Computational protocol: Density, Demography, and Influential Environmental Factors on Overwintering Populations of Sogatella furcifera (Hemiptera: Delphacidae) in Southern Yunnan, China

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Protocol publication

[…] To analyze the pattern of S. furcifera population density with respect to longitude and latitude of each sampling site, the corresponding data were loaded into Surfer 10.0 (Golden Software Inc., Golden, CO) and contour maps were generated and coupled with the topography of Yunnan using Kriging methods ().To further analyze the relationship between various insect parameters and latitude and elevation, density and ratios of YNs, ONs, and MAs were calculated for each site and illustrated as bar charts with localities and latitudes on the X axis and population density on the Y axis using Grapher 8.0 (Golden Software Inc., Golden, CO), also, a contour map of the ratio of nymphs (including YN and ON) was generated and coupled with the topography of Yunnan using Kriging methods.Long-term climate data were obtained for each of the 105 sites from BioClim (averaged over 1950–2000) (www.worldclim.org) and used to generate ecogeographical variables (EGVs). The r29 dataset from BioClim, which includes data for all of Yunnan as well as part of southern China and Indochina (with 30 arc second resolution), was obtained and then cropped by the political boundary of Yunnan Province in GlobalMapper 11.0 (www.globalmapper.com). We extracted the following data for each sampling site using DIVA-GIS 7.5 (www.diva-gis.org) () and stored in an Excel spreadsheet: site altitude (Alt), and eight winter-related EGVs for the period 1950–2000, including isothermality (It, Bio3), temperature seasonality (Tseason, Bio4), minimum air temperature of coldest month (TminCM, Bio6), mean air temperature of driest quarter (TmeanDQ, Bio9), mean air temperature of coldest quarter (TmeanCQ, Bio11), precipitation of the coldest month (PCM, Bio14), precipitation of driest quarter (PDQ, Bio17), and precipitation of coldest quarter (PCQ, Bio19). The denotations in parentheses are the variable names uses in this research and the EGV names designated by BioClim.The distribution of S. furcifera population density data was first tested for normality using a histogram with normality curve in SPSS 13.0 (SPSS Inc., Chicago, IL), given that skewed data can affect the resulting regression models.We let D represent the population density in all analyses that were performed using SPSS 13.0. We first performed a Pearson zero-order correlation to determine the correlation between D and the nine EGVs and to detect for possible autocorrelation between the variables, which were used to check for multicollinearity in linear stepwise regression (using the forward-entering method) and to explore the relationship between D and each EGV, when using either the linear regression formula (in y = bx + C form) or the standardized regression formula (in y′ = βx form). The relative importance of each entered variable was evaluated by a Pearson one-order partial correlation. During the stepwise regression, the 3-σ criterion was adopted by casewise diagnosis for possible outlier in the dataset (). […]

Pipeline specifications

Software tools DIVA-GIS, SPSS
Applications Miscellaneous, Phylogenetics
Organisms Sogatella furcifera, Oryza sativa