旨在探明新疆荒漠绿洲稻区特殊生境下稻水象甲的空间分布格局及抽样技术,为该虫情预测预报及田间有效监测提供科学依据。应用扩散系数进行t检验,以丛生指数Moore I、平均拥挤度m*、聚集度指数m*/m、C_A指标、聚集强度K及扩散指数I_Q等6种聚集度指标相互印证,用Iwao回归、Taylor幂法则、聚集均数(λ)及U检验,对稻水象甲幼虫、蛹两种不同虫态下种群空间格局及抽样技术进行研究。2种虫态下稻水象甲均呈密度依赖型聚集分布,m*-m回归表明;其空间分布的基本成分均是稻水象甲个体群,但幼虫个体间相互排斥,蛹相互吸引。Taylor幂法则分析表明:均值与聚集度呈显著正相关;聚集均数(λ)分析表明:稻水象甲幼虫、蛹的聚集均是由其本身的聚集行为与环境共同影响所致,且蛹的聚集程度高于幼虫。此外,用Iwao回归法,建立最适理论抽样模型:N=(t/D)~2[(α+1)/m+β-1)],计算出在不同密度(m)下稻水象甲幼虫和蛹的理论抽样数,随着幼虫、蛹密度的增大,所需抽样数逐渐减少,m0取平均每穴幼虫数为12头时,两种虫态序贯抽样公式依次为T_(1(n)),T_(0(n))=12n±18.527 0n^(1/2)、T_(1(n)),T_(0(n))=12n±22.200 9n^(1/2),经U检验,稻水象甲两种虫态各抽样方法均可靠,田间最适抽样方法幼虫为"Z"字形取样法(0.140),蛹则为大5点取样法(0.177)。综上,两种虫态下稻水象甲均为聚集分布,且蛹的聚集程度高于幼虫的聚集强度,其聚集原因均是由其本身的聚集行为与环境共同影响所致,在大田抽样中,幼虫、蛹的最适抽样依次为"Z"字形取样法和大5点取样法。
Spatial distribution patterns and sampling technique of rice water weevil(RWW),Lissorhoptrus oryzophilus Kuschel in special habitat region of Xinjiang desert oasis was studied,the results provide a theoretical basis for pest forecast and effective monitoring.By crosschecking 6 aggregation indices:t-test,Moore I,Mean Crowding m*,Contag m*/m,Cassie indecx C_A,Negitive binomial distribution K and difussion index I_Q,and using Iwao's regression methods,Taylor's power principle,aggregation average(λ)and U-test,spatial distribution patterns and sample method of rice water weevil larvae and pupa in different insect instar were investigated.It indicated that the L.oryzophilus had an aggregated spatial pattern with density dependence.m*-mregression showed that the distribution patterns of rice water weevil was grouped by individuals,the larvae repelled each other but pupae attracted.Taylor's power principle indicated that mean and aggregation degree was significantly positively related;aggregation average(λ)showed that aggression behavaor was caused by both RWW's congregation habit and environmental factors,and the index of pupae was higher than that of larvae.In addition,the optimal theoretical sampling model was established by Iwao's regression methods:N=(t/D)2[(α+1)/m+β-1)],and theoretical sampling numbers of larvae and pupae under different densities(m)RWW were caculated.The results depicated that the sampling number was gradually reduced along with the increase of the density of larva and pupa.When control threshold of larvae and pupae was 12 per plant,the sequential sampling formula with 2 different insect states were T_(1(n)),T_(0(n))=12n±18.527 0n~(1/2) and T_(1(n)),T_(0(n))=12n±22.200 9n~(1/2).The sampling methods of RWW were reliable to check by using U test.The optimal sampling method in the field was"Z"pattern sampling method(0.140),for larvae and great five plots sampling method for pupae(0.177).Above a