Fun in the Sun at Merrymakedge Beach

The sky was gloomy as raindrops fell onto the BIObus and woke us this morning.  Hoping the weather would clear, we travelled to our farthest sites near Big Dam Lake.  The sampling sites are very different in vegetation, but are similarly exhausting to locate; both require GPS coordinates and bushwhacking to gain access.  The day had turned hot and humid as we hiked to the bus after performing site maintenance, so we travelled to Merrymakedge Beach to spend the rest of the afternoon.

A large Luna Moth found on the side of the night sheet at Merrymakedge Beach in Kejimkujik National Park, NS.
A large Luna Moth found on the side of the night sheet at Merrymakedge Beach in Kejimkujik National Park, NS.

Here we swam in the sparkling freshwater of Kejimkujik Lake and enjoyed basking in the sun.  The beach was covered in fine pebbles, turning to larger stones as the water deepened further from the shore.  Flipping over few choice rocks and exposing their underside, we were able to find a lot of insect larvae clinging to the hard surfaces; they were hiding between the stones and underlying substrate.  We chose to aquatic collect with this discovery.  Among the most commonly encountered were mayflies, which scuttled across the rock surfaces.  There were also Caddisflies, a few differing beetles, and many tiny water fleas.

Katelyn Lutes, Graham Ansell and Martin Zlatkin at Merrymakedge Beach in Kejimkujik National Park, NS.
Katelyn Lutes, Graham Ansell and Martin Zlatkin at Merrymakedge Beach in Kejimkujik National Park, NS.

We remained at Merrymakedge Beach long after sunset to do a night sheet; a nocturnal UV-powered trap to collect insects attracted to the glow.  This night, the insects by the lake were extremely active and the trap was buzzing loudly with swarming black flies and larger Caddisflies (Order: Trichoptera).  Caddisfly adults emerge from the aquatic larvae encountered earlier; they typically make silken cases underwater for protection.  The silk is webbed together, and particles adhere to it, camouflaging the insect.  They can be made with twigs, small pebbles, leaves or other debris in the water.  These cases catch the water current; the web filters small particulate matter that is fed on. The cases also act as a useful indicator of which caddisfly species they are. Conversely, adults look so similar that their appearance alone cannot discriminate it from other species of the order.  It is remarkable that aquatic Trichoptera larvae found earlier can be so distinctive, but molt into morphologically identical adults.

One of the most noteworthy insects we encountered on the night sheet was a large Luna Moth.  This beautiful moth (which also graces the sides of the BIObus) is mint green in colour, with a white furry body and feathery antennae.  It rested motionless on the sheet, lethargic because of the cold night temperature.  After collecting insects found on the night sheet we anxiously drove back to our campsite, eager to jump into out sleeping bags and go to bed after a long day spent outside.

-Katelyn

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