A Surprise on Pender Island

A good portion of today was spent aquatic sampling at Greenburn Lake on South Pender Island. While sorting through the clutter of bottom debris dumped into our white pan, we found an assortment of different aquatic invertebrates which were all fascinating. But we were particularly captivated by what we found resting on a nearby log on the water’s edge. It was a giant water bug (Belostomatidae).

The odds are good that your memories as a child include “pond aquaria” full of fascinating aquatic insects captured during an adventurous expedition to your local pond or creek. It is also very likely that the dragonflies, mayflies and caddisflies confined to your jam-jar aquaria soon perished to the depleting oxygen levels in their confined living spaces, leaving true bugs, such as the robust monstrosities of the aquatic insect world, the giant water bugs, as the most conspicuous survivors. This occurs because, unlike most other aquatic insects, true bugs are not dependent on absorbing oxygen from the water. They obtain air at the surface using a variety of appendages, including flaplike structures at the tip of their abdomen, as seen in our giant water bug. What’s neat about giant water bugs is that they are voracious predators, often seen with frogs, fish or other prey impaled upon the beak, which serves as both a deadly syringe to inject toxic saliva and a drinking straw through which to slurp up the prey’s dissolved body contents.

Adjacent to the lake was a small ditch that seemed worth the effort to search for small, frenetic invertebrates. While peering over the water’s edge, I saw a glimpse of what appeared to be a large, stocky fish. Gazing into the water as still as possible, like a wading heron, so as to not frighten this fish again, I finally saw it. My heart raced with excitement. It was a rough-skinned newt (Taricha granulosa). This is an animal I’ve been wanting to see ever since I was six years old reading my field guide book to the reptiles and amphibians of Canada. What is interesting about these newts is that they produce a powerful toxin, tetrodotoxin (TTX), from granular glands located on the skin. The amount of toxin per newt varies geographically, with some regions bearing newts with extreme toxicity and some regions with newts of low toxicity. When provoked, rough-skinned newts will display an unusual reflex, in which the head is bent back and the tail curled up to expose the animal’s bright-coloured belly as a warning to would-be predators.