Microsatellite loci for great white herons and great blue herons (Aves,Ardeidae, Ardea herodias)

We used an enrichment technique to isolate 60 microsatellite loci in Ardea herodias. We developed primers for 17 loci, screened for variation in A. herodias and attempted to amplify these loci in three closely related species (A. alba, A. cinerea and A. cocoi). Fifteen loci were polymorphic in A. herodias. Observed heterozygosities ranged from 0.10 to 0.81. Two loci appeared to be monomorphic in A. herodias, but exhibited variation in product size among species within the genus. Our ability to amplify polymorphic products in closely related species suggests that these markers may be useful in other herons.     

The complete mitochondrial genomes of sixteen ardeid birds revealing the evolutionary process of the gene rearrangements

Background

The animal mitochondrial genome is generally considered to be under selection for both compactness and gene order conservation. As more mitochondrial genomes are sequenced, mitochondrial duplications and gene rearrangements have been frequently identified among diverse animal groups. Although several mechanisms of gene rearrangement have been proposed thus far, more observational evidence from major taxa is needed to validate specific mechanisms. In the current study, the complete mitochondrial DNA of sixteen bird species from the family Ardeidae was sequenced and the evolution of mitochondrial gene rearrangements was investigated. The mitochondrial genomes were then used to review the phylogenies of these ardeid birds.

Results

The complete mitochondrial genome sequences of the sixteen ardeid birds exhibited four distinct mitochondrial gene orders in which two of them, named as “duplicate tRNA^Glu–CR” and “duplicate tRNA^Thr–tRNA^Pro and CR”, were newly discovered. These gene rearrangements arose from an evolutionary process consistent with the tandem duplication - random loss model (TDRL). Additionally, duplications in these gene orders were near identical in nucleotide sequences within each individual, suggesting that they evolved in concert. Phylogenetic analyses of the sixteen ardeid species supported the idea that Ardea ibis, Ardea modesta and Ardea intermedia should be classified as genus Ardea, and Ixobrychus flavicollis as genus Ixobrychus, and indicated that within the subfamily Ardeinae, Nycticorax nycticorax is closely related to genus Egretta and that Ardeola bacchus and Butorides striatus are closely related to the genus Ardea.

Conclusions

The duplicate tRNAThr–CR gene order is found in most ardeid lineages, suggesting this gene order is the ancestral pattern within these birds and persisted in most lineages via concerted evolution. In two independent lineages, when the concerted evolution stopped in some subsections due to the accumulation of numerous substitutions and deletions, the duplicate tRNAThr–CR gene order was transformed into three other gene orders. The phylogenetic trees produced from concatenated rRNA and protein coding genes have high support values in most nodes, indicating that the mitochondrial genome sequences are promising markers for resolving the phylogenetic issues of ardeid birds when more taxa are added.

Electronic supplementary material

The online version of this article (doi:10.1186/1471-2164-15-573) contains supplementary material, which is available to authorized users.     

Fossil birds of the Kibish Formation

The Kibish Formation has yielded a small collection of bird fossils, which are identified here as belonging to five species in four different families: Pelecanidae (pelicans), Anhingidae (darters), Ardeidae (herons) and Phasianidae (gamefowl). Two species of pelicans are identified: Pelecanus cf. P. onocrotalus, and P. aff. P. rufescens. The darter is referrable to Anhinga melanogaster. The heron is identifiable as Ardea sp., and the gamefowl as Numidinae indet. (guineafowl). Pelecanus cf. P. onocrotalus is represented by, among other remains, a well-preserved partial skull. Four of the birds are thus referrable to extant taxa that provide some paleoenvironmental clues for Member I of the Kibish Formation. The two species of pelican, the darter, and the heron indicate the presence of local freshwater bodies, a lake or a slow river, supporting resources of fish. The guineafowl is poorly informative ecologically, but probably excludes the notion that the local terrestrial landscape was treeless.     

Field experiments on the effect of ticks on breeding success and chick health of cattle egrets

Abstract Two experiments compared broods that were naturally tick-infested with an equal number that were rendered tick-free by application of an acaricide to their nests and of barriers against further infestation. In the first experiment conducted in 1991–92 nestlings in tick-infested broods had up to 159 larval ticks at once and a mean infestation of 23.6 larval ticks per chick per day. The chick's mean tick load was inversely correlated with its longevity. Chicks that survived to at least 18 days post-hatching had significantly lower larval tick loads than those that died by 18 days, excluding the third-hatched chick in each brood whose survival rate was low irrespective of tick-infestation. At 7 days post-hatching, tick-infested chicks had a lower haematocrit and higher polychromasia than tick-free chicks. I infer that blood loss anaemia caused the deaths of tick-infested chicks in their first week. None died in their second week and the demise of those in their third week may have been due to the paralysis manifested prior to their death. I conclude that heavy tick infestation of their chicks reduced the breeding success of the parent egrets below that of the egrets whose chicks were kept free of ticks. In the second experiment in the 1992–93 season the mean level of tick infestation was much lower (5.1 per chick) and these chicks survived equally with tick-free chicks through fledging.     

Nonheterochronic developmental changes underlie morphological heterochrony in the evolution of the Ardeidae

Evolutionary changes in developmental timing and rates (heterochrony) are a source of morphological variation. Here we explore a central issue in heterochronic analysis: are the alterations in developmental timing and rates the only factor underlying morphological heterochrony? Tarsometatarsal growth through endochondral ossification in Ardeidae evolution has been taken as a case study. Evolutionary changes in bone growth rate (morphological heterochrony) might be either (a) the result of alterations in the mitotic frequency of epiphyseal chondrocytes (process‐heterochrony hypothesis), or (b) the outcome of alterations in the number of proliferating cells or in the size of hypertrophic chondrocytes (structural hypothesis). No correlation was found between tarsometatarsal growth rates and the frequency of cell division. However, bone growth rates were significantly correlated with the number of proliferating cells. These results support the structural hypothesis: morphological acceleration and deceleration are the outcome of evolutionary changes in one structural variable, the number of proliferating cells.     

福建漳江口红树林鹭科鸟类巢址选择

2011年4～5月、2012年4～5月,采用样线调查和样方调查相结合的方法对福建漳江口红树林国家级自然保护区内鹭科鸟类巢址与影响其选择的因子进行研究.t-检验结果显示,红树基径、盖度、距地面平均高度、植株密度及秋茄比5个参数在巢区样方(n=23)与对照样方(n=37)之间存在显著差异(P＜0.05),桐花比、距道路距离、距村庄距离与距池塘距离4个参数存在极其显著差异(P＜0.01).主成分分析表明,植被结构和干扰条件是影响鹭科鸟类巢址选择的主要因子,植被结构不仅能够影响鹭科鸟类群落结构,还受到鹭科鸟类集群繁殖影响.     

REVIEWS

Avian remains from the Early Miocene (～17 Ma) Moghra Formation of Egypt include new records of ‘waterbirds’ (storks, herons, pelicans and allies) and a ratite. Only a single avian fossil has been previously reported from Wadi Moghra and, thus, additional knowledge of the avifauna complements previously documented faunal and floral assemblages and provides a more complete picture of the Early Miocene ecosystem of that locality. The presence of ciconiiforms and pelecaniforms is consistent with the relatively abundant records of ‘waterbirds’ from other African freshwater fossil localities. Moreover, avian fossils from Wadi Moghra provide new insight into the avifaunal composition of the Early Miocene in Africa, a period that is relatively underrepresented in the avian fossil record of that continent.     

从12S rRNA基因序列推测鹭科13种鸟类的系统发生关系

对鹭科12个种的线粒体12S rRNA基因全长约975bp的序列进行了测定,并从GenBank获得黄顶夜鹭12S rRNA基因全序列。比对后的序列长993bp,含363变异位点,288个多态位点,187个简约信息位点。使用邻接法和最大简约法重建的分子系统树将13种鹭聚为2支：第一支包括白鹭、中白鹭、大白鹭、池鹭、牛背鹭、苍鹭、草鹭、夜鹭、黄顶夜鹭,第二支由黄苇渴Gan、黑苇Gan、栗苇Gan、大麻Gan组成。结果提示将鹭科分为鹭亚科和Gan亚科的传统观点是合理的,不支持Payne将鹭科分为日鹭亚科(Ardeinae)、夜鹭亚科(Nycticracinae)、Gan亚科(Botaurinae)和虎鹭亚科(Tigrisomatinae)的观点。进一步的分析表明：白鹭在系统演化中要早于大白鹭和中白鹭分支出来,大白鹭和中白鹭与苍鹭、草鹭和牛背鹭间的亲缘关系较近,而与白鹭较远,支持Sibley(1990)将大白鹭和中白鹭作为独立的大白鹭属(Casmerodius)和中白鹭属(Mesophoyx)的建议;黑Gan、栗苇Gan与黄苇Gan在系统发生中构成一单系群,提示将黑Gan置于苇Gan属(Ixobrychus)是合适的[动物学报49(2)：205—210,2003]。     

Long-term trends of heron and egret populations in Italy, and the effects of climate, human-induced mortality, and habitat on population dynamics

Factors affecting bird population dynamics include climate, harvesting by humans, and habitat changes. Here, we describe the long-term (1972–2006) population trends of seven heron species in NW Italy, an area holding important European breeding populations of these species. Grey (Ardea cinerea), purple (Ardea purpurea), and squacco (Ardeola ralloides) herons, and little egrets (Egretta garzetta) exhibited a strong logistic increase, leveling off around year 2000 at 3–23 times their initial level. Black-crowned night herons (Nycticorax nycticorax) began by increasing like the former species but then dropped to initial levels. Such trends were found to be influenced by several candidate ecological factors, as assessed by ARIMA models. Specifically, grey herons increased following a decrease in human-induced mortality, as quantified by an index of hunting pressure, and an increase in winter temperatures. Little egrets increased mainly with the increase of the extent of ricefields, whereas squacco herons increased with increasing rainfall in the African wintering range. Black-crowned night herons were also positively affected by increasing African rainfall, but only during 1972–1988, whereas in later years competition with other herons could have affected the species’ decline. The improved protection of colony sites by special reserves was unlikely to be the primary trigger of the observed increase, although obviously important for the long-term population persistence. In conclusion, our study shows that heron populations of southern Europe are sensitive to environmental and climatic changes, as well as to temporal variation in human disturbance and changes in foraging habitats, though the importance of the different factors differs among species.     

鹭科鸟类群落的空间生态位和种间关系

本文应用空间生态位理论,分析了浙江太公山常绿落叶针阔混交林鹭类繁殖季节的群落结构。鹭类群落由池鹭Ａｒｄｅｏｌａｂａｃｈｕｓ、白鹭Ｅｇｒｅｔａｇａｒｚｅｔａ、夜鹭Ｎｙｃｔｉｃｏｒａｘｎｙｃｔｉｃｏｒａｘ、牛背鹭Ｂｕｂｕｌｃｓｉｂｉｓ组成。根据鹭类的水平分布、垂直分布、栖位分布的生态位宽度值,采用Ｓｃｈｏｅｎｅｒ（１９６８）生态位重叠、Ｃｏｄｙ（１９７４）“总和α”的方法制作了群落矩阵表和树杈状图。讨论了鹭类群落对空间的利用及种间的相互作用。