Download Trophic relationships

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
CPOM
Leaching
DOM
Microbes
Shredders
Feces
FPOM
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