ABSTRACT
Objective To understand the natural population dynamics and spatial distribution of Tyrophagus putrescentiae in storage flour,so as to provide an evidence for its prevention and control. Methods The samples from five sampling points in Wuhu City were collected monthly from January to December,2013,and examined and counted for T. putrescentiae. The disper-sion pattern target,Iwao's m*--x regression analysis and Taylor's lgS2-lg-x regression analysis were used for analyzing the spa-tial distribution pattern of T. putrescentiae in the storage flour. Results The peaks of population dynamics of T. putrescentiae were discovered in July and September. The indexes of dispersion were as follows:I>0,CA>0,m*/-x >1;and the linear re-gression equation of Iwao:m*=3.7403+1.0175-x (r=0.9958)and Taylor:lgS2=0.5004+1.1349 lg-x (r=0.8328) showed that the spatial distribution pattern of T. putrescentiae in the storage flour was assembled. Conclusion The peak of pop-ulation dynamics of T. putrescentiae in the storage flour in Wuhu City is a double peak type,and the spatial distribution pattern of T. putrescentiae is assembled.
ABSTRACT
Objective To characterize the population dynamics and spatial distribution of Aleuroglyphus ovatus in the flour warehouse,so as to provide the basic evidence for improving the sampling guidelines that are essential for effective pest monitor?ing and management. Methods The samples from flour warehouses of four localities were collected,examined and counted for A. ovatus in every month in Wuhu City. The dispersion pattern target,Iwao m*/-x regression analysis and Taylor power method were used for analyzing the spatial distribution pattern of A. ovatus in the flour warehouses. Results The peaks of population dynamics of A. ovatus were discovered in July and September,respectively. The indexes of dispersion were as follows:I>0, CA>0,m*/-x >1. At the same time,the parameters in the equation of Iwao:m*=5.471+1.022-x (r=0.999)and Taylor:lgS2=0.697+1.111 lg-x (r=0.987)showed that the spatial distribution pattern of A. ovatus was assembled. Conclusion The peaks of population dynamics of A. ovatus in the flour warehouse are bimodal pattern ,and the spatial distribution pattern of A. ovatus is assembled.
ABSTRACT
The objectives of this study were to evaluate the influence of propagules source and the implication of tree size class on the spatial pattern of Xylopia brasiliensis Spreng. individuals growing under the canopy of an experimental plantation of eucalyptus. To this end, all individuals of Xylopia brasiliensis with diameter at soil height (dsh) > 1 cm were mapped in the understory of a 3.16 ha Eucalyptus spp. and Corymbia spp. plantation, located in the municipality of Lavras, SE Brazil. The largest nearby mature tree of X. brasiliensis was considered as the propagules source. Linear regressions were used to assess the influence of the distance of propagules source on the population parameters (density, basal area and height). The spatial pattern of trees was assessed through the Ripley K function. The overall pattern showed that the propagules source distance had strong influence over spatial distribution of trees, mainly the small ones, indicating that the closer the distance from the propagules source, the higher the tree density and the lower the mean tree height. The population showed different spatial distribution patterns according to the spatial scale and diameter class considered. While small trees tended to be aggregated up to around 80 m, the largest individuals were randomly distributed in the area. A plausible explanation for observed patterns might be limited seed rain and intra-population competition.
Os objetivos deste estudo foram avaliar a influência da fonte de propágulo e a implicação de diferentes classes de tamanho sobre o padrão de distribuição espacial de indivíduos de Xylopia brasiliensis Spreng. crescendo sob o dossel de um plantio experimental de eucalipto. Para isso, todos os indivíduos de X. brasiliensis com diâmetro à altura do solo (das) > 1 cm foram mapeados em uma área de 3,16 ha no sub-bosque de um plantio de Eucalyptus ssp. e Corymbia spp., localizado no município de Lavras, MG. O maior e mais próximo indivíduo reprodutivo de X. brasiliensis foi considerado como fonte de propágulos. Foram utilizadas regressões lineares para avaliar a influência da fonte de propágulos sobre parâmetro populacionais (densidade, área basal e altura). O padrão de distribuição espacial das árvores foi avaliado por meio da função K de Ripley. O padrão geral demonstrou que a distância da fonte de propágulo teve forte influência sobre a distribuição espacial das árvores, principalmente as menores, indicando que quanto mais próximo à fonte de propágulos, maior a densidade e menor a altura das árvores. A população demonstrou diferentes distribuições espaciais de acordo com a escala analisada. Enquanto árvores menores tenderam a estar agregadas até uma escala de 80 m, os maiores indivíduos estavam aleatoriamente distribuídos na área. Uma explicação plausível para os padrões observados poderia ser a limitação espacial da chuva de sementes e a competição intraespecífica.