“Ew bugs!” – might be your automatic response, but modern culture has shifted the sense of awe and wonder for intricate insects into disgust and fear. When a bug lands near or on us, our instinct shouldn’t be to run away, but rather appreciate its beauty and existence. As a child, I was captivated by just about anything that could crawl, imagining where it was going, and what mission it was on, watching in amazement as nests transformed into thriving new life. I didn’t need to know that they are essential pollinators, important food sources for others, or massively important for all life around me, in order to understand their existence and beauty. This rhetoric should not fade as we grow older, but our awareness of the interconnectedness of life should expand with us.
Our local lakes and streams are home to many essential insects that support our ecosystem. Understanding them provides valuable insight into the health of the waters we depend on. In particular, benthic macroinvertebrates play an important role in nutrient cycling within aquatic food webs and also influence microbial production and the release of greenhouse gasses. “Benthic” refers to the ecological region at the lowest level of a body of water, such as an ocean, lake or stream, including the sediment surface and some sub-surface layers. This is where some macroinvertebrates begin their life. Macroinvertebrates are animals lacking a backbone and large enough to see without a microscope. Some commonly known examples are crayfish, snails, leeches, worms, dragonflies, beetles, and flies. While macroinvertebrates can be aquatic or terrestrial, many aquatic organisms begin their life in water before becoming terrestrial as adults.
The mayfly is especially unique because of their two distinct winged stages in its adult life cycle. They begin as a Nymph, living on the river bed where they help keep the water clean by feeding on algae, and plant life. Next, they molt, shedding their skin and emerging from the water as duns. They float on the surface to dry out their wings, becoming an easy snack for aquatic predators. A few hours later, the duns take flight seeking shelter in bankside vegetation. Then comes a second transformation, where it molts once more, transforming into a brightly coloured spinner. As a spinner, they have no mouth, relying only on their energy reserves, their sole purpose is to breed. Mating happens in the air, after which the female drops to the water’s surface to lay her eggs, which sink down to the bottom. This marks the end of the adult mayfly’s life, as they are soon picked off by fish.
Since 2013, Lake Windermere Ambassadors have been collecting information on macroinvertebrates in Windermere Creek through the Canadian Aquatic Biomonitoring Network (CABIN). Some notable species are found to be present such as Ephemeroptera (mayflies), Plecoptera (stoneflies) and Trichoptera (caddisflies). These are important because they are more sensitive to change in the aquatic environment and are deemed important bioindicator taxa for assessing freshwater quality. If only pollutant-tolerant species were present, it would indicate a concern for the water quality. These insects are vital to a healthy ecosystem, so the next time you see one, try remembering what mission it’s on and how beautifully intricate they are.
