03 生殖行為 動物行為學 通識

1. 國立臺南大學 通識課程 2011年春 03 生殖行為動物行為學 通識 鄭先祐(Ayo) 國立 臺南大學 環境與生態學院 生態科學與技術學系 教授 Ayo NUTN Web: http://myweb.nutn.edu.tw/~hycheng/

2. 03 生殖行為 • 3.1 性擇 (Sexual selection) • 3.2 性內天擇 – 競爭性伴 • 3.3 性間天擇 – 選擇性伴 • 3.4 性衝突 (Sexual conflict) Ayo 2011 動物行為學(通識)

3. 3.1 性擇 (Sexual selection) 有些物種奇特的特徵，是來自性擇的結果： 性內天擇(Intrasexual selection)：雄性競爭性伴 同性(通常是雄性)個體相互打架(競爭)，贏者可以獲得性伴(雌性)。 演化朝向增大競爭用武器。 性間天擇(Intersexual selection)：雌性選擇性伴 通常是雌性個體按其喜愛，選擇接受為性伴 雄性為吸引雌性，而競爭。 Ayo 2011 動物行為學(通識)

4. 生殖行為的性差異 雄性的招潮蟹有大螯。 雄性間的打鬥和吸引雌性 於動物世界 雄性為獲得雌性，競爭 雌性選擇是否接受某個雄性個體 (性伴) 雄性與雌性的配對策略差異是來自 生殖投資量的差異。 配子生產，受精卵孕育和親代照顧 Ayo 2011 動物行為學(通識)

5. 生殖行為的性差異 雌性產生較少、較大，較耗能的卵子；雄性產生數百萬小的精子。 雄性競爭為獲得較有限的資源(雌性的卵) 雌性個體提高其生殖成功率，是要找到最佳雄性，讓其有限的卵授精。多個性伴，並不會增加其生殖成功率。 雄性生殖成功率，因增多性伴，而增加。 雄性個體往往是 “undiscriminating eagerness” 雌性個體則是 “discriminating passivity” Ayo 2011 動物行為學(通識)

6. Differences in parental care There is differential investment in offspring between the sexes Also responsible for competition and mate choice The sex that provides more parental investment for offspring (usually the female) becomes a limiting resource The sex that invests less (the male) competes for access to females Females have the luxury of choosing among available suitors Ayo 2011 動物行為學(通識)

7. 案例：求偶角色 in katydids (螽蟴) 雌性個體產生子代的數量，受到來自雄性個體的禮物 (spermatophore) (精蟲包)的提升。 來自雄性個體的禮物，其重要性取決於食物的供應量。 當食物缺乏情況，禮物就非常重要。 雌性個體未獲得雄性個體而競爭(females compete for males) 當食物豐盛時，禮物的重要性下降。 Males compete for females Ayo 2011 動物行為學(通識)

8. 性別角色互換的物種 當雄性個體比雌性個體，投資更大於照顧子代。 Females of these species compete for males Males are discriminating in their choice of mates 於性別角色互換的物種 males are choosy Females actively compete for mates Ayo 2011 動物行為學(通識)

9. 案例：生殖競爭 in meerkats Meerkats 是合作繁殖的非洲哺乳類。 單一顯要的雌性個體 monopolizes reproduction 雌性個體表現標準哺乳類的特質，greater parental investment (gestation and lactation) • 雌性個體間的生殖機會競爭，相當激烈。 • 雌性繁殖者，有較大的體重，testosterone, 和aggression Ayo 2011 動物行為學(通識)

10. 雌性於求偶和交配過程，未必是被動。 雌性個體於生殖活動過程，會主動參與。 誘發交配 from one or several males 案例：雌性果蠅 approach and pursue males 雌性個體以becoming immobile，表現出 their enthusiasm and willingness to mate 案例：雌性 bonobos (倭黑猩猩) are dominant to males and mate promiscuously (混雜地) With males from within their community and other communities Ayo 2011 動物行為學(通識)

11. Bonobos (倭黑猩猩) • 倭黑猩猩，又名矮黑猩猩或侏儒黑猩猩，英文名：Bonobo或Pygmy Chimpanzee， • 學名是「Pan paniscus」。 Ayo 2011 動物行為學(通識)

12. 確保交配：dominance behavior 雄性個體確保交配，by dominating other males and excluding competitors from females 這需要投資於更強壯和更有效的「武器」。但雌性個體就不需要。 案例：如鳥類和哺乳類，雄性個體通常比雌性個體，體型較大，而擁有較大的打鬥能力和生殖成功率。 Sexual dimorphism Ayo 2011 動物行為學(通識)

13. Sexual dimorphism Results from 雄性個體間的競爭 雌性個體對詞性生殖成功率的影響 掠食壓力，對雄性和雌性的差異 食物的差異 案例： 蚊子的口器，雌雄有差異。 雄性是吸食花蜜，磁性是吸食血液。 purple-throated carib hummingbirds (蜂鳥) 雌雄各吸食不同類花的花蜜，其雌雄的鳥嘴長度與彎度各不同。 Ayo 2011 動物行為學(通識)

14. Purple-Throated Carib (Eulampis jugularis ) hummingbirds Ayo 2011 動物行為學(通識)

15. Male dominance relationships 於有形成雄性顯要地位關係的物種，高位階的雄性有較高的生殖活動力和有較高的生殖成功率。 顯要的雄性個體可干擾次位階雄性個體的交配行為。 次位階雄性個體，只能偷偷進行交配。 The Stump-tailed Macaque (Macaca arctoides), also called the Bear Macaque, is a species of macaque found in Southern Asia. Ayo 2011 動物行為學(通識)

16. 確保交配：另類生殖策略 藍鰓魚(bluegill sunfish)，雄性表現出多型態(polymorphism) parentals or cuckholders Parental雄性個體，七歲才性成熟。 Compete for sites, guard females, and care for the young Cuckholders雄性，兩歲就性成熟。 Do not build and defend nests, or provide parental care Ayo 2011 動物行為學(通識)

17. 另類生殖策略 • Parental雄性個體，七歲才性成熟。 • Cuckholders雄性，兩歲就性成熟。 • Sneakers: 小型雄性個體，偷偷溜入巢內排精。 • Satellites: 較大型雄性個體，長相類似雌性個體(female mimics) with the coloration and behavior of mature females. Female mimics enter a nest and release sperm。 Ayo 2011 動物行為學(通識)

18. bluegill sunfish (藍鰓太陽魚) • 分布於北美洲聖勞倫斯河五大湖區與密西西比河流域至墨西哥北部間的溪流及湖泊中。 Ayo 2011 動物行為學(通識)

19. 兩生類雄性交配策略(mating tactics) Male natterjack toads employ loud, energetically expensive calls to attract females. All males are capable of calling Large males are callers Small males are satellites that remain silent and intercept females attracted to the calls of the other male Intermediate males alternate opportunistically Ayo 2011 動物行為學(通識)

20. Male Dall’s porpoisesguard their mates Male-female pairs of Dall’s porpoises Maintain shorter distances between one another Remain close for longer durations Surface in synchrony and Are less likely to join other individuals or groups Males respond more aggressively to approaches by adult males Ayo 2011 動物行為學(通識)

21. Mate guarding reduces extra-pair fertilization Male mate guarding reduces the risk of cuckoldry A male Seychelles warbler closely follows his mate prior to egg laying The time when she is most receptive Guarding make sense: a pair produces a single clutch with a single egg To ensure that the nestling is his own Ayo 2011 動物行為學(通識)

22. Sperm competition: removing rival sperm A male removes rival sperm Damselfly males use their penis to transfer their sperm and remove sperm previously deposited by competitors Male spider crabs push the ejaculates of earlier males to the top of the female’s sperm storage receptacle and seal them off with a gel Ayo 2011 動物行為學(通識)

23. Sperm competition: sperm heteromorphism The simultaneous production by a single male of at least two types of sperm in the same ejaculate One sperm morph can fertilize eggs (eusperm) And one cannot (parasperm) Occurs in mollusks(軟體動物), insects, fishes Ayo 2011 動物行為學(通識)

24. Hypotheses for the evolution of parasperm 扮演於精蟲競爭時的功能 Killing or displacing sperm Inhibiting remating by the female or blocking sperm Facilitating the survival, transport or readiness of eusperm Providing nutrients to the female, eggs or the eusperm Diluting the effects of spermicides produced by females Ayo 2011 動物行為學(通識)

25. Avoiding sperm displacement: retaliatory (回敬的) copulations Males try to prevent sperm displacement by rival males 案例：Rocky Mountain bighorn sheep females mate with several males Subordinate males (coursing rams公羊) force copulations on ewes(母羊) guarded by tending rams Tending and coursing rams copulate with ewes(母羊) to increase the proportion of their own sperm in the female Dominant males mate right after copulation by a coursing ram Ayo 2011 動物行為學(通識)

26. Avoiding sperm displacement: retaliatory copulations • Dominant males mate right after copulation by a coursing ram • Displaces rival sperm • Sperm from the last mating fertilizes the eggs Ayo 2011 動物行為學(通識)

27. Avoiding sperm displacement: prolonged (拖延的) mating Two hypotheses to explain the function of prolonged mating Extended mate guarding: reduces the chances that the female will be inseminated by another male Ejaculate transfer hypothesis: prolonged mating results in more of the male’s sperm being transferred to the female Ayo 2011 動物行為學(通識)

28. Avoiding sperm displacement: prolonged (拖延的) mating • 案例：A large orb-weaving spider copulates several hundred times with a female • Smaller, peripheral males hang around but don’t copulate • Supports the mate-guarding hypothesis • Mating duration did not influence the number of sperm • The ejaculate transfer hypothesis is not supported • orb-weaving spider Ayo 2011 動物行為學(通識)

29. Avoiding sperm displacement: repellents and copulatory plugs Males may apply a repellent (驅除的) odor to their mates 案例：Male neotropical butterflies (橘釉蛺蝶) transfer an “antiaphrodisiac” pheromone to a female, making her repulsive to other males A male may deposit a copulatory plug in the female’s reproductive tract 案例：In many snakes, lizards, marsupials, rodents, bats and primates • neotropical butterflies (橘釉蛺蝶) Ayo 2011 動物行為學(通識)

30. Male spiders use copulatory plugs In Argiope aurantia, the male dies within seconds of mating Becoming a whole-body mating plug Copulating male golden orb web spiders protect their paternity by leaving parts of their pedipalps in the genital openings of females Ayo 2011 動物行為學(通識)

31. Some male spiders leave parts of their copulatory organs in the genital tracts of females with which they have mated. Such parts appear to obstruct matings by subsequent males. Male’s pedipalps (E, embolus 栓子 ), C for conductor 導體. Ayo 2011 動物行為學(通識)

32. Females may benefit by mating with more than one male Mating with several males may Increase the probability of fertilization Increase the genetic diversity of offspring Result in the accumulation of material benefits if males provide nutritional gifts at copulation Ensure that a female’s sons are good at the game of sperm competition, if the trait is heritable Ayo 2011 動物行為學(通識)

33. Sexual interference: infanticide Infanticide: killing a competitor’s offspring In both invertebrates and vertebrates Infanticidal males kill unrelated infants Increasing a male’s chance of siring the next infants • Here, a lion has killed the cub of a rival male. Ayo 2011 動物行為學(通識)

34. Intersexual selection One sex chooses individuals of the other sex as mates Females often do the choosing Males compete among themselves to be chosen Sometimes males choose and female compete Characteristics used by females to select a mate should affect female fitness Be assessable (可評估的) Vary among males Ayo 2011 動物行為學(通識)

35. Criteria by which females choose mates Females choose mates on the basis of their ability to provide Sufficient sperm Useful resources Parental care Genes that are good or compatible Direct material benefits obtained by the female: sufficient sperm, useful resources food or nest and parental care Indirect benefits: good or compatible genes benefit the female’s offspring Ayo 2011 動物行為學(通識)

36. Ability to provide sufficient sperm Female stone crabs prefer unmated males and use chemical cues to assess male ability to transfer sufficient sperm Males experience sperm depletion with successive matings Females spend more time near unmated males Ayo 2011 動物行為學(通識)

37. Males provide useful resources Females choose a mate on the quality of resources he provides Females receive immediate gains from gifts Or long-term benefits from access to valuable resources (food or nest sites) Females that exchange mating for material goods are advantaged Resources improve offspring survivorship and competitive ability Females evaluate potential mates through their material goods Ayo 2011 動物行為學(通識)

38. Males present a gift of prey nuptial gifts in scorpionflies Female choose male that bring relatively large prey items during the courtship process These nuptial gifts, which are consumed during courtship, provide females with a direct tangible benefit, food. There is a positive relationship between prey size and copulation time. Ayo 2011 動物行為學(通識)

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43. Some animals offer themselves as gifts In some spiders, scorpions, and mantids (螳螂) The male gives his body to the cannibalistic female The male redback spider (紅背蜘蛛) stores his sperm in a tightly coiled structure (a palp) on his head The coil unsprings and sperm is transferred while the female eats him Ayo 2011 動物行為學(通識)

44. Some animals offer themselves as gifts • Males gain two advantages from suicidal behavior • A cannibalized male fertilizes twice as many eggs as a male who survives copulation because he copulates twice as long • A female is less likely to mate again after she’s eaten • redback spider (紅背蜘蛛) Ayo 2011 動物行為學(通識)

45. Females selecting a mate assesses the quality of his territory Female house wrens select a mate based on the number of nest sites in his territory Males with the most nest boxes were selected first Extra nest sites decrease the chances that the female’s own nest would be found by predators Ayo 2011 動物行為學(通識)

46. Females assess a male’s parental abilities In other species, females evaluate the amount or quality of food on a male’s territory Females use physical or behavioral features of males to predict parental quality Some female birds judge male parental ability on the quality of nutritional gifts provided during courtship Lots of high-quality gifts signal a male’s superb foraging skill and willingness to feed his mate and offspring Ayo 2011 動物行為學(通識)

47. Females assess a male’s parental abilities • A male European crossbill passes regurgitated(反芻) seeds to a female. • Females may judge the parental ability of a male by the quality and quantity of gifts provided during courtship feeding. Ayo 2011 動物行為學(通識)

48. Female gobies judge males They use a current’s speed to judge the parental abilities of potential mates Male gobies (蝦虎魚) build nests and provide sole care to the eggs Female gobies favor males that court in the fastest water Only exceptional males can dance in fast currents Males unable to court in fast currents are less well-conditioned and more likely to consume their eggs Courting in fast current is an “honestsignal” of a male’s ability to offer paternal care Ayo 2011 動物行為學(通識)

49. Male gobis court in fast currents The water velocity where a male dances is positively correlated with survival of his eggs Ayo 2011 動物行為學(通識)

50. Male physical condition and dominance indicate genetic quality Male satin bowerbirds build stick structures (bowers) they display to females Males decorate their bowers (涼亭) They prefer blue and purple flowers Orange, red, and pink are unacceptable Males also chew leaves and paint the mixture on the walls Bowers and their decorations indicate male quality Males steal decorations from competitors Ayo 2011 動物行為學(通識)