Bio2 Lecture 23

Bio2 Lecture 23 - Bio2 Lecture 23 Male Strategies...

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Unformatted text preview: Bio2 Lecture 23 4/14/05 Male Strategies- Infanticide – lion killing clubs of previous dad- copulatory plugs – muck up female genitalia- coercion – rape- mate guarding – guarding female during fertile period- prolonged copulation – form of mate guarding or copulatory plug o living chastity plug o water striders – small male locked in copula with female, evolved hooks that allow him to cling to her once they have mated which doesn’t allow other males to mate with her, female also has special spines that allow her to dislodge him if she wanted to do so o dogs will have a really large penis once he ejaculates, and they are connected for an hr.- sperm competition – removal or dilution of competitor’s sperm o dragon flies – on a male’s penis he has a scrape to scrape off sperm and cork screw to remove the sperm of the females’ previous mate, whoever mates with her last will mate with her Mating Systems Monogamy – 1 female / 1 male- benefits are that there is much much much less male male competition, and humans have serial monogamy Polyandry - 1 female / many males- very rare, less than 1% of animals have a polyandry mating system- you have fertility insurance- reduces infanticides- many more opportunities for female to increase genetic diversity of offspring Polygyny – 1 male / many females- overwhelmingly common- most males in this system die virgins Monogamy- females are scarce- social cooperation for parental care- male perspective, its easier for him to enforce her chastity- male never sure about paternity, but female always certain of maternity- for birds: o monogamous female: 8 offspring, 18.5 g. wt. o widow: 6 offspring, 16.5 g. wt.- with every monogamous system, cheating is almost always a factor, it increases genetic diversity of male, and fitness of female Polyandry- less than 1% are polyandry- extremely rare- queen honeybee, mates with as much as 20 different males o goes through a nuptial flight once she hatches, then mates, and then just has babies o mates then has to store enough sperm to last her the next 2 years, which is the rest of her life o the male also uses a copulatory plug, he amputates his penis, but female/queen can remove it if she wishes- Rattlebox moth o Females will compete for males o In the chimps, sex forms social ties, in these the females give a resource as well o The caterpillars feed on rattlebox plant, very few herbivores feeding on it, chemically protected because it produces alkaloids o Rattlebox moth stores alkaloid and passes to female when they mate and...
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Bio2 Lecture 23 - Bio2 Lecture 23 Male Strategies...

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