Adult Mayfly by Carl Haensel photos by the author Caddis larva cases On a warm, spring day along a trout stream, the air literally buzzes with life. Insects of many shapes, sizes and colors fly through the air and dance on the water. Trout swim to the surface, rising to eat mayflies, caddisflies and other insects. Collectively called macroinvertebrates, these small insects are some of the most important organisms that trout eat. Knowing where they live and when they hatch can help all anglers be more successful on the water. Mayflies are a trout angler's best friend. They emerge around the same time each year and offer a consistent pattern. Some anglers wait all year for specific species of mayflies like the green drake to hatch. They have a three-step life cycle and emerge directly from a nymph to an adult. Most mayflies emerge once a year. The adults live only for a few hours or a day. They generally emerge in the afternoon and evening, and trout feed most actively on them at dusk. Many mayflies have common names given to them by anglers, and dozens of mayfly species are available for anglers to observe and imitate on trout streams. Look to the hatch chart in this article for some information about specific species, when they hatch and what flies to use to imitate them. 16 Pennsylvania Angler & Boater * March/April 2014 This pair of adult golden stoneflies was found in the grass along a trout stream. They often rest during the day and become more active and return to lay their eggs in the evening. PFBC Facebook: PaFishandBoat