鸻鹬类在迁徙停歇地雄性早现的初步研究

【作者】 惠鑫；

【导师】 马志军；

【作者基本信息】 复旦大学 ， 生态学， 2010， 硕士

【摘要】 雄性早现是指雄性相对于雌性更早进入繁殖状态或更早到达繁殖地的现象。在春季迁徙季节,许多类群候鸟的雄性个体相对雌性个体更早到达繁殖地,表现出雄性早现现象。然而,前期研究对象主要集中于在野外通过观察可以直接进行性别鉴定的两性异形物种,两性同形的物种可能表现出不同的情形。在非繁殖期,许多类群的候鸟会呈现年龄结构、雄性比例、体型大小等各方面的差异性分布。差异性分布的到达日期假说与雄性早现的限制性假说密切相关。鸻鹬类是候鸟的重要类群之一。数以千万计的鸻鹬类每年在极地和北温带之间的繁殖地以及热带到南半球之间的非繁殖地来回迁徙。由于鸻鹬类的分布较广,数量繁多,种间形态相似,常被作为生态学、行为学以及进化生物学的重要研究对象。然而,除了反嘴鹬(Recurvirostra avosetta)、弯嘴滨鹬(Calidris ferruginea)和西滨鹬(Calidris mauri)等少数种类外,大部分鸻鹬类的雄性早现未见报道(性别角色颠倒的斑腹矶鹬(Actitis macularia)和瓣蹼鹬(Phalaropodidae)的雌性早现曾有过研究),而且雄性早现对鸻鹬类迁徙停歇生态的影响更是缺乏深入的研究。东亚-澳大利西亚候鸟迁徙路线是世界八大水鸟迁徙路线之一,覆盖了北至西伯利亚东部和阿拉斯加,南至东亚、东南亚以及澳大利亚、新西兰的大片区域,每年超过五百万只鸻鹬类在此路线上迁徙。然而,候鸟的雄性早现现象的大多数数据来自于太平洋-美洲迁徙路线及欧洲-非洲迁徙路线,而东亚-澳大利西亚迁徙路线上候鸟的差异性迁徙的相关研究很少。已有的研究表明,东亚-澳大利西亚候鸟迁徙路线的鸻鹬类鸟类在性别和年龄结构上存在差异性迁徙、分布的情况。本论文选取在迁徙停歇地停歇的的鸻鹬类为研究对象,分两部分展开相关研究：第一部分,采用分子生物学手段,对2008年春季迁徙期间在崇明东滩停歇的大滨鹬(Calidris tenuirostris)、红腹滨鹬(Calidris canutus)、红颈滨鹬(Calidrisruficollis)、黑腹滨鹬(Calidris alpina)、尖尾滨鹬(Calidris acuminata)、跷嘴鹬(Xenuscinereus)和斑尾塍鹬(Limosa lapponica),以及在渤海湾停歇的红腹滨鹬、红颈滨鹬、弯嘴滨鹬和三趾鹬(Calidris alba),共计九种鸻鹬类进行性别的鉴定,分析春季迁徙期间鸻鹬类在迁徙停歇地的雄性比例随时间变化规律。第二部分,采取分子生物学手段,对2007年冬季在福建莆田、湖南洞庭湖、安徽菜子湖、崇明东滩、江苏连云港和渤海湾六个地点越冬的黑腹滨鹬进行性别鉴定,了解越冬期不同性别黑腹滨鹬的差异性分布规律,并探讨鸻鹬类迁徙过程中的雄性早现现象与越冬期纬度分布的性间差异的关系。主要结论如下：1.对在迁徙停歇地捕捉到的鸻鹬类的性别与到达日期的分析表明：在崇明东滩停歇的红腹滨鹬、红颈滨鹬、尖尾滨鹬、跷嘴鹬和斑尾塍鹬出现雄性早现现象,其雄性个体依次分别比雌性个体提前9天、9.5天、10.5天、5.5天和4天到达崇明东滩,其中尖尾滨鹬和跷嘴鹬的雄性比例(雄性／总数)随时间显著下降(P<0.05)；而大滨鹬的雌性个体较雄性个体提前10.5天到达崇明东滩,雄性比例随时间变化显著上升,表现出明显的雌性早现现象(P<0.05)；黑腹滨鹬的两性个体同时到达崇明东滩。在渤海湾停歇的红腹滨鹬、红颈滨鹬、弯嘴滨鹬和三趾鹬均出现雄性早现现象,其雄性个体依次分别比雌性个体提前2.5天、5.5天、4天和3.5天到达渤海湾,其中弯嘴滨鹬和三趾鹬的雄性比例随着时间显著下降(P<0.05)。2.结合斑尾塍鹬、黑腹滨鹬的雄性比例随时间的变化趋势的特征与亚种信息,我们推测,在同一亚种中,斑尾塍鹬呈现雌性早现现象,而黑腹滨鹬呈现雄性早现现象。因此,九种鸻鹬类中,呈现雄性早现的有：红腹滨鹬、红颈滨鹬、尖尾滨鹬、弯嘴滨鹬、黑腹滨鹬、跷嘴鹬和三趾鹬；呈现雌性早现的有：大滨鹬和斑尾塍鹬。3.由于在鸻鹬类中,雌性个体略大于雄性个体是较普遍的现象,且在我们研究的出现雄性早现的红腹滨鹬、红颈滨鹬、斑尾塍鹬与黑腹滨鹬都存在这个现象。因此,敏感性假说可能不适用解释鸻鹬类两性个体的迁徙模式。事实上,我们的研究对象中只有大滨鹬、尖尾滨鹬和斑尾塍鹬的春季两性差异性迁徙规律符合敏感性假说的假定。4.通过对比福建莆田、湖南洞庭湖、安徽菜子湖、崇明东滩、江苏连云港和河北唐山六个地点越冬的黑腹滨鹬的雄性比例、体重、体型大小(喙长、翅长、跗蹠长)、状态指数(体重／翅长、体重／跗踱长)与纬度分布之间的关系,我们发现,雄性黑腹滨鹬个体的体重、体型大小(喙长、翅长、跗踱长)以及状态指标(体重／翅长、体重／跗踱长)值各项指标值均显著小于雌性个体(P<0.05)。随着纬度的升高,雄性比例及喙长均逐渐降低,体重及体重／翅长、体重／跗踱长的状态指标值均逐渐升高,而翅长与跗踱长随纬度变化规律不明显。该结果同时支持了差异性分布的资源分隔假说与体型大小假说,而否定了到达日期假说与捕食风险假说。结合已有知识,我推测资源分隔是造成越冬期黑腹滨鹬差异性的主要原因,但这需要进一步的研究。5.根据黑腹滨鹬冬季差异性分布规律、雄性早现发生情况、婚配体制与繁殖行为等已有知识,我推测限制性假说作为黑腹滨鹬出现雄性早现现象的解释。由于限制性假说同样适用于弯嘴滨鹬及斑尾塍鹬,因此,我推测其可能在鸻鹬类的春季两性差异性迁徙中具有普适性。更多还原

【Abstract】 Protandry refers the earlier arrival to breeding sites or reproductive stages of male animals relative to females on average. Many migrants express protandrous arrival timing during spring migration. Studies had been mainly concerned on sexual dimorphism species, however, sexual homomorphous species may show different patterns. Similarly, many avian migrants show differential distributions during non-breeding season, mainly on sexs, ages and body sizes.Waders are one of the most important groups of migrants. Millions of waders migrate from breeding areas in polar region and temperate zones to the tropical and Southern Hemisphere. Waders are the important groups for ecological, behavioural and evolutionary researches because of their widely distribution, massive number and similar morphologic characteristics. However, protandrous arrival timings of waders were poorly studied except Pied Avocet(Recurvirostra avosetta), Curlew Sandpiper (Calidris ferruginea), Western Sandpiper(Calidris mauri) and some sexual reversal species, e.g. Phalarope (Phalaropodidae) and Spotted Sandpiper (Actitis macularia).The East Asian-Australasian Shorebird Flyway, which links the breeding grounds in eastern Siberia with the non-breeding grounds in Australia and New Zealand, is used by more than five million migratory shorebirds annually. However, most of the former studies have been assembled in the Pacific-American Flyway and African-European Flyway, little is known about the occurrence of differential migration in the East Asian-Australasian Flyway. Former studies showed that differential migration happens in this flyway.In this thesis, I will first introduce six hypotheses to explain migrants’ protandrous arriving, including rank advantage, susceptibility, constraint, mate opportunity, waiting cost and mate choice hypothesis, five hypotheses to explain differential migration of males and females, including dominance, body size, arrival time, predation risk and resource partitioning hypothesis, then we try to test the hypotheses of waders’arrival timing and wintering segregation in two parts as below:First, I collected feather samples and data of waders during 2008 spring migration in Chongming Dongtan and Hebei Tangshan, used genetic methods to sex the birds, including Great Knot(Calidris tenuirostris), Red Knot(Calidris canutus), Red-necked Stint(Calidris ruficollis), Dunlin(Calidris alpina), Sharp-tailed Sandpiper(Calidris acuminata), Terek Sandpiper (Xenus cinereus), Bar-tailed Godwit (Limosa lapponica) which stopped at Chongming Dongtan, and Red Knot, Red-necked Stint, Curlew Sandpiper (Calidris ferruginea), Sanderling (Calidris alba) which stopped at Hebei Tangshan. Then compared sex ratios with capture dates to find differential spring migration patterns between sexes.Second, in order to test constraint hypothesis in protandrous dunlin, I collected feather samples and data of dunlins wintering in Fujian Putian, Hunan Dongting Lake, Anhui Caizi Lake, Chongming Dongtan, Jiangsu Lianyungang and Hebei Tangshan during Dec.2007 to Mar.2008, used genetic methods to sex the samples. Then, I studied the differential distribution patterns of wintering dunlin, and discussed the relationship between wintering sexual segregation and protandrous arrival timing.The main conclusions were as below:1. Red Knot, Red-necked Stint, Sharp-tailed Sandpiper, Terek Sandpiper and Bar-tailed Godwit which stop at Chongming Dongtan show protandrous arrival timing, males arrive at Chongming Dongtan 9 days,9.5 days,10.5 days,5.5 days and 4 days earlier than females, male ratio decline significantly in Sharp-tailed Sandpiper and Terek Sandpiper. Protandry occure in Red Knot, Red-necked Stint, Curlew Sandpiper, Sanderling which stop at Hebei Tangshan, males arrive at Hebei Tangshan 2.5 days,5.5 days, 4 days,3.5 days earlier than females, male ratio decline significantly in Curlew Sandpiper and Sanderling.2. According to the "male ratio-date" analysis, combine with subspecies of Dunlin and Bar-tailed Godwit in China, we infer that Dunlin show protandrous arrival timing, and Bar-tailed Godwit show protogynous arrival timing within one subspecies. Thus, I conclude that protandry occurs in Red Knot, Red-necked Stint, Dunlin, Sharp-tailed Sandpiper, Terek Sandpiper, Curlew Sandpiper and Sanderling, whereas protogyny occurs in Great Knot and Bar-tailed Godwit.3. Sexual size dimorphism is not so obvious in waders than in passerines, but females are a bit larger than males in most species. And this pattern happens in Red Knot, Red-necked Stint, Dunlin, and Bar-tailed Godwit, which show prominent protandrous arrival timing. Thus susceptibility hypothesis cannot be the unanimous explanations of waders’sexual differential migration, only protandrous Sharp-tailed Sandpiper and protogynous Great Knot fit its hypothesis. 4. According to data of dunlins wintering in Fujian Putian, Hunan Dongting Lake, Anhui Caizi Lake, Chongming Dongtan, Jiangsu Lianyungang and Hebei Tangshan, we studied the relationship between latitude and wintering dunlins’sex ratio, body mass, bill length, body size including wing and tarsus length. Although not significant, we found sex ratio decline, bill length decline and body mass rise along with the rise of latitude, whereas wing length and tarsus length do not show apparent linear trend. Our results supported resource partitioning and body size hypothesis, and denied arrival timing and predation risk hypothesis. We infer resource partitioning hypothesis as the main explanation of dunlins’wintering segregation, which need further research.5. With dunlins wintering pattern, mating system, protandrous arrival timing, and other relative knowledge, I infer constraint hypothesis as the explanation of protandrou arrival timing of dunlin. As it is also suitable for Curlew Sandpiper and Bar-tailed Godwit, I infer constraint hypothesis may explain most waders’ protandrous/protogynous arrival timing.更多还原