Flat-headed Mayfly Nymph (top right), Aquatic Sowbug (middle), Caddisfly Larva (bottom)
Scientific Name: Heptagenia (top right), Asellus aquaticus (middle), Trichoptera (bottom)
Order & Family: Ephemeroptera (Heptageniidae) for Mayfly, Isopoda (Asellidae) for Sowbug, Trichoptera (various families) for Caddisfly
Size: Mayfly nymph: 10-25mm; Aquatic Sowbug: 5-15mm; Caddisfly larva: 5-30mm (depending on species)
Natural Habitat
Freshwater streams, rivers, and lakes, typically on rocks, debris, or submerged vegetation.
Diet & Feeding
Mayfly nymph (Heptageniidae): Scrapers, feeding on diatoms and algae. Aquatic Sowbug: Detritivores, feeding on decaying organic matter. Caddisfly larva: Varies greatly by species, includes detritivores, herbivores, and predators.
Behavior Patterns
Mayfly nymphs are typically flattened to cling to rocks in fast-flowing water. Aquatic sowbugs are scavengers, often found under rocks or debris. Caddisfly larvae are known for building protective cases from silk and various materials like sand, pebbles, or plant fragments; they are important indicators of water quality.
Risks & Benefits
These are all important components of aquatic ecosystems. They are vital food sources for fish and other aquatic organisms. Their presence and abundance are often used as bioindicators of water quality. They pose no direct risks to humans.
Identified on: 9/17/2025