Lecture 21- Predator/Prey dynamics

Question 1

what is in the best interest for both the prey and predator?

Answer 1

to end a predation event as early as possible to avoid damage and energy loss

Question 2

fish have adapted severl anti-predato strategies including:

Answer 2

1. avoiding detection
2. evading pursuit
3. preventing or deflecting attacks
4. discourage handling

Question 3

avoiding detection- what techniques do fish use to end the predation event before it starts

Answer 3

1. Camoflauge
2. countershading- allowing the fish to be hard to detect when seen from above or below
3. Chemical conealment- attempt to hide ones odour to avoid detection. like the parrot fish which encompass themselves in a mucous coating at night, not a common strategy in fish.

Question 4

three different camoflauge techniques:

Answer 4

1. protectinve resemblance: hide in plan site by looking like something else ex.) hairy frogfish
2. disruptive colouration: hige your body outline like the anglefish
3. Background matching- traditional camoflauge like a flounder

Question 5

evade pursit: at this part of the cycle the predator has seen you and you want to avoid a long pursuit or physical confrontation. what are some strategies?

Answer 5

1. aposematic (warning colouration); send a signal that you are poisonous or otherwise painful to eat. ex.) spotted mandarin
2. Move to shelter: the predator knows you are there but is unable to get at you. ex.) clownfish
3. Mimicry:
   batesian: when a non-harmful species mimics a harmful one. ex.) black saddled toby
   Mullurian: when 2 harmful species converge on the same warning colouration to increase the chances of a predator learning to avoid them. ex.) reef blennies

Question 6

prevent attack- now the predator is coming after you and need to run or mount a defense, what are some techniques the fish use?

Answer 6

1. evsive maneuvers: dashing, quick maneuvers or flying
2. deflect with structural defenses: again advertising that you are painful to eat like the lion fish.
3. dilution effect: decrease your own odds of being eaten a super common social behaviour!
4. predator confusion: fish schools create predator confusion by coalescing into various shapes and/or making it hard to focus on one individual.
5. visual signals or alarm chemicals: warn nearby neighbors of danger and let ex.) convict cichlid

Question 7

discourage handling- now they have and shit got real. what are strategies fish have for this situation

Answer 7

1. spines or armour: make it hard or painful for them to eat you. ex.) trigger fish
2. mucous: make it easier to slip away or in extreme causes, like the hagfish, can choke the predator
3. chemical defense: taste bad or poisonous. ex.) stonefish are super venomous

Question 8

the predation cycle consists of what?

Answer 8

searching
pursuing
attacking
captuirng and 
handling

Question 9

searching be one or two things

Answer 9

active or passive

Question 10

active searching:

Answer 10

you are using all your senses and experience probing high probability hiding spots or focusing on a known high value prey

Question 11

passive searching:

Answer 11

is usually assocoated with some form of cryptic colouration. These predators will sit and wait for prey to pass by and usually depend on only one or 2 senses like the stargazer fish

Question 12

what is another form of strategy for group foraging?

Answer 12

group foragers have a much higher success rate at finding prey but when you do find food there are more mouth to feed. ex.) goat fish

Question 13

pursuing- predators have highly derived body forms unique to their type of pursuit. what are some stratgies they have for this?

Answer 13

1. sustained chase: these fishes are not agile but are very fast like the black marlin
2. Maneuvering: these fishes are better in shorter chases that require quick changes in direction. often sleder like discus fish.
3. ambush: these fish are modified for quick bursts of power like stargazers

Question 14

describe mimicry in predators

Answer 14

1. similar to protectice resemblace these predators attempt to resemble part of the landscale like the south american leaf fish to attract invertebrates
2. disruptive colouration: as with prey the predator is attempting to hide his body outline like the gopher rockfish

Question 15

attack and capture- this is the moment at which the predaot makes a move on its prey; the main difference between groups at this stage is how they select or make first contact with the prey following the pursit/ searching phase. what is some techniques fish use for this stage?

Answer 15

1. Fast Predators: overtake and grab their prey. often selecting a specific individual from a school to avoid predator confusion from the school of fish. predators will spot any fish that looks or acts differently in the group.
2. ) ambush predaotrs: often dont mae a choice but grab whatever swims by. They are able to create large amounts of negative pressure by rapidly opening their mouth and drawing prey in.
3. ) many predators will stun or attempt to confused prey before making a strike like the flashlight fish

Question 16

what plays the biggest role in predator handling?

Answer 16

teeth! fish are either shredded (red pirhana) or swallowed head first and teeth just hold the animal