What is communication? Eläinten signalointi. What is communication? Kommunikointi/signalointi. Eläinten signalointi. receiver.

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1 Eläinten signalointi What is communication? sender receiver signal information Arja Kaitala Ekologia Oulun Yliopisto 1 The process in which a sender uses a specially evolved signal to modify the behavior of a receiver implies that response must benefit sender on average response may have + or effect on receiver fitness decision and response 2 What is communication? Kommunikointi/signalointi Who benefits? Change in sender s fitness Change in receiver s fitness positive negative/zero - Ryhmän sisäiset (valta) suhteet - Seksuaalivalinta/Parinvalinta - Ravinnon ym resurssi positive true communication/ honesty manipulation/ deception =signal =signal negative/zero eavesdropping/ (vakoilu) -no signalexploitation =cue Difference between cues and signals Mosquito use co 2 to locate a mammal but co 2 is not a signal Vain rehellinen signaali on evolutiivisesti vakaa koska se hyödyttää kumpaakin osapuolta 3 - Pedoilta suojautuminen 4 Eläinten signalointi Signaalin lähettäjän päämäärä on vaikuttaa vastaanottajan käyttäytymiseen lähettäjän eduksi Signaalin evolutiivista merkitystä voidaan mitata: - miten voimakkaan reaktion se saa vastaanottajalla - miten paljon se hyödyttää/haittaa lähettäjää 5 6 1

2 Konflikti (asevarustelu) yleistä: Yksilöiden välinen konflikti: Emon ja poikasen välillä Koiraiden ja naaraiden välillä Ryhmässä yksilöiden välinen hierarkia Peto-saalis suhde Lois-isäntäsuhde Chase away selection, naaraalle suurempi hyväksymiskynnys Konflikti paritteluista : - ylenpalttinen parittelu naaraalle haitallista ja koiraille edullista -naaraalle värkkejä estämään paritteluja Signaalin teho Jos signaalin lähettäjiä ylenmäärin, vastaanottaja kehittyy valikoivammaksi -chase away sexual selection 7 8 Where do signals come from? Sensory exploitation herkkä kohta Naaraan preferenssi luonnonvalinnan kautta jotain naaraan kannalta oleellista asiaa kohtaan, mitä koiraan ominaisuus muistuttaa Two general scenarios Sender precursors: signals arise from inadvertent cues, or as a byproduct of some activity performed in a specific context Receiver precursors: signal givers tap into preexisting perceptual mechanisms of receivers 9 10 Runaway -sexual selction Mikäli signaali kasvaa liikaa, lähettäjälle suuret kustannukset luonnonvalinta asettaa rajat sen vahvuudelle

3 Signal evolution Koiraan ornamentti indikaattori koiraan laadusta Proposed stages in the evolution of a communication function The transition to bilateral benefit if there is a selective benefit to the sender Ornamentin koko indikoi koiraan kykyä vastustaa loisia 13 Evolutionary stable signal Sorensen & Stacey (1999) 14 The sender s perspective A display is a means of manipulation Signalling is costly May draw attention of predators and parasites Energetic expenditure Signals should be optimum balance between greater effectiveness and lower fitness cost The receiver s perspective Conflict interests in signal evolution Sexual signalling (males vs. females) Food allocation (parents vs. offspring) - Threath displays during aggressive interactions RHP = resource holding power Signals are evolutionary stable if both sender and receiver benefit from the signalling system Genetic relatedness: Kin selection Monogamous females: signal they have mated (extremely rare) Human language Taistelu rituaalit kilpailijan arvioimiseen - Hyödyttää kumpaakin osapuolta, koska estää vahingoittumista Signal reliability In nature there may be indirect assessment: RHP

4 How do animals communicate? Form and function Sensory modalities Olfactory / chemical Auditory Visual Tactile/vibrational electrical Signal property Sensory modality Olfactory Auditory Visual Tactile Range Long Long Medium Short Transmissions Slow Fast Fast Fast Sender location Difficult Varies Easy Easy Production cost Low High Medium Low Evolution of animal signals Traits specialized for communication Bright colours (e.g. birds & butterflies) (Luento: Pe klo 10, B233) Calls (frogs & crickets) Pheromones (moths, ants & other insects) Aggressive posturing (lizards & fishes) Function Attract a mate, deter a rival, warn conspecifics of an approaching predator, alert offspring Individuals in a group always unequal, maintenance of dominance needs communication (mating never random, offspring not treated equal) Mammal history: why we have poor vision? Signalointi usein monimutkainen prosessi: Mikä on signallointia? Kuka viestittää ja kenelle? Signalointi usein monimutkainen prosessi: - Ja altis huijaukselle

5 Miten käki löytää isäntänsä? -oppiminen What are pheromones? a chemical signal transmitted between members of the same species Very common in nature (In humans) often unconscious Invertebrate & vertebrate olfaction Noses to catch molecules The first pheromone identified Silk moth Bombyx mori Female sex pheromone bombykol Butenandt et al female silk moths were needed to produce 12 mg material for the first pheromone identification 27 Sam Woo/University of California Davis 28 Important points 1. More interactions are mediated by pheromones than by any other kind of signal 2. Independent evolution of particular molecules as signals 3. Like insects, mammals can use small molecules, as pheromones for sexual signalling Confused? Why don t moths & elephants get confused Does moth attract elephants? No, small quantity of pheromone picograms per hour from female moth Does elephant attracted moths? (Z)-7-dodencen-1-yl acetate is just 1 of 6 required chemicals of his species pheromone blend (Each moth species has different combination) Rasmussen et al Elephants and some moths share the same sex pheromone

6 Costs of chemical signalling Costs of chemical signalling Low metabolic cost compared with that of other signals the lifetime cost to a male boll weevil beetle (Anthonomus grandis) to produce sex pheromone is estimated at only 0.2% of its body weight (Hedin et al. 1974). In contrast, male crickets devote over half their daily respiratory budget to acoustic signalling (Prestwich 1994). Advantage for small organism Chemical signal travels further Ipmworld.umn.edu naturefg.com 31 But in most animals not limited to the simple cost of production Time and energy costs in territorial animals: the time taken to maintain scent marks in species which do not synthesise their pheromones themselves: collecting plant materials used as pheromones or pheromone precursors Cheating 32 Sex pheromones Pheromones and sexual selection Which sex should call? Usually female moths attract males visual or acoustic signals, almost always produced by the male. Low energy cost and small risk of predation (Except for the male). A low pheromone release rate selects for strong, effective searchers Selection for great sensitivity to detect pheromones huge feathery antennae of males neurosensory adaptations faster flight or greater ability to track a complex pheromone plume Pheromones and sexual selection Contest African cockroach (Nauphoeta cinerea) Dominance based entirely on odor cues Male pheromones operate as badges of high status in male-male interarction and female choice Females prefer to mate with the dominant male, identified by his odour Mate quality and courtship Short-range pheromones Females/males choose by using odour as cues to his/her quality E.g. in mammals: Male social status, the quality of nutrients he has consumed, his reproductive state, his immunological genotype or other genetic compatibility and his health. In humans MHC-genes

7 Indusoitu puolustus: jokin luotettava ympäristön signaali aikaansaa puolustusreaktion - Kasvit tuottavat myrkkyä vasta kun niitä vaurioitetaan, ruutana kavaa koreutta Vedessä tuoksuilla valtava merkitys - Jos ruutana laitetaan lampeen, johon pannaan vettä, jossa uitettu nälkäistä haukea, joka on syönyt kalaravintoa, ruutana kasvaa korkeutta Lopuksi: Useiden eläinten aistit ovat kehittyneemmät kuin ihmisen Monilla hyönteisillä, linnuilla ja nisäkkäillä huomattavasti tarkempi kuva ympäristöstä ja lajitovereista kuin meillä (perustuen, näkö haju ja/tai kuuloaistiin) ja kommunikaatio tapahtuu kaikkien näiden aistien avulla. Kohtuu heikosti tiedetään, miten ne käyttävät tätä tietoa