【作者】 张文；

【导师】 杜波；

【作者基本信息】 兰州大学 ， 生物学·动物学， 2021， 硕士

【摘要】 基于广义适合度概念上发展而来的亲缘理论(Kinship Theory),是动物行为研究过程中被广泛应用的理论框架之一,是解释动物的利他行为、群居行为和亲子冲突等进化的有力工具。然而,该理论的应用当前仍然受到两个问题的困扰,其一是动物是否真正具备亲属识别的能力;其二是动物在识别亲属过程中究竟依赖于哪些线索。对这两个问题的探索是完善亲缘理论的重要步骤。本研究以在青藏高原上繁殖的一个灰喜鹊(Cyanopica cyanus)种群作为研究对象,从两方面对亲缘理论进行了研究。首先,通过在野外进行实验设计的方法探索了灰喜鹊在亲子识别过程中依赖的信号,以及亲子识别机制的转化过程。实验类型包括巢位置变更实验、后代交叉养育实验、加副巢实验和交叉养育后代的重选择实验。然后,通过分析雏鸟不同日龄大脑转录组的差异表达基因,确定是否有与雏鸟表型发育相关的基因可能在灰喜鹊亲子识别过程中发挥着重要作用。本论文的一些主要发现如下所示。1)在巢位置变更实验中,分别在孵卵期和育雏期将目标巢在不同方向上移动不同距离。通过观察成鸟是否返回被操作巢并恢复正常的繁殖行为,来判断亲本是否能够准确进行亲子识别。这个实验发现,灰喜鹊在亲子识别过程中依赖的信号存在一个转化的过程。在孵卵期及育雏早期,亲本主要依赖巢的空间位置作为识别后代的信号;在育雏后期,亲本对巢位置的依赖性降低,转为依赖幼鸟的表型性状(特别是乞食鸣叫)作为亲子识别的主要信号。2)在后代交叉养育实验中,将两两配对的目标巢的后代进行交换培养(一个全部为卵,另外一个全部为雏)。通过监测成鸟在后代的表型信号发生明显改变后是否会采取相对应的抚育行为,来判断灰喜鹊是否能准确识别后代。这个实验发现,处于孵卵期的亲本并不能准确识别后代,而处于育雏后期的亲本能够识别亲生后代,表明灰喜鹊对后代的识别能力是随着雏鸟日龄增加逐渐建立的,这个时间拐点大约在雏鸟11日龄左右。3)在加副巢实验中,在灰喜鹊的原巢旁边填加一个副巢,然后把本巢雏鸟和其它巢的雏鸟分别放于原巢或副巢内。通过观察亲本对不同身份的雏鸟的递食偏好,来判断亲本是否能准确识别亲生后代。这个实验结果进一步证明,灰喜鹊对后代的识别能力随雏鸟日龄增加逐渐建立,其时间拐点在雏鸟11日龄左右。4)在对雏鸟不同日龄的大脑转录组进行差异表达基因的分析之后,本论文发现与动物声信号发育有关的基因——Foxp2的表达量随雏鸟日龄的变化曲线,符合灰喜鹊亲子识别能力的建立过程。这一结果表明,在灰喜鹊的亲子识别机制的转化过程中,雏鸟的鸣声发育及其相关的Foxp2基因可能发挥着关键作用。综上所述,本论文通过对灰喜鹊进行的野外实验研究和不同日龄的雏鸟的转录组比较研究,发现灰喜鹊对后代的识别能力存在一个建立的过程,并且这个过程与后代的表型性状发育有关。后代的乞食鸣声及其相关的Foxp2基因可能在灰喜鹊亲子识别机制的转化时发挥着关键作用。更多还原

【Abstract】 The kinship theory that is founded on the concept of inclusive fitness is one of the most important theories widely used in the researches of animal behaviors.Although it has been considered as a powerful tool to explain the evolution of animal social behaviors,such as the altruism,group-living,and parent-offspring conflicts,et al.,it remains being challenged by two unresolved questions.One is that whether animals really have the ability of distinguishing their relatives from unrelated individuals;and the other is what type of cues has been used by animals in their kin recognition.To address these two questions will be helpful to broaden the usage of kinship theory in the studies of animal behaviors.In this study,I addressed the above two questions by investigating how did parents of the azure-winged magpie(Cyanopica cyanus)recognize their offspring.Two kinds of investigations were carried out in a population that bred on the Tibetan Plateau.First,a series of experiments were designed in the field,including the nest position change experiment,cross-fostering experiment,nest duplication experiment and the experiment of re-selection between cross-fostered nestlings.These experimental investigations aimed to determine the types of cues that were used by parents to find their offspring,as well as how did parental dependence on different cues change with the growth of offspring.Second,comparative analysis of the brain transcriptome of different-aged nestlings were carried out to examine which gene might play an important role in the offspring recognition by the azure-winged magpie.The major findings of this study are listed below.1)In the nest position change experiment,a focus nest was first removed to a new position,by different directions and different distances.Then,parents were monitored to determine whether they returned to the manipulated nest and restore their interrupted behaviors,by which it can be verified whether parents could locate their own offspring.This experiment was carried out at the stages of incubation and nestlings,respectively.Finally,it was uncovered that the cues that parents of the azure-winged magpie used in offspring recognition changed with the growth of nestlings.At incubation,they relied largely on the nest position to locate their offspring;whereas during the nestling period,particularly at the later stage,they began to rely on the phenotypic traits,such as nestling’s begging call,to locate their own offspring.2)In the cross-fostering experiment,the nest content of two paired nests were exchanged,one contained only eggs and the other contained only nestlings.By monitoring whether parents changed their parental behaviors according to the cues of nest content,it can be determined whether they are capable of recognizing their own offspring.The findings in this experiment indicated that parents cannot recognize their own offspring at the stage of incubation;however,they began to gain such an ability during the nestling period.At the nestling age of 11 days or so,parents can almost recognize their own offspring.3)In the nest duplication experiment,a new nest was fixed nearby the position of a focus nest.By placing their own offspring and unrelated young into the focus nest or the duplicated nest,parents were monitored to determine whether they provisioned their offspring in priority.The findings of this experiment further proved that parents of the azure-winged magpie began to gain the ability of offspring at the nestling age of 11 days or so.4)By comparative analyzing the brain transcriptome of different-aged nestlings,this study identified that the Foxp2 gene may play a key role in the offspring recognition of the azure-winged magpies.As the variation of m RNA expression of the FOXP2 gene changed with the nestling age,it is fitting curve accorded with the process of parents gained the ability of offspring recognition.It seems that the acoustic characteristics of nestling begging call are almost fixed near the nestling age of 11 days,which in turn drove parents of the azure-winged magpie to transform their offspring recognition from relying on nest position cue to relying on nestling phenotypic cues.In conclusion,by experimentally investigating how did parents of the azurewinged magpie recognize their own offspring from a manipulated nest or from a mixed brood,this study found that azure-winged magpie parents might have gradually obtained the ability of offspring recognition,which is tightly linked with the development of nestling’s phenotypic traits.Based on the comparative analysis of brain transcriptome of different-aged nestlings,it suggests that nestlings’ begging call,in addition to the Foxp2 gene that has been considered to link with animal acoustic traits,may play a key role in the transformation of offspring recognition mechanisms by the azure-winged magpie.更多还原