1366 research outputs found
Sort by
Diversification dynamics of freshwater bivalves (Unionidae: Parreysiinae: Coelaturini) indicate historic hydrographic connections throughout the East African Rift System
Get PDFInvertebrates are exceptionally diverse, but many are in decline because of anthropogenic changes to their habitat. This situation is particularly problematic for taxa that are not well monitored or taxonomically poorly understood, because the lack of knowledge hampers conservation. Despite their important functional role in freshwater ecosystems, African bivalves of the family Unionidae remain poorly studied compared to their highly threatened relatives in Europe, the U.S.A. and Canada. To resolve relationships and to study diversification dynamics in space and time, we performed time-calibrated phylogenetic studies and biogeographical modeling on the unionids from the East African Rift System and surroundings, including representatives of all currently recognized Afrotropical genera except for Brazzaea (and Unio from southern Africa). Our analyses indicate that all sampled Afrotropical unionids belong to the tribe Coelaturini (subfamily Parreysiinae), as does the genus Moncetia from Lake Tanganyika, which is currently attributed to the family Iridinidae. Colonization of Africa from Eurasia by Parreysiinae occurred ~17 Ma ago, and the subsequent diversification of Coelaturini in Africa continued at a steady pace, although net diversification decreased over time as more niches and ecoregions became occupied. Clades in Coelaturini largely reflect drainage basins, with the oldest lineages and highest regional diversity occurring in Lake Tanganyika, followed by the Congo Basin watershed in general. The species assemblage of Lake Tanganyika reflects multiple independent events of colonization and intralacustrine diversification since the Late Miocene or Early Pliocene. The clades of other regions, including that containing the species from Lake Malawi, are comparatively young. Biogeographical analyses indicate that the colonization history was mainly driven by cladogenesis in sympatry, whereas few anagenetic events contributed to the modern distribution of Coelaturini. Ancestral range estimations demonstrate that Coelaturini originated in the Victoria and/or Tanganyika ecoregions, and that the Congo Basin played an essential role in the colonization of Africa by Coelaturini.The attached document is the authors’ final accepted/submitted version of the journal article. You are advised to consult the publisher’s version if you wish to cite from it.NHM Repositor
From text to structured data: Converting a word-processed floristic checklist into Darwin Core Archive format
Get PDFThe paper describes a pilot project to convert a conventional floristic checklist, written in a standard word processing program, into structured data in the Darwin Core Archive format. After peer-review and editorial acceptance, the final revised version of the checklist was converted into Darwin Core Archive by means of regular expressions and published thereafter in both human-readable form as traditional botanical publication and Darwin Core Archive data files. The data were published and indexed through the Global Biodiversity Information Facility (GBIF) Integrated Publishing Toolkit (IPT) and significant portions of the text of the paper were used to describe the metadata on IPT. After publication, the data will become available through the GBIF infrastructure and can be re-used on their own or collated with other data.This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.NHM Repositor
Comparative morphology of immature Trictenotoma formosana Kriesche, 1919 and systematic position of the Trictenotomidae (Coleoptera, Tenebrionoidea)
Get PDFDetailed description and illustrations of immature Trictenotoma Gray, 1832 (Trictenotomidae Blanchard, 1845) are presented for the first time, based on larvae and pupae of T. formosana Kriesche, 1919. Characters exhibited by the mature larva are similar to those described by Gahan (1908) for T. childreni Gray, 1832, which was based on a single specimen. The phylogenetic position of Trictenotomidae has varied among Scarabaeoidea, Chrysomeloidea and Tenebrionoidea, though recent studies place the family clearly among the latter. Features of the immature stages described here corroborate this placement. Evidence supports placement within or near the “salpingid group” (Pythidae, Salpingidae, Boridae, Pyrochroidae). Distinguishing features of the mature trictenotomid larva include the absence of stemmata, antennal sensorium, urogomphal pit(s) and lip, the presence of paired series of longitudinal ridges on the meso- and metathorax and abdominal tergites 1–8 and sternites 2–8, a paired arcuate row of 12–15 asperities on the anterior margin of sternite 9 and relatively short, upturned urogomphi. The systematic position of trictenotomids within the Tenebrionoidea Latreille, 1802 is confirmed. The phylogenetic relationships among Trictenotomidae and other “salpingid group” members (e.g., Pythidae Solier, 1834 and Salpingidae Leach, 1815) are highlighted and discussed, solving an almost two centuries old puzzle in Coleoptera systematics.This is an open access article, available to all readers online, published under a creative commons licensing (https://creativecommons.org/licenses/by/4.0/). The attached file is the published version of the article.NHM Repositor
Pigs vs people: the use of pigs as analogues for humans in forensic entomology and taphonomy research
Get PDFMost studies of decomposition in forensic entomology and taphonomy have used non-human cadavers. Following the recommendation of using domestic pig cadavers as analogues for humans in forensic entomology in the 1980s, pigs became the most frequently used model cadavers in forensic sciences. They have shaped our understanding of how large vertebrate cadavers decompose in, for example, various environments, seasons and after various ante- or postmortem cadaver modifications. They have also been used to demonstrate the feasibility of several new or well-established forensic techniques. The advent of outdoor human taphonomy facilities enabled experimental comparisons of decomposition between pig and human cadavers. Recent comparisons challenged the pig-as-analogue claim in entomology and taphonomy research. In this review, we discuss in a broad methodological context the advantages and disadvantages of pig and human cadavers for forensic research and rebut the critique of pigs as analogues for humans. We conclude that experiments using human cadaver analogues (i.e. pig carcasses) are easier to replicate and more practical for controlling confounding factors than studies based solely on humans and, therefore, are likely to remain our primary epistemic source of forensic knowledge for the immediate future. We supplement these considerations with new guidelines for model cadaver choice in forensic science research.Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.NHM Repositor
3D virtual histology at the host/parasite interface: visualisation of the master manipulator, Dicrocoelium dendriticum, in the brain of its ant host
Get PDFSome parasites are able to manipulate the behaviour of their hosts to their own advantage. One of the most well-established textbook examples of host manipulation is that of the trematode Dicrocoelium dendriticum on ants, its second intermediate host. Infected ants harbour encysted metacercariae in the gaster and a non-encysted metacercaria in the suboesophageal ganglion (SOG); however, the mechanisms that D. dendriticum uses to manipulate the ant behaviour remain unknown, partly because of a lack of a proper and direct visualisation of the physical interface between the parasite and the ant brain tissue. Here we provide new insights into the potential mechanisms that this iconic manipulator uses to alter its host’s behaviour by characterising the interface between D. dendriticum and the ant tissues with the use of non-invasive micro-CT scanning. For the first time, we show that there is a physical contact between the parasite and the ant brain tissue at the anteriormost part of the SOG, including in a case of multiple brain infection where only the parasite lodged in the most anterior part of the SOG was in contact with the ant brain tissue. We demonstrate the potential of micro-CT to further understand other parasite/host systems in parasitological research.Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/.NHM Repositor
Cryptic Diversity within the Major Trypanosomiasis Vector Glossina fuscipes Revealed by Molecular Markers
Get PDFBackground
The tsetse fly Glossina fuscipes s.l. is responsible for the transmission of approximately 90% of cases of human African trypanosomiasis (HAT) or sleeping sickness. Three G. fuscipes subspecies have been described, primarily based upon subtle differences in the morphology of their genitalia. Here we describe a study conducted across the range of this important vector to determine whether molecular evidence generated from nuclear DNA (microsatellites and gene sequence information), mitochondrial DNA and symbiont DNA support the existence of these taxa as discrete taxonomic units.
Principal Findings
The nuclear ribosomal Internal transcribed spacer 1 (ITS1) provided support for the three subspecies. However nuclear and mitochondrial sequence data did not support the monophyly of the morphological subspecies G. f. fuscipes or G. f. quanzensis. Instead, the most strongly supported monophyletic group was comprised of flies sampled from Ethiopia. Maternally inherited loci (mtDNA and symbiont) also suggested monophyly of a group from Lake Victoria basin and Tanzania, but this group was not supported by nuclear loci, suggesting different histories of these markers. Microsatellite data confirmed strong structuring across the range of G. fuscipes s.l., and was useful for deriving the interrelationship of closely related populations.
Conclusion/Significance
We propose that the morphological classification alone is not used to classify populations of G. fuscipes for control purposes. The Ethiopian population, which is scheduled to be the target of a sterile insect release (SIT) programme, was notably discrete. From a programmatic perspective this may be both positive, given that it may reflect limited migration into the area or negative if the high levels of differentiation are also reflected in reproductive isolation between this population and the flies to be used in the release programme.
Author Summary
Glossina fuscipes s.l. tsetse flies are responsible for transmission of approximately 90% of the cases of Human African Typanosomiasis in Sub Saharan Africa. It was previously proposed on the basis of morphology that G. fuscipes is composed of three sub-species. Using genetic evidence from G. fuscipes nuclear, mitochondrial and symbiont DNA, we show that the morphological subspecies do not correspond well to genetic differences between the flies and morphologically similar flies may have arisen more than once in the evolution of this species. Instead, we found at least 5 main allopatrically distributed groups of G. fuscipes flies. The most genetically distinct group of flies originated from Ethiopia, where a sterile insect release programme is planned. Given that tsetse control often exploits species-specific behaviours there is a pressing need to establish the taxonomic status and ranges of these five groups. Moreover given that we were only able to perform limited sampling in many parts of the species distribution further groups within G. fuscipes are likely to be awaiting discovery.© 2011 Dyer et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.NHM Repositor
Deep-Sea Exploration of the US Gulf of Mexico with NOAA Ship Okeanos Explorer
Get PDFOceanography articles are licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution, and reproduction in any medium or format as long as users cite the materials appropriately (e.g., authors, Oceanography, volume number, issue number, page number[s], figure number[s], and DOI for the article), provide a link to the Creative Commons license, and indicate the changes that were made to the original content.NHM Repositor
Conservation challenges for a microscopic world: Documenting desmids
Get PDFFreshwaters are amongst the most threatened habitats in the world. Many waters in the UK have irreversibly changed or disappeared and those that remain are under immense pressure largely due to habitat loss, pollution, recreation, abstraction and the introduction of nonnative species. Climate change is also becoming a major concern for freshwater life. The conservation of biodiversity associated with freshwaters has for obvious reasons focused on the larger animal and plant species, however, microorganisms such as the algae play a fundamental role in these ecosystems and constitute rich assemblages which are also threatened. Desmids are a diverse group of freshwater microalgae which dominate the algal flora of nutrient poor, lentic waters and are particularly diverse in such oligotrophic habitats as moorland pools and shallow lakes. They are ecologically highly sensitive, acting as useful indicators of water quality. The conservation of microscopic organisms poses many difficulties due to taxonomic impediments and lack of knowledge of ecology and distribution. To gain a better understanding of desmid distribution patterns across the UK and Ireland this project has undertaken the digitisation of 50 years worth of biological recording data collated by desmid expert David Williamson. Reliable datasets of species occurrence are essential to biodiversity research and conservation so these data, in conjunction with published literature, will provide a basis for developing a more robust checklist of verified desmid taxa known to occur in the UK and Ireland and provide distribution information for these taxa. Furthermore, this will enable us to review the conservation status of the desmid flora and provide data of practical use in the designation and management of protected freshwater habitats.© British Phycological Society. Final manuscript version attached.NHM Repositor
Ineffectiveness of light emitting diodes as underwater deterrents for Long-tailed Ducks Clangula hyemalis
Get PDFGillnet bycatch accounts for over 400,000 bird mortalities worldwide every year, affectinga wide variety of species, especially those birds that dive when foraging. Technologicalsolutions to improve gillnet visibility or deter birds from approaching nets, such as LEDlights, are essential for aiding diving birds to perceive nets as a hazard. Designing suchsolutions requires obtaining visual and behavioural ecology information from species toassess their ability to see the warning devices, and to examine their behavioural responsesto them. Seaducks, particularly Long-tailed DucksClangula hyemalis,have high bycatchmortality rates. We examined the visualfields of four Long-tailed Ducks to understandtheir three-dimensional view around the head. The visualfield characteristics of thisspecies indicate a reliance on visual guidance for foraging associated with their capture ofvaried, mobile prey in their generalist diet. We subsequently conducted dive tank trials totest the effectiveness of 12 different LED treatments as visual deterrents to the underwaterforaging behaviour of 8 Long-tailed Ducks. During each trial, ducks were offered foodrewards from a specific underwater location in a dive tank, having the choice of whether totake the food or not. At the same time, they were exposed to either one LED light or thecontrol (no light) to determine whether the presence of each light affected the foragingsuccess rate of dives compared to the control. Exposure of ducks to all 13 treatmentcombinations was randomised over the trial period. White lights with an increasingflashrate were shown to have a significant positive effect on foraging success, and likely acted asa visual attractant, rather than as a deterrent. No light treatment significantly reduced theforaging success of ducks. LED lights did not inhibit the feeding of Long-tailed Ducks. Suchlights may be ineffective as underwater visual deterrents when deployed on gillnets, whilewhiteflashing lights may make foraging sites more attractive to Long-tailed Ducks.©2020 The Authors. Published by Elsevier B.V. This is an open access article under the CCBY-NC-ND license.NHM Repositor
Entrapment in plastic debris endangers hermit crabs
Get PDFCC-BY-NC-ND at https://www.sciencedirect.com/science/article/pii/S0304389419316577Significant quantities of plastic debris pollute nearly all the world’s ecosystems, where it persists for decades and poses a considerable threat to flora and fauna. Much of the focus has been on the marine environment, with little information on the hazard posed by debris accumulating on beaches and adjacent vegetated areas. Here we investigate the potential for beach debris to disrupt terrestrial species and ecosystems on two remote islands. The significant quantities of debris on the beaches, and throughout the coastal vegetation, create a significant barrier which strawberry hermit crabs (Coenobita perlatus) encounter during their daily activities. Around 61,000 (2.447 crabs/m2) and 508,000 crabs (1.117 crabs/m2) are estimated to become entrapped in debris and die each year on Henderson Island and the Cocos (Keeling) Islands, respectively. Globally, there is an urgent need to establish a clear link between debris interactions and population persistence, as loss of biodiversity contributes to ecosystem degradation. Our findings show accumulating debris on these islands has the potential to seriously impact hermit crab populations. This is important for countless other islands worldwide where crabs and debris overlap, as crabs play a crucial role in the maintenance of tropical ecosystems.© 2019 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license
(http://creativecommons.org/licenses/BY-NC-ND/4.0/). The attached file is the published pdf.NHM Repositor