STUDIES ON THE POPULATION SPATIAL PATTERNS OF DENDROLIMUS TABULAEFORMIS (TSAI ET LIU) LARVAE AND PUPAE ON EVERY STRATUM OF VERTICILLATE-BRANCHES(SVB)OF PINE AND THE LAW OF SPATIAL PATTERN VARYING AMONG STRATA (SVBs)
Abstract:In most of the reported studies on spatial pattern of insect populations,the natural habitat unit (NHU) of population individuals is essentially assumed as point,i.e., the number of individuals within a NHU as basic unit for surveying,assessing and interpreting spatial pattern, But in fact the NHU of insect population is generally a multidimensional structure rather than point. Therefore the much spatial information may be lost owing to this inappropriate assumption. In this paper, pine tree,the NHU of Dendrolimus tabulaeformis,is considered as one-dimensional axis composed of strata of verticillate-branches(SVBs) rather than points. Based on the above idea,spatial patterns of Dendrollmus tabulaeformis larvae and pupae on every SVB were assessed and interpreted with Taylor‘s power law model and the author‘s reinterpreted Taylor‘s power law,and the law of spatial patterns varying among strata was analysed with Fuzzy Clustering Analysis (FCA),Grey Clustering Analysis (GCA) and Trend Curved Surface Analysis (TCSA)methods. Also within-pine-tree vertical distribution aggregation of population was discussed. It coneiudes that: (1)according to the author‘s reinterpreted Taylor‘s power law, the spatial pattern of larvae and pupae on every SVB follows inverse densitydependent aggregation,and the critical density m of the population aggregation was calculated, so the spatial pattern continuum on every SVB can be deseribed quantitatively; (2)the resuits of FCA,GCA,and TCSA show that the alw of spatial pattern aggregation varying among Strata is non-liner and oscillatory,and the Strata can be clustered into several types according to the characteristics of the population aggregation; (3)within-pine-tree vertical distribution also follows inverse density-dependent aggregation.