Multiple Events of Dispersal and Radiation of the Tribe Miconieae (Melastomataceae) in the Caribbean

In the Caribbean region, the Melastomataceae are represented by about 450 species (from 28 genera), close to 400 of them endemic. The majority of these endemic species (approximately 330) belong to the tribe Miconieae, a monophyletic group characterized by flowers with inferior or partly inferior ovaries that develop into baccate fruits, stamens with no or only poorly developed connective appendages, and the absence of megastyloids and imbricate bracts at the base of the flowers. A phylogenetic analysis of 460 accessions from 450 species of the tribe Miconieae, including 139 present in the Antilles (103 of these endemic), was performed based on nuclear (nrITS) and plastid (ndhF) DNA sequence data. This analysis shows that most of the Caribbean endemics are the product of five radiation events: (1) a clade containing the Caribbean endemic (or near-endemic) genera Pachyanthus, Calycogonium, Tetrazygia and Charianthus, as well as a few representatives of Miconia and Leandra. (2) The genus Mecranium. (3) The Caribbean species of Miconia section Chaenopleura (which are probably not the sister group of Andean Chaenopleura). (4) The Greater Antillean species of Clidemia and Ossaea (including Sagraea). (5) The Lesser Antillean representatives of Clidemia. Caribbean endemics that are more closely related to mainland species, rather than other Caribbean species are rare, and these often are segregates of widespread continental species. Because of a lack of resolution at the base of several clades, it is currently not possible to determine which mainland groups are the closest relatives of these Caribbean endemics, thus preventing us from establishing unequivocally the geographical origins of these species.

---

Resumen  En la región del Caribe la familia Melastomataceae está representada por cerca de 450 especies (de 28°géneros), 400 de ellas endémicas. La mayoría de estas especies (approximately 330) pertenecen a la tribu Miconieae, un grupo monofilético caracterizado por flores con ovario parcial o totalmente ínfero que se desarrollan en frutos bayados, estambres con apéndices ausentes o poco desarrollados, ausencia de mega estiloides, y la ausencia de brácteas imbricadas en la base del as flores. Se realizó un análisis filogenético basado en secuencias nucleares (nrITS) de cloroplasto (ndhF) para la tribu Miconieae. El análisis incluyó 460 individuos, representando 450 especies de la tribu, de las cuales 139 están presentes en el Caribe (103 de estas endémicas). El análisis muestra que la mayoría de las especies endémicas del Caribe son producto de cinco eventos de radiación: (1) Un clado que contiene los géneros endémicos (o casi endémicos) Pachyanthus, Calycogonium, Tetrazygia y Charianthus, así como representantes de Miconia y Leandra. (2) El género Mecranium. (3) las especies Antillanas de Miconia sección Chaenopleura. (4) Las especies de las Antillas mayores de Clidemia y Ossaea (incluyendo Sagraea). (5) Las especies de las Antillas menores de Clidemia. Especies endémicas del Caribe que son hermanas o que están cercanamente relacionadas con especies del continente, y no con especies de la región son raras, y generalmente son segregadas de especies de amplia distribución. Debido a la falta de resolución en la base de muchos de estos clados en este estudio, en este momento no es posible determinar con precisión que grupos presentes en el continente son hermanos a los grupos del Caribe, por lo que no es posible establecer los orígenes geográficos de la mayoría de grupos endémicos.

     

Low Inbreeding and High Pollen Dispersal Distances in Populations of Two Amazonian Forest Tree Species

Recent studies suggest that tropical tree species exhibit low inbreeding and high gene dispersal levels despite the typically low density of conspecifics in tropical forests. To examine this, we undertook a study of pollen gene dispersal and mating system of two Amazonian tree species. We analyzed 341 seeds from 33 trees at four microsatellite loci in a Carapa guianensis population from Brazil, and 212 seeds from 22 trees at four microsatellite loci in a Sextonia rubra population from French Guiana. Differentiation of allele frequencies among the pollen pool of individual trees was Φ_FT= 0.053 (95% CI: 0.027–0.074) for C. guianensis and Φ_FT= 0.064 (95% CI: 0.017–0.088) for S. rubra. The mean pollen dispersal distances were estimated at 69–355 m for C. guianensis , and 86–303 m for S. rubra , depending on the pollen dispersal model and the estimate of reproductive tree density used. The multi-locus outcrossing rate was estimated at 0.918 and 0.945, and the correlation of paternity at 0.089 and 0.096, for C. guianensis and S. rubra , respectively, while no significant levels of biparental inbreeding were detected. Comparing trees with high and low local density of conspecifics, we found no evidence for differences in inbreeding levels. The results are discussed within the framework of the emerging picture of the reproductive biology of tropical forest trees.     

Dispersal of Two Species of Trichoptera from Desert Springs: Conservation Implications for Isolated vs Connected Populations

During the Pleistocene, when the climate was wetter and cooler, aquatic habitats in the Great Basin of western North America were much more extensive and connected. As the climate warmed over the last 10000 years, many of these habitats dried but others remained as isolated springs and inland lakes. The isolation of desert springs and lack of dispersal between populations of non-vagile species (e.g. fish, spring snails) has led to genetic differentiation and speciation. However, the extent to which vagile species of aquatic insects disperse from spring to spring is unknown. We examined the population genetics of two caddisflies, Hesperophylax designatus (Limnephilidae) and Lepidostoma ojanum (Lepidostomatidae) that occur in isolated springs in Nevada and eastern California to determine the extent of their dispersal from spring to spring. Mitochondrial DNA sequences indicate that the populations of L. ojanum are isolated and that the populations represent management units. In contrast, H. designatus individuals are flying from spring to spring and their populations are connected by dispersal. Disturbance impacts (e.g. grazing by ungulates, water extraction) that eliminate poor dispersers (e.g. L. ojanum) locally may result in permanent losses of genetic diversity; this is less likely with broader dispersers such as H. designatus.     

Discriminating between the Effects of Founding Events and Reproductive Mode on the Genetic Structure of Triops Populations (Branchiopoda: Notostraca)

Crustaceans that initially colonize a freshwater temporary pond can strongly bias the subsequent genetic composition of the population, causing nearby populations to be genetically distinct. In addition, these crustaceans have various reproductive modes that can influence genetic differentiation and diversity within and between populations. We report on two species of tadpole shrimp, Triops newberryi and Triops longicaudatus “short”, with different reproductive modes. Reproduction in the tadpole shrimp can occur clonally (parthenogenesis), with self fertilization (hermaphroditism), or through outcrossing of hermaphrodites with males (androdioecy). For all these reproductive modes, population genetic theory predicts decreased genetic diversity and increased population differentiation. Here we use mitochondrial control region (mtCR) sequences and nuclear microsatellite loci to determine if the difference in reproductive mode affects the high genetic structure typical of persistent founder effects. Previous authors indicated that T. newberryi is androdioecious because populations are composed of hermaphrodites and males, and T. longicaudatus “short” is hermaphroditic or parthenogenetic because males are absent. In our data, T. newberryi and T. longicaudatus “short” populations were highly structured genetically over short geographic distances for mtCR sequences and microsatellite loci (T. newberryi: Φ_ST = 0.644, F _ST = 0.252, respectively; T. l. “short”: invariant mtCR sequences, F _ST = 0.600). Differences between the two Triops species in a number of diversity measures were generally consistent with expectations from population genetic theory regarding reproductive mode; however, three of four comparisons were not statistically significant. We conclude the high genetic differentiation between populations is likely due to founder effects and results suggest both species are composed of selfing hermaphrodites with some level of outcrossing; the presence of males in T. newberryi does not appreciably reduce inbreeding. We cannot exclude the possibility that males in T. newberryi are non-reproductive individuals and the two species have the same mating system.     

Dispersal Behavior and the Connectivity Between Wolf Populations in Northern Europe

ABSTRACT The isolated gray wolf (Canis lupus) population of the Scandinavian Peninsular is suffering from inbreeding depression. We studied dispersal of 35 wolves fitted with very high frequency (20) or Global Positioning System—global system for mobile (15) radiocollars in the neighboring Finnish wolf population. The growing wolf population in Finland has high numbers of dispersing individuals that could potentially disperse into the Scandinavian population. About half (53%) of the dispersing wolves moved total distances that could have reached the Scandinavian population if they had been straight-line moves, but because of the irregular pattern of movements, we detected no wolves successfully dispersing to the Scandinavian population. Dispersal to the Scandinavian population was also limited by high mortality of wolves in reindeer (Rangifer tarandus) management areas and by dispersal to Bothnian Bay at times of the year when ice was not present. We suggest that when a small wolf population is separated from source populations by distance, barriers, and human exploitation, wildlife managers could promote the population's viability by limiting harvest in the peripheral areas or by introducing wolves from the source population.     

A Novel Endogenous Betaretrovirus in the Common Vampire Bat (Desmodus rotundus) Suggests Multiple Independent Infection and Cross-Species Transmission Events

The Desmodus rotundus endogenous betaretrovirus (DrERV) is fixed in the vampire bat D. rotundus population and in other phyllostomid bats but is not present in all species from this family. DrERV is not phylogenetically related to Old World bat betaretroviruses but to betaretroviruses from rodents and New World primates, suggesting recent cross-species transmission. A recent integration age estimation of the provirus in some taxa indicates that an exogenous counterpart might have been in recent circulation.     

North American History of Two Invasive Plant Species: Phytogeographic Distribution, Dispersal Vectors, and Multiple Introductions

The North American historic phytogeographic distribution of mugwort (Artemisia vulgaris) and Japanese knotweed (Polygonum cuspidatum), two invasive perennial species introduced from Eurasia and East Asia respectively, was recreated using herbarium records. The putative initial introduction of these two species differs by c.a. 400 years, but their patterns of geographic distribution, introduction pathways, and local dispersal pathways are similar. Both species showed the expected logistic growth relationship between range size and the time following introduction, with lag phases of nearly 400 and 50 years for mugwort and Japanese knotweed respectively. The intrinsic growth rate was greater in Japanese knotweed than mugwort for the US, Canada, and North America. Both species were frequently found along waterway, railroad, and road rights-of-way. Introduction pathways differed, with Japanese knotweed commonly labeled as an ornamental escape (151 collections), while mugwort was commonly cited as an inadvertent component of ship ballast (20 collections). These potential founding populations were located across the final distribution for both species, suggesting anthropogenic large-scale dispersal across North America with local secondary spread. Range expansion appears to be active for both species in the US while nearing the carrying capacity in Canada. Managers of mugwort and Japanese knotweed can make use of this information on their range expansion dynamics and dispersal pathways by reducing anthropogenic dispersal and focusing resources on satellite populations and invasion corridors.     

Population Dynamic and Genetic Consequences of Spatial Density-Dependent Dispersal in Patchy Populations

Predictions about sex-specific, spatial density-dependent dispersal and their demographic and genetic consequences were tested in experimental populations of root voles (Microtus oeconomus). Each population consisted of two demes inhabiting equal-sized habitat patches imbedded in a barren matrix area. We used a neutral two-allele allozyme marker to monitor gene flow. Initially, the two demes were genetically distinct and had different densities so that the size of a high-density deme (genotype bb) was four times larger than that of a low-density deme (genotype aa). The sex-specific dispersal pattern was in accordance with our prediction. Male dispersal was unconditional on deme-specific densities, and the majority of the first-generation males became dispersed from both demes, whereas female dispersal was strongly density dependent, so that dispersal took place exclusively from the high-density to the low-density deme. The demographic implication of this dispersal pattern was that the initial density difference between the demes was quickly canceled out. We built a mathematical model that predicted that the initially rare allele (a) would increase in frequency given the dispersal pattern, and this was supported by our experimental data. This result relies mostly on the density-independent male-dispersal strategy, which presumably stems from inbreeding avoidance. Our study highlights the importance of incorporating sex-specific dispersal strategies in population genetic models. Sex-biased dispersal may act as a deterministic force counteracting the tendency for stochastic loss of alleles in small and fragmented populations.     

Dispersal,Mating Events and Fine-Scale Genetic Structure in the Lesser Flat-Headed Bats

Population genetic structure has important consequences in evolutionary processes and conservation genetics in animals. Fine-scale population genetic structure depends on the pattern of landscape, the permanent movement of individuals, and the dispersal of their genes during temporary mating events. The lesser flat-headed bat (Tylonycteris pachypus) is a nonmigratory Asian bat species that roosts in small groups within the internodes of bamboo stems and the habitats are fragmented. Our previous parentage analyses revealed considerable extra-group mating in this species. To assess the spatial limits and sex-biased nature of gene flow in the same population, we used 20 microsatellite loci and mtDNA sequencing of the ND2 gene to quantify genetic structure among 54 groups of adult flat-headed bats, at nine localities in South China. AMOVA and F_ST estimates revealed significant genetic differentiation among localities. Alternatively, the pairwise F_ST values among roosting groups appeared to be related to the incidence of associated extra-group breeding, suggesting the impact of mating events on fine-scale genetic structure. Global spatial autocorrelation analyses showed positive genetic correlation for up to 3 km, indicating the role of fragmented habitat and the specialized social organization as a barrier in the movement of individuals among bamboo forests. The male-biased dispersal pattern resulted in weaker spatial genetic structure between localities among males than among females, and fine-scale analyses supported that relatedness levels within internodes were higher among females than among males. Finally, only females were more related to their same sex roost mates than to individuals from neighbouring roosts, suggestive of natal philopatry in females.     

Bat rabies in Illinois: 1965 to 1986

From 1968 to 1986, Illinois (USA) citizens and agencies submitted 4,272 bats to the Illinois Department of Public Health for rabies testing. Of this number, 6% tested positive, a rate comparable to similar studies from other parts of North America. Due to sampling biases, the true infection rate among bats in Illinois is probably lower than 6%. Additional analysis relied on a subsample (n = 2,433) of the specimens collected from 1965 to 1986. Prevalences were significantly different among years, but no linear trends were found over the study period. Evidence for a local outbreak of bat rabies was found. Prevalences for the species with sample sizes adequate for statistical analysis were, from high to low: hoary bat (Lasiurus cinereus), 11%; red bat (L. borealis), 5%; silver-haired bat (Lasionycteris noctivagans), 4%; little brown bat (Myotis lucifugus), 4%; big brown bat (Eptesicus fuscus), 3%; Keen's bat (Myotis keenii), 2%; and evening bat (Nycticeius humeralis), 2%. The higher prevalences found among the non-colonial species (hoary, red and silver-haired bats) were consistent with similar studies. Considerable annual variation in prevalences was found within species, and the prevalence rankings of the species varied over the study period. Prevalences were significantly higher in females (6%) than in males (4%) when species were pooled, but no significant differences between sexes were found within species. In contrast to the other species analyzed, all of which had sex ratios favoring females, the big brown bat sample had a large majority of males. Prevalences were significantly higher in adults (6%) than in juveniles (3%) when species were pooled. Within individual species, significant differences between age groups were found only for hoary and red bats; in two species, juveniles had higher prevalences. Above average prevalences were observed in May and August to November. Southern Illinois had the highest prevalences; prevalences were intermediate in the north and lowest in the central region. Overall, the patterns of rabies prevalence among bats submitted by the public in Illinois from 1965 to 1986 were similar to those reported from other parts of North America.     

Role of Upwelling on Larval Dispersal and Productivity of Gooseneck Barnacle Populations in the Cantabrian Sea: Management Implications

The effect of coastal upwelling on the recruitment and connectivity of coastal marine populations has rarely been characterized to a level of detail to be included into sound fishery management strategies. The gooseneck barnacle (Pollicipes pollicipes) fishery at the Cantabrian Coast (Northern Spain) is located at the fringes of the NW Spanish Upwelling system. This fishery is being co-managed through a fine-scale, interspersed set of protected rocks where each rock receives a distinct level of protection. Such interspersion is potentially beneficial, but the extent to which such spacing is consistent with mean larval dispersal distances is as yet unknown. We have simulated the spread of gooseneck barnacle larvae in the Central Cantabrian Coast using a high-resolution time-series of current profiles measured at a nearshore location. During a year of high upwelling activity (2009), theoretical recruitment success was 94% with peak recruitment predicted 56 km west of the emission point. However, for a year of low upwelling activity (2011) theoretical recruitment success dropped to 15.4% and peak recruitment was expected 13 km east of the emission point. This is consistent with a positive correlation between catch rates and the Integrated Upwelling Index, using a 4-year lag to allow recruits to reach commercial size. Furthermore, a net long-term westward larval transport was estimated by means of mitochondrial cytochrome c oxidase subunit I (COI) sequences for five populations in the Cantabrian Sea. Our results call into question the role of long distance dispersal, driven by the mesoscale processes in the area, in gooseneck barnacle populations and point to the prevalent role of small-scale, asymmetric connectivity more consistent with the typical scale of the co-management process in this fishery.     

Improved Analysis of Long-Term Monitoring Data Demonstrates Marked Regional Declines of Bat Populations in the Eastern United States

Bats are diverse and ecologically important, but are also subject to a suite of severe threats. Evidence for localized bat mortality from these threats is well-documented in some cases, but long-term changes in regional populations of bats remain poorly understood. Bat hibernation surveys provide an opportunity to improve understanding, but analysis is complicated by bats'' cryptic nature, non-conformity of count data to assumptions of traditional statistical methods, and observation heterogeneities such as variation in survey timing. We used generalized additive mixed models (GAMMs) to account for these complicating factors and to evaluate long-term, regional population trajectories of bats. We focused on four hibernating bat species – little brown myotis (Myotis lucifugus), tri-colored bat (Perimyotis subflavus), Indiana myotis (M. sodalis), and northern myotis (M. septentrionalis) – in a four-state region of the eastern United States during 1999–2011.Our results, from counts of nearly 1.2 million bats, suggest that cumulative declines in regional relative abundance by 2011 from peak levels were 71% (with 95% confidence interval of ±11%) in M. lucifugus, 34% (±38%) in P. subflavus, 30% (±26%) in M. sodalis, and 31% (±18%) in M. septentrionalis. The M. lucifugus population fluctuated until 2004 before persistently declining, and the populations of the other three species declined persistently throughout the study period. Population trajectories suggest declines likely resulted from the combined effect of multiple threats, and indicate a need for enhanced conservation efforts. They provide strong support for a change in the IUCN Red List conservation status in M. lucifugus from Least Concern to Endangered within the study area, and are suggestive of a need to change the conservation status of the other species. Our modeling approach provided estimates of uncertainty, accommodated non-linearities, and controlled for observation heterogeneities, and thus has wide applicability for evaluating population trajectories in other wildlife species.     

Interaction of Two Populations of the Blue-Green Algae in Co-Culture

Interaction of the populations of two species of blue-green algae Tolypothrix tenuis and Anabaena variabilis "1058", in mixed culture, was observed in three different ways: (1) The growth competition was studied in mixed-culture, where the two species grew in one batch of culture. (2) The effect of the filtrate, the extracellular products, from the culture of one species on the growth of the other species was studied. (3) In fitrated culture, two algal species were cultivated separately in either side a U-form container partitioned by a micro-pore membrane in the middle. The extracellular products were permeable through the membrane from one side to the other side. The influonce of the biologically active substances prosduced by the algae at different growth stages can be observed and estimated. The growth was measured by dry weight of biomass andchlorophyll-a content. The proportion of components of phycobiliprotein (e. g. ratio of phycocyanin to phycoerythrin) was estimated as the specific growth rate of two blue-greens in the mixed cultures. 1. The results obtained are summarized as follows. There were three types of the bioactivity of the extracellular products: (1) The lethal effects on each other caused the by the lethal agents of these two blue-greens were different. (2) The suppressive effects on growth by each other in one community were also found. (3) Effect on growth promotion exhibited only in the extracellular products of A. variabilis "1058". 2. The results indicate that there occur a direct competitive interaction of two populations. This Competition was controlled by the bio-active substances of the extracellular products which might regulate the structural composition and inturn, the succession of the comunity.     

Key Source Habitats and Potential Dispersal of Triatoma infestans Populations in Northwestern Argentina: Implications for Vector Control

Background

Triatoma infestans —the principal vector of the infection that causes Chagas disease— defies elimination efforts in the Gran Chaco region. This study identifies the types of human-made or -used structures that are key sources of these bugs in the initial stages of house reinfestation after an insecticide spraying campaign.

Methodology and Principal Findings

We measured demographic and blood-feeding parameters at two geographic scales in 11 rural communities in Figueroa, northwest Argentina. Of 1,297 sites searched in spring, 279 (21.5%) were infested. Bug abundance per site and female fecundity differed significantly among habitat types (ecotopes) and were highly aggregated. Domiciles (human sleeping quarters) had maximum infestation prevalence (38.7%), human-feeding bugs and total egg production, with submaximal values for other demographic and blood-feeding attributes. Taken collectively peridomestic sites were three times more often infested than domiciles. Chicken coops had greater bug abundance, blood-feeding rates, engorgement status, and female fecundity than pig and goat corrals. The host-feeding patterns were spatially structured yet there was strong evidence of active dispersal of late-stage bugs between ecotopes. Two flight indices predicted that female fliers were more likely to originate from kitchens and domiciles, rejecting our initial hypothesis that goat and pig corrals would dominate.

Conclusions and Significance

Chicken coops and domiciles were key source habitats fueling rapid house reinfestation. Focusing control efforts on ecotopes with human-fed bugs (domiciles, storerooms, goat corrals) would neither eliminate the substantial contributions to bug population growth from kitchens, chicken coops, and pig corrals nor stop dispersal of adult female bugs from kitchens. Rather, comprehensive control of the linked network of ecotopes is required to prevent feeding on humans, bug population growth, and bug dispersal simultaneously. Our study illustrates a demographic approach that may be applied to other regions and triatomine species for the design of innovative, improved vector control strategies.     

Differential Susceptibility of Two Melolontha Populations to Infections by the Fungus Beauveria brongniartii

The susceptibility of second-instar larvae of the European cockchafer, Melolontha melolontha L., originating from two different geographical locations was investigated with eight isolates of the insect pathogenic fungus Beauveria brongniartii (Sacc.) Petch. 77-94% of larvae from northern Italy (Auer, South Tyrolia) succumbed to mycosis with an average survival time (AST) of 22.9-40.1 days. Infections in larvae from south-western Switzerland (Bramois, Valais) were 28-72% and the ASTs varied between 34.7-56.4 days. Differences in susceptibility between the two host populations may be explained by the historical ages of the two populations and the presence of B. brongniartii resulting in a coevolution of tolerance between the host and pathogen. The Italian population is occasionally infected by B. brongniartii; in comparison, the Swiss population has existed for at least 50 years and regular infections by the pathogen are observed. Coevolution between B. brongniartii and M. melolontha from Switzerland may explain the apparent resistance of the host towards this pathogen in laboratory assays.