L16: Food habit categorization

Diet categorization

1. Polyphage

• Generalist

• Eat a variety of different foods/species

2. Monophage

• Specialists

• Eat only one food/species

Categorization of how carnivores obtain prey

1. Predators: catch live prey

2. Scavengers: find dead prey (carrion)

3. Planktivores: prey on plankton (zooplankton)

4. Spongivores: prey on spones

5. Crustacivores: prey on crustaceans (shrimp, crab, krill)

6. Insectivores: prey on insects (however many are seasonal: migration, facultative insectivores, creativity)

7. Myrmechophages: prey on ants or termites

8. Molluscivores: prey on mollusks (snails, squid, slugs)

9. Piscivores: prey on fish

10. Sanquivores: eat the blood or prey

What challenge do crustacivores, insectivores, and myrmecophages face

Crustaceans and insects have a chitin exoskeleton

• long-chain polysaccharide (comparable to cellulose)

• flexible and tough in natural form

• combined with CaCO 3 in shells of crustaceans (stronger, less flexible)

Solution to animal who consume chitin

• some species egest the exoskeleton

• some species remove parts of the exoskeleton

• some species have chitinase

Characteristics of omnivores

• opportunistic feeders of seasonal foods

• will store foods if necessary

• will scavenge carrion if necessary

• eat a wide variety of different foods

• low risk of nutritional deficiency

• difficult to classify or categorize

To obtain the necessary nutrients/energy, herbivores may have to:

1. Eat all/many parts of a plant (not just leaves/stems)

   ...roots, fruits, seeds, pollen, nectar, bark

2. Eat all/many plant groups (not just monocotyledons)

   ...dicotyledons

   ...phytoplankton, fungi, algae, lichen, moss

Categorization of how herbivores obtain food

1. Grazers: eat ground level vegetation (grasses/forbs)

2. Browsers: eat vegetation above ground (leaves, buds, fruits)

3. Intermediate: graze from ground level and brows above

4. Folivores: eat leave

5. Mycophages: eat fungi (fungivores)

6. Lichenophages: eat lichnes

7. Frugivores: eat fruits (succulent or dry, all contain seeds), usually small animals

8. Granivores: just eat dried fruit and seeds of fruit

9. Nectarivores & pollenphages: eat nectar and/or pollen

Succulent fruit

high in sugar, low in Ca (also seasonal)

Dry fruit

high in fat (seasonal, but storable)

Grasses characteristics

• thicker cell walls

• low growth (ground level)

• more homogeneous

• easier to obtain

Pollen

high in protein

Nectar

• high in sugars, low Ca

• nectivorous diets often supplemented with insects

Browses characteristics

• thinner cell walls (but higher lignin content)

• higher growth (above ground)

• more heterogenous

• more prone to seasonal variation

• more difficult to obtain (more chemical/physical protection)

What is special about the honey possum

is one of the few, if only, obligate nectarivore/pollenphage

• marsupial