Today I’m giving a presentation to third graders at CIA (Caribbean International Academy) about the relationships between plants and animals on St. Martin. Often insects and plants have evolved together to have both symbiotic and confrontational relationships. This photo shows an Ornate Moth feeding on nectar from a wild pea plant. Plants provide nectar for insects (and other animals) in exchange for pollinating their flowers. This moth, for example, may bring pollen grains from one pea flower to the next while feeding. By pollinating the flowers, the moth facilitates the reproduction of the plant, producing the seeds (peas) that will grow the next generation of pea plants.
But it’s not so simple. The caterpillars of this moth feed on the pea plant, and they often chew their way into the pea pods to eat the growing seeds. To defend itself, the plant produces toxins, particularly in the peas, to discourage animals from eating them. But the caterpillars have evolved resistance to the toxins, and even use them to make themselves toxic to would-be caterpillar predators.
So, the plant provides food for the moth, which helps pollinate the plant to create seeds that the caterpillars eat, which the plant has made toxic, but the caterpillars have adapted to tolerate and use to protect themselves from predators.
