Theories for the Evolution of Alarm Calls

Theories for the ontogenesis of affright blackguards apprehension Call growth Altruism or Kin Selection?Taylor RystromIntroductionHumans arouse always been fascinated by creature communication. One important mirror image of animal communication is scandalise key outs. disheartenment borders, even rightally de nonative misgiving environs, can be observed across many diverse species. Prairie dogs pass by alerting roars specific even to the shirt color that a nigh human is wearing (Slobodchikoff 2009). Male blue monkeys give dismay calls that ar specific to predator type, standoffishness, and location (Murphy et al. 2013). Even African elephants, who learn relatively few predators, give alarum calls when they hear the sound of bees (King et al. 2010). al whiz why did these cast down calls, a seemingly altruistic act, evolve in so many contrary animal mathematical groups? How did some get so specific? Sherman lays out six interesting theories of the phylogen esis of shock calls. Alarm calls could have evolved to divert the attention of the predator, discourage the predator, alert relatives of the caller, help the group which the caller resides in, reduce the later return of the predator, or reprove others who get out reciprocating at a later time (Sherman 1977). The main findings have signaled that terror calls have every evolved as an altruistic act, possibly with reciprocity among the group, or as a mechanism to protect affinity (Trivers 1971, Sherman 1977). As for functionally referential alarm calls, meaning that the alarm calls encode specific education most the predator, growing has been suggested as a response to the need for disparate escape methods from incompatible predators repayable to the home ground of the group (Furrer and Manser 2009).Altruism suppositionAlthough Koenig (1988) points out that there is no comm just accepted definition of selflessness in demeanoural ecology (Koenig 1988), it can be explai ned for the purposes of this review as an act that has a cost to the various(prenominal) and a benefit for others. joint selflessness, which Trivers argues to be present in alarm- call birds (Trivers 1971), would be a type of selflessness which benefits the individual completely when some other party reciprocates the act toward the first individual (Koenig 1988). Trivers suggests that alarm work in birds is reciprocal self-sacrifice because alarm calling keeps predators from specializing on the location and species of the caller (Trivers 1971). However, Koenig points out that reciprocal altruism is lock speculative in birds (Koenig 1988). Furthermore, it is un in all probability if alarm calling is altruistic and intrinsic selection acted on the individual that had the novel gene for alarm calling, the animal would have no gain in fitness, the gene would not spread, and the quality would not evolve (Charnov and Krebs 1975). This being said, if alarm calling is an altrui stic behavior, it essential have evolved because of some benefit to the caller (Charnov and Krebs 1975). One speculation is that an alarm call could encode the presence of a predator however get around out the location of the predator, thus causing confusion of the dispersal of the quid while the caller knew exactly how to escape the predator (Charnov and Krebs 1975). However, it has been prep be that manly blue monkeys can in fact encode the predator distance and location, thereby giving all immediate information to their conspecifics (Murphy 2013).Problems arise in this surmisal when specific species of birds are studied more closely. The alarm calls of mavin species of jay, the Siberian jay, were closely analyzed due to the personality of the groups of this species of jay. In this species, the jays swear in social groups comprised of one dominant demeanor pair, their offspring, and sometimes non-related immigrant birds (Griesser and Ekman 2004). If alarm calling is al truistic in this species, the dominant breeding pair would call whenever a predator is nearby, regardless of whether they were with immigrants or kin (Griesser and Ekman 2004). However, the results showed that females called only during the breeding season while their kin was present, while males called indiscriminately (Griesser and Ekman 2004). This raises further questions about the intentions of males do they call indiscriminately to selfishly protect time to come yoke or to dilute a predator attack by providing benefits to immigrants in the group to reduce the callers chance of being attacked? willow tree tree tits also give alarm calls, but Hogstad (1995) suggests that this is a form of cooperator investing and evolved for this purpose. Males are dominant and breeding pairs last for several years, so if a female dies, especially during the winter, the male partner will possible be unpaired the following breeding season (Hogstad 1995). Adult willow tit males gave alarm ca lls more frequently when they could see their mates than when they could not this implies that alarm calling for this species is primarily a form of mate investment (Hogstad 1995). Since the benefit of having a mate the following season is fairly elephantine for a male willow tit, this is not an altruistic act.Studies regarding animals other than birds suggest that alarm calling is not an altruistic act. Alarm calling would only be categorized as altruistic if the calling was costly to the caller in some way (Koenig 1988). Round-tailed squirrels only give alarm calls when they are already retreating, thus not endangering themselves (Dunford 1977). Marmots do not reduce their proclaim chances of survival because they rarely call when exposed to predators, and their calls are acoustically unenviable to detect by predators (Barash 1975). There is no real threat to either of these species when they give alarm call, thus destroying the option of alarm calling being altruistic. Further more, icteric marmots can identify who produced an alarm call and will thin out calls after many false alarms (Blumstein and Daniel 2004). Although this seems to support the hypothesis for reciprocal altruism since identification of false callers is important for the reciprocity, there are no cognise cases of which rodents take turns calling.Kin Selection TheoryThe kin selection theory requires that kin be nearby when alarm calls are given for the function of alerting kin of danger. Kin selection is not altruistic because protect offspring and other kin is a way to protect the future of ones own genes. The evolution of alarm calls due to kin selection is definitely dependent on the social system of the species. Beldings domain squirrels have a social system where females generally outride in their natal land their whole lives and males are polygynous, do not defend any mates or offspring, and emigrate from their natal territory alone, constantly moving after they mate (Sherman 1977). Sherman (1977) found through an elongated observational study that females call frequently when relatives are nearby and do not call at all when they have no living(a) kin meanwhile, males rarely call. In another study regarding ground squirrels, Dunford (1977) found that males do sometimes call but this is only when they are juveniles and their pose and siblings are near. Sherman (1977) hypothe sized that the function of alarm calling is nepotism, and that the evolution of this behavior is due to kin selection.Similar results are found with Gunnisons prairie dogs (Hoogland 1996). Females with kin in the homogeneous territory called more often than females who did not have nearby kin. This species has a slightly different social system than Beldings ground squirrels. Males guard 3-4 females and move between adjacent territories, and it was observed that males give alarm calls regardless of whether or not they had kin in the territory (Hoogland 1996). It is likely that t he males had kin in adjacent territory, so these kin could theoretically be close enough to benefit from an alarm calls. These prairie dogs assess their own in the flesh(predicate) safety before calling, as they are more likely to call if they are farther from the danger (Hoogland 1996). Previously it had been found that male Black-tailed prairie dogs only give alarm calls only after they sire offspring in the territory (Hoogland 1983). These studies show extreme support for the hypothesis that alarm calls evolved as a form of selecting for kin.A study on chipmunk alarm call behavior offers support that there could be a reciprocal altruism component to the maintenance of alarm calling in the species (Smith 1978). This is because they are one of few species in which all members of the group can and do give alarm calls (Smith 1978). Although kin selection was most likely the basis for the evolution of the behavior since older females with many nearby daughters give the most alarm cal ls (Smith 1978), it is interesting that both seemingly opposing hypotheses can work together.When yellow-bellied marmots call, the spotted predators almost always leave. However, not all of these marmots call. Blumstein and Armitage (1975) found that the calling is generally a safe activity for these marmots so there is not much cost associated with alarm calls. Their hypothesis is that some individuals do not call because they are trying to reduce reproductive argument (Blumstein and Armitage 1975). Females are the most likely to call, and only when they have vulnerable young. So if another female refrains from calling when she spots a threat, she will reduce the competition for her young since the most vulnerable are the young which are swinish to the threat (Blumstein and Armitage 1975).Further Extensions and ConclusionsThere are also factors which affect the complexness of alarm calls, including the level of sociality and habitat composition of species. Sociality and communica tive complexity were compared across three different sciurid rodents, and only in marmots did communicative complexity increase with sociality there was no correlation for prairie dogs or squirrels (Blumstein and Armitage 1997). This implies that alarm repertoire size has many factors, such as facial and laryngeal morphology and habitat acoustics (Blumstein and Armitage 1997). home ground could square off the evolution of functionally referential alarm calls because if different escape routes are needed for different predators due to the physical nature of the habitat, then it would be beneficial to your survival to have different alarm calls for all(prenominal) type of predator to streamline the escape (Furrer and Manser 2009). However, this hypothesis is not completely supported by data. In Gunnisons prairie dogs, the habitat does fix the alarm calls they have been found to change their alarm call dialects for different levels of vegetation cover (Perla and Slobodchikoff 2002) . However, meerkats and Cape ground squirrels live in the same habitat yet only meerkats have functionally referential alarm calls thus habitat does not have a profound influence on the evolution of functionally referential alarm calls (Furrer and Manser 2009). The continuing evolution of alarm calls into more complex communication like functionally referential alarm calls is an important angle of study.How much of alarm call behavior is learned? Female Campbells monkeys produce three alarm calls in the wild but only two in captivity, one of which is not observed in the wild (Oattara et al. 2009). This implies that the capacity for alarm calling evolves, but not fully utilized if not needed. This study also suggests that in order for alarm call behavior to be expressed in a population, the threat of predation must be large. Since captive monkeys do not have predators, they have lost vocalizations associated with this danger (Oattara et al. 2009).The evolution of alarm calls is no si mple matter. When factoring in the specific ecology of each species studied to give alarm calls, it all comes down to each species sprightliness history. It makes sense evolutionarily for a species which live in social groups comprised of kin and non-related individuals to call to warn kin, and if only females live near kin, for females to predominantly call. However, if a species lives in a different type of social group, alarm calling does not necessarily have to function as a way to warn kin. Alarm calling in species of many different types of social groups should be studied in regards to the hypotheses offered by Sherman (1977) in order to find support for other evolutionary drivers as well as reciprocal altruism and kin selection.Literature CitedBarash, David P. Marmot Alarm-Calling and the Question of Altruistic Behavior.American Midland Naturalist94.2 (1975) 468. Print.Blumstein, Daniel T. The Evolution of functionally Referential Alarm Communication Multiple Adaptations Mult iple Constraints.Evolution of Communication3.2 (1999) 135-47. Print.Blumstein, Daniel T., and Janice C. Daniel. Yellow-bellied Marmots withdraw between the Alarm Calls of Individuals and Are More Responsive to Calls from Juveniles.Animal Behaviour68.6 (2004) 1257-265. Print.Blumstein, Daniel T., and Kenneth B. Armitage. Does Sociality Drive the Evolution of Communicative Complexity? A Comparative Test with Ground plate Sciurid Alarm Calls.The American Naturalist150.2 (1997) 179-200.JSTOR. Web. 14 Mar. 2014.Blumstein, Daniel T., and Kenneth B. Armitage. Why Do Yellow-bellied Marmots Call?Animal Behaviour56 (1998) 1053-055.JSTOR. Web. 1 Mar. 2014.Charnov, Eric L., and John R. Krebs. The Evolution of Alarm Calls Altruism or Manipulation?The American Naturalist109.965 (1975) 107-12.JSTOR. Web. 15 Mar. 2014.Dunford, Christopher. Kin Selection for Ground Squirrel Alarm Calls.The American Naturalist111.980 (1977) 782. Print.Furrer, RomanD., and MartaB. Manser. The Evolution of UrgencyBase d and Functionally Referential Alarm Calls in GroundDwelling Species.The American Naturalist173.3 (2009) 400-10. Print.Griesser, Michael, and Jan Ekman. Nepotistic Alarm Calling in the Siberian Jay, Perisoreus Infaustus.Animal Behaviour67 (2004) 933-39.Science Direct. Web. 14 Mar. 2014.Hogstad, Olav. Alarm Calling by willow tree Tits, Parus Montanus, as Mate Investment.Animal Behaviour49.1 (1995) 221-25. Print.Hoogland, John L. Nepotism and Alarm Calling in the Black-tailed Prairie Dog (Cynomys Ludovicianus).Animal Behaviour31.2 (1983) 472-79. Print.Hoogland, John L. Why Do Gunnisons Prairie Dogs Give Anti-predator Calls?Animal Behaviour51.4 (1996) 871-80. Print.King, Lucy E., Joseph Soltis, Iain Douglas-Hamilton, Anne Savage, and Fritz Vollrath. Bee affright Elicits Alarm Call in African Elephants. Ed. Karen Mccomb.PLoS ONE5.4 (2010) E10346. Print.Koenig, Walter D. trilateral Altruism in Birds A Critical Review.Ethology and Sociobiology9.2-4 (1988) 73-84. Print.Murphy, Derek, St ephen E.g. Lea, and Klaus Zuberbhler. Male Blue Monkey Alarm Calls encode pirana Type and Distance.Animal Behaviour85.1 (2013) 119-25. Print.Ouattara, Karim, Klaus Zuberbhler, Eliezer K. Ngoran, Jean-Emile Gombert, and Alban Lemasson. The Alarm Call System of Female Campbells Monkeys.Animal Behaviour78.1 (2009) 35-44. Print.Perla, Bianca S., and C. N. Slobodchikoff. Habitat Structure and Alarm Call Dialects in Gunnisons Prairie Dog (Cynomys Gunnisoni).Behavioral Ecology13.6 (2002) 844-50.Oxford Journals. Web. 6 Feb. 2014.Sherman, P. W. Nepotism and the Evolution of Alarm Calls.Science197.4310 (1977) 1246-253. Print.Slobodchikoff, C. N., Andrea Paseka, and Jennifer L. Verdolin. Prairie Dog Alarm Calls Encode Labels about Predator Colors.Animal Cognition12.3 (2009) 435-39. Print.Smith, Stephen F. Alarm Calls, Their Origin and Use in Eutamias Sonomae.Journal of Mammalogy59.4 (1978) 888. Print.Trivers, Robert L. The Evolution of Reciprocal Altruism.The Quarterly Review of Biology46.1 ( 1971) 35. Print.