Find research datasets worth reusing

Data from: Internal acoustic structuring in pied babbler recruitment cries specifies the form of recruitment

Language is inherently combinatorial, and parallels of this combinatorial capacity are found in nonhuman systems, with animals combining sounds and calls into larger meaningful structures. However, further analogue examples are central in unveiling the diversity, distribution, and evolutionary drivers of combinatoriality. Here, we provide evidence for internal "meaning-refining" acoustic variation within a larger stereotyped signal in pied babblers (Turdoides bicolor). Using acoustic analyses, we demonstrate that males produce 2 long, raucous, "cry-like" structures, both starting with a wind-up segment grading into repetitions of A/single-note or AB/double-note motifs. Behavioral observations indicated that, consistent with similarities in their larger stereotyped structure, both variants function overall in recruiting group members during locomotion, but the internal A or AB substructure specifies the "precise" form of recruitment, from approaching the caller's announced location to following it over longer distances. Playing back cries from a stationary loudspeaker further supported that the 2 variants elicit different responses, with more individuals approaching the loudspeaker in response to single-note compared with double-note cries. Additionally, despite similarities in overall distance travelled, group movement was only directional for single-note, but undefined for double-note cries. We suggest that the overall structure of the 2 cry variants conveys the same general meaning, with embedded variation refining this meaning. These results further illustrate the variability of generative mechanisms outside of human language and lend support to the hypothesis that combinatorial structuring may have emerged in species with limited or fixed vocal repertoires in order to enhance communicative output.

Data from: Population structure of a global agricultural invasive pest, Bactrocera dorsalis (Diptera: Tephritidae)

Bactrocera dorsalis, the Oriental fruit fly, is one of the world's most destructive agricultural insect pests and a major impediment to international fresh commodity trade. The genetic structuring of the species across its entire geographic range has never been undertaken, because under a former taxonomy B. dorsalis was divided into four distinct taxonomic entities, each with their own, largely non-overlapping, distributions. Based on the extensive sampling of six a priori groups from 63 locations, genetic and geometric morphometric datasets were generated to detect macrogeographic population structure, and to determine prior and current invasion pathways of this species. Weak population structure and high genetic diversity were detected among Asian populations. Invasive populations in Africa and Hawaii are inferred to be the result of separate, single invasions from South Asia; while South Asia is also the likely source of other Asian populations. The current northward invasion of B. dorsalis into central China is the result of multiple, repeated dispersal events, most likely related to fruit trade. Results are discussed in the context of global quarantine, trade and management of this pest. The recent expansion of the fly into temperate China, with very few associated genetic changes, clearly demonstrates the threat posed by this pest to ecologically similar areas in Europe and North America.

opencc-zeroDec 2012View details →

Data from: Population genetic structure of Picea engelmannii, P. glauca and their previously unrecognized hybrids in the central Rocky Mountains

Areas of geographic overlap between potentially hybridizing species provide the opportunity to study interspecific gene flow and reproductive barriers. Here we identified hybrids between Picea engelmannii and P. glauca by their genetic composition at 17 microsatellite markers, and determined the broad-scale geographic distribution of hybrids in the central Rocky Mountains of North America, a geographic region where hybrids and isolation between species had not previously been studied. Parameter estimates from admixture models revealed considerable variation in ancestry within and among collection sites, suggesting that within this area of geographic overlap, the interaction of the two species varies extensively. The results document a previously unrecognized patchy distribution of hybrids between P. engelmannii and P. glauca, including locations where hybrids were not known or expected to exist. Further, the ancestry of many hybrids was consistent with multiple generations of hybridization, with probable directional backcrossing to P. engelmannii, suggesting a relatively porous species boundary. The identification and characterization of hybridization between these spruce in this region raises the question of what factors maintain barriers to gene flow in these long-lived forest trees. The current research lays the groundwork for future study of the ecological and evolutionary contexts of their hybridization, as well as of differential introgression and permeability of species boundaries.

Data from: Social structure contains epidemics and regulates individual roles in disease transmission in a group-living mammal

Population structure is critical to infectious disease transmission. As a result, theoretical and empirical contact networks models of infectious disease spread are increasingly providing valuable insights into wildlife epidemiology. Analysing an exceptionally detailed data set on contact structure within a high-density population of European badgers Meles meles, we show that a modular contact network produced by spatially structured stable social groups, lead to smaller epidemics, particularly for infections with intermediate transmissibility. The key advance is that we identify considerable variation among individuals in their role in disease spread, with these new insights made possible by the detail in the badger data set. Furthermore, the important impacts on epidemiology are found even though the modularity of the badger network is much lower than the threshold that previous work suggested was necessary. These findings reveal the importance of stable social group structure for disease dynamics with important management implications for socially-structured populations.

Data from: A structured training program for health workers in intravenous treatment with fluids and antibiotics in nursing homes: a modified stepped-wedge cluster-randomised trial to reduce hospital admissions

Objectives: Hospitalization is potentially detrimental to nursing home patients and resource demanding for the specialist health care. This study assessed if a brief training program in administrating intravenous fluids and antibiotics in nursing homes could reduce hospital transfers and ensure high quality care locally. Design: A pragmatic and modified cluster randomized stepped-wedge trial with randomization on nursing home level. Participants: 330 cases in 296 nursing home residents from 30 nursing homes were included. Cases were patients provided intravenous antibiotics or intravenous fluids, in nursing home or hospital. Primary outcome was localization of treatment, secondary outcomes were number of days treated, days of hospitalization among admitted patients, type of antibiotics used and 30-day mortality. Intervention: The nursing homes sequentially received a one-day educational program for the health workers including theory and practical training in intravenous treatment of dehydration and infection, run by two skilled nurses. After completing the training program, the nursing homes had competence to provide intravenous treatment locally. Results: The intervention had a highly significant effect on treatment in nursing homes (OR 8.35, 2.08 to 33.6; P<0.01, or RR 2.23, 1.48 to 2.56). The number treated in nursing homes was stable over time; the number treated in hospital gradually decreased (chi square for trend P< 0.001). Among patients receiving intravenous antibiotics in the nursing homes, 50 (46%) died within 30 days, compared to 30 (36%) treated in the hospital (P=0.19). Among patients receiving intravenous fluids locally, 21 (19%) died within 30 days, compared to 2 (8%) in the hospital group (P=0.34). Mortality was associated with reduced consciousness and elevated c-reactive protein. Conclusions: A brief educational program delivered to nursing home personnel was feasible and effective in reducing acute hospital admissions from nursing homes for treatment of dehydration and infections.

Data from: Assessing the impacts of imperfect detection on estimates of diversity and community structure through multispecies occupancy modeling

Detecting all species in a given survey is challenging, regardless of sampling effort. This issue, more commonly known as imperfect detection, can have negative impacts on data quality and interpretation, most notably leading to false absences for rare or difficult‐to‐detect species. It is important that this issue be addressed, as estimates of species richness are critical to many areas of ecological research and management. In this study, we set out to determine the impacts of imperfect detection, and decisions about thresholds for inclusion in occupancy, on estimates of species richness and community structure. We collected data from a stream fish assemblage in Algonquin Provincial Park to be used as a representation of ecological communities. We then used multispecies occupancy modeling to estimate species‐specific occurrence probabilities while accounting for imperfect detection, thus creating a more informed dataset. This dataset was then compared to the original to see where differences occurred. In our analyses, we demonstrated that imperfect detection can lead to large changes in estimates of species richness at the site level and summarized differences in the community structure and sampling locations, represented through correspondence analyses.

Data from: Global mtDNA genetic structure and hypothesized invasion history of a major pest of citrus, Diaphorina citri (Hemiptera: Liviidae)

The Asian citrus psyllid Diaphorina citri Kuwayama, is a key pest of citrus as the vector of the bacterium causing the 'huanglongbing' disease (HLB). To assess the global mtDNA population genetic structure, and possible dispersal history of the pest, we investigated genetic variation at the COI gene collating newly collected samples with all previously published data. Our dataset consists of 356 colonies from 106 geographic sites worldwide. High haplotype diversity (H-mean = 0.702 ± 0.017), low nucleotide diversity (π-mean = 0.003), and significant positive selection (Ka/Ks = 32.92) were observed. Forty-four haplotypes (Hap) were identified, clustered into two matrilines: Both occur in southeastern and southern Asia, North and South America, and Africa; Lineages A and B also occur in eastern and western Asia, respectively. The most abundant haplotypes were Hap4 in lineage A (35.67%), and Hap9 in lineage B (41.29%). The haplotype network identified them as the ancestral haplotypes within their respective lineages. Analysis of molecular variance showed significant genetic structure (FST = 0.62, p < 0.0001) between the lineages, and population genetic analysis suggests geographic structuring. We hypothesize a southern and/or southeastern Asia origin, three dispersal routes, and parallel expansions of two lineages. The hypothesized first route involved the expansion of lineage B from southern Asia into North America via West Asia. The second, the expansion of some lineage A individuals from Southeast Asia into East Asia, and the third involved both lineages from Southeast Asia spreading westward into Africa and subsequently into South America. To test these hypotheses and gain a deeper understanding of the global history of D. citri more data-rich approaches will be necessary from the ample toolkit of next generation sequencing (NGS). However, the current paper may serve to guide such sampling and in the development of biological control programs against the global pest D. citri.

Data from: Strong effects of coral species on the diversity and structure of reef fish communities: a multi-scale analysis

While there is increasing evidence for habitat specialization in coral reef fishes, the extent to which different corals support different fish communities is not well understood. Here we quantitatively assess the relative importance of different coral species in structuring fish communities and evaluate whether sampling scale and coral colony size affect the perceived strength of fish-habitat relationships. Fish communities present on colonies of 8 coral species (Porites cylindrica, Echinopora horrida, Hydnophora rigida, Stylophora pistillata, Seriatopora hystrix, Acropora formosa, A. tenuis and A. millepora) were examined in the Lizard Island lagoon. Additionally, the differences in fish communities supported by 3 coral species (P. cylindrica, E. horrida, H. rigida) were investigated at 3 spatial scales of sampling (2x2 m, 1x1 m, 0.5x0.5 m). Substantial differences in fish communities were observed across the different coral species, with E. horrida and H. rigida supporting the most fish species and individuals. Coral species explained more of the variability in fish species richness (20.9-53.6%), than in fish abundance (0-15%). Most coral species supported distinctive fish communities, with dissimilarities ranging from 50 to 90%. For 3 focal coral species, a greater amount of total variation in fish species richness and fish abundance was evident at a larger scale of sampling. Together, these results indicate that the structure of reef fish communities is finely tuned to coral species. Loss of preferred coral species could have profound effects on reef fish biodiversity, more so than would be predicted on the basis of declining coral cover alone.

Data from: Genetic diversity and population structure of Urochloa grass accessions from Tanzania using simple sequence repeat (SSR) markers

Urochloa (syn.—Brachiaria s.s.) is one of the most important tropical forages that transformed livestock industries in Australia and South America. Farmers in Africa are increasingly interested in growing Urochloa to support the burgeoning livestock business, but the lack of cultivars adapted to African environments has been a major challenge. Therefore, this study examines genetic diversity of Tanzanian Urochloa accessions to provide essential information for establishing a Urochloa breeding program in Africa. A total of 36 historical Urochloa accessions initially collected from Tanzania in 1985 were analyzed for genetic variation using 24 SSR markers along with six South American commercial cultivars. These markers detected 407 alleles in the 36 Tanzania accessions and 6 commercial cultivars. Markers were highly informative with an average polymorphic information content of 0.79. The analysis of molecular variance revealed high genetic variation within individual accessions in a species (92%), fixation index of 0.05 and gene flow estimate of 4.77 showed a low genetic differentiation and a high level of gene flow among populations. An unweighted neighbor-joining tree grouped the 36 accessions and six commercial cultivars into three main clusters. The clustering of test accessions did not follow geographical origin. Similarly, population structure analysis grouped the 42 tested genotypes into three major gene pools. The results showed the Urochloa brizantha (A. Rich.) Stapf population has the highest genetic diversity (I = 0.94) with high utility in the Urochloa breeding and conservation program. As the Urochloa accessions analyzed in this study represented only 3 of 31 regions of Tanzania, further collection and characterization of materials from wider geographical areas are necessary to comprehend the whole Urochloa diversity in Tanzania.

opencc-zeroDec 2013View details →

Data from: Insect adhesion on rough surfaces: analysis of adhesive contact of smooth and hairy pads on transparent micro-structured substrates

Insect climbing footpads are able to adhere to rough surfaces, but the details of this capability are still unclear. To overcome experimental limitations of randomly rough, opaque surfaces, we fabricated transparent test substrates containing square arrays of 1.4 µm diameter pillars, with variable height (0.5 and 1.4 µm) and spacing (from 3 to 22 µm). Smooth pads of cockroaches (Nauphoeta cinerea) made partial contact (limited to the tops of the structures) for the two densest arrays of tall pillars, but full contact (touching the substrate in between pillars) for larger spacings. The transition from partial to full contact was accompanied by a sharp increase in shear forces. Tests on hairy pads of dock beetles (Gastrophysa viridula) showed that setae adhered between pillars for larger spacings, but pads were equally unable to make full contact on the densest arrays. The beetles' shear forces similarly decreased for denser arrays, but also for short pillars and with a more gradual transition. These observations can be explained by simple contact models derived for soft uniform materials (smooth pads) or thin flat plates (hairy-pad spatulae). Our results show that microstructured substrates are powerful tools to reveal adaptations of natural adhesives for rough surfaces.

opencc-zeroDec 2015View details →

Data from: A genome-wide assessment of genetic diversity and population structure of Korean native cattle breeds

Background: The native cattle breeds are an important genetic resource for meat and milk production throughout Asia. In Asia cattle were domesticated around 10,000 years ago and in Korea cattle are being raised since 2000 B.C. There are three native breeds of cattle in Korea viz. Brown Hanwoo, Brindle Hanwoo and Jeju Black. While one of these breeds, Brown Hanwoo, is a part of a Food and Agricultural Organization and national genetic evaluation plans, others get little attention. This study is an effort to understand and provide a detailed insight into the population structure and genetic variability of the Korean cattle breeds along with other Asian breeds using various methods. In this study we report the genetic variation and structure of the Korean cattle breeds and their comparison with five other Asian cattle breeds along with a panel of animals from European taurine, African taurine and indicine cattle breeds. Results: Asian cattle were found to be least differentiated which reflects their recent history. Amongst the Asian breeds Hainan, which is an indicine breed, had the lowest gene diversity while Yanbian had the highest followed by Mongolian and Korean cattle. Amongst the Korean breeds Brown Hanwoo had the highest diversity followed by Brindle Hanwoo and Jeju Black. The genetic diversity in Asian cattle breeds was found comparable to the European taurines and more than the African taurines and Zebu cattle. Korean cattle breed, Brown Hanwoo was consistently found to be closer to Yanbian, a Chinese cattle breed. We found low divergence and moderate levels of genetic diversity among the native Korean breeds. Indicine introgression from Hainan was seen in other Asian breeds. From Europe, Limousin, Holstein and Hereford introgression was found in Asian breeds. Conclusions: In this study we provide a genome-wide insight into the genetic history of the native cattle breeds of Korea. The outcomes of this study will help in prioritization and designing of the conservation plans.

Data from: Geographic ranges of genera and their constituent species: structure, evolutionary dynamics, and extinction resistance

We explore the relationships among the geographic ranges of genera, the ranges and positions of their constituent species, and the number of species they contain, considering variation among coeval genera and changes within genera over time. Measuring range size as the maximal distance, or extent, between occurrences within a taxon, we find that the range of the most widespread species is a good predictor of the range of the genus, and that the number of species is a better predictor still. This analysis is complicated by a forced correlation: the range of a genus must be at least as large as that of each of its constituent species. We therefore focus on a second measure of range, the mean squared distance, or dispersion, of occurrences from the geographic centroid, which, by analogy to the analysis of variance, allows the total dispersion of a genus to be compared to the mean within-species dispersion and the dispersion among species centroids. We find that among-species dispersion is the principal determinant of genus dispersion. Within-species dispersion also plays a major role. The role of species richness is relatively small. Our results are not artifacts of temporal variation in the geographic breadth of sampled data. The relationship between changes in genus dispersion and changes in within- and among-species dispersion shows a symmetry, being similar in cases when the genus range is expanding and when it is contracting. We also show that genera with greater dispersion have greater extinction resistance, but that within- and among-species dispersion are not demonstrable predictors of survival once the dispersion of the genus is accounted for. Thus it is the range of the genus, rather than how it is attained, that is most relevant to its fate. Species richness is also a clear predictor of survival, beyond its effects on geographic range.

Data from: Structural biomechanics determine spectral purity of bush-cricket calls

Bush-crickets (Orthoptera: Tettigoniidae) generate sound using tegminal stridulation. Signalling effectiveness is affected by the widely varying acoustic parameters of temporal pattern, frequency and spectral purity (tonality). During stridulation, frequency multiplication occurs as a scraper on one wing scrapes across a file of sclerotized teeth on the other. The frequency with which these tooth–scraper interactions occur, along with radiating wing cell resonant properties, dictates both frequency and tonality in the call. Bush-cricket species produce calls ranging from resonant, tonal calls through to non-resonant, broadband signals. The differences are believed to result from differences in file tooth arrangement and wing radiators, but a systematic test of the structural causes of broadband or tonal calls is lacking. Using phylogenetically controlled structural equation models, we show that parameters of file tooth density and file length are the best-fitting predictors of tonality across 40 bush-cricket species. Features of file morphology constrain the production of spectrally pure signals, but systematic distribution of teeth alone does not explain pure-tone sound production in this family.

Data from: Near infrared spectroscopy (NIRS) predicts non-structural carbohydrate concentrations in different tissue types of a broad range of tree species

1. The allocation of non-structural carbohydrates (NSCs) to reserves constitutes an important physiological mechanism associated with tree growth and survival. However, procedures for measuring NSC in plant tissue are expensive and time-consuming. Near-infrared spectroscopy (NIRS) is a high-throughput technology that has the potential to infer the concentration of organic constituents for a large number of samples in a rapid and inexpensive way based on empirical calibrations with chemical analysis. 2. The main objectives of this study were (i) to develop a general NSC concentration calibration that integrates various forms of variation such as tree species and tissue types and (ii) to identify characteristic spectral regions associated with NSC molecules. In total, 180 samples from different tree organs (root, stem, branch, leaf) belonging to 73 tree species from tropical and temperate biomes were analysed. Statistical relationships between NSC concentration and NIRS spectra were assessed using partial least squares regression (PLSR) and a variable selection procedure (competitive adaptive reweighted sampling, CARS), in order to identify key wavelengths. 3. Parsimonious and accurate calibration models were obtained for total NSC (r2 of 0·91, RMSE of 1·34% in external validation), followed by starch (r2 = 0·85 and RMSE = 1·20%) and sugars (r2 = 0·82 and RMSE = 1·10%). Key wavelengths coincided among these models and were mainly located in the 1740–1800, 2100–2300 and 2410–2490 nm spectral regions. 4. This study demonstrates the ability of general calibration model to infer NSC concentrations across species and tissue types in a rapid and cost-effective way. The estimation of NSC in plants using NIRS therefore serves as a tool for functional biodiversity research, in particular for the study of the growth–survival trade-off and its implications in response to changing environmental conditions, including growth limitation and mortality.

Data from: Structural habitat predicts functional dispersal habitat of a large carnivore: how leopards change spots

Natal dispersal promotes inter-population linkage, and is key to spatial distribution of populations. Degradation of suitable landscape structures beyond the specific threshold of an individual's ability to disperse can therefore lead to disruption of functional landscape connectivity and impact metapopulation function. Because it ignores behavioral responses of individuals, structural connectivity is easier to assess than functional connectivity and is often used as a surrogate for landscape connectivity modeling. However using structural resource selection models as surrogate for modeling functional connectivity through dispersal could be erroneous. We tested how well a second-order resource selection function (RSF) models (structural connectivity), based on GPS telemetry data from resident adult leopard (Panthera pardus L.), could predict subadult habitat use during dispersal (functional connectivity). We created eight non-exclusive subsets of the subadult data based on differing definitions of dispersal to assess the predictive ability of our adult-based RSF model extrapolated over a broader landscape. Dispersing leopards used habitats in accordance with adult selection patterns, regardless of the definition of dispersal considered. We demonstrate that, for a wide-ranging apex carnivore, functional connectivity through natal dispersal corresponds to structural connectivity as modeled by a second-order RSF. Mapping of the adult-based habitat classes provides direct visualization of the potential linkages between populations, without the need to model paths between a priori starting and destination points. The use of such landscape scale RSFs may provide insight into predicting suitable dispersal habitat peninsulas in human-dominated landscapes where mitigation of human–wildlife conflict should be focused. We recommend the use of second-order RSFs for landscape conservation planning and propose a similar approach to the conservation of other wide-ranging large carnivore species where landscape-scale resource selection data already exist.

opencc-zeroDec 2011View details →

Data from: Modelling dynamics in protein crystal structures by ensemble refinement

Single-structure models derived from X-ray data do not adequately account for the inherent, functionally important dynamics of protein molecules. We generated ensembles of structures by time-averaged refinement, where local molecular vibrations were sampled by molecular-dynamics (MD) simulation whilst global disorder was partitioned into an underlying overall translation–libration–screw (TLS) model. Modeling of 20 protein datasets at 1.1–3.1 Å resolution reduced cross-validated R_free values by 0.3–4.9%, indicating that ensemble models fit the X-ray data better than single structures. The ensembles revealed that, while most proteins display a well-ordered core, some proteins exhibit a 'molten core' likely supporting functionally important dynamics in ligand binding, enzyme activity and protomer assembly. Order–disorder changes in HIV protease indicate a mechanism of entropy compensation for ordering the catalytic residues upon ligand binding by disordering specific core residues. Thus, ensemble refinement extracts dynamical details from the X-ray data that allow a more comprehensive understanding of structure–dynamics–function relationships.

opencc-zeroDec 2013View details →

Data from: Population genetic structure of the Pocillopora damicornis morphospecies along Ningaloo Reef, Western Australia

The effective management of a coral reef system relies on a detailed understanding of the population structure of dominant habitat-forming species. For some corals, however, high levels of phenotypic plasticity have made species delineation based on morphological characteristics alone unreliable, suggesting that previous studies of population genetic structure may have been influenced by the inclusion of multiple genetic lineages in the analyses. We examined the population structure of the Pocillopora damicornis morphospecies along the World Heritage Ningaloo Coast, Western Australia, and recovered 2 mitochondrial haplotypes from sympatrically occurring colonies possessing morphological characteristics consistent with taxonomic classification of P. damicornis. Despite a high degree of genetic differentiation between these lineages, we detected low levels of unidirectional admixture between them, suggesting that reproductive barriers are not fully developed. We found dual modes of reproduction for both lineages with considerable variation in the contribution of sexual reproduction among sample sites. Lastly, we identified a high dispersal potential of sexually produced propagules in the most common lineage with positive spatial autocorrelation detected over distances up to 60 km. Based on these results, it appears that populations of P. damicornis have a high capacity to recover from environmental perturbations as long as the effects of disturbances are patchy across Ningaloo Reef.

Data from: Integrated analysis and visualization of group differences in structural and functional brain connectivity: applications in typical ageing and schizophrenia

Structural and functional brain connectivity are increasingly used to identify and analyze group differences in studies of brain disease. This study presents methods to analyze uni- and bi-modal brain connectivity and evaluate their ability to identify differences. Novel visualizations of significantly different connections comparing multiple metrics are presented. On the global level, "bi-modal comparison plots" show the distribution of uni- and bi-modal group differences and the relationship between structure and function. Differences between brain lobes are visualized using "worm plots". Group differences in connections are examined with an existing visualization, the "connectogram". These visualizations were evaluated in two proof-of-concept studies: (1) middle-aged versus elderly subjects; and (2) patients with schizophrenia versus controls. Each included two measures derived from diffusion weighted images and two from functional magnetic resonance images. The structural measures were minimum cost path between two anatomical regions according to the "Statistical Analysis of Minimum cost path based Structural Connectivity" method and the average fractional anisotropy along the fiber. The functional measures were Pearson's correlation and partial correlation of mean regional time series. The relationship between structure and function was similar in both studies. Uni-modal group differences varied greatly between connectivity types. Group differences were identified in both studies globally, within brain lobes and between regions. In the aging study, minimum cost path was highly effective in identifying group differences on all levels; fractional anisotropy and mean correlation showed smaller differences on the brain lobe and regional levels. In the schizophrenia study, minimum cost path and fractional anisotropy showed differences on the global level and within brain lobes; mean correlation showed small differences on the lobe level. Only fractional anisotropy and mean correlation showed regional differences. The presented visualizations were helpful in comparing and evaluating connectivity measures on multiple levels in both studies.

Data from: Predator personality structures prey communities and trophic cascades

Intraspecific variation is central to our understanding of evolution and population ecology, yet its consequences for community ecology are poorly understood. Animal personality—consistent individual differences in suites of behaviors – may be particularly important for trophic dynamics, where predator personality can determine activity rates and patterns of attack. We used mesocosms with aquatic food webs in which the top predator (dragonfly nymphs) varied in activity and subsequent attack rates on zooplankton, and tested the effects of predator personality. We found support for four hypotheses: 1) active predators disproportionately reduce the abundance of prey, 2) active predators select for predator-resistant prey species, 3) active predators strengthen trophic cascades (increase phytoplankton abundance), and 4) active predators are more likely to cannibalize one another, weakening all other trends when at high densities. These results suggest that intraspecific variation in predator personality is an important determinant of prey abundance, community composition, and trophic cascades.