William O C Symondson's research while affiliated with Cardiff University and other places

Publications (94)

Preprint
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Eurasian otters are apex predators of freshwater ecosystems and a recovering species across much of their European range; investigating the dietary variation of this predator over time and space therefore provides opportunities to identify changes in freshwater trophic interactions and factors influencing the conservation of otter populations. Here...
Preprint
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1. Generalist invertebrate predators are sensitive to weather conditions, but the relationship between their trophic interactions and weather is poorly understood. This study investigates how weather affects the identity and frequency of spider trophic interactions as mediated by prey community structure, web characteristics and density-independent...
Article
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The diet of an individual animal is subject to change over time, both in response to short-term food fluctuations and over longer time scales as an individual ages and meets different challenges over its life cycle. A metabarcoding approach was used to elucidate the diet of different life stages of a migratory songbird, the Eurasian reed warbler (A...
Preprint
Full-text available
The diet of an individual animal is subject to change over time, both in response to short-term food fluctuations and over longer time scales as an individual ages and meets different challenges over its life cycle. A metabarcoding approach was used to elucidate the diet of different life stages of a songbird, the Eurasian reed warbler (Acrocephalu...
Article
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Although studying the diet of threatened species is crucial in terms of conservation, the diet of the Madeiran Storm Petrel (Hydrobates castro) and the vulnerable, Azores-endemic Monteiro's Storm Petrel (H. monteiroi) is mostly unknown. The only information available to date comes from anecdotal observations, analysis of mercury levels and stable i...
Preprint
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Nutrient-specific foraging is the ecological theory that generalist consumers select food resources based on their nutritional content. While laboratory experiments support this, it has not yet been demonstrated in invertebrate predators in the field. We combined dietary metabarcoding with prey abundance and macronutrient content data to analyze nu...
Article
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Introduced species can exert disproportionately negative effects on island ecosystems , but their potential role as food for native consumers is poorly studied. Telfair's skinks are endemic omnivores living on Round Island, Mauritius, a globally significant site of biodiversity conservation. We aimed to determine the dietary diversity and key troph...
Article
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Spiders are among the dominant invertebrate predators in agricultural systems and are significant regulators of insect pests. The precise dynamics of biocontrol of pests in the field are, however, poorly understood. This study investigates how density-independent prey choice, taxonomy, life stage, sex, and web characteristics affect spider diet and...
Article
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1. The use of ecological replacements (analogue species to replace extinct taxa) to restore ecosystem functioning is a promising conservation tool. However, this approach is controversial, in part due to a paucity of data on interactions between analogue species and established taxa in the ecosystem. 2. We conducted ecological surveys, comprehensiv...
Article
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Metabarcoding provides a powerful tool for investigating biodiversity and trophic interactions, but the high sensitivity of this methodology makes it vulnerable to errors, resulting in artefacts in the final data. Metabarcoding studies thus often utilise minimum sequence copy thresholds (MSCTs) to remove artefacts that remain in datasets; however,...
Article
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Interactions between hosts and their resident microbial communities are a fundamental component of fitness for both agents. Though recent research has highlighted the importance of interactions between animals and their bacterial communities, comparative evidence for fungi is lacking, especially in natural populations. Using data from 49 species, w...
Article
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Background Energy landscapes provide an approach to the mechanistic basis of spatial ecology and decision-making in animals. This is based on the quantification of the variation in the energy costs of movements through a given environment, as well as how these costs vary in time and for different animal populations. Organisms as diverse as fish, ma...
Preprint
Metabarcoding provides a powerful tool for investigating biodiversity and trophic interactions, but the high sensitivity of this methodology makes it vulnerable to errors, resulting in artefacts in the final data. Metabarcoding studies thus often utilise minimum sequence copy thresholds (MSCTs) to remove artefacts that remain in datasets; however,...
Article
Full-text available
Dietary analysis using DNA metabarcoding is a powerful tool that is increasingly being used to further our knowledge of trophic interactions in highly complex food webs but is not without limitations. Omnivores, the most generalist of consumers, pose unique challenges when using such methods. Here, we provide the rationale to understand the problem...
Article
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Macronutrients, comprising carbohydrates, proteins and lipids, underpin many ecological processes, but their quantification in ecological studies is often inaccurate and laborious, requiring large investments of time and bulk samples, which make individual‐level studies impossible. This study presents MEDI (Macronutrient Extraction and Determinatio...
Article
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The subfamily Aphrodinae (Hemiptera: Cicadellidae) contains ~33 species in Europe within four genera. Species in two genera in particular, Aphrodes and Anoscopus, have proved to be difficult to distinguish morphologically. Our aim was to determine the status of the putative species Anoscopus duffieldi, found only on the RSPB Nature Reserve at Dunge...
Article
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1. Money spiders (Linyphiidae) are an important component of conservation biological control in cereal crops, but they rely on alternative prey when pests are not abundant, such as between cropping cycles. To optimally benefit from these generalist predators, prey choice dynamics must first be understood. 2. Money spiders and their locally availabl...
Article
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Elucidating the diets of insect predators is important in basic and applied ecology, such as for improving the effectiveness of conservation biological control measures to promote natural enemies of crop pests. Here, we investigated the aphid diet of two common aphid predators in Central European agroecosystems, the native Coccinella septempunctata...
Article
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Among spiders, taxonomically the most diversified group of terrestrial predators, only a few species are stenophagous and feed on ants. The levels of stenophagy and ant-specialisation vary among such species. To investigate whether stenophagy is only a result of a local specialisation both fundamental and realised trophic niches need to be estimate...
Article
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In Europe, the German Bight is one of the most important non-breeding areas for protected red-throated divers (Gavia stellata). It is unclear what attracts the birds to this area, especially as the food composition of seabirds outside the breeding season is notoriously difficult to study. To obtain information on prey species composition of red-thr...
Article
Predators that prey on dangerous species have evolved effective capture traits. In spiders, venom and silk represent distinct substances associated with prey capture. However, the use of such adaptations comes at a cost. Based on a possible trade-off, the use of only one effective capture mechanism should be optimized if a predator is to specialize...
Article
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In the last paragraph of the Origin of Species, Darwin (1859) marvels at the diversity of life forms, the complexity of links between them, and the forces creating this “tangled bank”. In this text, we may see the origins of community ecology – today defined as ‘the study of the interactions that determine the distribution and abundance of organism...
Article
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Dietary changes linked to the availability of anthropogenic food resources can have complex implications for species and ecosystems, especially when species are in decline. Here, we use recently developed primers targeting the ITS2 region of plants to characterise diet from faecal samples of four UK columbids, with particular focus on the European...
Article
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DNA metabarcoding is a rapidly growing technique for obtaining detailed dietary information. Current metabarcoding methods for herbivory, using a single locus, can lack taxonomic resolution for some applications. We present novel primers for the second internal transcribed spacer of nuclear ribosomal DNA (ITS2) designed for dietary studies in Mauri...
Article
DNA metabarcoding is a technique used to survey biodiversity in many ecological settings, but there are doubts about whether it can provide quantitative results, i.e. the proportions of each species in the mixture as opposed to a species list. While there are several experimental studies that report quantitative metabarcoding results, there are a s...
Article
Network analysis is increasingly widespread in ecology, with frequent questions asking which nodes (typically species) interact with one another and how strong are the interactions. Null models are a way of addressing these questions, helping to distinguish patterns driven by neutral mechanisms or sampling effects (e.g. relative abundance of differ...
Article
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Each spring great numbers of shorebirds gather in Delaware Bay, USA during the reproductive season of Horseshoe Crabs Limulus polyphemus to capitalize on crab eggs. Due to overharvesting, the abundance of both crabs and their eggs has significantly declined in the last two decades, and little is known about alternative food types. We examined poten...
Article
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Background and purpose: Generalist predatory carabid beetles can control the abundance of a range of prey species within ecosystems, including certain pests. In terms of bio-control, these unspecialised predators may be sustained in the field when pest populations are low by predating on other animals such as earthworms. The aim of this study was t...
Article
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Trichomonosis, caused by the protozoan Trichomonas gallinae, is an emerging infectious disease in finches, and is more commonly found in columbids and raptors. Infections can be sub-clinical or cause morbidity and mortality, but the parasite is currently only detectable by incubation of an oral swab. Here, we test whether T. gallinae parasites can...
Data
Table S2. Data used in models of relationships between physical habitat and agricultural land cover.
Article
Spiders, a group of predominantly insectivorous predators, occasionally use plant food to supplement their insect prey. In the current review, we tracked down 95 reported incidents of spiders feeding on plant food under natural conditions. Globally, >60 spider species representing ten families have been observed feeding on plant materials from over...
Data
Fig. S1. Locations of River Habitat Survey and water chemistry/invertebrate monitoring sites. Fig. S2. Distribution of sites, split into five groups based on modelled likelihood of having arable land cover. Fig. S3. Distribution of sites, split into five groups based on modelled likelihood of having improved pasture land cover.
Data
Table S4. Correlations between environmental covariates and treatment land covers across the whole data set and within propensity groups. Table S5. Number of sites per propensity group. Table S6. Estimated responses of river habitat characteristics to agricultural land cover with data set split into differing number of propensity groups. Table S...
Data
Table S3. Data used in models of relationships between water quality and invertebrate response variables and agricultural land cover.
Article
Detection of prey DNA from faecal samples is a non-invasive method being successfully applied to the dietary analysis of birds as well as other vertebrates and invertebrates. We have employed this technique to examine the significance of Horseshoe Crab eggs (Limulus polyphemus) for Dunlins (Calidris alpina), Semipalmated Sandpipers (Calidris pusill...
Article
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1. Although agriculture is among the world’s most widespread land uses, studies of its effects on stream ecosystems are often limited in spatial extent. National monitoring data could extend spatial coverage and increase statistical power, but present analytical challenges where covarying environmental variables confound relationships of interest....
Article
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True predators are characterised by capturing a number of prey items during their lifetime and by being generalists. Some true predators are facultative specialists, but very few species are stenophagous specialists that catch only a few closely related prey types. A monophagous true predator that would exploit a single prey species has not been di...
Article
Many Lepidoptera larvae use pieces of vegetation bound with silk to construct or disguise their cocoons. Here we report the first known case of a caterpillar building its cocoon entirely out of fragments of resin, broken away from sheets of dried resin on the trunk of a tree and held together with silk. The behaviour of the larva (possibly Negritot...
Article
Eleven microsatellite markers were developed for the leafhoppers of the genus Aphrodes using shotgun pyrosequencing and will be used to study the genetic diversity, population structure and gene flow within and between species in this genus in order to assess their conservation status. The number of alleles per locus ranged from 3 to 10, while obse...
Conference Paper
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There appear to be no limits to the organismal scale at which trophic interactions can be measured. To date, there have been ecological analyses using PCR to study the diets of whale sharks and giant squid at one end of the spectrum, with juvenile linyphiid spiders and Collembola at the other. Interactions have included predation, herbivory, parasi...
Article
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Predatory carabid beetles are important for regulating prey abundance in terrestrial ecosystems. While surveys of carabid diet have revealed many insights into trophic interactions, the high species diversity and heterogeneous developmental stages of prey identified in the gut have made further advances difficult. In addition, the carabid gut conta...
Book
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This volume explains the key ideas, questions and methods involved in studying the hidden world of vibrational communication in animals. The authors dispel the notion that this form of communication is difficult to study, and show how vibrational signaling is a key to social interactions in species that live in contact with a substrate, whether it...
Article
Knowledge of the dietary choices and trophic niches of organisms is the key to understanding their roles in ecosystems. In seabird diet studies, prey identification is a difficult challenge, often yielding results with technique-specific biases. Additionally, sampling efforts are often not extensive enough to reveal intra-populational variation. Im...
Article
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The slugs of Britain and Ireland form a well-studied fauna of economic importance. They include many widespread European species that are introduced elsewhere (at least half of the 36 currently recorded British species are established in North America, for example). To test the contention that the British and Irish fauna consists of 36 species, and...
Article
Reliable delimitation and identification of species is central not only to systematics, but also to studies of biodiversity, ecology and pest management. In the era of Internet-based biodiversity databases misidentifications are rapidly disseminated and may have far-reaching consequences. Leafhoppers from the genus Aphrodes (Hemiptera, Cicadellidae...
Article
Prevalence and intensity of parasitic infections is often higher in male than in female vertebrates. This bias may represent either differences between host sex in exposure or susceptibility to parasites. The former may be due to sex-specific behaviour of the host, including differential habitat use or diet. Differences in susceptibility are often...
Article
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The dynamics of predation on parasites within prey has received relatively little attention despite the profound effects this is likely to have on both prey and parasite numbers and hence on biological control programmes where parasites are employed. The nematode Phasmarhabditis hermaphrodita is a commercially available biological agent against slu...
Article
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Variation in prey resources influences the diet and behaviour of predators. When prey become limiting, predators may travel farther to find preferred food or adjust to existing local resources. When predators are habitat limited, local resource abundance impacts foraging success. We analysed the diet of Myotis lucifugus (little brown bats) from Nov...
Article
Contamination pathways in complex food chains in soil ecosystems can be difficult to elucidate. Molecular analysis of predator gut content can, however, rapidly reveal previously unidentified trophic interactions between invertebrates and thereby uncover pathways of pollutant spread. Here we measured concentrations of the toxic metals lead, cadmium...
Article
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Migration is widespread among vertebrates, yet bat migration has received little attention and only in the recent decades has a better understanding of it been gained. Migration can cause significant changes in behaviour and physiology, due to increasing energy demands and aerodynamic constraints. Dietary shifts, for example, have been shown to occ...
Article
In this investigation, we use variation in wing morphology, echolocation behaviour, patterns of habitat use and molecular diet analysis to demonstrate that six species of sympatric insectivorous bats in Jamaica show significant differences that could explain resource partitioning among the species. High-intensity echolocating species that used shor...
Article
Generalist species with numerous food web interactions are thought to provide stability to ecosystem dynamics; however, it is not always clear whether habitat generality translates into dietary diversity. Big brown bats are common across North America and employ a flexible foraging strategy over water, dense forests, forest edges and rural and urba...
Article
Reptiles are declining in many parts of the world, mainly due to habitat loss and environmental change. A major factor in this is availability of suitable food. For many animals, dietary requirements shift during developmental stages and a habitat will only be suitable for conserving a species if it supports all stages. Conventional methods for est...
Article
Predators can provide a valuable ecosystem service by suppressing crop pests. However, intraguild predation, where predators compete for the same prey resource whilst consuming each other, may destabilize population dynamics and increase the risk of pest outbreaks. Very little is known about intraguild predation in open fields or the strengths of t...
Data
Sex differences in biometrics of European Storm Petrels (Hydrobates pelagicus) attracted to playback calls in Southern Europe. (DOC)
Data
Mean body measurements (mm) and body mass (g) for Hydrobates pelagicus caught in Portugal between 1989–2008 (± SE). (DOC)
Article
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Molecular sexing revealed an unexpectedly strong female bias in the sex ratio of pre-breeding European Storm Petrels (Hydrobates pelagicus), attracted to playback of conspecific calls during their northwards migration past SW Europe. This bias was consistent across seven years, ranging from 80.8% to 89.7% female (mean annual sex ratio ± SD = 85.5%...
Article
1 Biological control by conservation of native natural enemies can, at its best, reduce the need for pesticides and prevent detrimental effects upon the environment. The present study investigated the role of ground‐active generalist predators as natural enemies of two tortricid pests in apple orchards. 2 Predation rates were compared on the well e...
Article
IntroductionWhy Use Molecular Markers?The Basics: Detecting Predation on a Target Prey SpeciesMultiplexingAnalysis of Prey ChoiceQuantitative (‘Real Time’) PCRCloning and SequencingSources of ErrorPyrosequencing and Future DevelopmentsConclusion References
Article
Little quantitative ecological information exists on the diets of most invertebrate feeding reptiles, particularly nocturnal or elusive species that are difficult to observe. In the UK and elsewhere, reptiles are legally required to be relocated before land development can proceed, but without knowledge of their dietary requirements, the suitabilit...
Article
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The analysis of food webs and their dynamics facilitates understanding of the mechanistic processes behind community ecology and ecosystem functions. Having accurate techniques for determining dietary ranges and components is critical for this endeavour. While visual analyses and early molecular approaches are highly labour intensive and often lack...
Article
Primers were developed for leafhoppers of the genus Aphrodes amplifying 84-244 bp fragments of the mitochondrial cytochrome oxidase subunit I gene. DNA was extracted from legs of over 100-year-old archived museum specimens, amplified and sequenced. The fragments contain sufficient variation to unequivocally identify the different species. The major...
Article
Species- and group-specific PCR primers were developed to study predation on pest and nonpest invertebrate species by generalist carabid predators in agroecosystems. To ensure the amplification of degraded DNA in predator gut samples, amplicons were designed to be less than 300 bp. Specificity of primers was assessed by cross-amplification against...
Article
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Landscape management affects species interactions within a community, leading to alterations in the structure of networks. Modules are link-dense regions of the network where species interact more closely within the module than between modules of the network. Insufficient network resolution has meant that modules have proved difficult to identify,...
Article
Vibrational signalling is a widespread form of animal communication and, in the form of sexual communication, has been generally regarded as inherently short-range and a private communication channel, free from eavesdropping by generalist predators. A combination of fieldwork and laboratory experiments was used to test the hypothesis that predators...
Article
Rowson, B., Tattersfield, P. & Symondson, W. O. C. (2010). Phylogeny and biogeography of tropical carnivorous land-snails (Pulmonata: Streptaxoidea) with particular reference to East Africa and the Indian Ocean. —Zoologica Scripta, 40, 85–98. A phylogeny is presented for the speciose, near pan-tropical, carnivorous achatinoid land-snail superfamily...
Article
The carabid beetle Pterostichus melanarius is a major natural enemy of pests, such as aphids and slugs in agricultural systems. Earthworms are a dominant non-pest component of the diet of P. melanarius which help sustain the beetles during periods when the pest population is low or absent. In this study we wanted to test whether this predator exerc...
Article
In agricultural systems, polyphagous beetles and spiders are abundant components of the beneficial arthropod community. Although data on the dietary ranges of these groups is increasing, remarkably little is understood regarding how individuals interact with their prey at small spatial scales. We demonstrate the utility of a spatially-explicit netw...
Article
Natural enemies that control pests usually allow farmers to avoid, or reduce, the use of pesticides. However, modern farming practices, that maximize yields, are resulting in loss of biodiversity, particularly prey diversity. Does this matter? Pests continue to thrive, and without alternative prey the predators should, perforce, concentrate their a...
Article
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While many studies have demonstrated that organic farms support greater levels of biodiversity, it is not known whether this translates into better provision of ecosystem services. Here we use a food-web approach to analyse the community structure and function at the whole-farm scale. Quantitative food webs from 10 replicate pairs of organic and co...
Article
Earthworms play a major role in many aspects of soil fertility, food web ecology and ecosystem functioning, and hence are frequently the subjects of, for example, ecological and toxicological research. Our aim was to examine the genetic structure of common earthworm species, to identify cryptic lineages or species that may be distinct ecotypes or b...
Article
Summary • Polyphagous predators, such as spiders and beetles, perform a fundamental ecosystem service as regulators of agricultural pests, particularly aphids. They are most effective when they colonize the crop before the pest has reached its exponential growth phase. However, this is also when predators find themselves in a state of near-starvati...