辽东栎主要种实害虫种群生态位研究

Niche analysis of the main seed pests of Quercus liaotungensis

【目的】通过调查辽东栎种实害虫群落组成及为害特点,分析各种害虫对资源的利用程度,探究其相互之间的竞争共存机制和混合为害特点,为辽东栎种实害虫科学测报和综合防控提供理论依据。【方法】在梁峁缓坡、阴坡和半阳向沟坡地设置3个试验样地,采用典型抽样法按对角线5点取样法选取15株样树,并采用阶层抽样法调查每株树冠东、南、西、北4个方位的上、中、下3个层次害虫群落组成及为害特点;在树冠下布设2m×2m小样方,收集样方内所有种子,并在体视显微镜下解剖橡实,按不同资源序列及等级统计种子内幼虫种类与数量;采用Levins生态位宽度指数和Pianka生态位重叠指数进行生态位分析。【结果】优势种柞栎象Curculio dentipes空间生态位宽度最大(0.999 2±0.000 3),桃蛀野螟Dichocrocis punctiferalis营养生态位宽度最大(0.9961±0.0015),榛实象Curculio dieckmanni时间生态位宽度最大(0.966 8±0.004 9)。柞栎象和栎实黑象Curculio sp.的混合为害率最高(10.72%),三维生态位重叠最大(0.881 9±0.002 3),均显著高于其它混合为害种类(P<0.01)。【结论】柞栎象、榛实象和桃蛀野螟分别占据最大空间资源、最长时间资源和最多营养资源,且分布较广,发生分散,常造成严重为害;柞栎象和栎实黑象、柞栎象和栗子小卷蛾、榛实象和桃蛀野螟、桃蛀野螟和栗子小卷蛾、柞栎象和桃蛀野螟在时间上具有同步性、空间上具有同域性、营养上具有同质性,两两具有类似的资源占有量,当种群数量增加时,种间竞争加剧,常造成严重混合为害。

[Objectives]To investigate the community composition and damage caused by seed pests of Quercus liaotungensis, including the degree of utilization of various resources by these pests and their competitive coexistence with other pest species. [Methods]From mid-April to October 2020, standard sampling methods were used to identify three test sample sites, after which the diagonal line 5 point sampling method was used to select 15 sample trees, within which the tree stratum sampling method was used to collect seed samples from 2 m×2 m squares situated at three levels in the south, east,west and northern aspects of the canopy. Seeds samples were brought back to the laboratory and acorns were dissected under a stoichiometric microscope. The species and number of larvae in seeds were counted and classified into different resource sequences and grades. Niche analysis was conducted using Levin’s niche width index and the Pianka niche overlap index, and the significance of differences analyzed using Duncan’s multiple test method. [Results]Curculio dentipes had the largest spatial niche width(0.999 2±0.000 3), Dichocrocis punctiferalis the largest trophic niche width(0.996 1±0.001 5) and Curculio dieckmanni the largest temporal niche width(0.966 8±0.004 9). The mixed damage rate was(10.72%) and the highest three-dimensional niche overlap(0.881 9±0.002 3) was between Curculio dentipes and Curculio sp.;significantly higher than that between other species(P < 0.01). [Conclusion]C. dentipes, C. dieckmanni and D. punctiferalis have respectively the largest spatial resources, the longest time resources and the most nutritional resources. These species are widely distributed and often cause serious seed damage. The following pairs of species;C. dentipes and Curculio sp., C. dentipes and C. glandicolana, C. dieckmanni and D. punctiferalis, D. punctiferalis and C. glandicolana and C. dentipes and D. punctiferalis,are sympatric in both space and time and often causing serious damage to Q. liaotungensis seeds.