The evolutionary history of <Emphasis Type="Italic">Senna</Emphasis> ser. <Emphasis Type="Italic">Aphyllae</Emphasis> (Leguminosae–Caesalpinioideae), an endemic clade of southern South America

In the legume genus Senna, series Aphyllae includes seven species of leafless shrubs and subshrubs from arid, semiarid and xerophilous areas of three different biogeographic subregions in southern South America. In this study, we investigated the evolutionary history of Aphyllae in a molecular phylogenetic framework. We reconstructed phylogenetic relationships among Aphyllae species based on DNA sequence data of four plastid (rpS16, rpL16, matK, trnL-F) and one nuclear (ITS) region from 23 accessions, analyzed with parsimony, Bayesian and maximum likelihood methods. We inferred the evolutionary and biogeographic history estimating divergence times and reconstructing ancestral character states and ancestral areas of distribution. Series Aphyllae was found to be monophyletic, and the taxa formed two main clades: Clade A gathering S. aphylla var. aphylla, S. crassiramea, S. rigidicaulis and S. spiniflora; and Clade B grouping S. acanthoclada, S. aphylla var. divaricata, S. aphylla var. pendula and S. pachyrrhiza. The morphologically complex S. aphylla appears thus polyphyletic. Molecular dating and ancestral area reconstructions suggest that the Aphyllae clade started to diversify in the South American Transition Zone in the Late Pliocene. Based on these results, we hypothesize that this diversification occurred during the last period of Andean uplift with the aridification in South America. The ancestral character state reconstructions suggest that, in addition to the loss of leaves in adult plants, series Aphyllae evolved various morphological features, such as fastigiate, thickened or decumbent–subdecumbent branches during the colonization and establishment in different arid and semiarid lands in South America.     

The Evolutionary History and Genetic Diversity of Kinkajous, <Emphasis Type="Italic">Potos flavus</Emphasis> (Carnivora,Procyonidae)

The genus Potos (Procyonidae) is currently recognized as a monotypic genus comprising the single species Potos flavus, the kinkajou. Kinkajous are widely distributed throughout forested habitats of tropical Central and South America, extending from eastern Brazil across central Bolivia, eastern Peru, northern Ecuador, Guianas, Suriname, Venezuela, Colombia, and then through Central America and into western Mexico. The taxonomic history of the species is complex, with seven or eight subspecies historically recognized to acknowledge the phenotypic variation among populations. In this study, the systematics and the evolutionary history of Potos flavus were investigated based on the mitochondrial gene cytochrome b, including specimens from a large range of localities, covering most of the distribution of the species, from central Middle America (Costa Rica and Panama) through South America (Ecuador, Peru, Bolivia, Brazil, Guyana, and French Guiana). Analyses of 30 Potos flavus sequences showed 27 haplotypes that were grouped in five main clades in all phylogenetic analyses. These clades suggested a high geographic structure with specimens from (1) Costa Rica, (2) Guianas and North Brazil, (3) North Peru, (4) Ecuador and Panama, (5a) interfluves Branco-Negro rivers in the Brazilian Amazon, (5b) Eastern Atlantic Forest, (5c) Amazonian lowlands east Negro river including Bolivia, Peru, and West Brazil. Each of these clades differs from 4.5 % to 9.3 % in their genetic distance estimates, which suggests that the specific status of some of these lineages should be reconsidered. Divergence dating and biogeographic analysis suggested that crown Potos diversified in the Miocene-Pliocene in South America, and geographic barriers, such as savannas and rivers, may have played a significant role in the kinkajou diversification.     

Divergence in selection of host species and plant parts among populations of a phytophagous insect

The diversification of phytophagous insects is often attributed to diverging processes of host plant specialization onto different, often closely related, host plants. Some insect clades have diversified by specializing not only on different plant species but also on different plant parts of the same hosts. This is the case in Greya moths (Prodoxidae) where both Greya obscura and G. politella are tightly linked to host plants of the genus Lithophragma (Saxifragaceae). We assess how these species differ in their choice of plants and use of plant parts. Previous work showed that strong local host specialization in G. politella is mediated by floral scent variation among Lithophragma species. Here, we identify geographic variation in host plant use in the close relative G. obscura, relate the emerging patterns to previous studies of geographic variation in host use in G. politella and evaluate potential processes underlying the variation among and within species. First, we show that G. obscura also uses floral chemistry to locate hosts but that additional plant cues must be involved in deciding whether to oviposit on a plant, because females did not discriminate against chemically different host species in no-choice trials. We also found that, although all known populations of G. politella oviposit only in flowers, all G. obscura populations examined here distributed their eggs among both floral and scape tissues both in the field and in laboratory experiments. The distribution of eggs among plant parts, however, varied among moth populations, and also depended on the Lithophragma species they attacked. Together, these results show the potential for phytophagous insect species and populations to diverge in use of plant parts as part of the process of speciation and adaptation. These two layers of specialization enhance the potential for subsequent diversification in phytophagous insect lineages.     

Diversification of <Emphasis Type="Italic">Caiophora</Emphasis> (Loasaceae subfam. Loasoideae) during the uplift of the Central Andes

Andean orogeny and the ecological changes that followed promoted diversification in plant and animal lineages since the Early Miocene. The angiosperm genus Caiophora (Loasaceae, subfam. Loasoideae) comprises around 50 species that are endemic to South America. These are distributed from southern Ecuador to Central Chile and Argentina. Bee pollination and distribution at low-intermediate elevations probably represent the ancestral condition in the lineage that includes Caiophora and its allied genera. The majority of Caiophora species grow at high elevations in the Andes, where some depend on vertebrate pollination. Previous studies did not resolve phylogenetic relationships within Caiophora, which precluded the dating of the origin and divergence of this group. We used markers of one nuclear (ITS) and one plastid region (trnS ^GCU -trnG ^UUC ) to solve phylogenetic relationships among 19 Caiophora species (including different accessions). We also included 10 species of the allied genera Blumenbachia and Loasa. Aosa rostrata and Xylopodia klaprothioides were used as outgroups. Phylogenetic reconstruction strongly supports the monophyly of Caiophora, and although several clades within this genus are poorly supported, our study yielded a better infra-generic resolution than previous studies. The origin of Caiophora is dated to the Early-Middle Miocene and can be related to the uplift of the Cordilleras Frontal and Principal and to Pacific marine transgressions. According to our estimations, Caiophora began to diversify during the Middle-Late Miocene and this unfolding proceeded eastwards during the Pliocene and the Pleistocene, in parallel to the uplift of different Andean mountain ranges.     

A taxonomic and phylogenetic study of the <Emphasis Type="Italic">Golovinomyces biocellatus</Emphasis> complex (Erysiphales,Ascomycota) using asexual state morphology and rDNA sequence data

The Golovinomyces biocellatus complex consists of powdery mildew (Erysiphales) species restricted to hosts of the family Lamiaceae. Previous authors used minor morphological features of the sexual state and host range data to split the complex. The data, however, were not sufficient to define a convincing species concept. Our taxonomic study is based on molecular phylogenetic and asexual state morphology data. For morphological studies, mainly features of the asexual morph (conidiophores, conidia, germination patterns) were studied using light and scanning electron microscopy. Detailed line drawings of asexual state features are provided. For phylogenetic analyses, two markers (rDNA: ITS, LSU) of 64 specimens were applied. The phylogeny resulted in two major clades. Clade I consists of specimens with Lamiaceae hosts and three specimens of Verbena. Clade II consists of two sister groups, the first (IIa) with Salvia spp. and the second (IIb) with Lycopus europaeus (the type host G. biocellatus) and Glechoma. Clades I and IIb and two subclades of IIa with Salvia hosts are characterized by specific morphological traits (differences in conidiophore length, conidial shape, width, and germination patterns). Based on these data, we suggest to consider specimens of clades I (including specimens on Verbena) and IIb and the two subclades of IIa as distinct species, namely G. monardae, G. biocellatus, G. salviae, and G. neosalviae sp. nov. A key for the identification of species based on asexual state features is provided. The results are discussed with respect to host range, jumps, co-evolutionary aspects, and distribution patterns.     

Phylogeny of the Neotropical sages (<Emphasis Type="Italic">Salvia</Emphasis> subg. <Emphasis Type="Italic">Calosphace</Emphasis>; Lamiaceae) and insights into pollinator and area shifts

Salvia subg. Calosphace (Lamiaceae, Lamiales) is a highly diverse clade endemic to the New World. The phylogenetic relationships of Calosphace have been previously investigated using DNA sequences of nuclear ITS region and plastid psbA–trnH intergenic spacer, but the resulting trees lack resolution and support for many clades. The present paper reassesses the phylogenetic relationships of subgenus Calosphace, including a broader taxon sampling, with a special focus on representing previously unsampled sections, and using an additional plastid marker (trnL–trnF region). Our results show increased resolution and overall patterns of support, recovering ten main clades. Within core Calosphace, the most inclusive of these main clades, 17 new subclades were identified. Of the 42 sections for which more than one species was analysed, only 12 are monophyletic. Our biogeographical analysis identified at least twelve migrations to South America from Mexican and Central American lineages, in agreement with previous suggestions of multiple origins of South American Calosphace diversity. This analysis also confirmed a colonization of the Antilles by Andean lineages. The reconstruction of ancestral states of pollination syndromes showed multiple shifts to ornithophily from melittophily and one reversal to the latter.     

Pleistocene climatic fluctuations explain the disjunct distribution and complex phylogeographic structure of the Southern Red-backed Salamander, <Emphasis Type="Italic">Plethodon serratus</Emphasis>

The southeastern United States (U.S.) has experienced dynamic climatic changes over the past several million years that have impacted species distributions. In many cases, contiguous ranges were fragmented and a lack of gene flow between allopatric populations led to genetic divergence and speciation. The Southern Red-backed Salamander, Plethodon serratus, inhabits four widely disjunct regions of the southeastern U.S.: the southern Appalachian Mountains, the Ozark Plateau, the Ouachita Mountains, and the Southern Tertiary Uplands of central Louisiana. We integrated phylogenetic analysis of mitochondrial DNA sequences (1399 base pairs) with ecological niche modeling to test the hypothesis that climate fluctuations during the Pleistocene drove the isolation and divergence of disjunct populations of P. serratus. Appalachian, Ozark, and Louisiana populations each formed well-supported clades in our phylogeny. Ouachita Mountain populations sorted into two geographically distinct clades; one Ouachita clade was sister to the Louisiana clade whereas the other Ouachita clade grouped with the Appalachian and Ozark clades but relationships were unresolved. Plethodon serratus diverged from its sister taxon, P. sherando, ~5.4 million years ago (Ma), and lineage diversification within P. serratus occurred ~1.9–0.6 Ma (Pleistocene). Ecological niche models showed that the four geographic isolates of P. serratus are currently separated by unsuitable habitat, but the species was likely more continuously distributed during the colder climates of the Pleistocene. Our results support the hypothesis that climate-induced environmental changes during the Pleistocene played a dominant role in driving isolation and divergence of disjunct populations of P. serratus.     

Phylogeography of the Ibero-Maghrebian red-eyed grass snake (<Emphasis Type="Italic">Natrix astreptophora</Emphasis>)

We examined phylogeographic differentiation of the red-eyed grass snake (Natrix astreptophora) using 1984 bp of mtDNA and 13 microsatellite loci from specimens collected across its distribution range in southwestern Europe and northwestern Africa. Based on phylogenetic analyses of mtDNA, European N. astreptophora constituted the sister clade to a weakly supported North African clade comprised of two deeply divergent and well-supported clades, one corresponding to Moroccan snakes and the other to snakes from Algeria and Tunisia. This tripartite differentiation was confirmed by analyses of microsatellite loci. According to a fossil-calibrated molecular clock, European and North African N. astreptophora diverged 5.44 million years ago (mya), and the two Maghrebian clades split 4.64 mya. These dates suggest that the radiation of the three clades was initiated by the environmental changes related to the Messinian Salinity Crisis and the reflooding of the Mediterranean Basin. The differentiation of N. astreptophora, with distinct clades in the Iberian Peninsula and in the western and eastern Maghreb, corresponds to a general phylogeographic paradigm and resembles the differentiation found in another co-distributed Natrix species, the viperine snake (N. maura). Despite both species being good swimmers, the Strait of Gibraltar constitutes a significant biogeographic barrier for them. The discovery that North Africa harbours two endemic lineages of N. astreptophora necessitates more conservation efforts for these imperilled snakes.     

The Calibrated Phylogeny of the <Emphasis Type="Italic">Drosophila fasciola</Emphasis> Subgroup (<Emphasis Type="Italic">D. repleta</Emphasis> Group Wasserman) Indicates Neogene Diversification of Its Internal Branches

The species of the Drosophila fasciola subgroup Wasserman represent the dominant section of the Drosophila repleta group Wasserman in the American rainforests and have a broad geographical distribution in the New World. However, despite of its wide range, the D. fasciola subgroup is one of the most overlooked D. repleta subgroups. Here, we report a molecular phylogenetic analysis focused on the D. fasciola subgroup using two mitochondrial [cytochrome oxidase subunit I (COI), cytochrome oxidase subunit II (COII)] and two nuclear [elongation factor-1alpha F1 (EF-alphaF1) and transformer (tra)] genes. Overall, we found that this subgroup is a monophyletic taxon, subdivided into two main internal branches: named Fas1 and Fas2 clades. The diversification of these clades is estimated to have begun in the middle Miocene, around 12 Ma [95% high posterior density (HPD) 9.0–15 Ma], and might be associated with the colonization of South America by Central America populations after the closure of Isthmus of Panama due to the temporal congruence between these events. The terminal branches had their origins estimated to be in the Pliocene or the Plio-Pleistocene transition. For the later estimates, both the geomorphological influences and the climatic oscillations of the Pleistocene may have played a role in shaping the diversification of the D. fasciola group.     

Systematic Studies of the Genus A<Emphasis Type="Italic">egialomys</Emphasis> Weksler et al., 2006 (Rodentia: Cricetidae: Sigmodontinae): Geographic Variation,Species Delimitation,and Biogeography

Aegialomys occurs in open habitats west of the Ecuadorean and Peruvian Andes, including the Galapagos Archipelago. This genus currently includes two species, A. galapagoensis and A. xanthaeolus. We studied patterns of geographic variation to characterize the morphologic and morphometric variation and recognize diagnosable clusters of samples. Employing this evidence, within a phylogenetic framework employing morphological, molecular, and concatenated matrices, we diagnose monophyletic lineages and assign the appropriate names to species–group taxa. Qualitatively, we noted geographic variation in some characters, and quantitatively there is a pronounced increase in cranial dimensions along the north–south distribution axis, revealing the existence of four distinct clusters: North, South, Extreme South, and Galapagos. These results, along with the phylogenetic relationships, allowed us to hypothesize that Aegialomys exhibits four monophyletic species that we call: Aegialomys galapagoensis, restricted to the Galapagos Archipelago; Aegialomys xanthaeolus, distributed from Ecuador to northern Peru; Aegialomys baroni, ocurring in Central Perú; and Aegialomys ica, distributed in southern Peru. Our distributional data suggest that species discontinuities are associated with some well-known barriers in the western portion of South America. Through the Andes and trans–Andean area, there are some geographic features or areas, the Huancabamba Depression, that historically played a key role as barriers to plant and animal dispersion or as a boundaries to species distribution.     

Species complex delimitation and patterns of population structure at different geographic scales in Neotropical silver catfish (<Emphasis Type="Italic">Rhamdia</Emphasis>: Heptapteridae)

The Neotropical catfish genus Rhamdia inhabits rivers and lakes from Mexico to Argentina. Previous studies have found that the taxonomy of this genus, as well as that of R. quelen, remains controversial. The present study aims to contribute to the understanding of Rhamdia systematics by delimiting putative species, and to elucidate the pattern of genetic differentiation of Rhamdia at different geographic levels within the cis-andean region. Species boundaries were defined by Generalized Mixed Yule Coalescent and Automatic Barcode Gap Discovery methods, and by phylogenetic analyses of cytochrome b (cyt b) sequences. Moreover, we performed phylogeographic analyses based on cyt b sequences and microsatellite markers. Patterns of differentiation were analyzed at three nested geographic levels: in the main cis-andean basins (macrogeographic scale); in the second major Neotropical basin system (mesogeographic scale), which encompasses La Plata basin, Patos-Merin basin, and the coastal lagoons draining to SW Atlantic Ocean; and finally, in the three most important coastal lagoons for artisanal fisheries in Uruguay (microgeographic scale). Sixteen species were found within Rhamdia, divided into two clades (cis- and trans-andean clades), each composed of eight putative species. Cis-andean Rhamdia species have probably diverged due to vicariance events occurring between and within basins since late Miocene-Pleistocene. Microgeographic scale analysis based on cyt b and microsatellite data revealed a high genetic structuring among the studied coastal lagoons. Mitochondrial and microsatellite markers enabled to identify three different populations, corresponding to the three coastal lagoons analyzed, which would have diverged recently and could be considered as different Management Units.     

Ancient DNA reveals complexity in the evolutionary history and taxonomy of the endangered Australian brush-tailed bettongs (<Emphasis Type="Italic">Bettongia</Emphasis>: Marsupialia: Macropodidae: Potoroinae)

The three surviving ‘brush-tailed’ bettong species—Bettongia gaimardi (Tasmania), B. tropica (Queensland) and B. penicillata (Western Australia), are all classified as threatened or endangered. These macropodids are prolific diggers and are recognised as important ‘ecosystem engineers’ that improve soil quality and increase seed germination success. However, a combination of introduced predators, habitat loss and disease has seen populations become increasingly fragmented and census numbers decline. Robust phylogenies are vital to conservation management, but the extent of extirpation and fragmentation in brush-tailed bettongs is such that a phylogeny based upon modern samples alone may provide a misleading picture of former connectivity, genetic diversity and species boundaries. Using ancient DNA isolated from fossil bones and museum skins, we genotyped two mitochondrial DNA (mtDNA) genes: cytochrome b (266 bp) and control region (356 bp). These ancient DNA data were combined with a pre-existing modern DNA data set on the historically broadly distributed brush-tailed bettongs (~300 samples total), to investigate their phylogenetic relationships. Molecular dating estimates the most recent common ancestor of these bettongs occurred c. 2.5 Ma (million years ago), which suggests that increasing aridity likely shaped their modern-day distribution. Analyses of the concatenated mtDNA sequences of all brush-tailed bettongs generated five distinct and well-supported clades including: a highly divergent Nullarbor form (Clade I), B. tropica (Clade II), B. penicillata (Clades III and V), and B. gaimardi (Clade IV). The generated phylogeny does not reflect current taxonomy and the question remains outstanding of whether the brush-tailed bettongs consisted of several species, or a single widespread species. The use of nuclear DNA markers (single nucleotide polymorphisms and/or short tandem repeats) will be needed to better inform decisions about historical connectivity and the appropriateness of ongoing conservation measures such as translocations and captive breeding.     

New evidence of floral elaiophores and characterization of the oil flowers in the subtribe Oncidiinae (Orchidaceae)

Elaiophores seems to be uncommon in Orchidaceae; however, the number of known species with floral oil glands has increased in recent years, principally in Oncidiinae. Oil rewards are used by bees of the tribes Centridini, Tapinotaspidini and Tetrapediini. Our aims were to identify the presence of elaiophores and to describe their structure in species of Gomesa, Grandiphyllum and Trichocentrum, and to compare our results with other studies of elaiophores in Oncidiinae. We selected a set of characters presumably associated with oil production in flowers of Oncidiinae, which were evaluated using a cluster analysis to identify different floral morphologies of the oil flowers. The correlation between morphological types of oil flowers and species of pollinators was examined. The cluster analysis distinguished two groups of species, one of them principally linked with pollination by bees of genus Centris and the other type associated to species of Paratetrapedia and Tetrapedia. The evaluation of these results into a phylogenetic framework of the Oncidiinae, adding more evidence that species of this subtribe with similar floral morphology associated with floral oil secretion arise in many independent clades, in parallel evolution with the oil-bee pollination.     

Geographic structuring into vicariant species-pairs in a wide-ranging,high-dispersal plant–insect mutualism: the case of <Emphasis Type="Italic">Ficus racemosa</Emphasis> and its pollinating wasps

Ficus and their mutualistic pollinating wasps provide a unique model to investigate joint diversification in a high dispersal system. We investigate genetic structuring in an extremely wide-ranging Ficus species, Ficus racemosa, and its pollinating wasp throughout their range, which extends from India to Australia. Our samples were structured into four large, vicariant populations of figs and wasps which may correspond to distinct (sub)species, located in India, China-Thailand, Borneo, and Australia. However, the genetically most divergent group was the Indian population for the figs and the China-Thailand population for the wasps, suggesting different evolutionary histories of populations. Molecular dating for the wasps shows that diversification of the pollinator clade is surprisingly old, beginning about 13.6 Ma. Data on both the host fig species and its pollinating wasps suggest that strong genetic flow within biogeographic groups over several hundreds of kilometers has limited genetic and morphological differentiation and, potentially, local adaptation. This is probably due to long-distance dispersal of pollinating wasps. The genetic clustering into large geographic units observed in F. racemosa and its pollinators is reminiscent of what can be observed in some other high-dispersal organisms characterized by morphology that varies little over huge distances. The implications of strong gene flow for diversification processes and adaptation to different ecological conditions in Ficus and their pollinating wasps are just beginning to emerge.     

Isolation and characterization of the C-class MADS-box gene from the distylous pseudo-cereal <Emphasis Type="Italic">Fagopyrum esculentum</Emphasis>

In the model species Arabidopsis thaliana, the floral homeotic C-class gene AGAMOUS (AG) specifies reproductive organ (stamen and carpels) identity and floral meristem determinacy. Gene function analyses in other core eudicots species reveal functional conservation, subfunctionalization and function switch of the C-lineage in this clade. To identify the possible roles of AG-like genes in regulating floral development in distylous species with dimorphic flowers (pin and thrum) and the C function evolution, we isolated and identified an AG ortholog from Fagopyrum esculentum (buckwheat, Family Polygonaceae), an early diverging species of core eudicots preceding the rosids-asterids split. Protein sequence alignment and phylogenetic analysis grouped FaesAG into the euAG lineage. Expression analysis suggested that FaesAG expressed exclusively in developing stamens and gynoecium of pin and thrum flowers. Moreover, FaesAG expression reached a high level in both pin and thrum flowers at the time when the stamens were undergoing rapidly increased in size and microspore mother cells were in meiosis. FaesAG was able to substitute for the endogenous AG gene in specifying stamen and carpel identity and in an Arabidopsis ag-1 mutant. Ectopic expression of FaesAG led to very early flowering, and produced a misshapen inflorescence and abnormal flowers in which sepals had converted into carpels and petals were converted to stamens. Our results confirmed establishment of the complete C-function of the AG orthologous gene preceding the rosids-asterids split, despite the distinct floral traits present in early- and late-diverging lineages of core eudicot angiosperms.     

Ant pollination of <Emphasis Type="Italic">Syzygium occidentale</Emphasis>, an endemic tree species of tropical rain forests of the Western Ghats,India

Although mutualism between ants and flowering plants is wide spread, ant pollination has not evolved as a major pollination syndrome. So far ant pollination has been reported largely in herbaceous species, growing in warm and dry habitats. While studying pollination ecology of Syzygium species (Myrtaceae), growing in tropical forests of the Western Ghats, India, we observed one of the ant species, Technomyrmex albipes, to be the dominant floral visitor in S. occidentale (Bourd.) Chithra among a range of other insect (species of Xylocopa and Trigona, and Apis cerana) and bird visitors. We studied the role of ant species in pollination when compared to other floral visitors. The fruit set in flowers exclusively visited by T. albipes was significantly higher than those visited by any other visitor. The day and night exclusive pollination experiments allowing only T. albipes indicated diel pollination by T. albipes, which was the only active flower visitor during the night. The breeding system of the species was studied through controlled pollinations. The species is partially self-compatible and exhibits considerable autogamy.     

Effects of alien invasion by <Emphasis Type="Italic">Bombus terrestris</Emphasis> L. (Apidae) on the visitation patterns of native bumblebees in coastal plants in northern Japan

When alien pollinator species enter a native community of pollinators in which resource partitioning has been established, the pollination network between plants and pollinators may be modified through the interactions between the pollinators over the use of floral resources. We observed the floral-use patterns of native (Bombus hypocrita and B. deuteronymus) and alien (B. terrestris) bumblebee species in a coastal grassland in northern Japan. We analyzed the factors determining resource partitioning patterns. B. hypocrita tended to visit flowers with shallow or wide open corollas, such as Rosa rugosa, whereas B. deuteronymus visited flowers with complex or deeper corollas, such as Lathyrus japonicus. Given the wider floral preference of B. terrestris, floral use by the alien bumblebees consistently overlapped with that of native bumblebees. The visitation of B. terrestris to R. rugosa flowers was positively correlated with that of B. hypocrita. These bumblebee species frequently used similar floral resources, in part because of the large overlap in the seasonality of their foraging activity. The visitation frequency of B. deuteronymus to L. japonicus flowers was independent of the visitation frequency of other bumblebee species. The major visitation periods of the bumblebees to L. japonicus flowers reciprocally differed between B. deuteronymus and B. terrestris, suggesting phenological resource partitioning between these species. Our study suggests that phenological niche partitioning is more common in specialized flowers (L. japonicus) than in generalized flowers (R. rugosa).     

Comparative phylogeography of diadromous and freshwater daces of the genus <Emphasis Type="Italic">Tribolodon</Emphasis> (Cyprinidae)

Far Eastern daces, genus Tribolodon (Cyprinidae), are thought to have diversified and developed unique diadromous life histories under changing conditions in the Sea of Japan and the surrounding environment. To examine the relationships between life history traits, distribution, and genetic population structures, we conducted a comparative phylogeographic analysis using partial mtDNA sequence data from samples collected over almost the full ranges of all four Tribolodon species. Phylogenetic analyses revealed several intraspecific haplotype groups that differentiated in the early Pleistocene to the Pliocene with or without geographic overlaps. A time-calibrated phylogeny suggested that the relatively smaller geographic ranges of the strictly freshwater species, T. sachalinensis and T. nakamurai, were explained not by the recent origins of these species, but by their limited dispersal abilities and smaller historical population sizes. The wider-ranging diadromous species, T. brandtii and T. hakonensis, exhibited similar major phylogeographic structures in their distributions, but the chronological order and timing of formation of this structure largely differed between the two species. In addition to those differences, the overlapping patterns of the differentiated intraspecific lineages in these species suggest dynamic, but somewhat restricted dispersal during the Plio-Pleistocene. Tribolodon hakonensis, one of the most widespread species of East Asian freshwater fishes, included both common and unique phylogeographic patterns compared to other fish species; the unique patterns (i.e., its wide range across freshwater biogeographic boundaries like the sea and mountains) would reflect its ecological features as a remarkable generalist inhabiting lakes, upper and lower reaches of rivers, and even coastal areas.