DISTRIBUTION OF INSECTS IN SOYBEAN FIELDS

1976 ◽  
Vol 108 (7) ◽  
pp. 767-771 ◽  
Author(s):  
Merle Shepard ◽  
G. R. Carner
Keyword(s):  
Spatial Distribution ◽  
Spatial Patterns ◽  
Trichoplusia Ni ◽  
Negative Binomial ◽  
Insect Pests ◽  
Distribution Patterns ◽  
Epilachna Varivestis ◽  
Anticarsia Gemmatalis ◽  
Poisson Series ◽  
Binomial Distributions

AbstractA 3-year study of spatial distribution patterns of insect pests in soybean fields revealed that the Poisson series described the distribution of most species. These species were: green cloverworms, Plathypena scabra (Fabricius); velvetbean caterpillars, Anticarsia gemmatalis Hübner; loopers Trichoplusia ni (Hübner), Pseudoplusia includens (Walker), and Heliothis spp. The Poisson with zeros distribution was second in characterizing the spatial patterns of many of the species. Field counts of Mexican bean beetles, Epilachna varivestis Mulsant, fitted the Neyman’s type A and negative binomial distributions most often.

scholarly journals The spatial distribution patterns of rainfall use efficiency (RUE) of evergreen coniferous forests in Chinese subtropical zone

2020 ◽  
Vol 48 (1) ◽  
pp. 492-502
Author(s):  
Xiu-Juan ZHANG ◽  
Jun-Bang WANG ◽  
Chu WU ◽  
Kamil KUČA
Keyword(s):  
Spatial Distribution ◽  
Spatial Patterns ◽  
Net Primary Productivity ◽  
Southern China ◽  
Distribution Patterns ◽  
Coniferous Forests ◽  
Southeastern Part ◽  
Subtropical Zone ◽  
Functional Convergence ◽  
Use Efficiency

Rainfall use efficiency (RUE) of subtropics evergreen coniferous forests and RUE spatial patterns in Chinese subtropical zone were estimated. RUE and ecosystem net primary productivity (NPP) spatial distribution, as well as the relationship between RUE and rainfall were particularly focused. RUE of subtropical evergreen coniferous forests and the spatial patterns were estimated based on the data collected from the related weather stations and peer-reviewed literatures. In our study, a gradually increasing tendency of NPP from northwestern to southeastern part of the subtropical zone is observed. No significant differences in RUE among these tree species are visible. RUE of the evergreen coniferous forests reduces as the rainfall increases. RUE reaches the peak when rainfall is less than 700 mm. However, the distribution of RUE is not evident. In linear regression, longitude, latitude, and PAR account for approximately 1.4% of the variability in RUE. These findings suggest that the RUE of evergreen coniferous forests in southern China has a functional convergence.

scholarly journals Spatial Patterns and Interspecific Associations During Natural Regeneration in Three Types of Secondary Forest in the Central Part of the Greater Khingan Mountains, Heilongjiang Province, China

Forests ◽  
2020 ◽  
Vol 11 (2) ◽  
pp. 152 ◽  
Author(s):  
Lingyu Zhang ◽  
Lingbo Dong ◽  
Qiang Liu ◽  
Zhaogang Liu
Keyword(s):  
Spatial Distribution ◽  
Spatial Patterns ◽  
Tree Species ◽  
Natural Regeneration ◽  
Random Distribution ◽  
Distribution Patterns ◽  
Forest Types ◽  
Development Stages ◽  
Interspecific Associations ◽  
Adult Trees

Seedling and sapling spatial patterns are important in community regeneration, and understanding the natural regeneration mechanisms of tree species in relation to spatial patterns will help improve forest management and community restoration efficiency. Based on data from three fixed plots established in birch forests (BF), coniferous and broadleaved mixed forests (CBMF) and coniferous mixed forests (CMF) in the central Greater Khingan Mountains in Heilongjiang Province, China, in 2017, we used the univariate and bivariate O-ring functions of the point pattern analysis method to evaluate the spatial patterns and associations of the main tree species in these three forest types at different development stages and identified the community successional stages according to the interspecific associations between dominant tree species and other tree species. The results showed that Betula platyphylla and Larix gmelinii in BF exhibited identical spatial distribution patterns and had a tendency to transition from an aggregated to a random distribution from saplings to adult trees, whereas every tree type in CBMF generally showed a random distribution. Adult trees of the main tree species in CMF, i.e., L. gmelinii and Picea koraiensis, mainly showed a random distribution, but P. koraiensis at other size classes generally showed an aggregated distribution. The intraspecific associations of the main tree species in BF and CMF at different development stages were constrained by the spatial scale within a given scope, while those in CBMF at different development stages were not significantly constrained by spatial scale. The results also show that the density of the three forest types was affected by the distance between the individuals of the various tree classes and adult trees, with different levels of influence. We analyzed the interspecific associations between dominant tree species and other tree species and then assessed community succession progress and found that the BF and CMF exhibited medium-term community succession, while the CBMF was in the primary stage. Our results further show that the spatial distribution patterns of the tree species in the small-diameter classes were jointly affected by adjacent habitats and diffusional limitations and that scale dependence existed in the intraspecific and interspecific associations. The analysis of the natural regeneration of spatial distribution and interspecific associations represents an efficient way to explore the stability of forest communities and dynamic changes in interspecific relationships during succession. The study results thus provide a theoretical basis for developing rational forest management measures.

scholarly journals SPATIAL DISTRIBUTION OF Chrysodeixis includens EGGS (WALKER, 1858) (LEPIDOPTERA: NOCTUIDAE) IN SOYBEAN CROP

2019 ◽  
Vol 17 (2) ◽  
pp. 51 ◽  
Author(s):  
Leandro Aparecido De Souza ◽  
José Carlos Barbosa ◽  
João Henrique Silva Carvalho ◽  
Leticia Serpa dos Santos ◽  
Diego Felisbino Fraga ◽  
...  
Keyword(s):  
Spatial Distribution ◽  
Negative Binomial Distribution ◽  
Binomial Distribution ◽  
Probabilistic Models ◽  
Negative Binomial ◽  
Binomial Distributions ◽  
Egg Distribution ◽  
Morisita Index ◽  
Lepidoptera Noctuidae ◽  
Chrysodeixis Includens

Among pest insects that attack soybean crops, Chrysodeixis includens (Walker, 1858) (Lepidoptera: Noctuidae) looper caterpillar deserves attention due to its key pest status in soybean crops. The spatial distribution of C. includens eggs should be investigated in order to understand the behavior of this species in the area. The aim of this study was to investigate the spatial distribution of C. includens eggs in soybean crops. The experiment was conducted with SYN 9070 RR soybean variety in an experimental area of the Teaching, Research and Extension Farm (FEPE) of FCAV/ UNESP, Jaboticabal, SP, Brazil. The area of 0.6 ha was divided into 60 equidistant plots of 100 m² each. For the study of the spatial distribution of P. includens eggs in the area, the following dispersion indexes were used: variance / mean ratio (I), Morisita index (Id), Green coefficient (Cx), k exponent of the negative binomial distribution for each sampling. Regarding the probabilistic models that describe the spatial distribution of a given variable, the data adjustment to the Poisson and negative binomial distributions was tested. According to values obtained for dispersion indexes, egg distribution occurred in an aggregate way, and the negative binomial distribution was the most appropriate probabilistic model to represent the distribution of C. includens eggs in the study area.

scholarly journals Spatial distribution of parasitism on Phyllocnistis citrella Stainton, 1856 (Lepidoptera: Gracillariidae) in citrus orchards

2008 ◽  
Vol 68 (4) ◽  
pp. 813-817 ◽  
Author(s):  
SM. Jahnke ◽  
LR. Redaelli ◽  
LMG. Diefenbach ◽  
CF. Efrom
Keyword(s):  
Spatial Distribution ◽  
Negative Binomial ◽  
Leaf Miner ◽  
Phyllocnistis Citrella ◽  
The North ◽  
Binomial Distributions ◽  
Solar Exposure ◽  
Significant Difference ◽  
Citrus Orchards ◽  
East And West

Many species of microhymenopterous parasitoids have been registered on Phyllocnistis citrella, the citrus leafminer. The present study aimed to identify the spatial distribution pattern of the native and introduced parasitoids of P. citrella in two citrus orchards in Montenegro, RS. The new shoots from 24 randomly selected trees in each orchard were inspected at the bottom (0-1.5 m) and top (1.5-2.5 m) stratum and had their position relative to the quadrants (North, South, East and West) registered at every 15 days from July/2002 to June/2003. The leaves with pupae were collected and kept isolated until the emergence of parasitoids or of the leaf miner; so, the sampling was biased towards parasitoids that emerge in the host pupal phase. The horizontal spatial distribution was evaluated testing the fitness of data to the Poisson and negative binomial distributions. In Montenegrina, there was no significant difference in the number of parasitoids and in the mean number of pupae found in the top and bottom strata (χ2 = 0.66; df = 1; P > 0.05) (χ2 = 0.27; df =1; P > 0.05), respectively. In relation to the quadrants, the highest average numbers of the leafminer pupae and of parasitoids were registered at the East quadrant (χ2 = 11.81; df = 3; P < 0.05), (χ2 = 10.36; df = 3; P < 0.05). In the Murcott orchard, a higher number of parasitoids was found at the top stratum (63.5%) (χ2 = 7.24; df =1 P < 0.05), the same occurring with the average number of P. citrella pupae (62.9%) (χ2 = 6.66; df = 1; P < 0.05). The highest number of parasitoids and of miners was registered at the North quadrant (χ2 = 19. 29; df = 3; P < 0.05), (χ2 = 4.39; df = 3; P < 0.05). In both orchards, there was no difference between the numbers of shoots either relative to the strata as well as to the quadrants. As the number of shoots did not varied much relative to the quadrants, it is possible that the higher number of miners and parasitoids in the East and West quadrants would be influenced by the higher solar exposure of these quadrants. The data of the horizontal spatial distribution of the parasitism fit to the negative binomial distribution in all sampling occasions, indicating an aggregated pattern.

Testing a procedure to determine spatial proximity in semi-free-ranging macaque groups

2021 ◽  
Vol 22 (1) ◽  
pp. 24-54
Author(s):  
Laura Mármol ◽  
Hélène Meunier ◽  
Ruth Dolado ◽  
Francesc S. Beltran
Keyword(s):  
Spatial Distribution ◽  
Spatial Patterns ◽  
Social Factors ◽  
Current Method ◽  
Distribution Patterns ◽  
Spatial Position ◽  
Spatial Proximity ◽  
Viable Option ◽  
Spatial Variables ◽  
Free Ranging

Abstract Individuals’ spatial position is affected by social factors. The majority of studies correlating spatial position and social factors have used methods with drawbacks. A more complete method was developed by Dolado & Beltran (2011) in captive animals. The present study aimed to apply a modified version of this method in two semi-free-ranging macaque groups. The proposed method divides group’s surroundings into different subareas, selecting different points in each subarea and calculating the coordinates of these points. We filmed each group and analyzed the videos using an activated time transition recording to determine the individuals’ coordinates. With these data, we calculated spatial variables, allowing us to obtain groups’ spatial patterns. The current method improves on previous procedures and could be applied to larger study areas and groups than the method of Dolado & Beltran (2011), thus representing a viable option for studying spatial distribution patterns in semi-free-ranging macaque groups.

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

Weed Science ◽  
1992 ◽  
Vol 40 (4) ◽  
pp. 554-557 ◽  
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.

Spatial distribution of tree species in a species-rich subtropical mountain forest in central China

2013 ◽  
Vol 43 (9) ◽  
pp. 826-835 ◽  
Author(s):  
Yili Guo ◽  
Junmeng Lu ◽  
Scott B. Franklin ◽  
Qinggang Wang ◽  
Yaozhan Xu ◽  
...  
Keyword(s):  
Spatial Distribution ◽  
Spatial Patterns ◽  
Tree Species ◽  
Habitat Heterogeneity ◽  
Growth Form ◽  
Species Coexistence ◽  
Species Abundance ◽  
Distribution Patterns ◽  
Spatial Distribution Patterns ◽  
Aggregation Intensity

Inferring the processes underlying the spatial distribution patterns of tree species is fundamental for understanding species coexistence. Here, we examined spatial distribution patterns of woody plants by using the univariate pair correlation function to quantify spatial patterns of species in a fullly mapped 25 ha subtropical plot in China. We analyzed the relationships between the species attributes and spatial distribution patterns of 137 tree species with at least one individual per hectare. The results showed that aggregated distributions were the dominant pattern for species in the Badagongshan subtropical forests, and that the percentage of significantly aggregated species decreased with increasing spatial scales. Rare species were more aggregated than intermediate and abundant species, but they were more easily influenced by habitat heterogeneity. Also, there was significantly negative relationship between species abundance and species aggregation intensity. The aggregation intensity showed negative relationships to species mean diameter at breast height (DBH) and maximum DBH, i.e., species became more regularly spaced as species stature increased. Species functional traits (e.g., growth form and phenological guild) also had obvious effects on the spatial patterns of species. However, spatial patterns of tree species were not related to the dispersal mode. Our results partially conformed to the prediction that species’ attributes influenced species’ spatial patterns following similar laws, even after controlling for the effects of habitat heterogeneity. Consequently, species attributes (species abundance, mean DBH, maximal DBH, growth form, phenological guild, etc.) and habitat heterogeneity may primarily contribute to spatial patterns and species coexistence in natural forests.

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.

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