|A field of 12 caddisfly cases.|
David also explained the grouping behavior:
"The clumping you see in that photo, is a pupal aggregation behavior. They do that, apparently, so that when they emerge, the adults will be in closer proximity to one another. They secrete pheromones for attraction, so closeness is probably pretty important."
|H. borealis - University of Alberta|
I was curious to see what these little guys/gals looked like but didn't want to break open a case which would harm them. I took some of the 6 mm cases off the rock and carried them home in water. Under the microscope the cases just sat there for several minutes and until I pushed them closer together. Then the action started.
The larvae feed primarily on diatoms, algae and detritus which they scrape off the rock surface. They will continue to grow and build their cases until maturity. The adults emerge, breed immediately, and fly low over or in the water to the delight of trout fishermen.
"Adult emergence throughout the season with a 5 to 6 month egg diapause. Both emergence and egg laying occur in the evening, the females will flop aimlessly on or near the water edge while extruding a mass of eggs (hangs off the tip of the abdomen), then later attaches the mass to a solid object.
Helicopsyche borealis - Boldsystems.org
H. borealis adults look different in flight from other Caddisflies. They fly with both wings in unison because the hindwing is attcahed to the forewing with a row of tiny hooks; normal Caddisflies beat their wings as two spread-out sets (LaFontaine, 1981)." University of Alberta
|Cheumatopsyche sp. out of its net - REK|
|Net-spinning Cheumatopsyche sp. - REK|
|Remains of the net - REK|
Thanks as always to Dr. David Bowles of Missouri State University for his patient guidance.