Alternative Male Strategies Male Mating Behavior: Discrete Behavioral Phenotypes Anatomical Dimorphism Mating Opportunities Producers/Scroungers; Social Parasites Frequency Dependent Equilibrium (ESS)?

Alternative Male Strategies Green Treefrog (Hyla cinerea) Two Male Mating Strategies: Callers Satellites

Green Treefrog Strategies Amphibians Males at Pond, Calls Attract Females, Females Arrive & Mate, Oviposition Calling Necessary Energetic Cost (?), Predators(?) Costs of Aggression

Green Treefrog Strategies Callers Larger Defend Calling Site (Cost) Call to Attract Females Females May Prefer Callers as Mates Over Satellites

Green Treefrog Strategies Satellites Smaller (Minimally) Silent Position Near Active Caller Try to Intercept Females Attracted to Vocalizations of Caller(s)

Green Treefrogs Perrill et al Anim Behav 30: 43. Release Female Green Treefrogs Satellites Same Reproductive Success as Callers Satellites Intercept Females, and Mate When Females Briefly Outnumber Callers

Male Strategy Equilibrium? p Frequency of Callers (1 – p) Frequency of Satellites Consider Fitness of Each Strategy at p = 0, and p = 1

Male Strategy Equilibrium? p = 0; All Satellites Satellites: No/Low Fitness; Females Not/Less Attracted in Absence of Male Vocalizations Rare Caller Attracts “All” Females; Caller Has Higher Fitness (Invades)

Male Strategy Equilibrium? p = 1; All Callers Females Attracted Rare Satellite Mates Without Incurring Costs of Calling Rare Satellite Higher Fitness (Invades)

Male Strategy Equilibrium?

p < p^Callers More Fit, Increase p p > p^Satellites More Fit, Decrease p p = p^Equal Fitness, Equilibrium Evolutionarily Stable

Alternative Male Life Histories Discrete Male Lifetime Strategies Bluegill Sunfish (Lepomis macrochirus) Males Differ: Age First Reproduction, Growth Rate Size, Coloration, Parental Care, Length of Life

Alternative Male Life Histories Gross, M.R. & Charnov, E.L Proc. Natl. Acad. Science USA 77:6937. Bluegill Sunfish: Ontario Freshwater Lakes: Nesting Colonies Males Obtain Small Territory, Substrate Nest, Parental Care

Bluegill Sunfish Life Histories Colony Males & Nests: Attract Females School of Gravid Females Arrives Enter Nest Single, Release Eggs Territorial Male Usually Fertilizes Eggs; Cares for (“Fanning”) Eggs & Larvae

Bluegill Sunfish Life Histories As Females Spawn Small Male May Intrude, Release Sperm Medium-sized Male, with Coloration of Female May Approach Nest & Release Sperm “Parasites” on Territorial Male’s Effort

Bluegill Sunfish Life Histories Three Male Behaviors: Parental (7 yrs old & older) Sneaker (2 – 4 yrs old) Satellite/Female Mimic (4 – 6 yrs old) Simply Age-Dependent Behavior?

Bluegill Sunfish Life Histories

Sunfish Growth Sensitive to Energetics Testis Growth, Sperm Production Reduces Increase in Body Size Fix Age, Males Capable of Reproduction Show Reduced Linear Growth

Bluegill Sunfish Life Histories Analysis of Sperm Production/Male Growth Two Alternative Reproductive Life Histories First 2 Yrs: No Difference Diverge as 2-Year Olds

Bluegill Sunfish Life Histories

Sneakers Age to Satellites Parental Past Age 7? Sneakers Injured, Susceptible to Infection Sneakers & Satellites Greater Age- Specific Mortality than Future Parentals Same Lifetime Reproductive Success?

Females: Courtship Costs Should Female Tolerate Courting Male? Benefits of Mating Reduced for Already-Mated Female Costs Loss of Foraging Opportunities Transmission Pathogens/Parasites Attraction of Predators

Females: Courtship Costs Female’s Decision Reproductive Status (Mated vs Virgin) Nutritional Status (Sated vs Food Deprived)

Courtship: Orb-Web Spider Herberstein et al Behavioral Ecology and Sociobology 51:440. Orb-web Spider Agriope keyserlingi Female Tolerance of Male on Web: Mating to Pre-copulatory Cannibalism

Courtship: Orb-Web Spider Virgin: Requires Eggs Fertilized Maximal Benefit of Mating Females May Mate With > 1 Male Improve Offspring Viability (Variability) Reduced Benefit of Mating Same Costs

Courtship: Orb-Web Spider Males: Tug Silk Threads of Web Signal to Female May Signal Potential Prey, Predators Steal Prey Female Has Captured

Courtship: Orb-Web Spider Costs to Female: Loss of Foraging Efficiency Prey Avoid Web, Males Damage Web Loss of Stolen Prey Exposure to Predators (Mantids) Increased Chance of Infection Males Can Injure Female

Courtship: Orb-Web Spider Field: Male on Web Prey Capture Rate reduced from to 0.05 items/hr Approach by Mantid Predators: 5 Times as Frequent at Courting Pairs

Courtship: Orb-Web Spider Lab: Frequency Female Attack & Cannibalism Greater Among Mated than Among Virgin (Fertilization Benefits) Mated Females: Only Sated Remated Frequency Female Attack & Cannibalism Greater Among Food-Deprived than Sated Females

Courtship: Orb-Web Spider Males: Preferred to Court Virgins Safer, More Eggs to Fertilize Deserted Larger Females