Lecture 9 - Social Behavior PDF

THE EVOLUTION OF BEHAVIOR https://study.com/academy/course/animal-behavior-study-guide.html EVOLUTIONARILY STABLE STRATEGIES (ESS) John Maynard Smith: “Evolution and the Theory of Games” (1982) A mathematical model to explain what we see in nature. An important concept of evolutionary game theory is...

THE EVOLUTION OF BEHAVIOR https://study.com/academy/course/animal-behavior-study-guide.html EVOLUTIONARILY STABLE STRATEGIES (ESS) John Maynard Smith: “Evolution and the Theory of Games” (1982) A mathematical model to explain what we see in nature. An important concept of evolutionary game theory is that of evolutionarily stable strategy (ESS): it is an activity which is consistently successful. An “evolutionarily stable strategy” constitutes the most adaptive solution under a prescribed set of conditions; i.e., when adopted by most members of the population, it cannot be bettered by any other strategy. https://en.wikipedia.org/wiki/Evolution_and_the_Theory_of_Games Evolutionarily Stable Strategies Richard Dawkins “A set of behaviors or traits (phenotype) that when adopted (evolved) by most members of a population cannot be invaded (replaced) by the spread of any rare alternative behavior or trait (has higher reproductive success than other phenotype-s-)” Maynard Smith & Price, 1973, Nature https://www.youtube.com/watch?v=mUxt--mMjwA GAME THEORY AND ANIMAL BEHAVIOR What behavioral strategy should individuals adopt to maximize their individual fitness? Does the best strategy depend on the strategy of other individuals? Should individuals behave aggressively and fight for resources or behave non-aggressively? If natural selection is “survival of the fittest,” then under what conditions should individuals engage aggressively in conflict for limited resources? Can aggressive and non-aggressive strategies coexist? https://www.amazon.com/Game-Theory-Animal-Behavior-Dugatkin/dp/0195137906 GAME THEORY: HAWKS-DOVES GAME OF FIGHTING https://www.youtube.com/watch?v=OmwERBoeLZU https://dhammawheel.com/viewtopic.php?t=28241 EVOLUTIONARILY STABLE STRATEGIES By definition, if adopted by most of a population, an ESS cannot be bettered by another activity (in games theory). An ESS is frequency-dependent E.g., protective aggression may be successful if one’s conspecifics stay and help with the fighting: muskoxs in a circle to protect young. https://twitter.com/drdibooj/status/595962614456438784 EVOLUTIONARILY STABLE STRATEGIES If few conspecifics are willing to stay and fight, the strategy will be considerably less successful. An important aspect of the concept: the best strategy for an individual depends on what the majority of the population is doing. https://www.sciencedirect.com/science/article/pii/S0376635711001884 RICHARD DAWKINS: THE SELFISH GENE A book on evolution by Richard Dawkins Dawkins uses the term "selfish gene" as a way of expressing the gene-centered view of evolution as opposed to the views focused on the organism and the group, popularizing ideas developed during the 1960s by W. D. Hamilton and others. From the gene-centered view, it follows that the more two individuals are genetically related, the more sense (at the level of the genes) it makes for them to behave selflessly with each other. https://www3.beacon-center.org/blog/2016/06/11/selfish-genes-and-the-resulting-gene-conflict/ Altruistic behavior Kin selection https://www.britannica.com/science/altruistic-behaviour https://corvidresearch.blog/tag/nest-helpers/ BEHAVIORAL ADAPTATIONS TO A SPECIFIC ENVIRONMENT There are many examples of a particular species being clearly and essentially perfectly suited to its environment. Black-headed gulls ground-nest on grassy sand dunes. They remove eggshells from nests right after hatching. http://speciesofuk.blogspot.com/2015/01/week-65-black-headed-gull.html BLACK-HEADED GULLS Tinbergen et al., (Behav. 19:74, 1962): if eggshells were left in nest, there was a much higher probability of those nestlings being eaten by some other animal. Result: intense selection for the alleles carried by parents who throw eggshells away. There are some closely related birds that have a different approach. http://www.imageinuk.com/Other/Black-headed-Gull-Story/ KITTIWAKES Cliff-nesting birds: kittiwakes, razorbills, guillemots; nest on tiny cliff ledges where no predator can land (Cullen, Ibis 99:275, 1957) Throwing out shells is not as beneficial to them. Did they learn it by example (cultural transmission of behavior) or did those who had this behavior simply leave more offspring (more successful in terms of fitness)? Evidence indicates that they inherited the behavior https://dissolve.com/video/Three-Kittiwakes-Rissa-tridactyla-nesting-cliff-chicks-rights-managed-stock-video-footage/002-D1267-1-800 A razorbill (Alca torda) and her egg on a ledge: the egg is an ovoid-pyramidal shape; if disturbed, they roll in a circle rather than fall off the ledge. https://onlinelibrary.wiley.com/doi/pdf/10.1111/ibi.12458 http://www.forthseabirdgroup.org.uk/pages/razorbill.htm http://www.bbc.co.uk/nature/23145291 Common Guillemot (Uria aalge) Incubate their single egg on exposed cliff ledges, no nest, close proximity to conspecifics → surface of eggshells contaminated with faeces, dirt, water, debris, which may impede gas exchange or facilitate microbial infection of the development of the embryo. The presence of SAM (shell accessory material) on the eggshell surface largely prevents pore blockages from occurring. Common Guillemot (Uria aalge) Males ensure the growth of their offspring after the chick is hatched. The male guides his offspring to the sea and he stays with his offspring for 5 to 7 weeks at sea. At sea, the male does not need to spend time and strength on flying back with food, but can just dive for it. So, the chicks leave the colony early: just 3 weeks after hatching and being only a quarter of the size of an adult → the faster growth at sea ensures survival of the population. ESS?? https://www.youtube.com/watch?time_continue=143&v=G4kqIXS1ruw http://scitech.au.dk/en/about-science-and-technology/current-affairs/news/show/artikel/why-do-guillemot-chicks-leap-from-the-nest-before-they-can-fly/ Sexual selection! http://ilnegoziovincente.it/tecniche-di-vendita-per-clienti-indecisi/ http://rebloggy.com/post/funny-my-work-valentines-day-evolution-at-its-finest-sexual-selection-it-s-all-a/43121428106 SEXUAL SELECTION It acts on likelihood to mate. Intrasexual selection: competition within one sex for mating opportunities (e.g., male-male fights) – Antlers Intersexual selection: affected by interactions between the two sexes (e.g., as a result of female choice) – Male ornaments http://www.museochies.it/1aita_museo/08uccelli.html https://www.chewy.com/prairie-dog-deer-antlers-giant-dog/dp/41275 Bird Of Paradise Courtship Spectacle - Planet Earth - BBC Earth https://www.youtube.com/watch?v=nWfyw51DQfU MALE-MALE COMPETITION A wide variety of adaptations on the part of males, many of which have a strong behavioral component. Fighting and selection for large body size: to acquire mates by correlating male dominance with mating success. Alternative mating tactics: – Mate guardian – Coalition formation: “making the best of a bad job” subordinate baboon males; macaques. – Frequency of copulation – Sperm competition https://www.youtube.com/watch?v=gsMx-nT1aPM https://www.sciencedirect.com/science/article/pii/S0003347209002164 MATE GUARDING Males adjust their mating guardian in relation to the risk of losing paternity to rivals. The more male neighbors around a breeding pair, the more time male warblers spend guarding their partner. http://slideplayer.com/slide/4187448/ FREQUENCY OF COPULATION Goshawk pairs may copulate up to 100 times prior to egg-laying Birkhead (Behav. 101:101, 1987) studied 131 species of birds Copulation frequency is not correlated with clutch size. Then why repeatedly engage in a behavior that puts the participants at risk? Copulation frequency is higher in colonial species where male is not always present Sperm competition: competition between the sperm of 2 or more for fertilization of the same set of ova → a key selective force reproductive anatomy, physiology & behavior in animal, shaping including mammals. https://en.wikipedia.org/wiki/Northern_goshawk SPERM COMPETITION When male competition continues after sperm is released in both internally and externally fertilizing species. Sperm host glands: poultry and many other birds. After mating, the hen stores the sperm in the tiny sperm host glands, between the vagina and the shell gland of the oviduct. The sperm can live in the sperm host glands for ∼ 2 weeks after mating. When an egg is laid, some sperm are squeezed out of the glands and they migrate up the oviduct to fertilize the next egg in the pipeline. http://www.pixoto.com/images-photography/animals/other/beautiful-color-rooster-80495382 SPERM HOST GLANDS From an evolutionary point of view, this feature aids in fertilization of the female. Has been shown that “last in - first out” rule applies here (Compton et al., Poultry Science 57:1696, 1978) So why is copulation frequency higher in species where the male is often absent? https://www.reference.com/pets-animals/hens-roosters-mate-2b3c41c0a5dfabf2 http://www.dummies.com/home-garden/hobby-farming/raising-chickens/starting-with-the-chicken-and-then-the-egg-growth-and-development/ FREQUENCY OF COPULATION AND SPERM COMPETITION By frequent mating, a male who leaves his mate will copulate upon returning in the hopes of diluting or overcoming any foreign sperm in her system. Some avian species with this mating strategy have enlarged male reproductive organs, suggesting that they are capable of mating frequently and with large quantity (Briskie, The Auk 110:875, 1993). Seasonal breeders: the testes enlarge during the breeding season and often change color: from yellow to white in most birds http://articles.extension.org/pages/65373/avian-reproductive-systemmale Japanese quail Female: vent Male: cloaca, proctodeal gland and foam; it gives sperm a boost in the race to fertilize eggs. http://www.g3journal.org/content/8/1/39 https://www.crescentquail.co.uk/quail-pedia.asp https://www.backyardchickens.com/threads/how-to-determine-sex-of-quail.1144183/ QUALITY OF SPERM Evidence: in many species, if several males mate with a female, quality and longevity of the sperm is important. One male may produce sperm that act quickly and effectively but do not last for long; primate sperm competition and speed; “kamikaze sperms” Thus, in a clutch of eggs, one male may sire the earlier offspring but another male with longer-lived sperm may sire later offspring. https://phys.org/news/2007-09-primate-sperm-competition.html https://www.psychologytoday.com/blog/how-we-do-it/201310/kamikaze-sperms-or-flawed-products ALTERNATIVE REPRODUCTIVE TACTICS (ARTs) Males often exhibit different tactics to increase their reproductive success. Small Chinook salmon (“jacks”), which return to the river of their birth 1 year or 2 before older and more aggressive hooknose , invest more energy in their sperm and gonads in a bid to outcompete their larger counterparts (Butts et al., 2017) → “sperm's athleticism”: – jack sperm swim faster than hooknose sperm and require less power to propel themselves through the water column – jack sperm are more efficient at swimming than hooknose sperm and swimming efficiency increases when the cells are activated in ovarian fluid Implications for farming, breeding and managing salmon stocks https://jeb.biologists.org/content/jexbio/220/12/2210.full.pdf THM Evolutionarily/Evolution ary Stable Strategies The game theory and animal behavior: fishers vs. pirates and hawks vs. doves Behavioral adaptation to specific environments: seabirds Sexual selection Male-male competitions: the four types Alternative Reproductive Tactics https://www.reddit.com/r/NatureIsFuckingLit/comments/7fp986/the_amazonian_royal_flycatcher_is_found_in/