Spatial Distribution of Venturia inaequalis Airborne Ascospores in Orchards

Apple scab (Venturia inaequalis) causes important economic losses in many apple production areas of the world. The disease is controlled by numerous fungicide applications regardless of the presence of ascospores in the orchard. Airborne ascospore concentration (AAC) can be measured in real time to time fungicide applications. However, the level of heterogeneity of the AAC in commercial orchards was unknown. Consequently, the spatial distribution of V. inaequalis ascospores was studied in a commercial apple orchard of 0.43 ha. The potential ascospore dose (PAD) and AAC were measured in 40 quadrats each of 108 m2. In each quadrat, the AAC was monitored during the major rain events in spring 1999 and 2000 using spore samplers. The variance-to-mean ratio for the PAD and for most of the AAC sampling dates was >1, indicating an aggregated pattern of distribution. None of the frequency distributions of the most important ascospore ejection events followed the Poisson probability distribution, indicating that the pattern of distribution was not random. For all events, AAC had an aggregated pattern of distribution as suggested by the negative binomial distribution. The PAD followed neither the Poisson nor the negative binomial distribution. Geostatistical analyses confirmed the aggregated pattern of distribution. The cultivars had an effect on the PAD and AAC distribution pattern, but both PAD and AAC were not uniformly distributed within a block of the same cultivar. Therefore, the number, location, and height of samplers required to estimate AAC in orchards need to be investigated before using information on AAC for decision making.

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DISTRIBUCIÓN ESPACIAL DE Vatiga spp. (HEMIPTERA: TINGIDAE) EN EL CULTIVO DE YUCA

Acta Biológica Colombiana ◽

10.15446/abc.v21n1.46762 ◽

2015 ◽

Vol 21 (1) ◽

Cited By ~ 1

Author(s):

Antonio De Souza Silva

Keyword(s):

Spatial Distribution ◽

Negative Binomial Distribution ◽

Binomial Distribution ◽

Field Data ◽

Negative Binomial ◽

Plant Leaves ◽

Frequency Distributions ◽

Morisita Index ◽

Best Fit

RESUMENEl objetivo de este trabajo fue generar informacion acerca de cuál es el modelo de disposición espacial de Vatiga spp. en el cultivo de la yuca. Se realizaron muestreos en dos áreas comerciales de 2500 m2, divididas en 100 parcelas. Se contaron adultos y de ninfas de Vatiga spp. en las hojas basales y medias de la planta. En total, se realizaron doce muestreos quincenalmente, desde febrero hasta abril de 2014, época de mayor incidencia de esta plaga. De forma general, a través de los índices de dispersión (varianza/media, índice de Morisita y exponente K) y las distribuciones de frecuencia, se observa que la distribución espacial de Vatiga spp. es agregada, es decir, el padrón de distribución Binomial Negativa fue el que resultó de mejor ajuste a los datos obtenidos a campo, con el conteo de los individuos.ABSTRACTThe aim of this study was to generate information about which is the model of spatial distribution of Vatiga spp. in the cassava culture. Sampling was conducted in two commercial areas of 2,500 m2, divided into 100 plots. Adults and nymphs of Vatiga spp. were counted in the basal and medium plant leaves. In all, twelve samples were taken fortnightly from February to April 2014, when occurs the highest incidence of this pest. Based in the indices of dispersion (variance/mean, Morisita index and K exponent) and the frequency distributions, it was observed that the spatial distribution of Vatiga spp. is aggregate, it means that the standard Negative Binomial distribution was the best fit to the field data obtained, with the counting direction of individuals.

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Spatial Distribution of Broadleaf Weeds in North Carolina Soybean (Glycine max) Fields

Weed Science ◽

10.1017/s0043174500058124 ◽

1992 ◽

Vol 40 (4) ◽

pp. 554-557 ◽

Cited By ~ 78

Author(s):

Lori J. Wiles ◽

Glenn W. Oliver ◽

Alan C. York ◽

Harvey J. Gold ◽

Gail G. Wilkerson

Keyword(s):

North Carolina ◽

Spatial Distribution ◽

Glycine Max ◽

Negative Binomial Distribution ◽

Binomial Distribution ◽

Negative Binomial ◽

Individual Species ◽

Frequency Distributions ◽

Binomial Distributions ◽

High Degree

Spatial distribution of broadleaf weeds within 14 North Carolina soybean fields was characterized by fitting negative binomial distributions to frequency distributions of weed counts in each field. In most cases, the data could be represented by a negative binomial distribution. Estimated values of the parameter K of this distribution were small, often less than one, indicating a high degree of patchiness. The data also indicated that the population as a whole was patchy. Counts of individual species were positively correlated with each other in some fields and total weed count could be represented by a negative binomial for 12 of the 14 fields.

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Niche Sharing in Intertidal Mollusks and Decapods in Rocky Shore of Easter Island

Vestnik Zoologii ◽

10.2478/vzoo-2019-0037 ◽

2019 ◽

Vol 53 (5) ◽

pp. 417-422

Author(s):

P. De los Ríos ◽

E. Ibáñez Arancibia

Keyword(s):

Spatial Distribution ◽

Negative Binomial Distribution ◽

Binomial Distribution ◽

Rocky Shore ◽

Negative Binomial ◽

Null Model ◽

Easter Island ◽

Published Data ◽

Distribution Analysis ◽

Field Works

Abstract The coastal marine ecosystems in Easter Island have been poorly studied, and the main studies were isolated species records based on scientific expeditions. The aim of the present study is to apply a spatial distribution analysis and niche sharing null model in published data on intertidal marine gastropods and decapods in rocky shore in Easter Island based in field works in 2010, and published information from CIMAR cruiser in 2004. The field data revealed the presence of decapods Planes minutus (Linnaeus, 1758) and Leptograpsus variegatus (Fabricius, 1793), whereas it was observed the gastropods Nodilittorina pyramidalis pascua Rosewater, 1970 and Nerita morio (G. B. Sowerby I., 1833). The available information revealed the presence of more species in data collected in 2004 in comparison to data collected in 2010, with one species markedly dominant in comparison to the other species. The spatial distribution of species reported in field works revealed that P. minutus and N. morio have aggregated pattern and negative binomial distribution, L. variegatus had uniform pattern with binomial distribution, and finally N. pyramidalis pascua, in spite of aggregated distribution pattern, had not negative binomial distribution. Finally, the results of null model revealed that the species reported did not share ecological niche due to competition absence. The results would agree with other similar information about littoral and sub-littoral fauna for Easter Island.

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Use of negative binomial distribution to describe the presence of Anisakis in Thyrsites atun

Revista Brasileira de Parasitologia Veterinária ◽

10.1590/s1984-29612012000100017 ◽

2012 ◽

Vol 21 (1) ◽

pp. 78-80 ◽

Cited By ~ 5

Author(s):

Patricio Peña-Rehbein ◽

Patricio De los Ríos-Escalante

Keyword(s):

Spatial Distribution ◽

Negative Binomial Distribution ◽

Binomial Distribution ◽

Negative Binomial ◽

Marine Fishes ◽

Intermediate Hosts ◽

Distribution Models ◽

Internal Organs ◽

Fishery Resource

Nematodes of the genus Anisakis have marine fishes as intermediate hosts. One of these hosts is Thyrsites atun, an important fishery resource in Chile between 38 and 41° S. This paper describes the frequency and number of Anisakis nematodes in the internal organs of Thyrsites atun. An analysis based on spatial distribution models showed that the parasites tend to be clustered. The variation in the number of parasites per host could be described by the negative binomial distribution. The maximum observed number of parasites was nine parasites per host. The environmental and zoonotic aspects of the study are also discussed.

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SPATIAL DISTRIBUTION AND SEQUENTIAL SAMPLING OF Brevipalpus phoenicis IN CITRUS

Revista Brasileira de Fruticultura ◽

10.1590/0100-29452016085 ◽

2016 ◽

Vol 38 (4) ◽

Author(s):

WALTER MALDONADO JR ◽

JOSÉ CARLOS BARBOSA ◽

MARÍLIA GREGOLIN COSTA ◽

PAULO CÉSAR TIBURCIO GONÇALVES ◽

TIAGO ROBERTO DOS SANTOS

Keyword(s):

Spatial Distribution ◽

Negative Binomial Distribution ◽

Binomial Distribution ◽

Negative Binomial ◽

Sequential Sampling ◽

Sampling Plan ◽

Goodness Of Fit Test ◽

Control Plan ◽

Sequential Sampling Plan ◽

Brevipalpus Phoenicis

ABSTRACT Among the pests of citrus, one of the most important is the red and black flat mite Brevipalpus phoenicis (Geijskes), which transmits the Citrus leprosis virus C (CiLV-C).When a rational pest control plan is adopted, it is important to determine the correct timing for carrying out the control plan. Making this decision demands constant follow-up of the culture through periodic sampling where knowledge about the spatial distribution of the pest is a fundamental part to improve sampling and control decisions. The objective of this work was to study the spatial distribution pattern and build a sequential sampling plan for the pest. The data used were gathered from two blocks of Valencia sweet orange on a farm in São Paulo State, Brazil, by 40 inspectors trained for the data collection. The following aggregation indices were calculated: variance/ mean ratio, Morisita index, Green’s coefficient, and k parameter of the negative binomial distribution. The data were tested for fit with Poisson and negative binomial distributions using the chi-square goodness of fit test. The sequential sampling was developed using Wald’s Sequential Probability Ratio Test and validated through simulations. We concluded that the spatial distribution of B. phoenicis is aggregated, its behavior best fitted to the negative binomial distribution and we built and validated a sequential sampling plan for control decision-making.

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Spatial Distribution of Eggs of Alabama argillacea Hübner and Heliothis virescens Fabricius (Lepidoptera: Noctuidae) on Bt and non-BtCotton

Anais da Academia Brasileira de Ciências ◽

10.1590/0001-3765201520140297 ◽

2015 ◽

Vol 87 (4) ◽

pp. 2243-2253

Author(s):

TATIANA R. RODRIGUES ◽

MARCOS G. FERNANDES ◽

PAULO E. DEGRANDE ◽

THIAGO A. MOTA

Keyword(s):

Spatial Distribution ◽

Negative Binomial Distribution ◽

Binomial Distribution ◽

Heliothis Virescens ◽

Negative Binomial ◽

Model Fitting ◽

Spatial Arrangement ◽

Distribution Model ◽

Aggregation Index ◽

Alabama Argillacea

ABSTRACT Among the options to control Alabama argillacea (Hübner, 1818) and Heliothis virescens (Fabricius, 1781) on cotton, insecticide spraying and biological control have been extensively used. The GM'Bt' cotton has been introduced as an extremely viable alternative, but it is yet not known how transgenic plants affect populations of organisms that are interrelated in an agroecosystem. For this reason, it is important to know how the spatial arrangement of pests and beneficial insect are affected, which may call for changes in the methods used for sampling these species. This study was conducted with the goal to investigate the pattern of spatial distribution of eggs of A. argillacea and H. virescens in DeltaOpalTM (non-Bt) and DP90BTMBt cotton cultivars. Data were collected during the agricultural year 2006/2007 in two areas of 5,000 m2, located in in the district of Nova América, Caarapó municipality. In each sampling area, comprising 100 plots of 50 m2, 15 evaluations were performed on two plants per plot. The sampling consisted in counting the eggs. The aggregation index (variance/mean ratio, Morisita index and exponent k of the negative binomial distribution) and chi-square fit of the observed and expected values to the theoretical frequency distribution (Poisson, Binomial and Negative Binomial Positive), showed that in both cultivars, the eggs of these species are distributed according to the aggregate distribution model, fitting the pattern of negative binomial distribution.

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Patterns of macroparasite aggregation in wildlife host populations

Parasitology ◽

10.1017/s0031182098003448 ◽

1998 ◽

Vol 117 (6) ◽

pp. 597-610 ◽

Cited By ~ 277

Author(s):

D. J. SHAW ◽

B. T. GRENFELL ◽

A. P. DOBSON

Keyword(s):

Poisson Distribution ◽

Negative Binomial Distribution ◽

Binomial Distribution ◽

Goodness Of Fit ◽

Negative Binomial ◽

Data Sets ◽

Frequency Distributions ◽

System A ◽

Host Sex ◽

Host Parasite

Frequency distributions from 49 published wildlife host–macroparasite systems were analysed by maximum likelihood for goodness of fit to the negative binomial distribution. In 45 of the 49 (90%) data-sets, the negative binomial distribution provided a statistically satisfactory fit. In the other 4 data-sets the negative binomial distribution still provided a better fit than the Poisson distribution, and only 1 of the data-sets fitted the Poisson distribution. The degree of aggregation was large, with 43 of the 49 data-sets having an estimated k of less than 1. From these 49 data-sets, 22 subsets of host data were available (i.e. host data could be divided by either host sex, age, where or when hosts were sampled). In 11 of these 22 subsets there was significant variation in the degree of aggregation between host subsets of the same host–parasite system. A common k estimate was always larger than that obtained with all the host data considered together. These results indicate that lumping host data can hide important variations in aggregation between hosts and can exaggerate the true degree of aggregation. Wherever possible common k estimates should be used to estimate the degree of aggregation. In addition, significant differences in the degree of aggregation between subgroups of host data, were generally associated with significant differences in both mean parasite burdens and the prevalence of infection.

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Spatial distribution and abundance of Hemigrapsus crenulatus (H. Milne Edwards, 1837) (Decapoda, Varunidae) in the Puerto Cisnes estuary (44°S, Aysen region, Chile)

Crustaceana ◽

10.1163/15685403-00003841 ◽

2018 ◽

Vol 91 (12) ◽

pp. 1465-1482 ◽

Cited By ~ 1

Author(s):

Rolando Vega-Aguayo ◽

Guillermo Figueroa-Muñoz ◽

Marco A. Retamal ◽

Patricio De los Ríos

Keyword(s):

Spatial Distribution ◽

Negative Binomial Distribution ◽

Binomial Distribution ◽

Negative Binomial ◽

Average Density ◽

Chilean Patagonia ◽

Wide Range ◽

The Status ◽

Estuarine Beaches ◽

Intertidal Level

Abstract Our knowledge on the status of Hemigrapsus crenulatus (H. Milne Edwards, 1837) populations along the Chilean coast is scarce. The aim of the present study was to quantitatively estimate the spatial distribution and abundance of Hemigrapsus crenulatus in the Puerto Cisnes estuary (44°S, Aysen region, Chilean Patagonia). The spatial distribution appeared to be aggregated, with 3.64 ± 7.99 ind/m2 as gross density, and 10.50 ± 10.62 ind/m2 as a potential ecological density, i.e., if the quadrants with zero individuals are not taken into consideration. The equation of the negative binomial distribution was: where: . The average density of Hemigrapsus crenulatus under stones is lower if all beach surfaces are considered. Its abundance or dominance on estuarine beaches probably would be due to the fact that this species is one of the crustaceans of the lower intertidal level that can survive under a wide range of salinity values.

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Spatial distribution in marine invertebrates in rocky shore of Araucania Region (38° S, Chile)

Brazilian Journal of Biology ◽

10.1590/1519-6984.208863 ◽

2020 ◽

Vol 80 (2) ◽

pp. 362-367

Author(s):

P. De los Ríos ◽

E. Carreño

Keyword(s):

Spatial Distribution ◽

Distribution Pattern ◽

Negative Binomial Distribution ◽

Binomial Distribution ◽

Rocky Shore ◽

Negative Binomial ◽

Marine Invertebrate ◽

Benthic Fauna ◽

Rocky Shores ◽

Invertebrate Species

Abstract The rocky shores in Chile have a wide invertebrate species diversity, that include species with marked abundances in determined regions. The aim of the present study is to analyse the spatial distribution pattern in different marine invertebrate species in rocky shore of Araucania region, considering if these species have random, uniform or associated patterns, and extrapolate if these patterns have Poisson, binomial or negative binomial distribution respectively. The results revealed the presence mainly of gastropods molluscs that would graze on benthic algae, these species have mainly aggregated pattern that has a robust negative binomial distribution pattern. The obtained results agree with observations for marine benthic fauna that mentioned the presence of aggregated pattern, has negative binomial distribution. Other ecological topics about spatial distribution were discussed.

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Linking parasite populations in hosts to parasite populations in space through Taylor's law and the negative binomial distribution

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1618803114 ◽

2016 ◽

Vol 114 (1) ◽

pp. E47-E56 ◽

Cited By ~ 9

Author(s):

Joel E. Cohen ◽

Robert Poulin ◽

Clément Lagrue

Keyword(s):

Spatial Distribution ◽

Negative Binomial Distribution ◽

Binomial Distribution ◽

Negative Binomial ◽

Parasite Load ◽

Host Individual ◽

Taylor’S Law ◽

Parasite Populations ◽

Relationship Of ◽

Better Than

The spatial distribution of individuals of any species is a basic concern of ecology. The spatial distribution of parasites matters to control and conservation of parasites that affect human and nonhuman populations. This paper develops a quantitative theory to predict the spatial distribution of parasites based on the distribution of parasites in hosts and the spatial distribution of hosts. Four models are tested against observations of metazoan hosts and their parasites in littoral zones of four lakes in Otago, New Zealand. These models differ in two dichotomous assumptions, constituting a 2 × 2 theoretical design. One assumption specifies whether the variance function of the number of parasites per host individual is described by Taylor's law (TL) or the negative binomial distribution (NBD). The other assumption specifies whether the numbers of parasite individuals within each host in a square meter of habitat are independent or perfectly correlated among host individuals. We find empirically that the variance–mean relationship of the numbers of parasites per square meter is very well described by TL but is not well described by NBD. Two models that posit perfect correlation of the parasite loads of hosts in a square meter of habitat approximate observations much better than two models that posit independence of parasite loads of hosts in a square meter, regardless of whether the variance–mean relationship of parasites per host individual obeys TL or NBD. We infer that high local interhost correlations in parasite load strongly influence the spatial distribution of parasites. Local hotspots could influence control and conservation of parasites.

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