Behavioral Ecology
Behavioral Ecology Overview
Source: SimUText Ecology. Simbio.com.
Compiled by: Dr. Greg George
Tinbergen's Questions
Mechanism (Causation)
Definition: Investigates the factors that trigger a specific behavior in an individual.
Ontogeny (Development)
Definition: Explores how a behavior develops over the lifespan of an individual.
Adaptive Value (Function)
Definition: Examines why a specific behavior is advantageous for the individual's survival and reproduction.
Phylogeny (Evolution)
Definition: Analyzes how a behavior has evolved over time and why it may differ between species.
Pika
Research Inquiry: What tasks were assigned regarding the pika, and what findings were reported?
Observe pika foraging behavior, specifically focusing on their selection of different plant species and flower colors.
Optimal Foraging Theory
Definition: Asserts that evolution has favored behaviors that maximize an individual's food harvest and/or intake rate.
Testing Hypotheses in Optimal Foraging
Behavioral ecologists ideally measure fitness variations with different foraging strategies.
Challenge: Measuring fitness is notably difficult.
Measuring Fitness
Inquiry: Which individual displays the greatest fitness?
An individual displays the greatest fitness when it maximizes its reproductive success, both directly through its own offspring and indirectly through the reproductive success of its relatives
Currency in Foraging
Concept: A viable approach is to measure 'currency', which refers to metrics correlated with fitness such as body mass, body size, or food acquisition rate.
Cost-Benefit Analysis in Foraging
Understanding Relationship: Any currency must factor in the benefits and costs associated with the foraging strategy.
Relationship Visualization in Cost-Benefit
Discussion Point: How should this relationship appear graphically?
Additional Complexity Consideration: Consider how adding a variable representing distance would alter the visual representation.
Predation Risk and Foraging Decisions
Concept: The risk of predation significantly influences an organism's foraging choices, contributing to the ecology of fear.
Assumptions of Optimal Foraging Theory
Key Assumptions:
Exclusivity of search and exploitation (i.e., cannot process prey while searching for new prey or simultaneously occupy a patch while looking for another).
Sequential encounters (i.e., items are encountered one at a time).
Complete information (i.e., the forager assumes it knows the boundaries of the model and has full awareness of environmental conditions and personal limitations).
Adding Complexity to Foraging Decisions
Example Inquiry: What should be consumed, such as how does the ratio of yellow to blue flowers affect pika foraging?
The reasons for this preference can include a higher concentration of essential micronutrients, vitamins, or minerals crucial for their overall health that might be lacking in higher-calorie plants. Additionally, visual cues may play a significant role in flower selection, as pikas may be attracted to specific colors that indicate nutrient-rich options.
Behavioral Inquiry: Why do pika preferentially select yellow flowers, even if they have lower caloric value?
Reasons can include a higher concentration of essential micronutrients, vitamins, or minerals crucial for their overall health that might be lacking in higher-calorie plants.
Study Case: Great Tit (Parus major)
Research Question: How does the great tit respond to variations in mealworm size?
Larger mealworms provide more calories; huge ones might be harder to handle or consume. Therefore, great tits would likely select a mealworm size that offers the best balance between caloric content and handling time, often favoring a medium-to-large size that is still efficiently digestible and manageable
Marginal Value Theorem
Definition: This theorem dictates when an organism experiencing diminishing returns should abandon a particular patch, mate, or other resource.
Influencing Factors: The distance to a patch significantly affects optimal foraging time within that patch.
Optimal Strategy: Resources should be abandoned when the average gain rate is maximized.
Prey and Patch Models
Integration: These models provide a unified framework for exploring the optimal combination of prey and patch decisions to maximize energy gain.
Distinct Decision Analyses
Prey Model: Focused on dietary inclusions.
Patch Model: Concentrated on the duration of stay within a foraging patch.
Game Theory in Behavioral Ecology
Definition: A study of strategic decision-making among multiple players, leveraging mathematics and logic to predict rational behaviors in contested scenarios.
Cooperation Dilemma: Even if cooperation yields better outcomes, selfish choices often prevail due to individual incentives in specific contexts.
Evolutionary Stable Strategy (ESS)
Concept: The outcome of the game involves identifying an ESS, which often surfaces during aggressive encounters, particularly when asymmetries exist among individuals.
Family Matters in Behavioral Ecology
Comparative Analysis: Evaluation of differences in parental responsibilities between species, such as Bower birds and Blue Tits.
Sexual Selection
Types of Selection:
Intrasexual Selection: Competition among individuals of the same sex for mates.
Intersexual Selection: Selection based on preferences of one sex for characteristics in another sex.
Species Area Curve
Research Inquiry: Investigates whether the treatment administered in research affects reproductive success rates.
Female Preferences in Mating Strategies
Species Examples:
Red-capped Manakin: Notable for courtship behaviors.
Birds-of-paradise: Known for elaborate mating displays.
Alternative Strategies in Mating
Concept: The prevalence of 'sneaky males' who engage in alternative reproductive strategies.
Cooperation in Behavioral Ecology
Theoretical Predictions: Optimality models and game theory typically predict selfish behavior, but cooperation may also arise.
Altruism Inquiry: Examines the reasons behind cooperation versus selfishness.
Reciprocity in Cooperation
Conditions Favoring Reciprocity:
Benefit for the recipient outweighs the cost to the actor.
Frequent repayment opportunities exist.
Individuals can recognize one another and remember past interactions.
Protection in Numbers
Concept: Explores how cooperation in groups can offer safety from predators (protection in numbers).
Fitness and Behavioral Ecology
Relatedness Principle: Individuals display altruistic behaviors towards their relatives, paralleling parental investment in offspring that boosts lifetime fitness.
Coefficient of Relatedness (r) in Diploid Species
Definitions and Examples:
Child and Parent: $r = 0.5$\n - Full Siblings: $r = 0.5$\n - Half Siblings: $r = 0.25$\n - Niece/Nephew and Aunt/Uncle: $r = 0.25$\n - Cousins: $r = 0.125$\n - Grandchild and Grandparent: $r = 0.25$
Inclusive Fitness
Definition: The cumulative effect of an individual's direct (personal reproductive success) and indirect (contributions to relatives' reproductive success) fitness.
Unusual Partnerships in Nature
Benefit to Helpers/Subordinate Males:
Inclusive Fitness benefits
Inheritance of territory
Learning opportunities for future reproductive success.
Eusocial Systems
Description: Represent an extreme form of social behavior characterized by a caste system.
Summary of Limitations in Behavioral Ecology
Concerns:
Testability issues in hypotheses.
Incomplete criteria (e.g., neglecting predator avoidance, need for hydration, mate finding, nest building, etc.).
Foragers often operate under incomplete information, leading to memory variations.
Final Note on Behavioral Ecology
Source Reminder: Compiled from SimUText Ecology. Simbio.com.
Compiled by: Dr. Greg George