Genetic diversity of the Khakass gene pool: Subethnic differentiation and the structure of Y-chromosome haplogroups

The structure of Khakass gene pool has been investigated: Y-chromosome haplogroup compositions and frequencies were described in seven population samples of two basic subethnic groups, Sagai and Kachins, from three geographically separated regions of the Khakass Republic. Eight haplogroups were detected in the Khakass gene pool: C3, E, N*, N1b, N1c, R1a1a, and R1b1b1. The haplogroup spectra and the genetic diversity by haplogroups and YSTR haplotypes differed significantly between Sagai and Kachins. Kachins had a low level of gene diversity, whereas the diversity of Sagai was similar to that of other South-Siberian ethnic groups. Sagai samples from the Askizskii district were very similar to each other, and so were two Kachin samples from the Shirinskii district, while Sagai samples from the Tashtypskii district differed considerably from each other. The contribution of intergroup differences among ethnic groups was high, indicating significant genetic differentiation among native populations in Khakassia. The Khakass gene pool was strongly differentiated both by haplogroup frequencies and by YSTR haplotypes within the N1b haplogroup. The frequencies of YSTR haplotypes within the chromosome Y haplogroups N1b, N1c, and R1a1 were determined and their molecular phylogeny was investigated. Factor and cluster analysis, as well as AMOVA, suggest that the Khakass gene pool is structured by territory and subethnic groups.     

Searching the peopling of the Iberian Peninsula from the perspective of two andalusian subpopulations: a study based on Y-chromosome haplogroups J and E

This study aims at a high-resolution analysis of Y-chromosome J and E haplogroups among Andalusians to reconstruct Neolithic, protohistorical and historical migrations in the Mediterranean region. Genotyping of two samples from Granada (n=250 males) and Huelva (n=167 males) (Spain) with Y-chromosome binary and microsatellite markers was performed, and the results compared with other Mediterranean populations. The two samples showed genetic differences that can be associated with different evolutionary processes. Migrations toward Andalusia probably originated in the Arabian Peninsula, Fertile Crescent, Balkan region and North Africa, and they would have predominantly occurred in protohistoric and historic times. Maritime travel would have notably contributed to recent gene flow into Iberia. This survey highlight the complexity of the Mediterranean migration processes and demonstrate the impact of the different population sources on the genetic composition of the Spanish population. The main in-migrations to Iberia most likely did not occur through intermediate stages or, if such stages did occur, they would have been very few.     

Ancient migratory events in the Middle East: new clues from the Y-chromosome variation of modern Iranians

Knowledge of high resolution Y-chromosome haplogroup diversification within Iran provides important geographic context regarding the spread and compartmentalization of male lineages in the Middle East and southwestern Asia. At present, the Iranian population is characterized by an extraordinary mix of different ethnic groups speaking a variety of Indo-Iranian, Semitic and Turkic languages. Despite these features, only few studies have investigated the multiethnic components of the Iranian gene pool. In this survey 938 Iranian male DNAs belonging to 15 ethnic groups from 14 Iranian provinces were analyzed for 84 Y-chromosome biallelic markers and 10 STRs. The results show an autochthonous but non-homogeneous ancient background mainly composed by J2a sub-clades with different external contributions. The phylogeography of the main haplogroups allowed identifying post-glacial and Neolithic expansions toward western Eurasia but also recent movements towards the Iranian region from western Eurasia (R1b-L23), Central Asia (Q-M25), Asia Minor (J2a-M92) and southern Mesopotamia (J1-Page08). In spite of the presence of important geographic barriers (Zagros and Alborz mountain ranges, and the Dasht-e Kavir and Dash-e Lut deserts) which may have limited gene flow, AMOVA analysis revealed that language, in addition to geography, has played an important role in shaping the nowadays Iranian gene pool. Overall, this study provides a portrait of the Y-chromosomal variation in Iran, useful for depicting a more comprehensive history of the peoples of this area as well as for reconstructing ancient migration routes. In addition, our results evidence the important role of the Iranian plateau as source and recipient of gene flow between culturally and genetically distinct populations.     

Genetic diversity of Khakassian gene pool: subethnic differensiation and the structure of Y-chromosome haplogroups,

The structure of Khakass gene pool has been investigated: compositions and frequencies of Y-chromosome haplogroups were described in seven population samples of two basic subethnic groups--Sagays and Kachins from three territorially distanced regions of Khakassia Republic. Eight haplogroups: C3, E, N*, N1b, N1c, R1a1a and R1b1b1 have been determined in Khakass gene pool. Significant differences between Sagays and Kachins were shown in haplogroup spectra and a level of genetic diversity in haplogroups and YSTR-haplotypes. Kachin samples are characterized by a low value of gene diversity, whereas the level of Sagay diversity is similar to that of other South-Siberian ethnoses. Sagay samples from Askizsky region are very similar to each other just as two Kachin samples from Shirinsky region, while Sagay samples from Tashtypsky region greatly differ from each other. A great portion of intergroup differences was determined among different ethnic groups, which testifies to significant genetic differentiation of native populations in Khakassia. Khakass gene pool is greatly differentiated both in haplogroup frequencies and in YSTR-haplotypes within N1b haplogroup. Frequencies and molecular phylogenesis of YSTR-haplotypes were revealed within N1b, N1c and R1a1 haplogroups of Y-chromosome. We carried out comparative analysis of the data obtained. The results of factor, cluster and dispersion analyses are evidence of structuredness of Khakass gene pool according to territorial-subethnic principle.     

Aedes albopictus in Italy and possible diffusion of the species into the Mediterranean area

Aedes albopictus (Skuse), the important Asian vector mosquito recently introduced in United States and Brazil, is reported from Genoa, North Italy. The infestation was discovered in a kindergarten pre-school center in September 1990 just after the summer holidays. Many discarded tires, well known to provide excellent breeding places for Ae albopictus, had been left in the school playground to be used as toys by the children. After sampling a few biting mosquito specimens for identification, the local health service carried out on September 18 an extensive indoor/outdoor treatment with pyrethroid insecticide. The extent of the infestation in the city of Genoa and in other areas of the Ligurian region has not been evaluated since the identification of the species was available in October, at the end of Ae albopictus reproductive period. A general survey in various Italian regions is being planned for the 1991 spring-summer period. The present record, together with the previous report of Ae albopictus in Albania, clearly supports the hypothesis of a spreading of the species in the Mediterranean area.     

Origin of Mediterranean insular endemics in the Boraginales: integrative evidence from molecular dating and ancestral area reconstruction

Aim The presence of numerous reliable fossils and the occurrence of many endemic island species make the Boraginales particularly suitable for integrative biogeographical studies. In this paper we aim to elucidate the time frame and events associated with the origin of selected borages endemic to the Mediterranean climate zone. More specifically, we describe and examine the alternative palaeo‐ and neoendemic hypotheses for their origin. Location Corsica and Sardinia (continental fragment islands) and the Canary Islands (an oceanic island archipelago). Methods Eighty‐nine accessions, representing 30 genera from five families ascribed to the Boraginales, were examined for six chloroplast DNA regions. We used an integrative approach including phylogenetic analyses (Mr Bayes ), Bayesian molecular dating (T3 package) with four fossil constraints on nodes, and biogeographical reconstructions (diva ) to elucidate the temporal and spatial origins of the Corso‐Sardinian and Canary Island endemics. Results Species of Echium endemic to the Canary Islands diverged from their continental sister clade during the Miocene (15.3 ± 5.4 Ma), probably after the rise of the oldest islands (c. 20 Ma). Corso‐Sardinian endemics of Borago diverged from their primarily North African sister clade during the late Miocene‐Pliocene (c. 6.9 ± 3.6 Ma), well after the initial fragmentation of the islands (c. 30 Ma). Similarly, Corso‐Sardinian endemics of Anchusa diverged from the South African Anchusa capensis during the Pliocene–Pleistocene (c. 2.7 ± 2.1 Ma). Main conclusions The present study reveals an Anatolian origin for Anchusa, Borago and Echium and underlines the importance of the Eastern Mediterranean region as a possible reservoir for plant evolution in the Mediterranean Basin. For Anchusa and Borago, the divergence from their respective sister clades on the two types of islands post‐dated the formation of the islands, thus supporting the neo‐endemic hypothesis, whereas the dating results for the origin of Echium endemics were less conclusive.     

Fuzzy species limits in Mediterranean gorgonians (Cnidaria,Octocorallia): inferences on speciation processes

The study of the interplay between speciation and hybridization is of primary importance in evolutionary biology. Octocorals are ecologically important species whose shallow phylogenetic relationships often remain to be studied. In the Mediterranean Sea, three congeneric octocorals can be observed in sympatry: Eunicella verrucosa, Eunicella cavolini and Eunicella singularis. They display morphological differences and E. singularis hosts photosynthetic Symbiodinium, contrary to the two other species. Two nuclear sequence markers were used to study speciation and gene flow between these species, through network analysis and Approximate Bayesian Computation (ABC). Shared sequences indicated the possibility of hybridization or incomplete lineage sorting. According to ABC, a scenario of gene flow through secondary contact was the best model to explain these results. At the intraspecific level, neither geographical nor ecological isolation corresponded to distinct genetic lineages in E. cavolini. These results are discussed in the light of the potential role of ecology and genetic incompatibilities in the persistence of species limits.     

Genetic diversity within a caste population of India as measured by Y-chromosome haplogroups and haplotypes: subcastes of the Golla of Andhra Pradesh

The extent of population subdivision based on 15 Y-chromosome polymorphisms was studied in seven subcastes of the Golla (Karnam, Pokanati, Erra, Doddi, Punugu, Puja, and Kurava), who inhabit the Chittoor district of southern Andhra Pradesh, India. These Golla subcastes are traditionally pastoralists, culturally homogeneous and endogamous. DNA samples from 146 Golla males were scored for seven unique event polymorphisms (UEPs) and eight microsatellites, permitting allocation of each into haplogroups and haplotypes, respectively. Genetic diversity (D) was high (range, 0.9048-0.9921), and most of the genetic variance (>91%) was explained by intrapopulation differences. Median-joining network analysis of microsatellite haplotypes demonstrated an absence of any structure according to subcaste affiliation. Superimposition of UEPs on this phylogeny, however, did create some distinct clusters, indicating congruence between haplotype and haplogroup phylogenies. Our results suggest many male ancestors for the Golla as well as for each of the subcastes. Genetic distances among the seven subcastes, based on autosomal markers (short tandem repeats and human leukocyte antigens) as well as those on the chromosome Y, indicate that the Kurava may not be a true subcaste of the Golla. Although this finding is based on a very small Kurava sample, it is in accordance with ethnohistorical accounts related by community elders. The Punugu was the first to hive off the main Golla group, and the most recently separated subcastes (Karnam, Erra, Doddi, and Pokanati) fissioned from the Puja. This phylogeny receives support from the analysis of autosomal microsatellites as well as HLA loci in the same samples. In particular, there is a significant correlation (r = 0.8569; P = 0.0097) between Y-chromosome- and autosomal STR-based distances.     

Genie differentiation in M. m. domesticus populations from Europe, the Middle East and North Africa: geographic patterns and colonization events

Geographic patterns of genie differentiation were investigated in the commensal house mouse subspecies, M. m. domesticus . The analysis by protein electrophoresis of 40 populations throughout Europe, the Middle East and North Africa indicated that genie differentiation was not highly structured on a macrogeographic scale. Mean genie distances between regions showed, however, that populations fell into three levels of differentiation: a low level in southern Europe within which interregional distances were no larger than intraregional ones, an intermediate level between southern European populations and North European and African ones, and finally, a higher level between all the latter and the Middle Eastern populations.
Gene flow estimates indicated that the homogeneity of southern European populations does not result from present high levels of gene flow, but more likely from a very recent ancestry. These data when argumented with the fossil records of mice from the Mediterranean Basin suggest a two-step colonization process, the most recent of which occurred very rapidly and resulted in the multiple founding of populations in southern Europe. The relationship of M. m. domesticus to other subspecies of mice is discussed in relation to introgression and taxonomy.
Microdifferentiation patterns with low levels of within population substructuring and of gene flow suggest that genie differentiation in the western European house mouse is largely determined by genetic drift and/or founder effects. Although historical factors are determinant in the large scale patterns of genie variation in commensal house mice, dispersal by man no longer seems to be a prominent feature moulding the genetic structure of M. m. domesticus .     

Wing dimorphism in the migratory locust,Locusta migratoria: differentiation of wing morph and phase polyphenism

A short‐winged morph was recently discovered in the migratory locust, Locusta migratoria. It is different from the normal, long‐winged morph not only in forewing length but also in hind femur length, displaying a dimorphism. To understand the significance of this dimorphism, other morphological characters were compared between the two morphs, and the time of differentiation of wing‐pad length was investigated. Wing weights were heavier in the long‐winged morph than in the short‐winged morph. This result showed that the short‐winged morph is not formed by a failure of wing expansion. No obvious morph‐specific differences were observed in wing venation, but wing allometry studies indicated that the distal areas of the fore‐ and hindwings were disproportionally reduced in the short‐winged morph compared to the long‐winged morph. The morphological differentiation of the wing pad between the two morphs was observed at the penultimate nymphal stage. The flight muscle was well developed in the two morphs, and no sign of flight muscle histolysis was detected in either morph after adult emergence. An analysis of adult body dimensions suggested that the density‐dependent phase shifts known for the long‐winged morph of this locust were also exhibited by the short‐winged morph, demonstrating that these shifts are not specific to the migratory long‐winged morph.     

Allozymic differentiation in the land snail Arianta arbustorum (Stylommatophora, Helicidae): historical inferences

The intraspecific genetic differentiation depends to a large part on historical factors. The mode of dispersal is an important determinant of the genetic diversity especially of newly founded populations. Fast long-distance colonization of formerly unsuitable habitats results in reduced genetic diversity and lineages originating from different glacial refugia form well-defined hybrid zones, where they meet. Slow dispersers, on the other hand, preserve their refugial genetic diversity. Paleontological findings and a previous analysis of mtDNA suggest that the land snail Arianta arbustorum, which today is widely spread across Europe, has survived the Pleistocene glaciations within the boundaries of permafrost. In the present paper, we asked, whether the differentiation of nuclear markers, i.e. allozymes, supports these results. We investigated the allozymic differentiation at 15 polymorphic loci in 14 Alpine and one English populations of the land snail A. arbustorum. Various tests of genetic population differentiation yielded ambiguous results. Allele frequencies differed significantly across populations and all but five pairwise F_ST values were significant. Genetic distances between populations were comparatively high. On the other hand, an exact test of population differentiation found no differences and the assignment of individuals to their populations of origin was poor. This indicates that allozymic differentiation is constrained. Whether these constraints are of natural or methodological nature remains open. Matrices of genetic and geographical distances were correlated only after removal of the English population from the analysis. Similarly, with one exception F_ST values increased as the number of regions included in the calculations increased. Thus, on a regional scale, we largely observed a pattern of isolation by distance, which does no longer hold on a larger scale. This is well in accordance with the previous findings based on mtDNA. Mitochondrial lineages were widely distributed across Europe and overlapped extensively. Considering the low potential for dispersal of a land snail, the patchy distribution of lineages, and the high genetic diversity also found in the present study suggests that A. arbustorum has survived the Pleistocene within the boundaries of permafrost.     

Origin and Diffusion of the House Mouse in the Mediterranean

The house mouse (Mus musculus), after humans, is the most widespread mammal on earth and one of the worst invasive species for both biological diversity and human health. This ubiquity is the consequence of its strong ecological relationship with humans, namely commensalism. Human activities promote its diffusion by eliminating ecological barriers and by increasing the human environment suitable for this species. This paper deals with recent zooarchaeological data that has helped to decipher the main factors of human evolution involved in the origin of commensal behaviour in the house mouse and in its invasive process throughout the Mediterranean. Understanding this process contributes to our overall knowledge on how human activities modelled mammalian diversity during Holocene. In the Near Eastern core of European Neolithisation, two factors are recognised as the main driving forces to explain the beginning of house mouse commensalism: rise of farming practices (cultivated fields, large scale grain storage, domestication of plants) and human dispersal of domesticated plants through the cultural area of the pre-ceramic Neolithic. These factors increased the attractiveness of the anthropic ecosystem as well as the diffusion vectors of mice by passive transport. Nevertheless, the Neolithisation of the Mediterranean did not promote the house mouse’s invasion of Europe. The commercial and demographic expansions of Phoenicians and Greeks during the last millennium bc were the vectors that allowed the house mouse to overwhelm the ecological barriers that previously prevented its westward invasion of the human environment.     

Origin of the mutations in the parkin gene in Europe: exon rearrangements are independent recurrent events, whereas point mutations may result from Founder effects

A wide variety of mutations in the parkin gene, including exon deletions and duplications, as well as point mutations, result in autosomal recessive early-onset parkinsonism. Interestingly, several of these anomalies were found repeatedly in unrelated patients and may therefore result from recurrent, de novo mutational events or from founder effects. In the present study, haplotype analysis, using 10 microsatellite markers covering a 4.7-cM region known to contain the parkin gene, was performed in 48 families, mostly from European countries, with early-onset autosomal recessive parkinsonism. The patients carried 14 distinct mutations in the parkin gene, and each mutation was detected in more than one family. Our results support the hypothesis that exon rearrangements occurred independently, whereas some point mutations, found in families from different geographic origins, may have been transmitted by a common founder.     

Male biased sex ratio in the Mediterranean fruit fly Ceratitis capitata, an example of Y-chromosome meiotic drive

A case of Y-chromosome meiotic drive is reported in the Mediterranean fruit fly Ceratitis capitata. It arose in an irradiated male and results in excess of males. Male excess is inherited strictly from father to son. A Y-linked factor MP (male producer) is proposed. Higher drive can be selected, but distortion declines rapidly in the absence of selection. Hybrid males from crosses between driving males and nondriving females also show drive but to a reduced extent, suggesting the action of suppressors. Sex ratio distortion is independent of postzygotic mortality, and is not associated with an obvious chromosome arrangement. Spermiogenesis in driving males is characterised by abnormalities in sperm tails and reduced numbers in some sperm cysts, whereas neighbouring cysts of the same MP testis are essentially wild type. The average number of missing sperms plus deformed sperms approximates to the average depression in female recovery among the progenies of siblings, suggesting that most of the missing or abnormal sperms would have given rise to females, that is, they would have been X-bearing. To explain the heterogeneity between neighbouring cysts, a theory is proposed that links it to variation in X-chromosome sensitivity to MP, arising by random suppression of the genetic basis of sensitivity during the six mitotic divisions in the origin of the cyst from its stem cell before meiosis.     

Natural enemies of Tuta absoluta in the Mediterranean basin,Europe and South America

The tomato leafminer Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae) represents a global threat to commercial tomato (Solanum lycopersicum L.) production, both in open field and greenhouse. Native to South America, it spread over the Mediterranean Basin, Europe, Africa and part of Asia in only 12 years, and currently it is reported in over 80 countries. Biological control is one of the options for its control and a large number of natural enemies has been reported in association with the pest, both in the areas of origin and of introduction. The egg parasitoid Trichogramma pretiosum, in South America, and the mirid predators Macrolophus pygmaeus and Nesidiocoris tenuis, in Europe and the Mediterranean basin, are used as commercial biocontrol agents. Even if several natural enemies might be promising candidates for biocontrol, their potential role in quantitative pest reduction has been seldom established under practical tomato production conditions.

Since climatic suitability indices predict a high probability for continued invasion by T. absoluta, mainly in China and the USA, there is an urgent need for new control options. In order to minimise the use of broad spectrum insecticides, biocontrol techniques should be considered. As tomato is produced seasonally, augmentative biocontrol seems to be the most effective control option, but pest reduction might be optimised by adding conservation biocontrol, and by combining biocontrol within IPM programmes.

Here, an overview of predators and parasitoids of T. absoluta in South American and Euro-Mediterranean regions, and their biological control efficacy under laboratory, semi-field and field conditions is provided.     

Fine‐scale genetic structure and inferences on population biology in the threatened Mediterranean red coral,Corallium rubrum

Identifying microevolutionary processes acting in populations of marine species with larval dispersal is a challenging but crucial task because of its conservation implications. In this context, recent improvements in the study of spatial genetic structure (SGS) are particularly promising because they allow accurate insights into the demographic and evolutionary processes at stake. Using an exhaustive sampling and a combination of image processing and population genetics, we highlighted significant SGS between colonies of Corallium rubrum over an area of half a square metre, which sheds light on a number of aspects of its population biology. Based on this SGS, we found the mean dispersal range within sites to be between 22.6 and 32.1 cm, suggesting that the surveyed area approximately corresponded to a breeding unit. We then conducted a kinship analysis, which revealed a complex half‐sib family structure and allowed us to quantify the level of self‐recruitment and to characterize aspects of the mating system of this species. Furthermore, significant temporal variations in allele frequencies were observed, suggesting low genetic drift. These results have important conservation implications for the red coral and further our understanding of the microevolutionary processes acting within populations of sessile marine species with a larval phase.     

Mutation rate switch inside Eurasian mitochondrial haplogroups: impact of selection and consequences for dating settlement in Europe

R-lineage mitochondrial DNA represents over 90% of the European population and is significantly present all around the planet (North Africa, Asia, Oceania, and America). This lineage played a major role in migration "out of Africa" and colonization in Europe. In order to determine an accurate dating of the R lineage and its sublineages, we analyzed 1173 individuals and complete mtDNA sequences from Mitomap. This analysis revealed a new coalescence age for R at 54.500 years, as well as several limitations of standard dating methods, likely to lead to false interpretations. These findings highlight the association of a striking under-accumulation of synonymous mutations, an over-accumulation of non-synonymous mutations, and the phenotypic effect on haplogroup J. Consequently, haplogroup J is apparently not a Neolithic group but an older haplogroup (Paleolithic) that was subjected to an underestimated selective force. These findings also indicated an under-accumulation of synonymous and non-synonymous mutations localized on coding and non-coding (HVS1) sequences for haplogroup R0, which contains the major haplogroups H and V. These new dates are likely to impact the present colonization model for Europe and confirm the late glacial resettlement scenario.     

Molecular evidences of single mutational events followed by recurrent crossing-overs in the common delta-globin alleles in the Mediterranean area

The human delta-globin gene (HBD) is one of the beta-like globin genes expressed in adults. In the Mediterranean countries the carriers of delta-thalassemia defects or Hb A2-variants are >1% and about 40/70 known alleles have been found in families with this ethnic origin. The scope of this study was to investigate the variability of the gene and of the chromosomal background in order to highlight the origin and spreading of the delta-globin gene alleles in the Mediterranean area. We carried out the characterization of the delta-globin gene alleles and of RFLP-haplotypes, SNPs and one microsatellite associated with them in 231 carriers originating principally from East Sicily. Seventeen alleles were identified, of which five were new. The chromosomes associated with mutated alleles from unrelated carriers were 158; the allele Hb A2-Yialousa accounted for about 75% of relative frequency, Hb A2-Mitsero for about 8%. The alleles were associated with RFLP 5'-haplotypes "- - - -" or "+ - + +", prevalent in the Mediterranean area, except Hb A2-Mitsero associated with the 5'-haplotype "Benin" "- - - +" and the Hb A2' associated with "+ - - +", both of African origin. Each allele showed linkage with one haplotype with these exceptions. The Hb A2-Yialousa showed heterogeneity of the 5'-haplotype in 2/58 chromosomes; the Hb A2-Mitsero showed SNPs and (A)gamma-microsatellite typical of a "Benin" haplotype found associated with the Hb C and Hb S chromosomes; the Hb A2-Yialousa (14/58 chromosomes), Hb A2-Mitsero, Hb A2-Pylos, Hb A2-Fitzroy showed heterogeneity in the 3'-haplotypes and beta-globin gene SNPs. The Hb A2-Coburg was found associated with the haplotype "+ - + +/+ +" different from that already reported "- - - -/+ -". With the exception of this last allele, the linkage of each mutation with a core of RFLPs or SNPs around or inside the delta-globin locus suggested the unicentric origin of the mutations followed by recurrent recombination events causing the chromosomal background heterogeneity.     

Climate and the complexity of migratory phenology: sexes,migratory distance,and arrival distributions

The intra- and inter-season complexity of bird migration has received limited attention in climatic change research. Our phenological analysis of 22 species collected in Chicago, USA, (1979–2002) evaluates the relationship between multi-scalar climate variables and differences (1) in arrival timing between sexes, (2) in arrival distributions among species, and (3) between spring and fall migration. The early migratory period for earliest arriving species (i.e., short-distance migrants) and earliest arriving individuals of a species (i.e., males) most frequently correlate with climate variables. Compared to long-distance migrant species, four times as many short-distance migrants correlate with spring temperature, while 8 of 11 (73%) of long-distance migrant species’ arrival is correlated with the North Atlantic Oscillation (NAO). While migratory phenology has been correlated with NAO in Europe, we believe that this is the first documentation of a significant association in North America. Geographically proximate conditions apparently influence migratory timing for short-distance migrants while continental-scale climate (e.g., NAO) seemingly influences the phenology of Neotropical migrants. The preponderance of climate correlations is with the early migratory period, not the median of arrival, suggesting that early spring conditions constrain the onset or rate of migration for some species. The seasonal arrival distribution provides considerable information about migratory passage beyond what is apparent from statistical analyses of phenology. A relationship between climate and fall phenology is not detected at this location. Analysis of the within-season complexity of migration, including multiple metrics of arrival, is essential to detect species’ responses to changing climate as well as evaluate the underlying biological mechanisms.