1,105 research outputs found

    NEW INDONESIAN COUNTRY RECORDS AND SPECIES INFORMATION FOR MEALYBUGS (HEMIPTERA PSEUDOCOCCIDAE) IN WIRJATI’S HISTORIC COLLECTION

    Get PDF
    Between 1955 and 1960, a collection of slide-mounted mealybugs (Hemiptera: Coccomorpha: Pseudococcidae) was prepared by Mrs Wirjati, using samples collected between 1916 and 1960 from a variety of hosts in Indonesia. The collection is a record of which species were established in the country in 1960. The slides, deposited at the Indonesian Ministry of Agriculture in Java, are the earliest material in the national mealybug collection. There are 181 temporary slide mounts of unstained, waxy mealybugs mounted in agar or gum chloral media that have dried out to varying degrees. Specimens were retrieved from 50 representative slides and re-mounted as stained, archival mounts in Canada balsam. The method used to retrieve the specimens from the old mounts is described. The re-mounted specimens were re-identified using up-to-date, published identification keys, resulting in new identities for most of the  specimens. Fifteen species belonging to 12 genera were identified, however specimens from four of the slides  could not be identified beyond genus level. The Wirjati slides of Antonina thaiensis Takahashi, Hordeolicoccus nephelii (Takahashi) and Paraputo corbetti (Takahashi) are new country records. The differences between the fauna in Wirjati’s collection and that found in Indonesia today are discussed

    A taxonomic update of Takahashi’s historic collection of mealybugs (Hemiptera: Pseudococcidae) from Malaysia and Singapore

    Get PDF
    Dr. Ryoichi Takahashi collected mealybugs (Hemiptera: Coccomorpha: Pseudococcidae) from Peninsular Malaysia and Singapore in 1943–1944, and mounted them in 39 permanent slide mounts using Canada balsam. The slides are deposited in the Department of Agriculture, Kuala Lumpur, Malaysia. The objective of this research was to update the identification of Takahashi’s specimens using recent taxonomic keys. Some preparations on cavity slides were re-mounted to facilitate identification. The re-mounted specimens, and those on the original slides, were re-examined and 12 species were identified. The Takahashi samples of Pseudococcus comstocki (Kuwana) and Rastrococcus mangiferae (Green) are the earliest records of these species from Peninsular Malaysia

    Parasite infections in a social carnivore: Evidence of their fitness consequences and factors modulating infection load

    Get PDF
    There are substantial individual differences in parasite composition and infection load in wildlife populations. Few studies have investigated the factors shaping this heterogeneity in large wild mammals or the impact of parasite infections on Darwinian fitness, particularly in juveniles. A host's parasite composition and infection load can be shaped by factors that determine contact with infective parasite stages and those that determine the host's resistance to infection, such as abiotic and social environmental factors, and age. Host–parasite interactions and synergies between coinfecting parasites may also be important. We test predictions derived from these different processes to investigate factors shaping infection loads (fecal egg/oocyte load) of two energetically costly gastrointestinal parasites: the hookworm Ancylostoma and the intracellular Cystoisospora, in juvenile spotted hyenas (Crocuta crocuta) in the Serengeti National Park, in Tanzania. We also assess whether parasite infections curtail survival to adulthood and longevity. Ancylostoma and Cystoisospora infection loads declined as the number of adult clan members increased, a result consistent with an encounter‐reduction effect whereby adults reduced encounters between juveniles and infective larvae, but were not affected by the number of juveniles in a clan. Infection loads decreased with age, possibly because active immune responses to infection improved with age. Differences in parasite load between clans possibly indicate variation in abiotic environmental factors between clan den sites. The survival of juveniles (<365 days old) to adulthood decreased with Ancylostoma load, increased with age, and was modulated by maternal social status. High‐ranking individuals with low Ancylostoma loads had a higher survivorship during the first 4 years of life than high‐ranking individuals with high Ancylostoma loads. These findings suggest that high infection loads with energetically costly parasites such as hookworms during early life can have negative fitness consequences

    Bigger is not always better : viability selection on body mass varies across life stages in a hibernating mammal

    Get PDF
    ACKNOWLEDGEMENTS: We would like to express our thanks to all the hard-working marmoteers, across the course of the study, that helped to collect the annual field data. In addition, we would like to specifically thank Kenneth B. Armitage for starting the project and access to the long-term body mass data. This work 431 was supported by an EASTBIO PhD studentship from the Biotechnology and Biological Sciences Research Council (BBSRC) and the University of Aberdeen, which was awarded to A.H.M.J. D.T.B was supported by the National Geographic Society, UCLA (Faculty Senate and the Division of Life Sciences), a Rocky Mountain Biological Laboratory research fellowship, and NSF-IDBR-0754247, DEB435 1119660 and 1557130 (to DTB); and NSF-DBI 0242960, 0731346, and 1262713 (to the RMBL).Peer reviewedPublisher PD

    Increased allocation to reproduction reduces future competitive ability in a burying beetle

    Get PDF
    1. The existence of a trade-off between current and future reproduction is a fundamental prediction of life-history theory. Support for this prediction comes from brood size manipulations, showing that caring for enlarged broods often reduces the parent's future survival or fecundity. However, in many species, individuals must invest in competing for the resources required for future reproduction. Thus, a neglected aspect of this trade-off is that increased allocation to current reproduction may reduce an individual's future competitive ability. 2. We tested this prediction in the burying beetle, Nicrophorus vespilloides, a species where parents care for their offspring and where there is fierce competition for resources used for breeding. 3. We manipulated reproductive effort by providing females with either a small brood of 10 larvae or a large brood of 40 larvae and compared the ability of these females, and virgin females that had no prior access to a carcass, to compete for a second carcass against a virgin competitor. 4. We found that increased allocation to current reproduction reduced future competitive ability, as females that had cared for a small brood were more successful when competing for a second carcass against a virgin competitor than females that had cared for a large brood. In addition, the costs of reproduction were offset by the benefits of feeding from the carcass during an initial breeding attempt, as females that had cared for a small brood were better competitors than virgin females that had no prior access to a carcass, whilst females that had cared for a large brood were similar in competitive ability to virgin females. 5. Our results add to our understanding of the trade-off between current and future reproduction by showing that this trade-off can manifest through differences in future competitive ability and that direct benefits of reproduction can offset some of these costs. 16-Apr-2020Read me for "Data from RichardsonStephensSmiseth_JournalofAnimalEcology.csv" This data file consists of a comma separated values spreadsheet (.csv), which provides data for the effects of allocation to reproduction via brood size manipulation on future competitive ability in contests for a carcass. Each line in the spreadsheet represents an individual, experimental female. female_id – individual ID of the female. eclosion – date of eclosion. death – date of death. lifespan – number of days lived from eclosion to death. treatment_code – experimental treatment (control = no breeding attempt, ten = brood of ten larvae, forty = brood of forty larvae). won – outcome of the contest (Y = female won, N = female lost, NA = unclear). outcome_clear – was the outcome of the contest clear? (Y = yes, N = no). size – size of the female, measured as pronotum width (mm). competitor_size – size of the virgin female competitor measured as pronotum width (mm). size_difference – absolute difference in size between focal female and her competitor (mm). brood_size – number of larvae in the experimental brood at dispersal. dot – number and placement of identifying marks (1 or 2 = number of dots, L or R = left or right elytra). female_pre_mass – female mass prior to initial reproductive attempt (g). female_post_mass – female mass after initial reproductive attempt (g). female_mass_change – female mass change during initial reproductive attempt (g). brood_mass_pre – mass of the brood of larvae when cross fostered and given to the female (g). brood_mass_post – mass of the brood of larvae at dispersal from the carcass (g). breeding_carcass_mass – mass of the mouse carcass used for breeding (g). competition_carcass_mass – mass of the mouse carcass females competed for (g). Funding provided by: Natural Environment Research CouncilCrossref Funder Registry ID: http://dx.doi.org/10.13039/501100000270Award Number: NE/L002558/

    Variation in developmental rates is not linked to environmental unpredictability in annual killifishes

    Get PDF
    Comparative evidence suggests that adaptive plasticity may evolve as a response to predictable environmental variation. However, less attention has been placed on unpredictable environmental variation, which is considered to affect evolutionary trajectories by increasing phenotypic variation (or bet hedging). Here, we examine the occurrence of bet hedging in egg developmental rates in seven species of annual killifish that originate from a gradient of variation in precipitation rates, under three treatment incubation temperatures (21, 23, and 25 degrees C). In the wild, these species survive regular and seasonal habitat desiccation, as dormant eggs buried in the soil. At the onset of the rainy season, embryos must be sufficiently developed in order to hatch and complete their life cycle. We found substantial differences among species in both the mean and variation of egg development rates, as well as species-specific plastic responses to incubation temperature. Yet, there was no clear relationship between variation in egg development time and variation in precipitation rate (environmental predictability). The exact cause of these differences therefore remains enigmatic, possibly depending on differences in other natural environmental conditions in addition to precipitation predictability. Hence, if species-specific variances are adaptive, the relationship between development and variation in precipitation is complex and does not diverge in accordance with simple linear relationships

    Global patterns of body size evolution are driven by precipitation in legless amphibians

    Get PDF
    This is the author accepted manuscript. The final version is available from Wiley via the DOI in this recordBody size shapes ecological interactions across and within species, ultimately influencing the evolution of large-scale biodiversity patterns. Therefore, macroecological studies of body size provide a link between spatial variation in selection regimes and the evolution of animal assemblages through space. Multiple hypotheses have been formulated to explain the evolution of spatial gradients of animal body size, predominantly driven by thermal (Bergmann's rule), humidity (‘water conservation hypothesis’) and resource constraints (‘resource rule’, ‘seasonality rule’) on physiological homeostasis. However, while integrative tests of all four hypotheses combined are needed, the focus of such empirical efforts needs to move beyond the traditional endotherm–ectotherm dichotomy, to instead interrogate the role that variation in lifestyles within major lineages (e.g. classes) play in creating neglected scenarios of selection via analyses of largely overlooked environment–body size interactions. Here, we test all four rules above using a global database spanning 99% of modern species of an entire Order of legless, predominantly underground-dwelling amphibians (Gymnophiona, or caecilians). We found a consistent effect of increasing precipitation (and resource abundance) on body size reductions (supporting the water conservation hypothesis), while Bergmann's, the seasonality and resource rules are rejected. We argue that subterranean lifestyles minimize the effects of aboveground selection agents, making humidity a dominant selection pressure – aridity promotes larger body sizes that reduce risk of evaporative dehydration, while smaller sizes occur in wetter environments where dehydration constraints are relaxed. We discuss the links between these principles with the physiological constraints that may have influenced the tropically-restricted global radiation of caecilians.Natural Environment Research Council (NERC)O2National Lottery - Big Lottery Fun

    Ambulatory dispersal in Tetranychus urticae: an artificial selection experiment on propensity to disperse yields no response

    Get PDF
    Dispersal to new hosts is an important process for an invasive herbivore, such as the two-spotted spider mite. A recent study, using artificial selection experiments, has suggested that genetic variation and genetic trade-offs are present for propensity to disperse in this species. However, due to the experimental setup alternative explanations for the response to selection could not be ruled out. Using an altered setup, we investigated whether the propensity for ambulatory dispersal differs genetically between individuals and whether genetic correlations with life-history traits exist. Upward and downward selection on propensity to leave the colony was performed for seven generations in four replicate artificial selection experiments and the results were compared to control lines. No consistent responses to selection were found and no significant effect on life-history traits (oviposition rate, juvenile survival, development rate and number of adult offspring) or sex ratio was present across the replicates. The data suggest that our base population of spider mites harbours at best a low amount of additive genetic variation for this behaviour

    Life history evolution, species differences and phenotypic plasticity in hemiparasitic eyebrights (Euphrasia)

    Get PDF
    Premise of the study: Species delimitation in parasitic organisms is challenging as traits used in the identification of species are often plastic and vary depending on the host. Here, we use species from a recent radiation of generalist hemiparasitic Euphrasia to investigate trait variation and trait plasticity. We test whether Euphrasia species show reliable trait differences, investigate whether these differences correspond to life history trade-offs between growth and reproduction, and quantify plasticity in response to host species. Methods: We perform common garden experiments to evaluate trait differences between eleven Euphrasia taxa grown on a common host, document phenotypic plasticity when a single Euphrasia species is grown on eight different hosts, and relate our observations to trait differences recorded in the wild. Key results: Euphrasia exhibit variation in life history strategies; some individuals transition rapidly to flower at the expense of early season growth, while others invest in vegetative growth and delay flowering. Life history differences are present between some species, though many related taxa lack clear-cut trait differences. Species differences are further blurred by phenotypic plasticity—many traits are plastic and change with host type or between environments. Conclusions: Phenotypic plasticity in response to host and environment confounds species delimitation in Euphrasia. When grown in a common garden environment it is possible to identify some morphologically distinct taxa, though others represent morphologically similar shallow segregates. Trait differences present between some species and populations demonstrates the rapid evolution of distinct life history strategies in response to local ecological conditions."Manyhosts.csv" contains morphological measurements from one Euphrasia arctica population from North Berwick, Scotland, grown with eight hosts. "Manyspecies.csv" contains morphological measurements of five Euphrasia species and six natural Euphrasia hybrids grown on a single host, Trifolium repens. "Earlylate.csv" contains repeated growth measurements at different times of year, used in correlations of height at end of season. "Wildcommon.csv" contains Euphrasia species grown in the common garden experiment and wild collected plants for trait comparisons.Data collection is detailed in the associated manuscript. Post collection data processing can be viewed at: https://github.com/Euphrasiologist/phenotypic_plasticity_euphrasi
    • 

    corecore