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Trophic relationships. Feeding roles in streams. Aquatic insects categorized:. Food type and how food is obtained Feeding guilds = functional groups. Base of trophic relationship. Productivity from? Microbial loop: Fungi, bacteria Use dissolved organic carbon (DOC)
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Trophic relationships Feeding roles in streams
Aquatic insects categorized: • Food type and how food is obtained • Feeding guilds = functional groups
Base of trophic relationship • Productivity from? • Microbial loop: • Fungi, bacteria • Use dissolved organic carbon (DOC) • Passed to protozoans, etc.
Invertebrate consumers • Food resources: • Periphyton • Macrophytes • Detritus • Animals
Feeding roles • Shredders • Leaves, associated microbiota (CPOM) • Chewing • Trichoptera, Plecoptera, Diptera CPOM = > 1 mm
Feeding Roles • Suspension feeder / filterer-collector • FPOM and microbiota • Sloughed periphyton • Use setae, nets, etc. • Net-spinning Trichoptera, Simuliidae, Ephemeroptera
Feeding Roles • Deposit feeder / collector-gatherer • FPOM and microbiota • Browse, collect on surface, burrow • Ephemeroptera, Chironomidae, Ceratopogonidae FPOM = < 0.5 mm
Feeding Roles • Grazer • Periphyton (mostly diatoms) by scraping • Macrophytes by piercing • Ephemeroptera, Trichoptera, Diptera, Lepidoptera, Coleoptera
Feeding Roles • Predator • Animals • Biting, piercing • Odonata, Megaloptera, Plecoptera, Trichoptera, Diptera, Coleoptera
Terrestrial Stream DOM Leaching CPOM Microbes Shredders FPOM Feces
FPOM consumers • Suspension and deposit feeders • Many adaptations for filtering • Philopotamidae caddisfly spins net
FPOM consumers • Suspension feeder • Black fly larvae = Simulidae
FPOM consumers • Deposit feeder = collector-gatherer • Some in sediments, some forage
Consumers of autotrophs • Grazers, piercers • Graze periphyton • Scraping mouthpart adaptations • Water penny beetle larva Psephenus
Consumers of autotrophs • Another grazer • Mayfly Stenonema • Brush algae, then collect it
Predators • Most engulf prey entire or in pieces; others have piercing mouthparts
Problems with trophic classification • Diet shifts with age and size • Many very young invertebrates feed on fine detritus, then change