Tiny Terrors

Get an inside look at science as it happens in the Caribbean. This week we discover some of the smallest scary beasts on St. Kitts and Nevis.

An Water Scavenger Beetle larva on the hunt for tadpoles.

In the wild and diverse tree of life, we often imagine ourselves at the top. Fair or not, we do have incredible power to shape the world. Beside us, we place animals we respect: the wise orangutan, the majestic eagle, the powerful elephant, the friendly dog and the dominating shark. Like us, all of these animals have a literal backbone.

What about the endless variety of invertebrates? What about the insects, worms, crabs and corals? For much of history, the average person didn’t think of them as animals at all. These spineless creatures were a lower class of being, worth little thought.

Though they are small, we’ve come to respect some insects. We know we can be laid low by the bite of a mosquito. We’ve watched beetles destroy forests. But we still tend to think of bugs as food for those with backbones—birds and lizards and frogs—and never the other way around.

In the ponds of St. Kitts and Nevis, the tables are often turned. While a caterpillar is a soft and juicy snack for a bird, a tadpole is often a soft and juicy snack for a bug. Aquatic insect hunters don’t care if you’ve got a backbone.

There is a surprising variety of aquatic beetles. A group known as Water Scavenger Beetles are often scavengers as adults. Their larvae, on the other hand, are almost always hunters. One specimen on St. Kitts was several inches long, with huge piercing hooks for mandibles. In our aquarium, it took to eating Cuban Tree Frog tadpoles one after the other.

Dragonfly nymphs can also eat tadpoles and small fish. They have an extendable “jaw” that is longer than their head. It can snap out to grab prey in the blink of an eye. The Creeping Water Bug is smaller, but still quite deadly. It has grabbing front legs like a praying mantis, but more pointy. Its mouth is like a straw, and it is happy to use a tadpole as a juice box.

The Creeping Water Bug has legs for grabbing.

These tiny terrors can’t do anything worse to us than perhaps a painful bite. But they are a reminder that insects and their kin can be deadly. They can dominate, and in their world just having a spine doesn’t make you safe.

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