Mountains of mayflies means it's time to compost

Probably best known to entomology students for their one-day adult life span, mayflies are benign creatures, and in fact are used as indicator organisms for clean water. Last year, however, residents of the Lake Erie's southern shoreline discovered a darker side to mayflies. Reflecting the lake's recovery from its previously polluted state, the insects' population exploded, taking everyone by surprise. Huge swarms descended on Port Clinton, Ohio (pop. 7,100) and surrounding Ottawa County. "At one point, enough of them settled into the transformers at the power company 40 miles away to cause a brownout all the way to Cleveland," reports Fred Snyder, a specialist with Ohio State University's Sea Grant Extension.

The swarms were a nuisance for two or three weeks in late June and early July, but worse was that - true to their ephemeral nature - they very quickly died. For those who were irritated by their flying forms, this may have seemed like a blessing at first, but residents and tourists suddenly found the streets and sidewalks covered with millions of insect bodies. "People were shoveling them off their walks and driveways into the streets," says Snyder, "and as they began to decay, the odor became very unpleasant. Before they were all cleared up, city crews had filled 35 large dump trucks with dead mayflies."

The arrival of these giant swarms was unexpected, so there was no real plan for dealing with the tons of insect bodies. Street sweepers and snowplows were used to load the dump trucks, and the mayflies were either landfilled or placed in shallow pits and covered with lime, neither of which proved to be satisfactory management techniques. Because projections of mayfly populations for 1997 and future years based on counts of the water borne nymphs indicate that last year's swarms were only the beginning, Thomas Brown, the mayor of Port Clinton and Ronald Bivens, safety/service director began working with Snyder and other advisors to develop better methods to handle the swarms. "This year, the plan is to try composting them," Snyder says. "We've applied for grant funds, but even if they don't come through, there at least will be a small-scale project."

Residents will be responsible for pushing the flies into the gutters where street sweepers are scheduled to pick them up every morning at 4:00 am. The insect bodies will then be taken to a city site and blended at a 2:1 ratio with wood chips and sawdust. On the advice of Harry Hoitink from Ohio State University, who has been consulting on the project, the mayfly/bulking agent blend will be piled between four and seven feet high on a one-foot thick bed of seasoned wood mulch and then covered with at least another foot of seasoned mulch. Using the static pile method, Snyder says they are projecting a composting time of between one and two months. As of late June, 1997, the swarms still hadn't arrived, but Snyder says lake temperatures this year are a bit cooler than usual. Ongoing developments will be reported in a future issue.