Effects Of Personality On The Breeding Strategy Of Azure-Winged Magpie

Animal personality refers to those behaviors showing inter-individual variation but intra-individual consistency over time or across contexts.The conceptual establishment of personality in researches of animal behavior,which is becoming a new viewpoint in illustrating the evolution of animal behaviors,has challenged the optimality theory because individual differences in behavioral responding to the same context mean that someone have acted in suboptimal ways.How to determine the adaptive significance of personality traits has become one hotspot in researches of animal behaviors.In the azure-winged magpies(Cyanopica cyanus)that breed on the Tibetan Plateau,I stimulated a ‘predator intruding' experiment to explore which behavior can be used as an agent of bold/shy personalities.Then,I examined the response of bold and shy individuals to the handling stress by recording their breathing rates.Finally,I compared the reproductive success and breeding parameters between bold and shy individuals.My major findings are listed below.1)Individual breeders,mainly males,exhibited different levels of aggression towards intruders of their territory,which can be used as an agent of bold(high aggressiveness)or shy(low aggressiveness)personalities.2)Individuals of different personality exhibited significant differences in their responding to the stimuli.Bold individuals had significantly lower breathing rates than shy individuals in the handling stress experiment;the breathing rates of bold individuals did not change with the successive measurements whereas shy individuals significantly decreased their breathing rates in successive measurements.3)Females in bold nests produced larger clutches and eggs than their counterparts in shy nests.It seems that the egg-laying strategy of bold breeders is“large clutch and large eggs” whereas that of shy breeders is “small clutch and small eggs”.4)Breeders in bold nests had fledged significantly more offspring than that in shy nests.This difference is directly determined by the fact that bold nests have larger clutch size than shy nests.As a result,it seems that the nestling-raising strategy of both bold and shy breeders is “raising in rich”.5)The provisioning rates of bold and shy nests,as well as that of bold and shy individuals,did not differ significantly;however,the food amount delivered to nestlings per feeding bout was significantly more in bold nests than in shy nests.As a result,bold nests fledged more offspring than shy nests.6)The hatching success did not differ significantly between bold and shy nests,whereas the fledging success of bold nests was significantly higher than shy nests.My findings have uncovered that bold and shy individuals differ significantly in their stress-responses and breeding parameters.First of all,bold and shy breeders have made different responses to the same type and intensity of stimuli.Bold breeders need higher intensity of stimulation before they show fear than shy breeders.Although shy breeders are easy to show fear when they first encounter a stimuli,they can overcome the fear in a shorter time than bold breeders.Moreover,bold individuals have invested more in current reproduction and they realize higher reproductive success than shy individuals.Bold breeders adopt “higher reproduction and raising in rich” strategy to enhance their reproductive success in current breeders;whereas shy breeders adopt “low reproduction and raising in rich” strategy to enhance their reproductive success in the whole life-time.It thus seems that animal personality traits may be another force driving the differentiation of animal breeding strategies at the individual level.