1. Sept. 27, 20101 Lecture 6 Communication & Sexual Selection

2. Sept. 27, 20102 Today’s topics 1. What is communication? 2. Modes of communication. 3. Function of communication. 4. What is sexual selection? –Intersexual selection –Intrasexual selection

3. Sept. 27, 20103 Communication (biological) An action on the part of one organism (sender) that alters the probability of occurrence of behavior patterns in another organism (the receiver) in a fashion adaptive to either one or both of the participants. Ultimately, communication functions to increase fitness.

4. Sept. 27, 20104 Displays and Signal Display – behavior pattern that conveys a message from one individual to another. Signal - the physical form in which a message is coded for transmission through the environment –Sound, color, odor, or postures

5. Sept. 27, 20105 Properties of signals Discrete vs. Graded –Discrete (digital) simple On or off –Graded (analog) variable range of intensity Vocalization signals are often graded.

6. Sept. 27, 20106 Composite signal – combination of 2 or more signals. Properties of signals cont…

7. Sept. 27, 20107 Mammals can usually detect dishonest signaling or “deceit” Elephant seals males may pretend to be females to sneak in for a copulation.

8. Sept. 27, 20108 Modes of communication Odor – usually pheromones Sound Visual Touch Electric field?

9. Sept. 27, 20109 Odors Priming pheromones – produce a generalized response –Example = induces estrus Signaling pheromones – rapid motor response –Example = induces fear

10. Sept. 27, 201010 Odor – urine or feces

11. Sept. 27, 201011 Odor – glands

12. Sept. 27, 201012 Odor – reception Flehmen – retraction of upper lip to collect scents (especially common during breeding season) http://thewildsource.com/tws/blog/post/2010/08/Mapula-Lodge-Video---Lion- Flehmen-Response.aspxhttp://thewildsource.com/tws/blog/post/2010/08/Mapula-Lodge-Video---Lion- Flehmen-Response.aspx

13. Sept. 27, 201013 Sound Immediate communication of current conditions. Vast inter and intraspecific differences in frequencies and amplification of sound –High frequencies = short-distance communication –Low frequencies = long-distance communication

14. Sept. 27, 201014 Sound Ultrasonic sound – frequencies above those audible to humans (>20,000 Hz).

15. Sept. 27, 201015 Sound Infrasonic sound – frequencies below those audible to humans (<20Hz)

16. Sept. 27, 201016 Sound Does sound communication always employ the vocal cords? –Moose = antler raking –Beaver = tail slap –Whale & dolphin = breaching & tail-slapping –Banner-tailed kangaroo rats = foot drumming Also rabbits, ungulates, spotted skunks, elephant shrews, and some marsupials

17. Sept. 27, 201017 Vision Precise communication with regards to space and time. Usually only effective during daylight and over short distances Social and diurnal mammals rely heavily on visual cues.

18. Sept. 27, 201018 Vision Flagging behavior –Distracting predators from others –Warning other members –Confusing predators –Signaling the predator –Eliciting premature pursuit

19. Sept. 27, 201019 Vision Signals –Antlers –Pelage –Bristling of pelage –Tail-wagging –Snarling –Stamping –Raking

20. Sept. 27, 201020 Touch Grooming Initiating mating Simulation excretion

21. Sept. 27, 201021 Electric field Little evidence that mammals use electric fields for communication –Common in some fish and frogs

22. Sept. 27, 201022 Additional Functions of Communication Group spacing and coordination Recognition (next lecture) Reproduction (next lecture) Aggression and Social Status (next lecture) Alarm Hunting for food Giving and soliciting care (next lecture) Soliciting play

23. Sept. 27, 201023 Alarm Signal to alert group members of danger. –http://www.youtube.com/watch?v=evSHfFgbvcAhttp://www.youtube.com/watch?v=evSHfFgbvcA http://www.youtube.com/watch?v=WilEzT73aHY

24. Sept. 27, 201024 http://www.youtube.com/watch?v=_UH-6r5jrGI http://www.youtube.com/watch?v=_UH-6r5jrGI Chimpanzee communication http://www.youtube.com/watch?v=A1WBs74W4ik&feature=channel http://www.youtube.com/watch?v=A1WBs74W4ik&feature=channel Wolf communication

25. Sept. 27, 201025 “playing” http://www.youtube.com/watch?v=fLhddID1-To Occurs widely in mammals, but is very rare in other taxa. –Explanation is debatable Practice motor skills? Enhance muscle development?

26. Sept. 27, 201026 Sexual Selection A process that produces anatomical and behavioral traits that affect an individual’s ability to acquire mates.

27. Sept. 27, 201027 Intersexual Selection Members of one sex choose certain mates of the other sex

28. Sept. 27, 201028 Indicator models (good genes) – assume that the trait favored by females in someway indicates male fitness. Handicap hypothesis – males possess costly traits to show that they must be fit to be able to afford them. –Important to this hypothesis is the notion of “truth in advertising”. Handicap must be honest and linked to overall genetic fitness.

29. Sept. 27, 201029 Symmetry Symmetry of paired traits may indicate fitness. –Greater asymmetry is associated with low food quality and quantity, habitat disturbance, pollution, disease, and genetic factors such as inbreeding, hybridization, and mutation. –Injury?

30. Sept. 27, 201030 MHC & body odor Major histocompatibility complex –Large genomic region in most vertebrates –Plays an important role in immune system and autoimmunity –May allow mammals to recognize genetic similarities in others. –Mus musculus Body odor and symmetry

31. Sept. 27, 201031 Intrasexual selection One sex compete among themselves for access to the other sex. –Highly ritualized battles.

32. Sept. 27, 201032 After copulation, the fight continues.. Sperm competition – a situation in which one male’s sperm fertilizes a disproportionate number of eggs when a female copulates with more than one male.

33. Sept. 27, 201033 Sperm competition Mate guarding Sperm dilution Copulatory plugs (rodents, bats, and some primates) – glandular secretion

34. Sept. 27, 201034 Sexually dimorphic Difference between the sexes in form, usually size. –Males often larger than females. –Opposite in microtines (subfamily Microtinae), most females larger than males.