Stream Animals & the Heterotrophic Food Chain

Processing of Organic Matter In fall, leaf debris from overhanging deciduous trees accumulates in the stream Flowing water leaches the leaves soluble organic matter as dissolved organic matter (DOM) or fine particulate organic matter (FPOM) The leaves remain as coarse particulate organic matter (CPOM)

Microbial Processing The remaining leaf surface is colonized by bacteria (on FPOM) and fungi (on CPOM) These microorganisms convert the cellulose and lignin into forms useable by invertebrates

Invertebrate Processing: 1) Shredders The shredders feed on the leaves and their resident microbes, and convert the CPOM into FPOM

Common Shredders Craneflies (Diptera) Caddisflies (Trichoptera) Stone-Fly Nymphs (Plecoptera) Crayfish

2) Filtering and Gathering Collectors FPOM carried down stream is acquired by the Filtering and Gathering Collectors, processed, and turned into DOM

Common Collectors Blackflies (Diptera) Fan and net spinning Caddisflies (Trichoptera) Midges

3) Scrapers, Piercers, & Gougers Algae and mosses coating the surface or rocks is processed too Scapers and Piercers feed on algae, while Gougers feed by burrowing into the trunks of fallen trees

Common Scrapers, Piercers, & Gougers Scrapers Beetle Larvae (Coleoptera) Mobile Caddisflies Snails Piercers Microcaddisflies Gougers Fly Larvae (Diptera)

Invertebrate Predators All the invertebrate organisms that process the leaves, algae, and wood are potential food for invertebrate predators One common predator is the Hellgramite or Dobsonfly Larvae (Megaloptera)