Young Acroneuria lycorias nymphs feed on leaves, and other decaying plant material, but as they grow in size these large nymphs turn into a fierce predator feeding on smaller aquatic insects. Baetis nymphs are one of their favored delights, and will actually hunt them by following the vibrations Baetis produce while swimming.

   Prior to hatching Acroneuria lycorias nymphs begin migrating from the fast running riffles to slower water areas along the edge of the river. Although A. lycorias nymphs spend their time roaming rifles as they mature, and hatching draws near they don�t seem to discriminate, and begin migrating into slower water areas. At this time nymphs can be found along the shore line in both fast water, and slower pools.

   Fishing a nymph imitation can be very productive during this migration period.

   Hatching is accomplished by the nymphs crawling out of the water, and up into the vegetation along the river bank at night. Where they shed their husk, and mate. Once this process begins hundreds if not thousands of A. lycorias can be found in the grass, and bushes along the river bank.

   Egg laying flights take place sometime during the next afternoon, early evening. This can be a spectacular scene with large swarms of these big stoneflies at times numbering in the thousands.

   Fishing an adult imitation at or after dark can be productive during this time.