1,721,038 research outputs found
FIGURE 2 in Molecular and morphological evaluation of the aphid genus Hyalopterus Koch (Insecta: Hemiptera: Aphididae), with a description of a new species
No full textFIGURE 2. Phylogeny of the genus Hyalopterus constructed from 1322 concatenated base-pairs (plus two informative gaps) from all four genes. The data was partitioned by gene, using the models of evolution given in Table 2, in the program MrBAYES. Node support for each clade is given as a posterior probability value. See Table 1 for detailed sample information.Published as part of Lozier, Jeffrey D., Foottit, Robert G., Miller, Gary L., Mills, Nicholas J. & Roderick, George K., 2008, Molecular and morphological evaluation of the aphid genus Hyalopterus Koch (Insecta: Hemiptera: Aphididae), with a description of a new species, pp. 1-19 in Zootaxa 1688 on page 7, DOI: 10.5281/zenodo.18057
FIGURE 1. Locus specific phylogenies for COI, 12S in Molecular and morphological evaluation of the aphid genus Hyalopterus Koch (Insecta: Hemiptera: Aphididae), with a description of a new species
No full textFIGURE 1. Locus specific phylogenies for COI, 12S, EF-1α, and Buchnera 16S. All trees are from analyses performed with MRBAYES, with node support given as posterior probabilities. Collection data for each specimen are provided in Table 1 and models of sequence evolution used for each gene are provided in Table 2.Published as part of Lozier, Jeffrey D., Foottit, Robert G., Miller, Gary L., Mills, Nicholas J. & Roderick, George K., 2008, Molecular and morphological evaluation of the aphid genus Hyalopterus Koch (Insecta: Hemiptera: Aphididae), with a description of a new species, pp. 1-19 in Zootaxa 1688 on page 6, DOI: 10.5281/zenodo.18057
Recommended from our members
Behavioral and physiological ecology of mosquito disease vectors (Diptera: Culicidae) as a function of aquatic macrophyte invasions
Full text linkAbstractBehavioral and physiological ecology of mosquito disease vectors (Diptera: Culicidae) as a function of aquatic macrophyte invasionsbyRakim Kareem Turnipseed Doctor of Philosophy in Environmental Science, Policy, and ManagementUniversity of California, BerkeleyProfessor George K. Roderick, Chair To investigate the impact of invasive aquatic weeds on mosquito populations in the Sacramento-San Joaquin River Delta, field and laboratory experiments were conducted to test the impact of invasive aquatic plants (water hyacinth, water primrose, and Brazilian waterweed) on the behavioral ecology of Culex pipiens, a primary mosquito vector for West Nile Virus (WNV). In an outdoor caged experiment containing larval mosquitoes and predatory Mosquitofish, mosquito survival was significantly higher among high densities of the three plant species than vegetation-free water. In intermediate plant densities, mosquito survival was higher among water hyacinth than both Brazilian waterweed and water primrose. In low plant densities, mosquito survival was higher among water hyacinth than Brazilian waterweed and vegetation-free water. In another caged experiment containing mesocosms, mosquito larval development time was completed more rapidly in the presence of intermediate densities of water hyacinth than all other treatments. In an outdoor caged choice experiment, mosquitoes laid more eggs in mesocosms containing intermediate densities of water hyacinth than all other treatments. Laboratory choice tests and an olfactometer experiment revealed that mosquitoes were more attracted to water that contained plants or plant infusions than water alone. These results suggest that water hyacinth provides both physical and chemical cues to some species of mosquitoes. Effective management of invasive water hyacinth in waterways may thus reduce mosquito populations and reduce human health risk
Recommended from our members
Global Population Genetics and Evolution of Invasive Biotypes in the Whitefly Complex Bemisia tabaci
Full text linkThe presence of morphologically cryptic lineages with divergent molecular, ecological, and physiological traits within a species is an intriguing evolutionary phenomenon that offers unique opportunities for evolutionary genetics studies. One such system is the whitefly species complex Bemisia tabaci (Hemiptera: Aleyrodidae), which comprises several cryptic lineages, known as “biotypes” with worldwide distribution, including two of the world's worst invasive pests. In this dissertation I take a population genetics approach to examine the global genetic structure of B. tabaci biotypes, with a focus on the origins, historical demography, and invasion pathways of the two invasive biotypes, known as “B” and “Q”.I begin with a historical overview of multilocus molecular markers used to examine aspects of the biology, ecology, and genetics of the B. tabaci species complex. The first markers employed were allozymes, particularly esterases, which became the basis for the biotype nomenclature, and were substantiated by ecological and biological data. The exploration of various DNA based markers has established that biotypes within B. tabaci are exceptionally diverse genetically, in spite of their identical morphologies.Global population genetics analyses using microsatellite markers showed that well-characterized B. tabaci biotypes correspond to real genetic entities with strong geographic structure, and limited or no gene flow among them. The resulting genetic clusters from this analysis are in general agreement with the only well-resolved global phylogeny of the species, which is based on a single mitochondrial gene (cytochrome oxidase I). However, some cases of conflict in the two sets of markers do exist, perhaps associated with the different modes of inheritance, thus cautioning against the use of mitochondrial DNA as a single marker for species or subspecies delineation.Analysis of genetic data with more sophisticated Bayesian coalescent-based approaches offers the opportunity to study both contemporary and ancestral invasion pathways. Using such an approach, I showed that divergence histories of the invasive biotypes B and Q coincided with periods of extensive human movement and trade of agricultural goods in the Mediterranean, the Middle East, and Africa during the Iron and Bronze Ages, and the Roman period. Results also indicate that ancestral populations to the current B and Q biotypes had much larger effective sizes than those of emerging biotypes, a pattern consistent with expectations of diversification in invasive species.In a contemporary context, I investigated the recent invasion history of biotype Q in the USA. I found that populations introduced into the USA originated from both the Western and Eastern Mediterranean, in at least three independent cryptic invasions, and spread directly from a single initial introduction site, likely through plant trade.Findings from this dissertation underscore the practical importance of better monitoring invasions of this insect and other invasive pests at points of entry and dispersal through trade of plant material. From a theoretical perspective, this work adds insights into the origins of biotypes, both in the B. tabaci complex and more generally, emphasizing the demographic processes involved in diversification of invasive biotypes. The research highlights the potential to use B. tabaci in studies of broader applied as well as evolutionary significance
Recommended from our members
Phylogeography and population genetics of diving beetles in New Guinea
Full text linkPredaceous diving beetles (Dytiscidae) are common inhabitants of both lentic and lotic freshwater systems worldwide. They have played a major role in our understanding of the relationship between habitat stability and evolution for dispersal propensity.Numerous endemic diving beetles can be found in on the island of New Guinea. However, like most micro-fauna on remote islands, their evolutionary history and population ecology is largely unknown. In this series of studies, I use both traditional Sanger sequencing and next- generation sequencing techniques to explore the phylogenetic relationship of beetles in a genus as well as the population genetic patterns within a species
Recommended from our members
The Systematics, Evolution, and Ecology of Hawaiian Cydia (Lepidoptera: Tortricidae)
Full text linkCydia Hübner 1825 is a genus of moths in the family Tortricidae with 231 named species and subspecies and is distributed on all continents except Antarctica. As larvae, many species feed within reproductive structures, such as fruits, seeds, and flowers, under bark, or within fleshy stems of at least 65 host-plant species including angiosperms and conifers. Many species, including codling moth, pea moth, spruce seed moth, pine seedworms, filbertworm, and hickory shuckworm are considered pests of agriculture and forestry. As a result, the biology, natural enemies, and pheromones of several species have been well-studied. The nomenclature and classification of Cydia has also been well-studied but is less resolved. Nineteen different genus names have been proposed for species in this genus, with Laspeyresia Hübner, and Carpocapsa Treitschke being in common usage until relatively recently. Following the rules governing the International Code of Zoological Nomenclature, Cydia is the valid genus name for all species congeneric with the codling moth, Cydia pomonella (Linnaeus), the type species of the genus. The relationship of Cydia to other genera in the tribe Grapholitini is a topic of continued debate. Some authors have suggested that the tribe is an evolutionary grade while others have presented evidence that Grapholitini is a monophyletic clade. Although some secondary sexual characters have been proposed, the genus Cydia can claim no synapomorphies that can be found in all Cydia species. To better understand the systematics and evolution of this group more detailed morphological, molecular, and ecological data are needed for non-pest species.At least 21 endemic species of Cydia are known from the Hawaiian Islands. Males of most species have a ventral pouch below the cubital vein of the hindwings similar to C. latiferreana (Walsingham), C. maackiana (Danilevsky), and several other Cydia species to a lesser extent, although this feature appears to have arisen independently in the Hawaiian group. Larvae, where known, feed on endemic plants in the family Fabaceae. Identification of species is made difficult by extreme polymorphism of wing patterns for some widespread species and a general reduction of morphological features in the genitalia of male moths, while some features of female genitalia, particularly the antrum and lamella postvaginalis, have diagnostic value. Eight new species of Hawaiian Cydia are described (C. mauiensis n.sp., C. velocilimitata n.sp., C. haleakalaensis n.sp., C. makai n.sp., C. koaiae n.sp., C. hawaiiensis n.sp., C. acaciavora n.sp., and C. anomalosa n.sp.) based on wing patterns and features of male and female genitalia. The thirteen previously known species are redescribed because original descriptions were inconsistent among authors and based solely on wing patterns. Distributions, host-plant affinities, and natural enemies for each species are discussed.A molecular phylogeny of 66 specimens representing 14 Hawaiian Cydia species plus 20 outgroup species was constructed using nuclear and mitochondrial DNA to assess the relative importance of host-plant affinities and geographic isolation in their diversification. Hawaiian Cydia is monophyletic and nested well-within the genus. They appear to have arrived in the Hawaiian Islands after the rise of Maui based on the basal position of several Maui and Hawaii Island species throughout the phylogeny. The earliest diverging species feed on Canavalia and dispersed across the high islands. Subsequent shifts to feeding on Sophora chrysophylla then Acacia koa were followed by speciation and the filling of these niches across the islands. The origin of Hawaiian Cydia remains obscure, but appears to be a separate colonization of remote Oceania from Cydia pseusomalesana Clarke in French Polynesia. It is likely that several more species of Hawaiian Cydia await discovery while several others probably have gone extinct in the 100 years since they were first collected. A broader survey of outgroup taxa from Asia and the Americas, and more informative genes in a molecular phylogeny may help resolve the origins of Hawaiian Cydia
Recommended from our members
The origins of marine biodiversity: Speciation and diversification in Caribbean corals (family Faviidae) and Indo-Pacific parrotfishes (genus Scarus).
Full text linkSpecies-rich coral reef systems present a paradox to evolutionary biologists. Many reef invertebrates and fish have enormous dispersal potential via a planktonic larval stage, presumably leading to widespread patterns of genetic panmixia at large spatial scales. In the context of such high connectivity, how can we begin to get diversification? In this dissertation, I examine this question in two different systems, Caribbean corals and Indo-Pacific parrotfishes, and in two dimensions - time and space. The timing and tempo of species diversification can tell us how geological and environmental change is correlated to species formation. At the same time, the spatial distribution of genetic variation can reveal how contemporary processes may have contributed to population splitting and eventually speciation. In Chapter 1, I examine the history of reef systems in the Caribbean basin by looking at macroevolutionary patterns in faviid coral. Combining a newly compiled fossil stratigraphy with a time-calibrated molecular phylogeny of extant Caribbean Faviidae, I show that these Caribbean corals are not related to their Mediterranean confamilials, and that all living species appear to have originated during a period of rapid environmental change in Mio-Pliocene. In Chapter 2, I examine cryptic speciation and the patterns of diversity in the parrotfish, Scarus ghobban. Though this species was thought to have a pan-Indo-Pacific distribution, a new mitochondrial phylogeny shows deep divergence between Indian and Pacific Ocean clades. Furthermore, these clades form a species complex with a Panamanian endemic species, Scarus compressus, and a newly described Western Australian endemic species. Finally, in Chapter 3, I use population genetics methods to take a deeper look at the history of these fishes in the Pacific and assess the spatiotemporal structuring of diversity. My results suggest those Pleistocene sea level fluctuations, peripheral isolation, and hybridization all played significant roles in creating and maintaining diversity in this complex.By assessing taxonomic and population dynamics in the framework of historic environmental processes, I begin to answer fundamental questions about evolution in both Caribbean and Indo-Pacific tropical marine systems. The linking of patterns of diversity over multiple time scales can provide clues about processes that are important to ecology of marine taxa both in the past and in the present. Further, understanding the distribution of basic evolutionary units (e.g. species or ESUs) identifies fundamental units for conservation. With coral reef ecosystems currently highly threatened by anthropogenic change, this knowledge will be essential in future conservation efforts
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Recommended from our members
Bees in a Changing World: How land surface phenology, bee community distributions, and pollinator-plant interactions are impacted by urbanization and agriculture
Full text linkBackgroundUrbanization and agricultural intensification of landscapes are influential drivers of global change, resulting in direct impacts on ecological communities and leading to shifts in species distributions and interactions. These landscapes are novel for many reasons, but an often overlooked aspect is how the phenology of vegetation can vary between land use types. Because such differences can impact floral-dependent species, I explored how human-altered landscapes affect bees, a group of high economic and ecological importance. I measured the phenological diversity of vegetation across a human-altered landscape, compared these findings to a spatio-temporal pollinator distribution dataset, and investigated how pollinator visitation translates to seed set.ApproachI collected and observed bees for three field seasons in a peri-urban landscape on the outskirts of the San Francisco Bay Area, California, where urban, agricultural, and natural land use types interface. To assess patterns of phenological change, I used seasonal remote sensing data from MOD13Q1 vegetation indices, which I complimented with collections of 91 bee species groups across different land use types. I examined how differences in bee populations between land use types impacted plant-pollinator interactions by making standardized observations of floral visitation and measuring seed set of yellow starthistle (Centaurea solstitialis), a common grassland invasive abundant in all land use types.Results & ConclusionI found phenological patterns in vegetation indices, total bee abundance, and species richness of human-altered landscapes to be out of sync between urban, agricultural, and natural areas. Vegetation indices were significant predictors of total bee abundance, a relationship that improved when time lags were included. Bee visitation was highest in urban and agricultural land use contexts, but seed set rates in these human-altered landscapes were lower than in natural sites. These results emphasize the importance of differences in temporal dynamics between land use types, a previously overlooked mechanism of global change
- …
