Aquatic Sampling at the Beaver Pond

E. C. Manning Provincial Park is a unique and beautiful park located in the Cascade Mountains of southwestern British Columbia. Established in 1941, the park consists of over 65,000 hectares of rugged forest-clad mountains, deep valleys, subalpine meadows, sun dappled lakes, and rushing white water. Every habitat within this park is home to different and seasonally variable insect fauna, providing a rich menu of natural novelties from which we can collect subjects for DNA barcoding.

A good portion of today was spent aquatic sampling at Beaver Pond, approximately 1 km from Manning Park Lodge. Sweeping through aquatic vegetation and bottom debris can yield hundreds of insects and other arthropods that might otherwise be overlooked, including larvae of dragonflies and damselflies (Order Odonata), mayflies (Order Ephemeroptera), caddisflies (Order Trichoptera) and non-insect arthropods like scuds or side-swimmers (Order Amphipoda) and crayfish (Order Decapoda).

Nets for collecting aquatic samples are stouter and shallower than aerial nets, and most aquatic sampling is done using a heavy and expensive “D net.” Collecting and observing aquatic insects and other non-insects arthropods is easiest if samples (taken with a net) are dumped into a white pan; individuals can be removed using a pair of forceps.

The monsters of the aquatic insect world, the dragonfly nymph, caught at Beaver Pond, 1km from Manning Park Lodge.
The monsters of the aquatic insect world, the dragonfly nymph, caught at Beaver Pond, 1km from Manning Park Lodge.

While sorting through the clutter of bottom debris dumped into our white pan, we discovered a dragonfly nymph. With luck, your sample can include some robust greenish or brownish dragonfly nymphs, torpedo-shaped if you have scooped up a darner nymph, perhaps broader and more sprawling if you have a skimmer nymph. Either way, dragonfly nymphs are hydraulic monstrosities quite unlike the aerial adults. If you disturb the nymph as it sits at the bottom of your pan of water you will see it fold its legs and shoot across the container as though by jet propulsion, blasting a clear path of debris with its jet exhaust. Even more interesting is the hydraulic-powered lower lip (labium) reminiscent of, but much more interesting than, the tongue of a frog or chameleon, which can shot forward to swipe an item of prey.

In the end, we ended up with some amazing and wonderful aquatic invertebrates, everything from amphipods to portable-case making caddisfly larvae, to the robust monstrosities of the aquatic insect world, the dragonfly nymph.

-Joey

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