Plant-Animal Interactions

A few weeks ago I was hand-weeding near the tomatoes when I found a weed I hadn't seen before. At first glance, it looked like it was bearing fruit, since it seemed to have tons of pods all over the plant. Curious, I took one of the pods off the plant and started to break it open so I could see the seeds inside. But the "seeds" inside the pod were moving...

Inside the curled-up leaves of this plant (the "pods") were hundreds of tiny critters. Critters that, at some point in their life cycle (probably when they were eggs) triggered a chemical reaction in the plant, which caused the leaves to curl around the eggs and protect them as they matured. Crazy, huh?

Here's another insect that does something even crazier.

The tomato hornworm is a loathed creature in farms and gardens - anywhere tomatoes are cultivated. Its mint-green coloring makes it blend in just well enough so when you're pruning or harvesting it's a shock (at least to me) to finally realize there's something there. It's mostly a shock though to see such a large caterpillar, since the tomato hornworm eats and eats and eats and grows and grows and grows. Remember Eric Carle's The Very Hungry Caterpillar? This is it. But this hungry caterpillar likes to eat your tomato plants.

So, in a sick yet poetic turn of events, the tomato hornworm is the favored host of the parasitic Braconid wasp, Cotesia, which lays its eggs inside the body of this squishy, green caterpillar. They hatch (inside the hornworm) and eat (also inside the hornworm) until they emerge to make their cocoons (on the body of the hornworm). Creepy poetic justice.

Tomato Hornworm covered in cocoons of the parasitic wasp Cotesia