing pollen from the fig in which she was born, squeezes thru a small hole that is accessible when the fig is in its infancy. This hole is so small that she typically loses her wings and antennae in her journey into the fig.

        Once inside, she moves about to lay her eggs in some of the flowers, while inadvertently pollinating other flowers. Her life ends here inside the fig. However her eggs hatch; the wee-ones feed and grow. The grub growth stimulates the tree not to drop the fig, allowing time for seeds to grow inside the fig along side the wasp.

         Wingless males eventually hatch, find a newborn female and mate. Having had the time of their life, they promptly chew a hole out of the fig and die. The winged females now have a tunnel for a smooth exit. Once out of the fig the females, loaded up on pollen from wandering around their birth fig, fly away to a new lovely smelling fig to lay their eggs. Hence the cycle continues and the figs ripen, are eaten and the seeds are spread. Yummy. Neither fig tree nor fig wasp could survive without each other. A relationship some believe has gone back in time some 60 million years. Geez. Sometimes it is really hard to break up.

        After discovering this tid-bit, I immediately went out in search for wasps. Luckily, a neighbor around the corner has a ginormous fig tree that overhangs their fortress of a fence onto the sidewalk bus stop. Many, many jumps later… I found a tall person to grab a few figs for me. Once cut open, this is what I found:

halved fig with wasps
P.S. Here is an informative site on the fig and its wasp: figweb

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