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Ch 6.docx

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Western University
Biology 3475A/B
Jeremy Mc Neil

Chapter 6 11122010 114100 AM Mating systems Monogamy mate with one partner Promiscuity mating with more than 1 partnerPolygamy polygyny males mate with many femalespolyandry female mates with many malesIntersexual selectionMate choiceWho is the choosy sex how do they use pheromones to make a choice how does the choosee use chemicals to be chosenthe one that invests the most in reproductionusually the female bc egg is larger than the sperm sperm is cheap eggs are a much greater investmentfemales are the choosy sex and will reject unacceptable malessexual selection is not staticit will change with age life expectancy andreproductive expectancyolder ones older males or poor quality males are better than no males at allIntrasexual selectionbigger more symmetric horns of a beetle is more attractive to femalespeacock beats other males trying to drive off competitionMale strategy mate as often as possible more matesmore progenymore genes are present in poplnLifetimeof matings vs totalof offspring positive relationshipR0996clear more matingsmore progenymore genes passed on to next genFemale strategy choose the best male possiblenuptial giftsscorpion flies good huntersgood preybetter genes sons more successfulthey give nuptial gifts o mating usually lasts for 2 hrs o sometimes females break if off at 18 min after taking gifts but not letting him transfer spermdishonesty o up until maximum time prior to the transfer of spermmales ejaculate contain lots of other stuff proteins etcRESOURCES male butterflies get salt and transfer salt to females that are salt limited to help her reproduce 2 male turkey colour cues noise making auditory visual cuesfemale makes a judgment whole body of theory about how honest the signal isis the message they are giving out honest or not eg Butterfly males have modified scales pheromone source that are straight when male emerges but as they get older lysosomes format dorsal end the zones become weak and male vibrates his wings particles fall onto the females antennae and she gets a chemical msg to decide if she should mate or notImportance of the male stignmaa in mating of T lineolaif scales are removed there is not chemical msgscraped off diff areas of the wingswasnt just the scales there ewre also glands under the wings then removed the glands that removed pheromone control cut wings but not the glandssignificantly higher when the pheromone was emitteddetectedBlow odour over antennaeodour emitted should go down for a younger male bc no lysosomes males emerge a few days before females
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