Lecture 12: Behavioral Ecology Flashcards
Animals need 3 critical needs
- Obtaining Food
- Finding mates
- Avoiding predators
Behavior
Behaviors can be genetic or learned
Behaviors often a product of both genes and environment
Behavioral decisions often
balance costs and benefits in the 3 critical needs/ interests for animals
Proximate Cause
Explanation of a behavior for a particular individual due to events occurring over their lifetime
Ultimate Cause
Evolutionary and historical reasons for a particular behavior
Example of how Behavior can be genetic with Cockroach
Cockroach traps set with glucose
Over time, the population exposed to these traps evolved behavior of avoiding glucose (even when not in a trap_
In comparison, wild type cockroaches still love it
How can behavior be learned?
Learned and passed through families
Ex. Dolphins use sponge to help protect nose when searching food
Behavioral ecology
study of the ecological and evolutionary basis of behavior
Foraging behavior
weighing costs and benefits in obtaining food
Optimal foraging theory
model that predicts how animals search for food by maximizing energy gain while minimizing costs
P= E/t
P=profitability
E= net energy value of food
t= time invested in obtaining and processing the food
What do species have to think about when favoring prey?
Elements that influence profitability: Net energy and Time invested
Elements that influence profitability via net energy and time invested are
Net energy:
+ energy obtained
- energy spent finding the food
- energy spent handling the food
Time invested:
+ time invested in finding
+ handling the food
Each patch has worms. More time spend in a patch the harder it is to find the next worm. How long should be a bird spend in a patch before giving up and going to a fresh patch?
Profitability of a patch may diminish over time
Stay too short: low profitability
Stay too long: low profitability
Find maximize the slope E/t for maximize profitability for optimal giving up time, time to look for next patch
Make a testable hypothesis for Optimal Foraging model/theory: Looking at if travel time increases, how does that change the ideal amount of time spent in a patch
Vary spacing between patches
Offer starlings worms on tables located at different distances from their nests
Increase in travel time, Increase in optimal giving up time
Trading off food for survival can
optimizing fitness
Ex. Elk have to balance eating how much grass in also surviving from predation from wolves
Elks more likely to be around in grassland when wolves are not around and are less likely to be around grassland and go to conifer forest when wolves arrive
Anti predator behaviors
Direct selective pressure for anti predator behavior to increase fitness and survival
Ex. Eyespots on a moth appear to be bigger than they are
Sealions sleep with one eye open; half of brain alert to keep eye out for predators
Springbok stotting behavior; tries to intimidate a lion
How effective are eyespots for predator deterrence?
Many different types of animals that have coloring that might be considered to be eyespots
Taking an animal (ex. cattle) that does not have eyespots and adding artificial eyespots to see if it will reduce predation
Look at cattle with 3 different treatments: eyes, X’s, and nothing
Outcome: Artificial eyespots decrease predation on cattle from ambush predators
Supports hypothesis that eyespots are effective
Evidence also supports alternative explanations that novel or rarely encountered conspicuous features may be intimating to predators
How good was control for experiment testing effectiveness for eyespots for predator deterrence?
Could have been better control with equal amounts of white and black paint used
Collective behavior
Choosing to live in groups
Pros of Collective behavior
Easy to find Mates
Reduced risk of predation: dilution effect, easier predator detection- many eyes to look for predator
Improved foraging success
Cons of Collective Behavior
Faster food depletion
Greater competition for food
Conspicuousness may increase predation
Greater disease risk
Optimal group size
Intermediate optimal value where maximized expected individual fitness
NOT STABLE!
Too small, low fitness
Too large, low fitness
Stable group size
Point in which it is slightly better for an individual to join group than be on its own
Usually larger than optimal group size
