Larvae of the alderfly Sialis mohri Ross were collected in barrier pitfall traps along the shoreline of Intermediate Lake during a 3-year period (2015–2017). Two barriers (each 1-m long) were used per trap in 2015 and 2016, being placed on opposite sides of a central collection cup that was about 1 m from the shoreline at time of deployment. In 2015, with two traps monitored at 4–to 18-day intervals from 19 April to 29 June, larvae were collected first during the 19 April – 7 May period and last during 16–31 May. In 2016, using the same two trap locations, with traps monitored (often daily) from 15 April through 9 June, larvae were collected first on 19 April, they peaked on 5 May, and were last collected on 7 June. In 2017, four traps (with one plastic barrier each) were placed near each other but with the collection cups at different distances from the shoreline (1, 2, 4 and 6 m), and checked from 15 April through 1 June. Overall, 71.1% of the larvae were collected at 1 m, 19.5% at 2 m, 8.9% at 4 m, and 0.5% at 6 m. During periods when traps were checked daily in the morning, 99% of all larvae collected in 2016 were trapped when it had rained the previous night (14.7%) or previous day (84.6%), and similarly 58% (46.1% and 12.1%, respectively) in 2017. This study documented timing of S. mohri larval emergence in spring, indicated that wet conditions favored emergence, and indicated that nearly all pupation sites were within 4 m of the shoreline.
Haack, Robert A.
"Alderfly (Megaloptera: Sialidae) Larval Emergence and Pupation Site Selection at Intermediate Lake, Antrim County, Michigan,"
The Great Lakes Entomologist, vol 56
Available at: https://scholar.valpo.edu/tgle/vol56/iss1/10