Robin Taylor

• The Ohio State University

Hughes and Madden's binary power law was used to analyse sample data of three life stages of gypsy moth ( Lymantria dispar ) and adult emerald ash borer ( Agrilus planipennis ), both important invasive forest pests in North America. Tally thresholds were used to convert quantitative gypsy moth data to binomial, presence–absence data for binary powe...

• The intimate relationship between sampling efficiency and Taylor's power law (TPL) was investigated with gypsy moth sample data. The data were used to compute sampling efficiency directly and indirectly by TPL. • Comparison of TPLs and efficiency plots of male and female pupae confirmed the identities linking TPL with sampling efficiency. Diverge...

From the back cover: Taylor's Power Law: Order and Pattern in Nature is a broad synthesis of this ubiquitous property of natural and man-made phenomena. This stimulating and approachable work surveys the biological and non-biological empirical data, describes the statistical uses of Taylor’s power law (TPL) and its relationship to statistical distr...

Modern intensive agriculture relies heavily on pesticides to control weeds, pathogens and insect pests. Forecasting and managing the impact of pests and pesticides on crop production is challenging. Since pest control tactics not only affect the target pest, but also initiate feedbacks within the field community, proper modelling of pest management...

Simulation of phosphorus (P) transfer from manured agricultural lands to water bodies via surface runoff and subsurface drainage is potentially of great help in evaluating the risks and effects of eutrophication under a range of best management practice scenarios. However, it remains a challenge since few models are capable of providing a reasonabl...

Useful in evaluating best management practices and nutrient management planning, the prediction of phosphorus (P) transfer from agricultural lands to water bodies via surface runoff and tile drainage remains as a challenge, as few models can provide reasonably accurate P loss simulations. The EPIC (Environmental Policy Integrated Climate) model was...

The growth of plants and insects occurs only above a minimum temperature threshold. In insects, the growth rate depends on the temperature above the threshold up to a maximum. In plants the growth rate above the threshold generally depends on the availability of sunlight. Thus, the relative growth rates of crops and insect phytophages are expected...

Watershed responses are affected by the watershed characteristics and rainfall events. The characteristics of soil layers are among the fundamental characteristics of a watershed and they are input to hydrologic modeling similar to topography and land use/cover. Although the roles of soils have been perceived, there are limited studies that quantif...

1. A relationship between sampling efficiency and Taylor's power law (TPL) is derived and illustrated with data from gypsy moth samples taken in Pennsylvania. 2. It is shown that attractant traps such as pheromone and light traps may exhibit density‐dependent sampling efficiency which can influence the parameters of TPL. 3. Comparison of the light...

In the first longitudinal study of nematode spatial distribution with sufficiently large samples to estimate Taylor's power law (TPL), we concluded that TPL is sensitive to life history strategy. We also observed that the value of TPL slope b was generally higher for more widespread and abundant taxa. We deduce that removal of empty samples increas...

The sustainability of agricultural land use has been the subject of integrated assessments for some time. In these assessments, knowledge of various disciplines is combined to assess, e.g., the drawbacks and benefits of new agrotechnologies, changes in management systems, and the introduction or abolition of agricultural policies. Crop models are o...

Giant ragweed has been increasing as a major weed of row crops in the last 30 yr, but quantitative data regarding its pattern and mechanisms of spread in crop fields are lacking. To address this gap, we conducted a Web-based survey of certified crop advisors in the U.S. Corn Belt and Ontario, Canada. Participants were asked questions regarding gian...

Stream water quantity and quality are dependent on the physical characteristics of a catchment. The effect of physical catchment characteristics (PCCs) on river flow is not adequately investigated in the upper Blue Nile River Basin. We selected two adjacent watersheds, Ribb and Gumara, of comparable area but significantly different long-term mean a...

SWAT (Soil and Water Assessment Tool) and APEX (Agricultural Policy/Environmental eXtender) are respectively large and small watershed simulation models derived from EPIC (Environmental Policy Integrated Climate), a field-scale agroecology simulation model. All three models are coded in Fortran and have evolved over several decades. They are widely...

Accurate spatial representation of climatic patterns is often a challenge in modeling biophysical processes at the watershed scale, especially where the representation of a spatial gradient in rainfall is not sufficiently captured by the number of weather stations. The spatial rainfall generator (SRGEN) is developed as an extension of the “weather...

Abstract Ambush foragers must employ a long-distance dispersal strategy to maximize reproductive success in the absence of hosts. This hypothesis was tested by comparing lateral dispersal of the ambusher, Steinernema carpocapsae, and cruiser, Heterorhabditis bacteriophora, nematodes from infected host cadavers in autoclaved, silt-loam soil in large...

It is well known that Taylor's power law describes spatial aggregation, but its ecological interpretation remains elusive. Here we used data on spatial organization of soil nematode communities in urban landscapes to test relationships between nematode life history characteristics and the power law aggregation indicator, b. Forty seven genera of so...

Limited input data per desired simulation area challenges watershed models capabilities. Weather input is essential for accurate modelling of hydrological processes, yet many world regions do not have these data readily available. The Agricultural Policy extender Model (APEX) offers a spatial weather generator to assist these data scarce regions. A...

Ambush foragers must employ some long-distance dispersal strategy to maximize reproductive success in the absence of hosts. To test this hypothesis we compared lateral dispersal of the ambusher, Steinernema carpocapsae and cruiser, Heterorhabditis bacteriophora from infected host cadavers in sterilized silt loam soil in microcosms (0.05 m2-1.5 m2)...

Dichotomy in foraging behavior of entomopathogenic nematodes is well recognized, however, little is known about their dispersal in the absence of hosts. We hypothesized that ambush foraging nematodes must employ some long-distance dispersal strategy to maximize reproductive success when they lack host information. We compared lateral dispersal of t...

Laboratory studies have identified dichotomy in foraging behavior of entomopathogenic nematode species but little is known about their dispersal in the absence of hosts. We compared the rate of lateral movement and dispersal pattern of the ambusher, Steinernema carpocapsae and cruiser, Heterorhabditis bacteriophora from infected host cadavers in st...

Lack of information on population biology of entomopathogenic nematodes (EPNs) is a major obstacle in establishing sustainable pest management programs and conservation approaches for using these biological control agents. It is critical to understand EPN spatial and temporal dynamics to replete this gap in knowledge. Laboratory studies have identi...

Laboratory studies have identified dichotomy in foraging behavior of entomopathogenic nematode species but little is known about their dispersal in the absence of hosts. We compared the rate of lateral movement and dispersal pattern of the ambusher, Steinernema carpocapsae and cruiser, Heterorhabditis bacteriophora from infected host cadavers in st...

Insect-nematode-bacterium mutualistic associations provide attractive systems for discovery of inter kingdom signal compounds and antibiotics. A better understanding of the biological meaning of the inter-specific diversity of compounds with antimicrobial activity of the Steinernema-symbiont Xenorhabdus bacteria may provide options for simultaneous...

A series of elegant laboratory studies show dichotomy in the foraging behavior of entomopathogenic nematodes (EPNs). However, how nematodes with ambusher and cruiser foraging strategies disperse in the field is unknown. Therefore, we compared the rate of lateral dispersal of a cruise foraging, Heterorhabditis bacteriophora and an ambusher, Steinern...

A series of elegant laboratory studies show dichotomy in the foraging behavior of entomopathogenic nematodes. However, how nematodes with ambusher and cruiser foraging strategies disperse in the field is unknown. Therefore, we compared the rate of lateral dispersal of a cruise foraging, Heterorhabditis bacteriophora strain GPS11 and an ambusher, St...

Computer-monitored flight mills were used to record the flight performance of the emerald ash borer, Agrilus planipennis Fairmaire. Flight performance of fed and unfed, and mated and unmated beetles of both sexes were recorded and compared. Mated females flew further per day and longer than unmated females or males. Mated females that were allowed...

The dispersal ability and unique foraging strategies of entomopathogenic nematodes, Heterorhabditis bacteriophora (cruiser) and Steinernema carpocapsae (ambusher) in soil, are the key factors which play a role in their effectiveness as biocontrol agents for soil inhabiting insect pests. The rate of lateral dispersal of Heterorhabditis bacteriophora...

The Emerald Ash Borer (EAB) beetle (Agrilus planipennis Fairmaire) is an invasive pest which has killed millions of ash trees since its discovery in 2002. It was detected in Point Pelee National Park on the north shore of Lake Erie in Ontario, Canada in the summer of 2007. Six rectangular plots containing a total of 610 ash trees were established i...

Functional guilds defined by nematode feeding types (bacteria-feeding, fungal-feeding, omnivore, predatory and plant-feeding) are further refined by colonizer-persister class (i.e. r-and K-strategists) which reflects life-history strategy. We compared spatial organization of nematode genera belonging to the same functional guild or colonizer-persis...

Although entomopathogenic nematodes are widely used as biological control agents for various economically important soil inhabiting insect pests, their population and spatial ecology has not been thoroughly investigated. Dispersal ability of entomopathogenic nematodes in soil is one of the key factors which play a role in their effectiveness as bio...

Broad-spectrum antibiotics produced by symbiotic bacteria [entomopathogenic bacterium (EPB)] of entomopathogenic nematodes keep monoxenic conditions in insect cadavers in soil. This study evaluated antibiotics produced by EPB for their potential to control plant pathogenic bacteria and oomycetes. Entomopathogenic bacterium produce antibiotics effec...

Despite the growing importance of entomopathogenic nematodes as biocontrol agents for soil inhabiting insect pests, little is known of their population and spatial ecology. In a series of three consecutive laboratory experiments, the horizontal movement of Heterorhabditis bacteriophora GPS11 strain was quantified in 5 cm deep autoclaved soil with 2...

1. The data for dispersal of Drosophila pseudoobscura of Dobzhansky & Wright (1943) were re-examined and an improved description found for them. 2. The equation that best described the dispersal of D.pseudoobscura was found not to be applicable to the dispersal of five other insect species. 3. Eight equations describing the density-distance relatio...

Entomopathogenic nematodes (Steinernematidae and Heterorhabditidae) are lethal obligatory parasites of insects and are found in soils throughout the world. The recognition that these nematodes are major natural enemies of soil insect pests has stimulated research into various aspects of their biology and enabled their use in augmentation and conser...

Nonfeeding infective juvenile (IJ) entomopathogenic nematodes (EPNs) are used as biological agents to control soil-dwelling insects, but poor storage stability remains an obstacle to their widespread acceptance by distributors and growers as well as a frustration to researchers. Age is one factor contributing to variability in EPN efficacy. We hypo...

Impaired wound healing is characteristic of diabetic patients. Potential reasons include poor inflammatory response, granulation tissue formation, and abnormal patterns of cytokine release and response. Vascular endothelial growth factor, abnormally regulated during healing in diabetics, is the major factor stimulating angiogenesis during normal wo...

Tomato yellow leaf curl virus (TYLCV) is the most frequently occurring virus in tomatoes in the Middle East, and the most harmful one. It is transmitted solely by the whitefly Bemisia tabaci (Gennadius). Within 4-6h of inoculative feeding, a whitefly can transmit TYLCV to a healthy plant with 80% probability. The symptoms are apparent after two to...

Qualitative and quantitative genetic analysis of life span in experimental adult animals predicts that resistance to stress and longevity are positively correlated, but such studies on field populations of animals are rare. We tested this hypothesis using dauer juveniles of 15 natural populations of the entomopathogenic nematode, Heterorhabditis ba...

The major cause of crop loss of greenhouse produce in Israel is a virus disease vectored by the tobacco whitefly, Bemisia tabaci. An exclusion screen developed to minimise B. tabaci entry to greenhouses has been adopted nationwide. To examine the cost effectiveness of greenhouse screening, a model was developed relating the aerial density of Bemisi...

Computer-monitored flight mills were used to record the flight performance of five species of nitidulids: Stelidota geminata (Say), S. Octomaculata (Say), S. ferruginea (Reitter), Carpophilus hemipterus (L.), and C. Lugubris Murray. Both Carpophilus species flew extensively, whereas the Stelidota species' flight was insufficient for analysis, and S...

A novel method for delivering the systemic insecticide acephate was tested with chrysanthemums and gerbera daisies. The method involves applying the insecticide to the interior surface of plant pots in paint. Two paints were tested, a latex paint and SpinOut, a paint already in use for controlling plant growth. The SpinOut used lacked the cupric hy...

The oleander scale, Aspidiotus nerii Bouché, is a polyphagous, cosmopolitan species almost always present on jojoba, Simmondsia chinensis (Link) Schneider, in its native Sonora desert and on plants introduced to Israel's Negev desert. Monthly samples of oleander scale taken at an experimental field at Omer, in the northern Negev, showed that the ov...

Application of pesticides through a hydraulic nozzle produces deposits on a plant surface which have a spatial structure with elements of deposit size, number per area, and toxin per deposit. To investigate the relative contributions of these elements to the interaction of deposit structure and toxicant efficacy, we used a stochastic cellular autom...

Pesticide deposits have a spatial structure having elements of size, number per area and toxicant per deposit. To investigate the relative contributions of these elements to the efficacy of the deposit structure, we developed a bioassay using the cabbage looper (Trichoplusia ni), cabbage, and a soluble concentrate formulation of fipronil [(±)-5-ami...

To investigate the spatial isotropy of Taylor's power law, data of the aerial population densities of western flower thrips, Frankliniella occidentalis (Pergande), were compared at 6 greenhouses in northeastern Ohio. The distributions were the smne in all 6 houses despite differences in crop (host plant) and in thrips population growth and developm...

Pesticides must be applied to the target area uniformly. Uniformity of sprayer output is typically described by the coefficient of variation (CV) of the spray emitted. However, deposit size, number, and concentration interactions are overlooked when using this static. A measurement technique and alternative statistics, capable of documenting and se...

A simple nozzle design/modification is presented which takes advantage of the known effect of the increasing biological efficacy of a pesticide with decreasing drop size for insecticides and perhaps fungicides. However, applying active ingredient (AI) in unassisted fine sprays leads to poor canopy penetration and increased drift hazard. Therefore,...

This study investigated an application of fuzzy modelling and conventional dynamic programming, to optimal biological control of a greenhouse mite/cucumber system. Based on a fuzzy model and a hypothetic nonfuzzy economic criterion of control cost and crop loss caused by pest mites, the optimal management strategies (with minimal control cost and c...

Biopesticides and agrichemicals are applied using basically the same equipment. The limitations imposed on biological or conventional chemical pesticides by current application systems are discussed. In general, any pesticide must be applied into a crop using the commonly used application system in that crop. This will normally be the hydraulic noz...

The ability of the sweet potato whitefly, Bemisia tabaci Gennad., to survive a range of environmental conditions was investigated in the laboratory. The range of temperature and humidity investigated corresponds to the normal climatic range during B. tabaci's summer migration in Israel. Adult whiteflies confined to small test cages were exposed to...

Some plants are more attractivee to agricultural, pests than the crop to which they are a pest. The use of these plants as indicator plants to monitor pest populations is examined. Bean plants were found to be effective indicators for forecasting the growth of carmine spider mite, Tetranychus sinnabarintus (Boisduval), on greehouse tomatoes, Lycope...

An efficient method for rapidly mass-screening insecticides for use against sap-feeding virus vectors is presented with a case study of 30 chemicals. The method permits large numbers of insecticides to be tested simultaneously and relatively inexpensively in a sequence of laboratory bioassays. The sequence is designed to find the most effective pes...

A system has been devised for determining the absolute capture efficiency of passive dosimeters. The system is composed of three components: a wind tunnel, a tracer atomizer, and a capture efficiency test device (CETD). The CETD consists of a series of cylinders separated by nylon screens to intercept and capture the spray containing a tracer. The...

One hundred and twenty mini-rose cuttings of each cultivar were planted in 6 inch pots and grown in a western flower thrips-infested greenhouse compartment at the Ohio Agricultural Research and Development Center, Wooster, Ohio. Plants were fertigated using 150 ppm 15-16-17 on a 3 fertilizeni leach schedule. On 13 February 1995, when the plants wer...

One hundred and forty-four Poinsettia cuttings were planted in 6 inch pots and grown in a silverleaf whitefly-infested greenhouse compartment at the Ohio Agricultural Research and Development Center, Wooster, Ohio. Plants were fertigated using 250 ppm 15-16-17 on a 3 fertilizer:l leach schedule. On 7 September 1995, when the plants were 11 wk old,...

Insecticide formulations and adjuvants are manipulated to optimize the pesticide deposit characteristics on the plant surface. The toxicity, deposit quality and quantity, together with the insect's pattern of feeding, detennine the insecticide's efficacy. A model of the dose-transfer process, The Pesticide Drop Simulator, was used to investigate th...

A statement of formulation effects on atomization by agricultural nozzles is already a requirement for the registration of a new chemical or formulation in the USA and parts of Europe. The laser-based instruments used for obtaining such data can be divided into two types: those that analyse the sample signal either spatially or temporally. It is kn...

The application of agrichemicals is a highly inefficient process and one of the main causes of the environmental and health risks currently associated with pesticide usage. Efforts to mitigate this inefficiency have largely been unsuccessful, due principally to the poor understanding of the processes involved in the spray application of pesticides,...

The flight periodicities of three species of Dalbulus leafhoppers were monitored in a controlled-environment chamber using Johnson-Taylor segregating suction traps. To assess their effect on flight activity, photoperiod and host plant age were experimentally manipulated to mimic conditions at different seasons in central Mexico. All three species f...

A multichannel, computer-monitored flight mill suitable for studying flight performance of small, weakly flying insects such as leafhoppers was developed. The flight mill uses a magnetic bearing and light-weight arm to minimize friction and drag. Sixteen mills can be monitored simultaneously by a PC. The construction of the mills and monitor, and d...

Arboreal and terresterial soil and lilter were sampled for macro-and microinvertebrates at two locations in a Venezuelan cloud forest. Fauna were most abundant in forest floor soil and associated litter. However, media suspended in the canopy and particularly those trapped in bromeliad shoots were most densely populated, while the diversities of th...

Catches by gypsy moth (Lymantria dispar (Linnaeus)) ‘milk-carton’ pheromone traps with (+)-disparlure were compared with estimates of the absolute aerial density of gypsy moths obtained using a suction trap of known absolute sampling efficiency. The mean number of male L. dispar caught per pheromone trap per day was found to be proportional to the...

The distribution and immigration trends of Empoasca fabae (Harris) in a managed alfalfa, Medicago sativa L., field were studied over a 3-yr period. In the second alfalfa growth cycle, E. fabae immigration into the field usually began after the alfalfa reached a height of 5 em. The rate of immigration into the field was constant until halfway into t...

Effects of two formulations of thuringiensin (ABG-6266 and ABG-6162A) on mortality, fecundity, and feeding of the twospotted spider mite, Tetranychus urticae Koch, were evaluated. Toxicities of the formulations were not significantly different. No differences in toxicity to protonymphs and deutonymphs were observed, but immature instars were signif...

Aerial density, flight thresholds, and periodicity were estimated for the house fly, Musca domestica L., and the stable fly, Stomoxys calcitrans (L.), from data collected by suction traps located in a dairy barn in Kansas between 1 July and 31 October 1970. M. domestica catches increased from July to August, declining to near zero by the end of Oct...

Accounting for the spatial distribution of individuals is an important issue in ecology and applied biology. The exponent, b, in the established empirical relationship1, s 2 = am b, between s 2, the spatial sample variance and m, the mean population density, conveys information about the spatial distribution of individuals of a particular species....

In statistical analyses of simulated insecticide efficacy trials it was found that changes in distribution of target insects caused by reductions in abundance may result in incorrect inferences. The severity of the problem is directly related to the index of aggregation from Taylor's power law. Thus, highly aggregated species, such as many pests, a...

A time series analysis of noctuid and sphingid moths caught at light traps in East Africa revealed the existence of sources of periodic variation in catch with three different wavelengths: lunar, annual and four-year. A comparison of catches of Spodoptera exempta (Walker) at different sites showed that site characteristics influence a light trap’s...

(1) The problem of the long-distance, return migration to their overwintering region by weakly flying aeroplankton was investigated. Aircraft-mounted nets were used to sample for migrant potato leafhoppers at an altitude of 152 m above ground level along a transect in Central Pennsylvania during the summers of 1981 and 1982. (2) The wind most frequ...

A predictive population dynamics model for potato leafhopper, Empoasca fabae (Harris), is presented. The model is based on a Leslie matrix design and uses a degreeday time scale. Linear regression is used to predict leafhopper immigration into the field, based on samples taken during the first 3 weeks following cutting. Laboratory and field data co...

The density/height profile of first-instar gypsy moth, Lymantria dispar (L.), was determined by sampling with airplanes up to 800 m above a moderately dense population of the moth in forests around Driftwood, Pa. A model is proposed suggesting that these flightless larvae were lifted there by atmospheric turbulence and that horizontal movement of c...

The preference of the nabid, Reduviolus americoferus (L.), for potato leafhopper nymphs, Empoasca fabae (Harris), and pea aphids, Acyrthosiphon pisum (Harris), was examined using functional response models. The nabid exhibited a type-II functional response to each prey. Handling time was much higher for the aphid than for the leafhopper (3.623 vs....

A cost-efficient, easy-to-use tow net for use on a high-wing monoplane was developed. Nets are deployed and retrieved while in flight. A 0.37-m2 net can be used by virtue of a rigging system that allows the net to collapse upon retrieval. Net design and sampling efficiency of the net are described.

Flight data gathered from suction trap (1982) and airplane (1981 and 1982) collections are presented for SIMULIUM JENNINGSI, one of Pennsylvania's most noxious pests. In central Pennsylvania, the seasonal flight peak occurred in mid-July; the hourly flight peak came between 1800 and 1900 h. The number of females captured was highly correlated with...

I have previously shown1 that some of the published regression equations for describing the decline of density of insects with distance from a centre of dispersal were each special cases of a more general equation: N = exp(a+bxc) (1) where N is density at a distance x from a centre of dispersal and a, b, and c are parameters. Equation (1) is a good...

(1) Of about 320 species of aphids whose aerial distributions were examined, only sexual autumn migrants of the hop aphid (Phorodon humuli Schrank) originated from dense, isolated and persistent population `patches'. (2) These source patches were hop gardens maintained in two small areas in southern England. (3) Patterns of aerial distribution were...

(1) A computer simulation model was developed for a migration of Schistocera gregaria: the locusts were reported to have reached the United Kingdom in 1954 and were described by Rainey (1963) who concluded from meteorological evidence and current locust reports that they originated in N.W. Africa. (2) The model follows the same basic assumptions th...

A concept is developed for the regulation of populations by density-dependent movement, rather than by overt competition alone. Fitness is seen as maximising the reproductive advantage of a balance between migratory and congregatory behaviours. Population density is shown to be spatially, as well as temporally dynamic and a mechanism is proposed th...