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Announcements Exam 3 - this Friday, April 27th (M-Z here; A-L 100 Greg Hall) Final - Friday May 11, 8am (A-L here; M-Z 100 MSEB) Conflict exam for final - Thursday 4 pm in 683 Morrill Hall (by instructor approval only) Extra credit assignments due Friday, May 4th! Assigned Reading Chapters from Book: 4, 11, 12, 13 Lecture 23: Mating systems • Types of mating systems and occurrence – Monogamy, polygyny, polyandry, promiscuity • Monogamy: why? -- resource-based mating systems • Polygyny threshold model • Leks: definition, conditions for evol., paradox • Polyandry: characteristics and benefits • EPCs within a socially monogamous mating system – Benefits & costs for males and females Lecture 24,25: Parental care • Sex differences, costs, tradeoffs (current vs. future) • Operational sex ratio & influence on parental care • Biparental care & paternal care • Offspring recognition: mechanisms & tradeoffs • Sibling conflict: parental & offspring perspectives • Parent-offspring conflict • Parental favoritism: ultimate explanation Parental favoritism Likely occurs when resources are variable and adults have more young than they can raise (bet hedging) Females can invest in eggs differently (even choose sex in some species). Young can be fed preferentially. Seychelles warbler Can parents control sex of offspring? Seychelles Warbler Lecture 26: Helpers at the nest • Sociality and the major transitions • Benefits and costs of sociality • Nest helpers – Overlapping generations (main social character) – Relationship with dispersal • Reasons for helping – Indirect genetic benefits (help relatives) – Territory limitation – Learning/experience • Reproductive Skew – Factors influencing degree of RS – Incentives to allow RS Lecture 27: Cooperation • Multicellularity: germ line and somatic tissue • Cooperation in multicellular organisms enhanced by genetic bottleneck every generation (r=1 for all cells) • E.g. social amoeba as a model – Social cheating in cooperative systems • Family based social groups – Balance of costs and benefits of whether to stay or disperse • Shared defenses (selfish reasons) • Shared resources (can be benefit or cost) The unicellular bottleneck Why break down a costly, multicellular organism each generation? Because all cells are genetically identical, r = 1. This aligns interests. When cheaters go through bottleneck, they are inviable (all acorns). Other potential benefits: dispersal diapause expose bad alleles Potential costs: ecological vulnerability costs and risks of development Lecture 28: Kin selection • Altruism: why? – Reciprocal Altruism & Prisoner’s dilemma: long term benefits of cooperating – Kin selection • Hamilton’s Rule – Relatedness (and relatedness w/in a population) • Factors that reduce selfish behavior Lecture 29: Eusociality I • • • • 3 characters that define eusociality Indirect fitness Haplodiploidy & influence on relatedness Problems with kin selection as sole ultimate explanation for eusociality – Alternatives: bivoltine life cycle – Colony level selection • Kin selection & conflict within societies – Conflict over sex ratio in social insects • Importance of kin recognition (& what can happen if it breaks down) Lecture 30: Eusociality II • Reproductive Skew as a continuum • Examples of eusocial taxa – Characteristics they share in common • Benefits of eusociality – Bigger you are, more you can grow – Better exploitation of resources – Often leads to great ecological success Lecture 31: Division of Labor • Understand: how can role specialization facilitate cooperation? (major transitions…) • Definitions: caste, role, polyethism • Examples of DOL • Behavioral roles in vertebrate societies – Direct vs indirect roles – Leadership and control • Naked Mole Rat DOL • Social Insect DOL: superorganism concept – 3 forms of DOL and mechanisms of caste differentiation – General idea of theoretical models of DOL Lecture 32: Pheromones • Long horned beetles – Important woodboring pests (introduced) • Contact pheromone – How males recognize females – Bioassay used to test for contact pheromone • Gas chromatography-mass spectrometry (GCMS) – Determine chemical composition of pheromones • Long-range pheromones – Males use to attract females – Conservation of signals across species but different combinations. Lecture 33: Sensory Systems • Properties of sensory systems (3) • Forms of sensory reception – Photo, chemo, mechano, etc. • Key concepts in sensory system function – Report relevant info, tuned to biologically relevant stimuli, topographical organization of brain • Bat echolocation: basic functioning Lecture 34: Neural Basis • Neuroethology • Roeder’s experiments with moth responses to bat sounds • Prey escape behavior – Sensory locomotor pathways • Regional organization in brains – Brain regions with specific functions – Left and right brain Lecture 35: Conservation • Captive Breeding & Reintroduction – Mating behavior – Survival skills development • Species management – Effective population size depends on mating system – Mating/nesting requirements in habitat • Cheetah controversy – Genetic bottleneck? Or just sensitive to predation? • Habitat loss & fragmentation – Understanding of dispersal, home ranges Lecture 35: Invasive Species • What are invasive species? • Behavior and invasions: – behavioral mechanisms of success – dispersal (natural versus human mediated) – sociality and allee effects Good Luck!