scholarly journals Use of a negative binomial distribution to describe the presence of Sphyrion laevigatum in Genypterus blacodes

2013 ◽  
Vol 22 (4) ◽  
pp. 602-604 ◽  
Author(s):  
Patricio Peña-Rehbein ◽  
Patricio De los Ríos-Escalante ◽  
Raúl Castro ◽  
Carolina Navarrete
Keyword(s):  
Spatial Distribution ◽  
Negative Binomial Distribution ◽  
Binomial Distribution ◽  
Negative Binomial ◽  
Distribution Model ◽  
Economic Resource ◽  
Spatial Distribution Model

This paper describes the frequency and number of Sphyrion laevigatum in the skin of Genypterus blacodes, an important economic resource in Chile. The analysis of a spatial distribution model indicated that the parasites tended to cluster. Variations in the number of parasites per host could be described by a negative binomial distribution. The maximum number of parasites observed per host was two.

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

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.

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

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.

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

2012 ◽  
Vol 21 (1) ◽  
pp. 78-80 ◽  
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.

The Stability of Weed Seedling Population Models and Parameters in Eastern Nebraska Corn (Zea mays) and Soybean (Glycine max) Fields

Weed Science ◽  
1995 ◽  
Vol 43 (4) ◽  
pp. 604-611 ◽  
Author(s):  
Gregg A. Johnson ◽  
David A. Mortensen ◽  
Linda J. Young ◽  
Alex R. Martin
Keyword(s):  
Negative Binomial Distribution ◽  
Binomial Distribution ◽  
Negative Binomial ◽  
Sequential Sampling ◽  
Mean Value ◽  
Distribution Model ◽  
Ratio Test ◽  
Weed Species ◽  
Sampling Procedures ◽  
Grass Weed

Intensive field surveys were conducted in eastern Nebraska to determine the frequency distribution model and associated parameters of broadleaf and grass weed seedling populations. The negative binomial distribution consistently fit the data over time (1992 to 1993) and space (fields) for both the inter and intrarow broadleaf and grass weed seedling populations. The other distributions tested (Poisson with zeros, Neyman type A, logarithmic with zeros, and Poisson-binomial) did not fit the data as consistently as the negative binomial distribution. Associated with the negative binomial distribution is akparameter.kis a nonspatial aggregation parameter related to the variance at a given mean value. Thekparameter of the negative binomial distribution was consistent across weed density for individual weed species in a given field except for foxtail spp. populations. Stability of thekparameter across field sites was assessed using the likelihood ratio test There was no stable or commonkvalue across field sites and years for all weed species populations. The lack of stability inkacross field sites is of concern, because this parameter is used extensively in the development of parametric sequential sampling procedures. Becausekis not stable across field sites,kmust be estimated at the time of sampling. Understanding the variability in it is critical to the development of parametric sequential sampling strategies and understanding the dynamics of weed species in the field.

scholarly journals SPATIAL DISTRIBUTION AND SEQUENTIAL SAMPLING OF Brevipalpus phoenicis IN CITRUS

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.

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

2015 ◽  
Vol 21 (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

<p class="p1"> <strong>RESUMEN</strong></p><p class="p3">El 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 m<span class="s1">2</span>, 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.</p><p class="p1"><strong>ABSTRACT</strong></p><p class="p2">The 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 m<span class="s1">2</span>, 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.</p>

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

Crustaceana ◽  
2018 ◽  
Vol 91 (12) ◽  
pp. 1465-1482 ◽  
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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