1 Introduction ____________________: Study of social relations. – Interactions between organisms and the environment mediated by behavior. ____________________: Branch of biology concerned with study of social relations. _____________: Number of offspring (genes) contributed by an individual to future generations. BIOL 3240 Plant and Animal Ecology – Sex & Social Relations

2 Introduction Fundamental Question: – ? – Female reproduction thought to be limited by … – Male reproduction limited by … Birds of Paradise… BIOL 3240 Plant and Animal Ecology – Sex & Social Relations

3 Introduction – Exhibit both male and female function. Which is the hermaphrodite? BIOL 3240 Plant and Animal Ecology – Sex & Social Relations

4 Mate Choice – Differences in reproductive rates among individuals as a result of differences in mating success. _____________________: Individuals of one sex compete among themselves for mates. BIOL 3240 Plant and Animal Ecology – Sex & Social Relations

5 Mate Choice _____________________: Individuals of one sex consistently choose mates among members of opposite sex based on a particular trait. BIOL 3240 Plant and Animal Ecology – Sex & Social Relations

6 Mate Choice and Sexual Selection in Guppies Given a choice, female guppies will mate with… – – Color characteristics that have been shown to confer mating advantage: BIOL 3240 Plant and Animal Ecology – Sex & Social Relations

7 Mate Choice and Sexual Selection in Guppies Endler performed natural selection study to test color pattern in guppies. – When freed from predation… WHAT HAPPENED? Kodric-Brown reported reproductive success was determined by a combination of male attractiveness and dominance status. – Observed attractive males tend to be …??? BIOL 3240 Plant and Animal Ecology – Sex & Social Relations

8 Mate Choice Among Scorpionflies Adult scorpionflies (genus Panorpa) feed on dead arthropods in the forest understory. – Dead arthropod supplies are often limited. Thornhill found that male Panorpa will take possession of, and guard, dead arthropods. – Larger males are more successful. BIOL 3240 Plant and Animal Ecology – Sex & Social Relations

9 Nonrandom Mating Among Wild Radish Wild radish flowers have both male ( ) and female ( ) parts, but cannot self- pollinate. Marshall found _____________ mating in wild radish populations. 0Radish1971.jpg BIOL 3240 Plant and Animal Ecology – Sex & Social Relations

10 Sociality Evolution of sociality is generally accompanied by: – – – Cooperation generally involves exchanges of resources or other forms of assistance. BIOL 3240 Plant and Animal Ecology – Sex & Social Relations

11 Sociality Eusociality – More complex level of sociality. Three major characteristics: – – – BIOL 3240 Plant and Animal Ecology – Sex & Social Relations

12 Different-headed Smoothies (aka Heterocephalus glaber) BIOL 3240 Plant and Animal Ecology – Sex & Social Relations

13 Cooperative Breeders Species living in groups often cooperate in rearing offspring. – What benefit do helpers gain ? Inclusive fitness: – Inherited territory: » Kin Selection BIOL 3240 Plant and Animal Ecology – Sex & Social Relations

14 Green Woodhoopoes Ligons found green woodhoopoes live in territories defended by flocks of – Only one pair breeds. Exhibit strong ____________. Scarcity of … – Bulk of young tend to be helpers ranging from half to full siblings. BIOL 3240 Plant and Animal Ecology – Sex & Social Relations

15 African Lions Packer and Pusey studied cooperation among African lions in the Serengeti. – Prides of female lions include 3-6 adults, but may contain as many as 18. Many forms of cooperation. – BIOL 3240 Plant and Animal Ecology – Sex & Social Relations

16 African Lions Males cooperate in territory defense. – Not always made up of close relatives. – Single males have no chance of claiming and defending a pride. – Probability of siring young depends on rank within coalition. – Reproductive success more variable in groups of 3-4 than in groups of 2. – Larger coalitions composed of relatives. BIOL 3240 Plant and Animal Ecology – Sex & Social Relations

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