Off The Beaten Path – The Index Eagle January 1992 by Bob Hubbard

This article is from the Index Eagle, January 1992 and authored by Bob Hubbard. He has given us permission to reprint his articles but PLEASE DO NOT PLAGIARIZE. This article may not be reproduced without the express written permission of IndexWa.org and/or Bob Hubbard.
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Off the Beaten Path – Jan 1992

She was few days short of a year in age. This pupa of a certain caddicefly of the family Limnephilfdae, and she was nearly at the end of her life’s cycle. She had lived until now in a series of portable sand-and-silk tubes or cases of her own making, dragging them around the stream bottom as she combed the area for decaying plant or animal matter, algae. and anything else she could scavenge to eat. Two months ago, she stopped eating, glued her case to a river bottom boulder, sealed up the ends of her case and went into a kind of hibernation while her body metamorphosed, changing into its pupal form. Now that changeover was complete and she was chewing away at the silk-and-sand barrier at the front of her case.

She was among the first to attach to her rock, and probably unaware that she had since been joined there by dozens of others of her species. Other rocks nearby, harbored similar concentrations of the squat cylindrical cases that went by the common name of Periwinkles. Inside these cases. other caddice flies were also waking up and starling to chew.

Tonight at dusk, and for the next three dusks, nearly the entire local population of this species of insect – hundreds of thousands. if not millions of individuals – was about to make a big, synchronized dash from river bottom to shore, right through a gauntlet of hungry trout.
The trout knew something was up; a few early emerging caddice flies had already been interrupted In their race for shore. The fat insects made excellent snacks, and throughout the afternoon more and more trout had drifted into the area in anticipation of a good meal. As dusk approached, the trickle of emerges increased to a gush, then a roar. The ‘hatch”, as the fishing people term it, was on.

The particular caddicefly we have introduced finally chewed her way out of the case during the height of the hatch. Her actions were typical of those of her kind. As soon as her body was out of the case it started generating a small amount of gas. This couldn’t escape through her pupal skin, so it started to accumulate under it, forcing it away from another layer of skin under it, her soon-to-be adult skin. The river current plucked her from her grasp on the case and she went tumbling away downstream. All around her the water was filled with other tumbling bodies. The trout swept through this horizontal hailstorm like wolves veering and snapping, enjoying this first course of a fine natural meal.

The caddice tumbled for a bit near the river bottom before the gasses under her skin caused her to rise to the surface. Her legs, short and strong during her larval phase, (the better to drag her heavy case around with), was now longer, and fringed with hairs. She worked those long legs now like mad oars with multiple knees, scrambling her way upward in a tangled blur of motion. The trout continued to dash around stuffing themselves, and several times in her ascent the caddicefly was buffeted by currents caused by the darting fish.

Reaching the surface, the caddicefly heads for the nearest shore. All around her are other caddiceflies with the same goal. Legs rowing, windmilling and thrashing, they head for shore like a miniature D-day fleet. Swirls and explosions of water all around tell the caddices of lost comrades and the narrowing of the gene pool. Rainbow missiles erupt from the water, jaws agape, insect victims centered between hookscarred lips. To the insects, the shore seems a long way away.

Each caddicefly must face ruthless enemies and appalling odds in its sprint to the beach. But because they have evolved a synchronized emergence. the caddiceflies make that dash in a crowd. The trout find themselves literally overwhelmed with food. and enough insects usually get through to assure continuation of their species. Once safely ashore, the caddiceflies crawl into the bushes and moult out of their pupal skin, whose only purpose seems to be to get the insect from its river bottom case to the shore. The now adult caddices must soon run another gauntlet of enemies, as the slim, moth like insects assemble over the river in large swarms to find potential mates. Bats and birds swoop through these swarms like trout of the air, gorging themselves. Thousands more of the insects are lost, but again their natural enemies are overwhelmed with prey, and many more caddices live long enough to find mates in the Single’s Bar atmosphere of the swarm.

The paired caddiceflies leave the swarm and fly to the nearby forest floor to consummate their ‘marriages”, and then the females fun a gauntlet one more time as they fly over to and into the river and swim and struggle their way back to the bottom again. Here they lay their sticky strings of eggs on the rocks and gravels, and finally, their life complete, they release their grip on the bottom and allow the gentle current to deliver them, slowly tumbling to the many mouths of the river.

Bob Hubbard