Novel large leaf packs measure aquatic insect emergence on a realistic scale

Studies have shown that emerging aquatic insects are an important food resource for terrestrial vertebrates and invertebrates.  Yet few experimental studies have tested how in stream processes affect emergence rates.  This is in part because emergence studies are usually conducted at the reach scale whereas experimental studies are often conducted at much smaller scales using leaf packs or enclosures.  We have designed an emergence trap that is compatible with enclosures traditionally used in experimental studies that focus on ecosystem processes or trophic interactions.  Specifically, we show how these leaf pack/emergence trap devices can be used to measure insect emergence from different leaf types.  Large leaf packs (0.5m²) were constructed using pvc pipe and vexar.  Pyramidal shaped emergence traps were attached for 48 hours once per week.  Emergence traps were lined with microfiber net connected to a two chambered plexiglass case with ethanol in the second chamber.  We show how this device can be used to compare insect emergence across leaves of different quality.  Other applications include studying how the presence or absence of fish and large invertebrates affect insect emergence.