| Personality is widely existed in animals,with important impacts and consequences on their behavior and survival.The underlying mechanisms for the generation and maintenance of personality trait polymorphism are complex and context-dependent.Previous studies showed that the behavior of social animals can be mutually affected,causing changes in the rate or type of behaviors performed(social facilitation),or convergence in behavior with the majority of neighbors(social conformity).Both facilitation and conformity effects can reduce direct competition and/or enable social coordination.The degree to which the behavior of individuals can be mutually affected depends upon their identities and traits.In addition,sexual selection is important in the generation and maintenance of personality changes.For instance,personality might affect female mate choice.Females can obtain reliable information by observing the consistency and differences of male behaviors.Traditional sexual selection theory holds that females can be directly or indirectly benefited by choosing a high-quality mate,but largely ignores the differences in their selection preferences and relative availability of different information.Many signals could reflect the body condition of males,which are generally correlated.Females may choose a mate based on one or more signals.However,few studies have considered the effects of multiple signals on female mate choice.In this thesis,I classified the personality types of Java sparrows(Lonchura oryzivora)by two personality tests,examined the influence of social companions on their personality traits,explored the role of personality of female and male in determining the mate choice of female,and further analyzed the influence of multiple quality signals on female mate choice.The main results are as follows:1.Across the six trials,individuals of Java sparrows consistently showed significant variation in activities(ICC(CI)= 0.267(0.144–0.430),F37,185 = 3.191,P < 0.001),indicating that activity could serve as a personality trait.However,activity varied systematically according to whether birds were tested alone or in the presence of companions.Irrespective of the gender of focal birds,individuals were more active in a social context than when alone(P < 0.05).2.Through personality tests,I screened out 19 individuals of bold Java sparrows,including 12 males and 7 females;14 individuals of shy Java sparrows,including 10 males and 4 females;and 45 intermediate individuals,including 15 males and 30 females.The activities of bold males were significantly higher than that of shy males(t = 2.081,df = 20,P = 0.05).Females preferred to choose bold males as mates(t =-4.173,df = 27,P < 0.001).There was no assortative mating phenomenon(P > 0.05),with bold females and shy females showing no significant differences in their preference for homotypic or heterotypic males.3.There were significant differences in sing parameters between bold males and shy males.The minimum frequency of bold male was significantly lower than that of shy male(t =-3.018,df = 13,P = 0.01),while sing duration was significantly longer than that of shy male(t = 5.062,df = 13,P < 0.001).There was a negative correlation between the minimum frequency of male sing and activity(r = 0.665,P < 0.001).In addition,the results of mate choice test showed that when there were two selection indicators,the mate preference of female Java sparrows were changed.Except for the test of the bold male play call-shy male play call group(t =-4.173,df = 27,P < 0.001),the preference of female Java sparrows in mate choice in the other three groups(bold male play sing-shy male play call group,bold male play call-shy male play sing group,and bold male play sing-shy male play sing group)changed from preference of bold males to random selection(P > 0.05).In summary,results from this study demonstrated that social context can facilitate the expression of individual activity in Java sparrow,with individuals being more active in the presence of conspecifics(especially males).These results supported the hypothesis that social isolation would cause behavioral inhibition,probably due to increased perception of risk.In terms of behavioral consistency,females of Java sparrow focused on the quality of male and preferred bold male as mate.With respect to the variation of behavioral level,females did not choose mates according to their own personality,suggesting that there was no assortative mating phenomenon.When played vocalization,the mate preferences of females were changed,which tend to be random.Results from this study highlight the importance of sexual selection in the generation and maintenance of personality evolution,support the "good-genes" model(bold males were more active),found the correlation between male vocalization and personality traits,confirmed that personality trait had a greater effect on female mate choice rather than vocalization. |
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