Sources of FOOD

Question 1

Autochthonous

Allochthonous

Answer 1

food from within the system

(ex: aufwuchs, algae on the bottom)

food from outside the system

(ex: leaves)

Question 2

1.Aufwuchs

Answer 2

• found on rocks, wood
• mostly algae (diatoms, greens), & fungi, bacteria

Question 3

Define and talk about Detritus

Answer 3

• dead organic matter, animal and plant
• various forms, both suspended in water column, and on bottom
• categorized according to particle size

Question 4

Functional feeding groups (5)

Answer 4

• shredders
• scrapers = grazers
• predators
• collectors (gatherers and filterers)
• deposit feeders

Question 5

Macrophytes

Answer 5

• of only minor importance, as insects generally do not eat live plants
• plants thought to possess chemicals making them unpalatable

Question 6

Shredders

Answer 6

–chew (shred) CPOM
–see CPOM diagram
–dead material = detritus
–most nutrition comes from fungi and bacteria (peanut butter)

EXAMPLES: _scud (Amphipoda), Tipulidae (Crane Flies), Pteronarcyidae _

Question 7

Scrapers = grazers

Answer 7

•scrape (rasp) algae from surface of hard surfaces.
•have special mandibles to do this (see slide)
•consume microscopic algae (mostly diatoms) and trapped FPOM (detritus)
•Example: - Baetidae (bullet shape mayflies)
- Elmidae (riffle beetles)

Question 8

Predators

Answer 8

• actively catch and consume animals
• all carnivorous

2 strategies:

1. Active chasing e.g., Perlidae (stone fly), Rhyacophilidae (free living
2. Sit and wait e.g., Dragonflies (Odonata), Water scorpions (Nepidae)

2 categories

1. Engulders - swallowers e.g., Perlidae, Odonata
2. Piercers e.g., Notonectidae, Nepidae, Belostomatidae

Question 9

Collectors

Answer 9

2 types

1. Gatherers -eat deposited FPOM (usually dead) at:

–banksides
–sheltered parts of riffle (behind rocks, etc.)

e.g., Heptageniidae (flat mayflies)
Leptophlebiidae (another mayflies)

2. Filterers -eat suspended FPOM (usually dead, but includes plankton below lakes, etc.)

–two types: passive and active

Question 10

i)Passive filter feeders:

Question 11

Active filter feeders

Question 13

5. Deposit feeders

Answer 13

•eat mud and digest organic matter (e.g., bacteria)
e.g., worms (e.g., families Tubificidae, Lumbriculidae)