BZ 300 1st Edition Lecture 18Outline of Last Lecture I. Mating Systema. Why Sex?i. Costsii. Benefitsb. Why males and females?i. Isogamyii. Anisogamyiii. Hermphroditesc. Sex ratiod. Sexual Selectioni. Darwin1. Mate Competition Sexual Selection2. Mate Choice Sexual Selectionii. Batemaniii. Trivers1. Parental Investment (PI)e. Heritability and Sexual Selectionf. Courtshipg. Functions of Courtship Behaviori. Sex/Species Recognitionii. Mate Attractioniii. Synchronization of Behavioriv. Overcoming Aggressionh. Honesty/ Dishonestyi. Misrepresentationii. Surreptitious MatingOutline of Current LectureI. Mate Choice continued…i. Mate Choice can be based on:i. Possessions of Potential Mateii. Indicator of Genetic Qualityiii. Nuptial Gifj. Female Mate Choicei. Good Genesii. Resourcesiii. “Sexy Son” HypothesisThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.k. Intersexual Selectioni. Fisher’s Runaway Selection Hypothesisii. Zahavi’s Handicap Hypothesisiii. Secondary Sexual Traitsl. Intrasexual Selectioni. Scramble Competitionii. Mate Guardingiii. Female Social Groupsiv. Cooperative Malesv. Leksa. Afer Matingvi. Sperm Competition1. Spawningvii. First Male Adaptionsviii. Secondary Male Adaptationsb. What If you Lose?ix. Alternative Strategies1. Conditional Strategies2. Behavior PolymorphismII. Mating Systemsa. Polygynyi. Resource-Defense Polygynyii. Female- Defense Polygynyiii. Male-Dominance Polygynyiv. Scramble Polygynyb. Monogamy c. Polyandryd. PolygynandryCurrent Lecture:I. Mate Choice continued…a. Mate choice can be based on:i. Possessions of potential mate i.e., territory, nesting sites.ii. Indicator of genetic quality1. Indicators of good health2. How it advertises itself3. How it takes care of itselfiii. Nuptial Gif1. Mainly in the form of food, proves that you can provide for the female and offspring.b. Female Mate choice:i. Good Genesii. Resourcesiii. Copying choice of other females, counts on the female to do initial evaluation. Occurs where males have polygamous relationships.iv. “Sexy Son” hypothesis- if the male is appealing to a lot of the females it will then tell the female that her sons will be ‘sexy’ and will be able to pass on those good genes. v. Male mate choice is a lot less studied.c. Intersexual Selection (Mate choice)- one sex is choosing the other. Selection is acting BETWEEN sexes, about choice. i. Fisher’s runaway selection hypothesis- inherited preference for trait. Ex. Peacock. No reason for the tail or feature to exist, but females have preferred it. The feature gets larger and larger until the excess feature is detrimental towards fitness and natural selection stops the process. ii. Zahavi’s handicap hypothesis- indicator of good genes. 1. With excess adornment, it shows to the female that the male must have awesome ability to take care of itself. Problem is that it is inherited in children. 2. In order to follow in evolution, it must show something in addition to just the tail that the female is attracted to, i.e., good genes, fitness, etc.iii. Secondary Sexual Traits- traits that go along with being that sex. In some traits serve more than one function. Sexual traits may also be beneficial in other areas. Ex. Antlersd. Intrasexual Selection- Male/ Male competitioni. The ‘winner’ gets the femaleii. Competition can occur before Mating1. Scramble competition- thirteen lined ground squirrel- run to the resource as fast as possible and to as many as they can before other males. The male who gets their first, simply gets the female, mating period is so short.2. Mate Guarding- a. Ex. Gammarid females mate right afer they molt, males will guard the female during molting to fend off other males.3. Female social groups- females hang out in groups to repel predators, much different reasons than reproduction. Common amongst ungulates.a. Synchronous- males can choose many different groupsb. Asynchronous- males stay with the group permanently *Look up in a book, a little confusing4. Cooperative Males- Males will defend area where males know the female will come and mate, if he owns the area he will get the female5. Leks- many males hang out in one area and the female comes and chooses the male she finds most attractive. 6. Competitive searching, call volume… a. Ex. Fireflies, respond to loudest male because it is more costly and gives a sense of fitness. 7. Ofen times excess adornments, can have different uses based on whether it is a female or male.a. Sticklebacks red belly- attracts females, but repels other malesiii. Afer Mating1. Sperm Competition- Adaption of males that will reduce the chances that another male sperm can penetrate a female that the original male already had sex with.a. Spawning: this may have been the first type of male-male competition.i. A lot of variability to force the males sperm to do better than other males:1. Can spawn in the right area2. May be more or less viscous3. Timing of release of sperm4. The distance of sperm to the eggiv. First Male Adaptations: 1. Mate guarding adaptations- guard female and keep her from mating with any other males. 2. Copulatory plugs: Males can develop copulatory plugs, where it blocks the female so nothing else can get in there.v. Second Male Adaptations: (afer males have already mated with a female)1. Last male that mates will ofen have majority of offspring, occurs in many insects2. Sperm Removal3. Space Occupying Substance- makes it difficult for the sperm to get through to the egg.4. Bruce Effect- females will end the pregnancy and abort them, if there is a strange male in the area. a. In mice, it is thought to be that the females are cutting their losses, to where their offspring will not be killed by strange male.b. In langer monkeys, the male kills the babies, the female is receptive to the new males in mating quickly because she is already lactating.c. Why? Dominant male time is limited, he needs to start fertilizingfemales right away to get as many males as possible.5. Sexual dimorphism and competition- not always an indicator of male/male competition and which male should be the biggest.e. What if you are a loser?i. Alternative strategies:1. Conditional Strategies- assume that behavior is plastic and depending on conditions an animal can behave in a number of ways. a. Ex. Bullfrogs: large males get the territories and have the highestmating succues. Males that