232 research outputs found
Reported climate change impacts on cloud forest ants are driven by sampling bias : a critical evaluation of Warne et al. (2020)
We present a reanalysis of the study by Warne et al. (2020), where authors reported substantial changes through time in a cloud forest ant assemblage in response to climate change after a decade. We show that these changes are due to major differences between the sampling periods in terms of sampling methods and effort. We stress the need for a fully standardized methodology to distinguish true climate change effects on communities from sampling bias.Czech Science Foundation and Leverhulme Trust.http://www.wileyonlinelibrary.com/journal/btphj2022Zoology and Entomolog
A simple method to account for thermal boundary layers during the estimation of CTmax in small ectotherms
As temperatures rise, understanding how ectotherms will become impacted by thermal stress is of critical importance. In this context, many researchers quantify critical temperatures – these are the upper (CTmax) and lower (CTmin) thermal limits at which organisms can no longer function. Most studies estimate CTs using bath-based methods where organisms are submerged within a set thermal environment. Plate-based methods (i.e. hot plates), however, offer huge opportunity for automation and are readily available in many lab settings. Plates, however, generate a unidirectional thermal boundary layer above their surface which means that the temperatures experienced by organisms of different sizes is different. This boundary layer effect can bias estimates of critical temperatures. Here, we test the hypothesis that biases in critical temperature estimation on hot plates are driven by organism height. We also quantify the composition of the boundary layer in order to correct for these biases. We assayed four differently sized species of UK ants for their CTmax in dry baths (with no boundary layer) and on hot plates (with a boundary layer). We found that hot plates overestimated the CTmax values of the different ants, and that this overestimate was larger for taller species. By statistically modelling the thickness of the thermal boundary layer, and combining with estimates of species height, we were able to correct this overestimation and eliminate methodological differences. Our study provides two main findings. First, we provide evidence that organism height is positively related to the bias present in plate-based estimates of CTmax. Second, we show that a relatively simple statistical model can correct for this bias. By using simple corrections for boundary layer effects, as we have done here, researchers could open up a new possibility space in the design and implementation of thermal tolerance assays using plates rather than restrictive dry or water baths
Low levels of intraspecific trait variation in a keystone invertebrate group
The trait-based approach to ecology promises to provide a mechanistic understanding of species distributions and ecosystem functioning. Typically, trait analyses focus on average species trait values and assume that intraspecific variation is small or negligible. Recent work has shown, however, that intraspecific trait variation can often contribute substantially to total trait variation. Whilst many studies have investigated intraspecific variation in plants, very few have done so for invertebrates. There is no research on the level of intraspecific trait variation in ants (Hymenoptera: Formicidae), despite the fact that there is a growing body of literature using ant morphological trait data and demonstrating that these insects play important roles in many ecosystems and food webs. Here, we investigate the intraspecific variability of four commonly used ant morphological traits from 23 species from the Maloti-Drakensberg Mountains of southern Africa. In total, we measured 1145 different individuals and made 6870 trait measurements. Intraspecific variation accounted for only 1–4% of total trait variation for each of the four traits we analysed. We found no links between intraspecific variation, phylogeny and elevation. On average, six individuals generated robust species means but under biased sampling scenarios 20 individuals were needed. The low levels of intraspecific morphological variation that we find suggest that the approach of using mean species traits is valid, in this fauna at least. Regardless, we encourage ant trait ecologists to measure greater numbers of individuals, especially across gradients, to shed further light on intraspecific variation in this functionally important group of insects
Using computer vision to understand the global biogeography of ant color
Organisms use color to serve a variety of biological functions, including camouflage, mate attraction and thermoregulation. The potential adaptive role of color is often investigated by examining patterns of variation across geographic, habitat and life-history gradients. This approach, however, presents a data collection trade-off whereby researchers must either maximize intraspecific detail or taxonomic and geographic coverage. This limits our ability to fully understand color variation across entire taxonomic groups at global scales. We provide a solution by extracting color data from more than 44 000 individual specimens of ants, representing over 14 000 species and morphospecies, using a computer vision algorithm on ant head images. Our analyses on this dataset reveal that ants are dominated by variation in the dark-pale color spectrum, that much of this variation is held within species, and that, overall, a suite of popular ecogeographic hypotheses are unable to explain intra- and interspecific variation in ant color. This is in contrast to previous work at the assemblage level in ants and other invertebrates demonstrating clear and strong links between variables such as temperature and the average color of entire assemblages. Our work applies a novel computational approach to the study of large-scale trait diversity. By doing so, we reveal previously unknown levels of intraspecific variation. Similar approaches may unlock a vast amount of data residing in museum and specimen databases and establish a digital platform for a data collection revolution in functional biogeography
Elevational gradients of reptile richness in the southern Western Ghats of India: Evaluating spatial and bioclimatic drivers
TparvaDB: a database to support Theileria parva vaccine development
We describe the development of TparvaDB, a comprehensive resource to facilitate research towards development of an East Coast fever vaccine, by providing an integrated user-friendly database of all genome and related data currently available for Theileria parva. TparvaDB is based on the Generic Model Organism Database (GMOD) platform. It contains a complete reference genome sequence, Expressed Sequence Tags (ESTs), Massively Parallel Signature Sequencing (MPSS) expression tag data and related information from both public and private repositories. The Artemis annotation workbench provides online annotation functionality. TparvaDB represents a resource that will underpin and promote ongoing East Coast fever vaccine development and biological research
The effect of fire on ant assemblages does not depend on habitat openness but does select for large, gracile predators
Ecosystems can respond in a variety of ways to the same agent of disturbance. In some contexts,
fire causes large and long-lasting changes to ecological communities. In others, fire has a limited or
short-lived impact on assemblages of animals and plants. Understanding why this occurs is critical if we
are to manage these kinds of disturbances across the globe. A recent synthesis proposed that these seemingly
idiosyncratic responses to fire can be understood in the context of habitat openness pre-disturbance.
Assemblages in open habitats should respond less to a single fire event that those in closed habitats. We
provide a test of this hypothesis by examining the response of ant (Hymenoptera: Formicidae) communities
to large-scale fire events in three habitats of different natural canopy openness on the Peloponnese
peninsula in Greece. We also test the hypothesis that assemblage responses to fire are trait dependent. Fire
simplifies the physical structure of the environment, increases insolation, and limits opportunities for ants
to exploit herbivorous feeding strategies. Consequently, we predict that ants will face a strong environmental
filter between unburnt and recently burnt plots, which will be reflected in their functional morphology.
Our analysis shows that burnt plots have more individual ants, more species and an almost complete compositional
change relative to unburnt plots. These changes do not depend on initial canopy openness.
Rather, we suggest that openness must be interpreted relative to the study taxon; for ants, openness should
be measured closer to the ground level. In our study, ground-level openness does not vary across the plots,
which may explain the results. Furthermore, ants in burnt plots are significantly larger, have relatively
longer legs, relatively longer mandibles, and more elongate heads. This morphotype fits with our prediction
of ants that can move and feed successfully in the burnt micro-landscape. Ultimately, more work is
needed to fully explore the relationship between habitat openness and the response to fire. Our results
showing a filtered set of ant morphologies in burnt environments suggest that ant traits may offer a further
way forward to understand the faunal response to fire and disturbance in general.http://www.esajournals.org/loi/ecspam2022Zoology and Entomolog
Premise Selection for Mathematics by Corpus Analysis and Kernel Methods
Smart premise selection is essential when using automated reasoning as a tool
for large-theory formal proof development. A good method for premise selection
in complex mathematical libraries is the application of machine learning to
large corpora of proofs. This work develops learning-based premise selection in
two ways. First, a newly available minimal dependency analysis of existing
high-level formal mathematical proofs is used to build a large knowledge base
of proof dependencies, providing precise data for ATP-based re-verification and
for training premise selection algorithms. Second, a new machine learning
algorithm for premise selection based on kernel methods is proposed and
implemented. To evaluate the impact of both techniques, a benchmark consisting
of 2078 large-theory mathematical problems is constructed,extending the older
MPTP Challenge benchmark. The combined effect of the techniques results in a
50% improvement on the benchmark over the Vampire/SInE state-of-the-art system
for automated reasoning in large theories.Comment: 26 page
Geographical variation in ant foraging activity and resource use is driven by climate and net primary productivity
AIM : Foraging activity is critical for animal survival. Comprehending how ecological
drivers influence foraging behaviour would benefit our understanding of the link between
animals and ecological processes. Here, we evaluated the influence of ecological
drivers on ant foraging activity and relative resource use.
LOCATION : Six Brazilian biomes: Amazon, Atlantic rainforest, Caatinga, Cerrado, Pampa
and Pantanal.
TAXON : Formicidae.
METHODS : We assessed ant foraging activity and resource use by sampling across 60
sites. We placed baited tubes that contained one of five liquid resources (sugar, lipids,
amino acid, sodium and distilled water). We used model selection to assess the influence
of ecological drivers (temperature, precipitation, temperature seasonality and
net primary productivity) on ant foraging activity and relative resource use.
RESULTS : Foraging activity was higher in wetter, more productive and less thermally
seasonal environments. The relative use of amino acids increased at higher temperatures
while the relative use of lipids decreased. The relative use of sugar increased in
drier and less productive environments with high-temperature
seasonality while the
relative use of amino acid and sodium decreased in those environments. The relative
use of lipids was complex: increasing with increasing temperature seasonality and
decreasing with increasing precipitation. Furthermore, the relative use of sodium was
greater where the foraging activity was high.
MAIN CONCLUSIONS : We demonstrate how ecological drivers are correlated with ant
foraging activity and resource use in the field across large spatial scales. The search for resources encompasses different interactions involving ants with abiotic and biotic
components in the ecosystem. Thus, we suggest that changes in climate and NPP,
which influence the intensity and the way that ants search for resources, will result in
changes in ant-mediated
ecological processes.Chaim J. Lasmar is a Post-doctoral researcher at the Programa de Pós-Graduação em Ecologia Aplicada (Universidade Federal de Lavras, Brazil). This study was part of his Ph. D. work at the Universidade Federal de Lavras with an internship period at the University of Liverpool.DATA AVAILABILITY STATEMENT: All data have been uploaded to Dryad (https://doi.org/10.5061/dryad.6wwpzgmxc).Fundação de Amparo à Pesquisa do Estado de Minas Gerais and Rufford Foundation.http://wileyonlinelibrary.com/journal/jbiam2022Zoology and Entomolog
From teaching physics to teaching children : beginning teachers learning from pupils
This paper discusses the development of beginning physics teachers' pedagogical content knowledge (PCK) in the context of teaching basic electricity during a one-year Professional Graduate Diploma in Education course (PGDE) and beyond. This longitudinal study used repeated semi-structured interviews over a period of four-and-a-half years. The interview schedule followed a line of development through the secondary school electrical syllabus in Scotland. Fifteen student teachers were interviewed during the PGDE year. Six of them were followed up at the end of the Induction Year (their first year as a newly qualified teacher), and again two-and-a-half years later. Thematic analysis of the interviews showed that before the beginning teachers had taught any classes, their initial focus was on how to transform their own subject matter knowledge (SMK) about electricity into forms that were accessible to pupils. As the beginning teachers gained experience working with classes, they gave vivid descriptions of interacting with particular pupils when teaching electricity which showed the development of their pedagogical knowledge. This played a significant role in the teachers' change of focus from teaching physics to teaching children as they transformed their SMK into forms that were accessible to pupils and developed their general pedagogical knowledge
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