Plants make their own tissue from inorganic molecules and solar energy, however
animals must eat other living things, plant or animal
a problem common to both food types is unpredictable location in time nad space. Consumer must
locate potential food. Finding it is just the first step
search▯ evaluation. Locates more than one item, how much net benefit will this give me?
food has energy value but also costs energy to evade toxins, and wastes
correlation of the success in finding food and the reproductive success. Have the most food, will
leave the most offspring (best fitness)
content of food source vs cost to get it
benefits and costs; gross genergycosts= net benefit
where does fitness and Darwinian selection come in
ignore some mussels and select from a limited size range compared to what is available
largest mussels have the greatest net benefit from the amount of flesh.
However, older/larger mussels are more lkely to have barnacles and have a greater possiblilty of
not being opened
Largest mussel shells are too thick to open
Most efficient way to gain the best net benefit that is cost effective.
** NW crows picking up shells: trying to break the shells.
Hard structure ▯ operculum protective layer last to be pulled in, lid to close the shell Crwos selective on sie of shell length.
Crows fly up and drop shell on rocks, keep dropping it until it breaks
They go up about 5 m
Why 5 m? [probability of breaking. Higher, risk other birds taking the prey
What to eat?
Fundamental decisions ▯ carnivore, omnivore, herbivore?
Lots of plants are indigestible
Cellulose: carbohydrate. Indigestible
Must have cellulose to break down plant matter
Plants produce thorns, hard shells, nuts,
** milkweed: toxins. Monarch butterfly adapted to injest these toxins. Not poisoned by it and can
store toxins in specialized
bamboo: cyanide and sharp fibers
acacia trees: attract ants with nector and the ants help to defend plants
animals that do not eat toxins
**Macaws: eat alkaline soil that has holing that help neutralize toxins that they eat
takes extra energy and time, but widens food source
carnivours ▯ predators
animals can move and run away leads to increase persuit and catch costs animals defend
not cost free to be a predator
energy used to search for food
lichens that they feed on don’t move but can be depleted
must migrate and move ▯ uses energy
** lizard/ skinks
could smell snake
dragged predator sent or control
observed feeding behaviour
skinks more active in control
presense of predator – inhibitory effect on skinks. If places to hide, more active if scent is there
avoidance of predators partial escape
in addition to searchin (non random) behaviours that take advantage of thers food source
reducing searching cost by following animals that know their area very well
make searching more efficient
make searching more efficient
bat hears frog who must call to attract females male cricket calling to female attracts ormae ochracea flies who lay eggs on cricket
sit and wait
larvae▯ doogdle bug
dig cone shape pits, wait at the bottom. The prey falls in and they poison their prey
rivers in Africa, must cross to get to next pach
wait because crocodiles migrate to wehre animals have to cross shallow water
increase the probability of being fed, because large herds of animals cross at different points during
Increase the probability that something good will come close by providing a bribe
Vibrate hair ▯ attrach small fish
Net increase in probability that more food will be caught. Spiders the only ones in terrestrial
unobious as possible stabilimenta: thick strands of silk
assumed to be stabilizing, actually reflect UV light strongly
most insects are attracted to UV
increase rate in capture because only a few parts are visible to prey
ornaments enhance the probability of getting food
sometimes opposite and web is more ovious to predators they lay and blendi n to ornaments and to
be less obvious
eat from animals without killing: blood feeding
not classic predators
vampire bats, oxpeckers
ectoparasites removing blood filled ticks, may wound animal and feed on flowing blood,
**moths: suck eye secretions from animals
**cuterebra emasculator flies: on squirrel
For consumers that eat from other animals, some kill their prey. Others consume only part of it
without killing (mosquitos, ticks, vampire bats)
Animals may immerse themselves in their foo item to reduce searching costs
** cuterebrid flies, lay their eggs on other animals so that their larvae can live
this is advantageous because they do not have to look for food on a daily basis.
Foraging search is done by the parent for the offspring (moths)
** lobocraspis griseifusa: feeding on the eye of a batang. Dipped into the edge of an
eye, feeding on the tear solutions. Rich in protein and sugars. **calpe eustrigata: feeding on skin of a tapir.
Parastic Manipulation **dirocoelium dendriticum/lancet liver fluke:
Cause ants to have irregular behaviour. Affect the neurobiology of the ants. Move to tops of blades
of grass, making them more susceptible to be eaten by the tertiary hosts.
Mammal ▯ pulmonate snail (cercariae)▯ ants (metacercariae)▯ mammal
When in the lung of snail, produce lots of mucus. Causes the snail to “sneeze” out the slime.
Supraesophageal ganglion: main brain. With many sub brains. Subesophageal ganglion: controls
muscles of the jaw. Parasites end up in body cavity.
Ants produce formic acid: burns predators.
Jaws clamp down on the tips of the blades of grass, unable to release the jaw. When eaten, the
parasites in the body cavity are free to infect the mammal
** Toxoplasma gondii
t. gondii takes advantage of rodents and makes them undergo risky behaviour where they are likely
to be predated by cats
encyst in supra esophogeal ganglion of carpenter ants. Alter the behaviour so they become
positively phototropic and wander aimlessly about. This makes then easy and attractive tatrgets for
robins, the definitive host of the fluke
land snail parasitized by leucochloridium fluke.
Snails under normal circumstances feed on underside of leaves. Under the affect of the parasite
they feed on the top of the leaf. Parasite grows up out of the main tissue onto the tentacles. They
look like worms, making them more susceptible to predatory birds
Nearly all animals are subject to predation by other organisms and most would be prey have some
means of reducing their likelihood of being captured and consumed
Behaviours form the standpoint of the predator
1.) cues associated with prey
chemically **sharks smelling blook in the water