Spatial distribution and habitat of the Anavilhanas Archipelago bird community in the Brazilian Amazon

This study is the first to present a quantitative survey of bird species occurring in the archipelago of Anavilhanas, located in the Rio Negro in the Brazilian Amazon and is part of the Anavilhanas Ecological Station. We asked whether bird community composition is similar among the islands, and between islands and areas dominated by the surrounding upland terra firme forest on the left (east) margin of the Rio Negro. The surveys were conducted in November and December of 1988, using two complementary methods with mist nets and boat transects. A total of 232 bird species was found for Anavilhanas including a survey done in 1998. The families Tyrannidae and Thamnophilidae showed the highest number of species (16.4% and 9.0% of the total respectively). Some species not well known or having limited distributions are relatively frequently encountered in the archipelago, such as Spizastur melanoleucus, Mitu tomentosa, Phaethornis rupurumii, Xiphorhynchus kienerii, Thamnophilus nigrocinereus, Myrmotherula klagesi, Myrmoborus lugubris, Pipra filicauda, and Cephalopterus ornatus. Hybrid Multidimensional Scaling (HMDS) ordination analysis indicated that the bird community composition is similar among islands. However, the bird community composition on the islands was significantly different from that in sites of terra firme forest at Rio Negro margins. Anavilhanas is a unique ecological system in the Amazon and has it own avifauna.     

Phylogeography of the Ryukyu robin (Erithacus komadori): population subdivision in land-bridge islands in relation to the shift in migratory habit

We analysed the mitochondrial control region sequences of 150 Ryukyu robins (Erithacus komadori) from five migratory and three sedentary populations. E. komadori is endemic to the subtropical Asian islands, is well differentiated among populations in morphology and migratory behaviour within its narrow habitat range, and is ideal for examining the effects of altered migratory habits on population differentiation. Maximum-likelihood analysis among the haplotypes resulted in the generation of a single tree in which two phylogenetic clades corresponding to the two subspecies were evident. Within the northern lineage, three distinctive subgroups of populations (one migratory and two sedentary groups) were observed by population genetic analysis. The migration-related wing morphology and molecular data were then compared among groups. The wing shape of the northern lineage was significantly more pointed than that of the southern sedentary lineage, and they were exclusively discriminated from each other. The difference was not so apparent between the sedentary and migratory groups within the northern lineage, suggesting that the present northern subspecies is primarily a migratory lineage. The different migratory behaviours of the robin played an apparent role in maintaining the genetic structure at two different levels--one between the southern and northern lineages and the other between the sedentary and migratory groups within the northern lineage. While gene flow had long been maintained among the islands occupied by migratory individuals, migrants have been unable to contribute to the gene pool of the sedentary populations despite passing through the breeding range of such populations twice each year.     

Phylogeography and population genetics of pine butterflies: Sky islands increase genetic divergence

The sky islands of southeastern Arizona (AZ) mark a major transition zone between tropical and temperate biota and are considered a neglected biodiversity hotspot. Dispersal ability and host plant specificity are thought to impact the history and diversity of insect populations across the sky islands. We aimed to investigate the population structure and phylogeography of two pine‐feeding pierid butterflies, the pine white (Neophasia menapia) and the Mexican pine white (Neophasia terlooii), restricted to these “islands” at this transition zone. Given their dependence on pines as the larval hosts, we hypothesized that habitat connectivity affects population structure and is at least in part responsible for their allopatry. We sampled DNA from freshly collected butterflies from 17 sites in the sky islands and adjacent high‐elevation habitats and sequenced these samples using ddRADSeq. Up to 15,399 SNPs were discovered and analyzed in population genetic and phylogenetic contexts with Stacks and pyRAD pipelines. Low genetic differentiation in N. menapia suggests that it is panmictic. Conversely, there is strong evidence for population structure within N. terlooii. Each sky island likely contains a population of N. terlooii, and clustering is hierarchical, with populations on proximal mountains being more related to each other. The N. menapia habitat, which is largely contiguous, facilitates panmixia, while the N. terlooii habitat, restricted to the higher elevations on each sky island, creates distinct population structure. Phylogenetic results corroborate those from population genetic analyses. The historical climate‐driven fluxes in forest habitat connectivity have implications for understanding the biodiversity of fragmented habitats.     

Phylogeography and population genetics of the endangered Amazonian manatee, Trichechus inunguis Natterer, 1883 (Mammalia, Sirenia)

We used mitochondrial DNA control region sequences to examine phylogeography and population differentiation of the endangered Amazonian manatee Trichechus inunguis. We observe lack of molecular differentiation among localities and we find weak association between geographical and genetic distances. However, nested clade analysis supports restricted gene flow and/or dispersal with some long-distance dispersal. Although this species has a history of extensive hunting, genetic diversity and effective population sizes are relatively high when compared to the West Indian manatee Trichechus manatus. Patterns of mtDNA haplotype diversity in T. inunguis suggest a genetic disequilibrium most likely explained by demographic expansion resulting from secession of hunting and enforcement of conservation and protective measures. Phylogenetic analysis of T. manatus and T. inunguis haplotypes suggests that T. inunguis is nested within T. manatus, effectively making T. manatus a paraphyletic entity. Paraphyly of T. manatus and recent divergence times of T. inunguis and the three main T. manatus lineages suggest a possible need for a taxonomic re-evaluation of the western Atlantic Trichechus.     

格庶尺蛾种群消长规律及综合治理研究

采取室内饲养和林间调查相结合的方法,研究了格庶尺蛾〔Ｓｅｍｉｏｔｈｉｓａ ｈｅｂｅｓａｔａ （Ｗａｌｋｅｒ）〕的生活史,种群消长与环境因素的关系和综合防治试验。提出了以营林措施为基础,应用白僵菌、苏云金杆菌生物防治为主,辅以化学、物理、人工防治和保护利种天敌的综合治理策略。     

Biology of parasite populations: population dynamics of bothriocephalids (Cestoda-Pseudophyllidea) in teleostean fish

Relationships between sympatric populations of four species of Cestoda belonging to the genus Bothriocephalus ( B. barbarus. B. gregarius, B. funiculus and B. scorpii ) and populations of their respective hosts Scophthalmus rhombus, Pserra maxima, Ciliata mustela and Myoxocephalus scorpius were investigated. The parasites were overdispersed within their host populations. The mean intensities of B. burbarus were 1.59 ( s.d. =0.83) in the Mediterranean (Gulf of Lions) and 1.25 ( s.d. =0.53) in the Atlantic (coasts of Brittany). The mean intensities of B. gregarius were 62.3 ( s.d. =49.7) in the Mediterranean and 14.06 ( s.d. =18.48) in the Atlantic, compared to 1.78 ( s.d. =0.3) for B. funiculus and 21.6 ( s.d. =17.3) for B. scorpii .
The distribution of prevalence of B. gregarius corresponded to a lognormal distribution while those of B. barbatus and B. fwticulus corresponded to negative binomials. No differences in infection could be related to host sex. The parasitization of B. gregariusdepended on host size. In brill, infection by E. barbatus was independent of host size and remained stable after the fish reached 180mm in length. Parasitization of turbot by E. gregarius was lower in young fish (≤110–150 mm) and increased with the host size. Compared to the Atlantic populations of B. gregarius and B. barbatus, the Mediterranean populations were more frequently and intensively infected. The differences in the population dynamics of B. gregarius and B. barbarus would appear to depend on whether or not the life cycle involves a paratenic host.     

中华花翅跳小蜂生物学特性和种群动态的研究

中华花翅跳小蜂Microterys sinicus Jiang是白蜡虫成虫产卵期的主要天敌。该蜂成虫喜在自然光下活动,取食和交配都在寄主树上进行。中华花翅跳小蜂每雌平均怀卵量34.39粒,产卵前期2～3天。产卵量、产卵率和产卵天数与温度密切相关,27℃时产卵量和产卵率最高。30℃时产卵天数最少。21～27℃卵孵化率达80%以上。幼虫共5龄。每头跳小蜂幼虫平均取食蜡虫卵数分别为：1龄14.6粒,2龄29.8粒,3龄69.4粒,4龄126.9粒。5龄幼虫不取食。全代发育起点温度和有效积温分别为11.84℃和574.32日·度。补充营养能显著延长成虫寿命和产卵天数,提高雌虫产卵量。中华花翅跳小蜂成虫在田间有两个高峰期,分别发生在4月上中旬和5月中下旬。每粒虫囊内跳小蜂幼虫数与白蜡虫健卵百分率呈负指数关系,拟合方程为：Y=96.0829Exp(-0.1872x)。     

Twenty years of understorey bird extinctions from Amazonian rain forest fragments: consistent trends and landscape-mediated dynamics

Aim We analysed presence/absence data for understorey bird species in rain forest fragments sampled from 1979 through 2001. Here we consider extinctions between 1992, when most fragments had been isolated for at least 8 years, and 2001. Our objectives were to determine whether high extinction rates documented soon after isolation continued through up to 20 years after isolation, and to examine fragment size and landscape effects on extinction. Location Biological Dynamics of Forest Fragments Project, near Manaus, Brazil. Methods Through 1992, birds were surveyed with standardized mist net sampling in ten 1‐ to 100‐ha fragments. We repeated the mist net protocol in 2000–01. We also added remote taping of the dawn chorus and tape playback surveys for species captured in 1991–92 but not in 2000–01. Results Between 1992 and 2001, 37 species went extinct in at least one fragment. As expected, extinction rate decreased with increasing fragment size. Over 30% of species went extinct in 1‐ha fragments, compared to about 5% in 100‐ha fragments. Extinction followed a predictable pattern: most species lost from 100‐ha fragments between 1992 and 2001 had already gone extinct in smaller fragments before 1992. Despite extinctions, fragments gained species between 1992 and 2001, apparently due to species moving through the developing second growth matrix. Fragments surrounded by old second growth had lower extinction rates than predicted based on fragment size alone. Main conclusions Sequential extinctions occurred for at least 20 years. Some additional species previously lost from smaller fragments may continue to go extinct in 100‐ha fragments. At the same time, species assemblages in 1‐ and 10‐ha fragments mostly reflect second‐growth dynamics by 20 years after isolation. High species loss predicted from the first few years after isolation has not occurred, almost certainly because of recolonization.     

Temporal and spatial dynamics of amphioxus population (Branchiostoma belcheri tsingtaneuse) and its influential factors in Luan River Estuary,China

Population distribution of amphioxus (Branchiostoma belcheri tsingtauense) was investigated in the Luan River Estuary from 1999 to 2011, to describe its trends and discover the factors that influence its decline. Amphioxus are distributed on the seabed at 5–10 m depth, between the Xinkai Estuary and the Dapu River Estuary, where the primary sand components of the sediment are medium and fine, with particle size ranging from 0.001 to 1 mm. In recent years, the population density and biomass of amphioxus have sharply decreased. Changes in sediment granularity composition may significantly influence amphioxus distribution. Our data showed that the highest density region of amphioxus occurred where >90% of the sediment particles were between 0.063 and 0.5 mm in size. A reduction in sediment discharge from Luan River and the expansion of raft‐breeding mariculture may be causing the decline in amphioxus through habitat destruction.     

Life history and population dynamics of southern Alaska resident killer whales (Orcinus orca)

Resident (fish eating) killer whales (Orcinus orca) in the North Pacific have been the subject of long‐term studies in several geographical regions. The current study examines population parameters in the southern Alaska resident population from 1984 to 2010 and develops a population model. The southern Alaska resident population ranges from southeastern Alaska through the Kodiak archipelago and contains over 700 individuals. We follow the life histories of 343 identifiable whales in 10 pods from two clans born before and during the study. Population parameters were comparable to those of the British Columbia northern resident population during the 1970s and 1980s, except that age of maturity was approximately one year earlier. The average annual rate of increase was slightly higher in Alaska (3.5%) than for the British Columbia northern residents (2.9%) and probably represents a population at r‐max (maximum rate of growth). Reasons for the high growth rate in Alaska could be a recovery following past anthropogenic mortalities, or more likely, a response to increasing salmon returns in recent decades, resulting in an increase in carrying capacity. The slow maturation and low rate of reproductive response makes these whales slow to recover from natural or anthropogenic catastrophes.     

海南儋州地区橘小实蝇成虫数量动态

【背景】橘小实蝇是热带、亚热带水果的重要害虫,在海南发生严重。【方法】利用橘小实蝇性诱剂进行田间诱捕,以诱到的雄成虫为指标,通过定期调查,获得了海南儋州地区4种样地橘小实蝇成虫的种群动态,并进一步通过相关分析,研究了芒果园橘小实蝇种群动态与温度和降雨量的相关性。【结果】儋州地区橘小实蝇种群周年发生,冬季种群数量较低,夏季种群数量较高。橘小实蝇种群高峰期发生于6月,其中芒果园达327.6头,蔬菜地为182.8头,办公区为150.0头,植物园为209.6头。在芒果园中,随着温度的升高,橘小实蝇的种群数量呈指数增长,其相关系数R=0.799;而与降雨量的相关系数较低,为0.367。【结论与意义】本研究可为儋州地区制定橘小实蝇综合防治策略提供理论依据。     

Contrasting patterns of genetic structure in Caryocar (Caryocaraceae) congeners from flooded and upland Amazonian forests

In the present study, we compare the genetic structure of a flooded forest tree Caryocar microcarpum and a terra firme forest tree Caryocar villosum in the lower Rio Negro region and test the hypothesis that the Rio Negro, the largest tributary on the left bank of the Amazon River, has been acting as a geographical barrier to gene flow between populations from the left and right banks. Seventeen adult individuals on the left bank and 27 on the right bank of Rio Negro were sampled for C. microcarpum, whereas 27 on the left and 20 on the right bank were sampled for C. villosum. Two chloroplast DNA regions were sequenced: the intron of trnL gene and the intergenic region between psbA and trnH genes; and all individuals were genotyped using ten microsatellite loci. The trnL intron and psbA‐trnH intergenic spacer generated fragments of 459 bp and 424 bp, respectively. For C. microcarpum, six haplotypes were identified for trnL and seven for psbA‐trnH. By contrast, only one haplotype was found for C. villosum for both sequences. The results obtained showed that the Rio Negro has not been a barrier to gene flow by pollen and seeds for either species. No genetic differentiation and a high migration rate between populations from the left and right banks of the Rio Negro were detected for the chloroplast sequences and nuclear microsatellites, for both C. villosum and C. microcarpum. Although the two analysed sequences showed a sharp topology difference, both indicated that multiple lineages may have contributed to the origin of C. microcarpum populations in the Rio Negro basin. Nevertheless, for C. villosum, from terra firme, the results obtained may provide evidence of a recent expansion of one maternal lineage from an ancient relic population surviving in one of the few moist forest refuges of the Guiana Shield during extended droughts of the glacial periods. We hypothesize that the contrasting environments colonized by this congener pair may have played an important role in shaping the genetic structure of both species. © 2009 The Linnean Society of London, Biological Journal of the Linnean Society, 2009, 98 , 278–290.     

Dependent population dynamics between chironomids (nonbiting midges) and Vibrio cholerae

Vibrio cholerae, the causative agent of cholera, is a natural inhabitant of the aquatic ecosystem. Chironomid (nonbiting midges) egg masses were recently found to harbour V. cholerae non-O1 and non-O139, providing a natural reservoir for the cholera bacterium. Chironomid populations and the presence of V. cholerae in chironomid egg masses were monitored. All V. cholerae isolates were able to degrade chironomid egg masses. The following virulence associated genes were detected in the bacterial isolates: hapA (100%), toxR (100%), hlyA (72%) and ompU (28%). The chironomid populations and the V. cholerae in their egg masses followed the phenological succession and interaction of host-pathogen population dynamics. A peak in the chironomid population was followed by a peak in the V. cholerae population. If such a connection is further substantiated for the pathogenic serogroups of V. cholerae in endemic areas of the disease, it may lead to a better understanding of the role of chironomids as a host for the cholera bacterium.     

多异瓢虫种群动态及捕食功能的研究

采用田间调查和室内实验。研究了多异瓢虫的种群消长规律和捕食功能，表明该虫在棉田发生量大，发生时间长、幼虫、成虫对棉蚜的功能反应为Ｈｏｌｌｉｎｇ－Ⅱ型，并随着幼虫的生长其捕食量逐渐增大。     

Postharvesting population dynamics of the South American sea lion (Otaria byronia) in the southwestern Atlantic

Many pinniped populations precipitously declined during the 19th and 20th centuries due to overharvesting. In Uruguay, the South American sea lion (SASL) was harvested until 1986. Birth rates in two nearby breeding colonies have had opposite trends for at least 20 yr. We assessed different mechanisms that could explain opposite trends in birth rates in the two SASL colonies. We compared feeding habits (δ¹⁵N and δ¹³C) of breeding females, birth mass, individual growth rate and early survival of pups and the social structure between colonies. Breeding females from the two colonies did not differ in their feeding habits. However, male and female pups grew faster but had a lower survival in the second month in the smallest colony. We found differences in the social structures, with a higher proportion of males in the smallest colony. The latter is important because peripheral SASL males may abduct and kill pups, which may explain the lower survival of pups in smaller colonies. We believe that the cumulative effects of population extractions have lowered the local SASL population size and disrupted its social structure to the point where Allee‐like effects could become important and hamper the recovery of the Uruguayan SASL population.     

Phylogeography of the chestnut‐tailed antbird (Myrmeciza hemimelaena) clarifies the role of rivers in Amazonian biogeography

Aim We examined patterns of spatial and temporal diversification of the Amazonian endemic chestnut‐tailed antbird, Mymeciza hemimelaena (Thamnophilidae), to evaluate the diversification of a widespread avian taxon across rivers that potentially represent major natural barriers. Location Lowland Amazonia. Methods Sequences of the mitochondrial ND2 and cytochrome b genes were investigated from 65 individuals distributed throughout the entire range of M. hemimelaena, and including the two currently valid subspecies M. h. hemimelaena and M. h. pallens. Based on a combination of phylogeographic tools, molecular dating, and population genetic methods, we reconstructed a spatio‐temporal scenario of diversification of M. hemimelaena in the Amazon. Results The data revealed three genetically divergent and monophyletic groups in M. hemimelaena, which can also be distinguished by a combination of morphological and vocal characters. Two of these clades correspond to the previously described taxa M. h. hemimelaena and M. h. pallens, which are separated by the upper Madeira River, a main Amazonian tributary. The third clade is distributed between the middle reaches of the Madeira River and the much smaller tributaries Jiparaná and Aripuanã, and, although currently treated as M. h. pallens, clearly constitutes an independent evolutionary lineage probably deserving separate species status. Molecular clock and population genetic analyses indicate that diversification in this group occurred throughout the Pleistocene, with demographic fluctuations assumed for M. h. hemimelaena and M. h. pallens. Main conclusions The findings implicate rivers as barriers driving diversification in the M. hemimelaena complex. Levels of mitochondrial DNA divergence and associated morphological and vocal traits support its division into at least three separate species with comparatively small ranges. The existence of a previously unrecognized lineage in the M. hemimelaena complex, and the high degree of population structuring found in M. h. hemimelaena underscore the pervasiveness of cryptic endemism throughout Amazonia and the importance of DNA‐based taxonomic and phylogeographic studies in providing the accurate estimates of diversity that are essential for conservation planning.     

Phylogeography of Ophiorrhiza japonica (Rubiaceae) in continental islands,the Ryukyu Archipelago,Japan

Aim Phylogeographical patterns in the Ryukyu Archipelago have been explained primarily by landbridge formation and the opening of two straits in the Pliocene, namely the Tokara and Kerama gaps. These old straits have been considered to be the barriers most likely to determine genetic boundaries. To test this, we conducted a molecular analysis of the herb Ophiorrhiza japonica. We discuss the causes of and processes involved in its phylogeographical structure and explore aspects of island separation other than the duration of the straits to explain genetic boundaries at the gaps. Location Ryukyu Archipelago, Japan. Methods Plants were collected from 40 localities in the archipelago and vicinity. Non‐coding regions of chloroplast DNA were sequenced. The genealogical relationships among haplotypes were estimated using a statistical parsimony network. To examine the phylogeographical structure, we compared two parameters of population differentiation, namely G_ST and N_ST, and conducted correlation analysis of genetic and geographical distances. Genetic boundaries were identified using Monmonier’s maximum difference algorithm. To test vicariance–dispersal hypotheses, that is, vicariance after migration via the Pliocene landbridge or over‐sea dispersal in the Pleistocene, molecular dating analysis was conducted. Results A statistical parsimony network revealed that the haplotypes from the Ryukyu Archipelago and northwards coalesce to one ancestral haplotype in Taiwan. A clear phylogeographical structure was observed: plants within the same population and populations in geographical proximity were phylogenetically close. A genetic boundary was recognized across the Kerama Gap, but not across the Tokara Gap. Dating analysis suggested that population divergence across the Kerama Gap occurred in the early to late Pleistocene. Main conclusions The statistical parsimony network suggests migration from Taiwan and northward range expansion in the archipelago. Based on the divergence time, over‐sea dispersal in the Pleistocene is likely, although migration via a Pliocene landbridge is not totally rejected. Negligible genetic differentiation across the Tokara Gap suggests recent over‐sea dispersal, possibly facilitated by the small geographical width of the gap. Conversely, the large genetic differentiation across the Kerama Gap is probably explained by the large geographical distance across it. The past splitting of a landbridge would have had a significant influence on population differentiation after a certain geographical distance was reached.     

Spatiotemporal population dynamics of the banana rind thrips,Elixothrips brevisetis (Bagnall) (Thysanoptera: Thripidae)

The understanding of how environmental factors and agricultural practices affect population dynamics of insect pests is necessary for pest management. Here, we provide insight into the ecology of the banana rind thrips Elixothrips brevisetis (Bagnall) (Thysanoptera: Thripidae) by collecting and analysing a spatiotemporal database of population estimates in Martinique (West French Indies). We assessed the influence of climatic variables (which were rainfall and temperature) and biotic variables (which were banana and three weed species) on the adult thrips abundance for different components of the banana plant (sucker, mother plant and bunch) and evaluated the effect of thrips abundance and standard bunch covers on damages. The abundance of thrips on the sucker, the mother plant, and the bunch was significantly related to the abundance on neighbouring banana plants, and spatial autocorrelation indicated that E. brevisetis dispersed for only short distances. The number of thrips on the mother plant and on the bunch was positively related to the number of thrips on the sucker, suggesting that the thrips may disperse from the sucker to the mother plant and then to the bunch. The abundance of thrips on the sucker increased with sucker height and was positively correlated with the mean daily rainfall during the 17 days before sampling; the length of that period might correspond with the time required for an individual to complete its life cycle. Covered bunches had 98% fewer thrips than non‐covered bunches, and the damage caused by thrips was linearly related to the number of thrips present between the 2nd and 4th week after flowering. Finally, we found that the presence of Alocasia cucullata, Dieffenbachia seguine and Peperomia pellucida is significantly related with a decrease in thrips abundance on banana plants, suggesting the use of these weeds as potential trap plants.