T10. 溝通 ( Communication)

1. 動物行為學 (通識) 國立臺南大學 通識課程 2011年春 T10. 溝通 (Communication) 鄭先祐 (Ayo)教授 國立台南大學 環境與生態學院 生態科學與技術學系 環境生態研究所 + 生態旅遊研究所 Ayo NUTN Web: http://myweb.nutn.edu.tw/~hycheng/

2. 溝通 (communication) • Introduction • Communication(溝通) • Defined as the transfer of information from a signaler to a receiver • Fig. 12.1 vervet (長尾黑顎猴) alarm calls • Fig. 12.2 clever house • 溝通與誠實 • 溝通化解問題 (solves problems) • How to coordinate group foraging (覓食) • How to find and secure a mate(伴侶) • How to warn others about predators(掠食者)

3. Vervets give different alarm calls depending on what type of predator has been sighted • (A) here we see vervets standing up after hearing a “chutter” alarm call indicating that a snake has been spotted. • When a leopard (B) is detected, vervets will give a “barking” alarm call and (C) climb up trees for safety.

4. clever house • Clever house was thought capable of incredible mental feats. • In fact, clever house was picking up very subtle cues from the individual who asked him a question.

5. 溝通與誠實 • Selection is thought to favor the most economical way to share information. • The natural selection should favor less exaggerated signals– which was referred to as “conspirational whispers”(共謀低語). • This is because signaling often involves some costs, and natural selection should favor minimizing these costs during conspirational whispers and hence reducing the conspicuousness(惹人注目)of the communication itself.

6. 案例：ptarmigans (雷鳥) • Both male and female rock ptarmigans are a stark white against the snow of winter. • Once spring arrive, females molt quickly, while males stay white, and as such the males are very conspicuous against the dark brown background. • Such conspicuousness attracts females, but it also attracts predators. • As the breeding season progresses, rather than molting, males soil their plumage to become less conspicuous.

7. Males communicate information to females via coloration, but when the period during which communication is useful comes to an end, they shut down the communication system in a cost-efficient manner– by soiling their white plumage. ptarmigans (雷鳥)

8. 溝通與誠實的案例：toads • Selection should favor females paying attention only to those cues that are in fact true indicators of larger size. • The case in toads, in whom deep croaks can only be produced by large males because of the design of their vocal system. • Female toads use the frequency of males’ calls to gauge their potential mate’s size. • Honesty is also possible when traits are not impossible, but merely very costly, to fake. (handicap principle).

10. 溝通化解問題 (solves problems) • How to coordinate group foraging(覓食) • 案例：Food calls in birds • 案例： Honeybees and the waggle dance • 案例： Chemical and vibrational communication in foraging ants • How to find and secure a mate(伴侶) • 案例： Birdsong • 案例： Aquatic insects • How to warn others about predators • 案例： Meerkats (狐獴) • 案例： Alarm calls

11. 案例： Food calls in birds • Colonial breeding cliff swallows live in nests that serve as “information centers”. • Using both playback experiments and provision experiments (putting food out to entice birds), Brown and his team found that cliff swallows gave off “squeak(吱吱叫) ” calls, which alerted conspecifics that a new food patch– often a swarm of insects– had been found.

12. The mean number of birds and squeak calls heard two minutes before and two minutes after insects were flushed by foraging birds.

13. Under certain conditions, ravens emit a loud “yell” upon uncovering a new food source, such yells attract other birds.

14. Honeybees and the waggle dance • 案例： bee foraging. • Honeybee foraging involves a complex communication system, including waggle dances. • This dance, along with other informational cues, gives bees in a hive information about the relative position of newly found food sources.

15. (A) Imagine a patch of flowers that is 1500 meters from a hive, at an angle 40 degrees to the right of the sun. (B) when a forager returns, the bee dances in a figure eight pattern. In this case, the angle between a bee’s “straight run” and vertical line is 40 degrees.

16. (C) The length of the straight run portion of the dance translates into distance from the hive to the food source.

17. Round dance Sickle dance Waggle dance When resources are close to the hive, honeybee foragers tend to use round dance. When resource are at greater distances, sickle dance When food is very far from a hive, waggle dance

18. 案例：Foraging ants (leaf-cutter ants) • Leaves must first be cut, then carried to the nest, ground up, chewed and treated with enzymes, placed into a “fungus garden”, and subsequently cultivated. • Two chemicals are particularly important, methyl 4-methylpyrrol-2-carboxylate and 3-ethyl-2,5 methylphrazine. • These substance are produced in the poison gland and used to recruit fellow workers to foraging sites. • Recruitment pheromones are incredibly powerful.

19. Leaf-cutter ants can ravage (毀滅) foliage in their path. The ants don’t attack all the leaves, however, but instead they often strip some leaves to the stalk, were leaving other leaves untouched.

20. While only 40% of the ants stridulated when cutting tough leaves, the number increased to 70% when the leaves were tender, and to almost 100% when either type of leaf was dipped in sugar water. Stridulating(發出刺耳聲) communication. A schematic of a leaf-cutter ant cutting a leaf and stridulating its gaster up and down. the vibrations were being sent along the length of a leaf in a long series of vibrational “chirps”.

22. minim workers hitchhiking on a leaf • These minim workers cannot cut leaves, but they are often found hitchhiking rides on leaves on the backs of leaf-cutters. • Minim protect these other leaf-cutting ants from attack by parasitic flies. • Hitchhiking minims apparently use the vibrational cues created by stridulating leaf-cutting nestmates to locate the leaf-cutters. • The stridulating signals emitted by leaf-cutters are used in numerous contexts. • One such venue is between leaf-cutters and minims, who use these signals to eventually hitch rides on cut leaves that are carried on leaf-cutters’ backs.

23. minim workers hitchhiking on a leaf

24. How to find and secure a mate(伴侶) • The role of • (1) vocal communication (birdsong) • (2) tactile communication (insects) • Birdsong: • In most species of songbirds, males don’t just learn a single song, they learn many different songs. • For example, the song sparrow sings about ten different songs, the western marsh wren sings morethan a hundred songs, and the brown thrasher sings an incredible thousand different songs.

25. 案例：Cowbirds • The role of repertoire size in the mating success of male brown-headed cowbirds. • Male cowbirds posses between two to eight different perched songs. • Earlier studies indicated a correlation between the size of the perched song repertoire and mating success. • Whether male repertoire size had an effect on female mate choice? • Five different song treatments

26. Five different song treatments • Smaller repertoire: s single perched song sung three times in succession by a male Santa Barbara cowbird. • --- by a male Ventura cowbird. • Larger repertoire: three different perched songs sung in quick succession by a male Santa Barbara cowbird. • -- by a male Ventura cowbird. • A control: from a different species (song sparrow)

27. Copulation solicitation displays (CSDs) • The length of time that a female displayed ritualized “copulation solicitation(誘惑) displays” (CSDs) to different songs was recorded and used as a measure of female choice. • Female cowbirds displayed longer CSDs when they heard cowbird versus song sparrow songs. • Females show a marked increase in CSD times when exposed to males with large song repertoires • Female had longer CSDs when they were exposed to three different songs than to the same song played three times.

28. Birdsong from a proximate perspective • Birdsong is incredibly diverse in terms of structure, pattern, tempo, frequency, and repertoire size. • However, the vocal organ used in birds, the syrinx, varies little between different species. • How is it possible that morphological invariance in the syrinx can translate into great diversity in birdsong? • The syrinx has two compartments—left and right– and that the two sides of a bird’s brain can control these compartment independently.

29. the different ways to sing • Independent bilateral phonation: Operate both sides of the syrinx independently without one side being dominant. (Brown thrasher and gray catbirds) • Unilateral dominance: Have one side of the syrinx dominate song generation. (Canaries) • Alternating lateralization: Alternate which side of the syrinx dominates during a song. (Brown-headed cowbirds) • Sequential lateralization: Have one side of the syrinx dominate for certain frequencies, and the other side dominate for the remainder of the frequencies used in a song. (Northern cardinal)

30. Ripple (波紋) communication and mate choice • In water striders, ripples are usually produced by an up-and-down movement of the legs, with both right and left legs in synchrony and in constant contact with the water surface. • The water striders produce different patterns of ripples for different kinds of behaviors, including signals for calling mates, courtship, copulation, post-copulation, sex discrimination, mate guarding, spacing, territoriality, and food defense.

31. Woodpecker alarm calls • While downy woodpeckers don’t give alarm calls when they are paired with same-sex partners, • they emit such alarm calls when they are paired with a member of the opposite sex

32. Development, learning, and alarm call communication in meerkats (狐獴) • Behavior observation indicates, compared to adults, • Pups were initially more likely to respond to alarm calls in the presence of less dangerous or nondangerous predators, and they were more likely to ignore alarm calls emitted in the presence of dangerous predators. • Pups don’t react as appropriately to alarm calls as adults. • age differences in reaction to alarm calls.

33. in meerkats, a pup's response to alarm calls was not as strong as the response seen in adults. (A) time until reaction after hearing playback of alarm call (B) duration of response to playback of alarm call

34. (C) length of time spent "scanning" the environment for predators after hearing predator alarm calls. Adults remain vigilant and continue to watch out for predators longer than do pups.

35. Alarm calls as deceptive communication • Because alarm calls are a powerful form of communication– failure to listen might lead to death– natural selection should favor paying close attention to such calls. • Nonetheless, these same selection pressures set up the possibility of using alarm calls in a deceptive manner. • Using alarm calls in a deceptive manner is probably the exception rather than the rule.

36. 案例：Vervets (長尾黑顎猴) • Verbets sometimes use deceptive predator alarm calls during some intergroup encounters – encounters that can lead to serious aggression between group members. • Male verbets five an alarm call when encountering a new troop, even though no predator is in the vicinity. • It was almost always a low-ranking male who gave the call.

37. Dishonest alarm calls in swallows? • Male swallow may emit false alarm calls when they see their mate engaging in an extrapair copulation. • These alarm calls break up extrapair matings. • When females were absent during egg laying, the males who returned to their nests almost always gave false alarm calls. • Male swallow who emitted false alarm calls during possible periods of extrapair copulations.

38. (A) Male barn swallows often give false alarm calls when their fertile mats leave the nest vicinity (B) These false alarm calls sometime disrupt extrapair copulations (EPCs) (C) Moller hypothesized that male swallows would five false alarm calls when they were at the greatest risk of EPCs to disrupt the EPCs. Colonial breeding males emitted false alarm calls during the period in which EPCs were most likely (during egg laying).

39. 案例：Alarm calls in Richardson’s squirrels • When alarm calls become less reliable, natural selection should favor paying less and less attention to them. • Two treatment (juveniles of squirrels) • Heard a recorded alarm call and then saw a predator (true alarm calls) • Heard a recorded alarm call. But no predator (false alarm calls)

40. Alarm calls in Richardson's squirrels. overtime, when predator alarm calls are unreliable, juvenile squirrels began to ignore such false alarm cues.

41. responses to reliable and unreliable alarm calls.

42. 問題與討論 Ayo NUTN website: http://myweb.nutn.edu.tw/~hycheng/