Wednesday, September 21, 2016

Can I Eat That?

As a college student, food is almost always on my mind, and why would that change in Costa Rica? The great thing about a tropical rainforest though, is that there are plenty of things to eat. In our first few days here, I’ve tasted many things and learned about the organisms that make these edible fruits.

While walking through the Wilson Botanical Garden for our plant field taxonomy class, we were focusing on leaf complexity, arrangement and other characteristics in order to identify plant families. Near the end of the class, we came across this gorgeous bush with bright red peppers, a member of the Solanaceae family which includes tomatoes, potatoes, eggplants and more. Inevitably, due to the fact that bright red peppers hung before us looking very tempting, “Can I eat that?” was uttered. With a mischievous smile, Mau said “Do you like spice?” I personally don’t like too much spice so I thought I’d pass on this plant, but after Tom and Sofi both bit a little off the end and stated that they liked it and took another bigger bite, my curiosity overcame my initial decision. So, I took a bite of the pepper and got a mouth full of seeds. The three of us looked at each other and realized the mistake of eating the seeds. I immediately regretted my decision as spiciness and pain filled my mouth. A few minutes later, as the pain plateaued and subsided, I learned a few things.
1.      Just because you can eat something doesn’t mean you should.
2.      The bright red color that attracted us to eat the pepper, also attracts other animals.
3.      The spice acts as a defense mechanism for the seeds of the plant. This particular plant’s seeds are dispersed by birds, who can’t taste the spiciness, but other animals attempting to eat the seeds will be deterred by the spiciness.

Besides tasting peppers that we find on our walks, we were also able to taste 47 different fruits as a part of our fruit lab. All of the fruits were native to the tropics and about half of the fruits were new to me. One of the fruits that we were able to try was the fig, which we had learned about a few days earlier. Figs are unique in the way that they grow and the way that they are pollinated.

Strangler figs are hemi-epiphytic with bird dispersed seeds. As the fig seed is dropped by a bird into a tree crevice, the seed germinates. The seed then sends roots down towards the ground and sends normal growth upwards. Multiple figs can land on a tree, and as they encounter the other figs, even if they are a different species, they fuse to make one larger plant. Eventually the fig becomes so large that it out competes the host tree for resources, killing the tree. Leaving only the strangler fig tree, with a now hollow core, as the victor.  

Eventually the fig tree produces fruits that are pollinated by wasps. Wasps crawl into the fruit, lay their eggs and die. The wasp offspring then hatch and mate with each other. Then the females collect pollen while the males dig a hole out of the fig. This exit isn’t for them, just for the females, as the males will die in the same fig they are born in. Once the female leaves to find a new fig to lay her eggs in, she brings with her pollen to pollinate the fig where she lays her eggs. This mutualistic relationship gives food and shelter to the wasps and provides pollination for the figs, so they can reproduce. So if you eat a wild fig you may also be eating a dead wasp (FYI: You don’t need to freak out, commercial figs do not need pollen to produce fruit, so figs in the grocery store shouldn’t have dead wasps in them).  So, the wild fig, like the pepper, is another fruit that might be better left uneaten.

Rachael Lewandowski-Sarette,
Northwestern University

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