豚草发生地土壤昆虫群落结构及动态

采用分层取样法、大类群分类法和数理统计方法，研究了普通豚草Ambrosia artemisiifolia和三裂叶豚草A．trifida发生地土壤昆虫的群落结构及动态。共采集土壤昆虫46个科（成虫与幼虫分开单列），隶属于12个目，其中弹尾目个体数占绝对优势（占土壤昆虫总个体数的80.879%），其次是膜翅目（8.765%）、鞘翅目幼虫（3.951%）和双翅目虫（3.093%），其余合计占3.312%。在46个科中，优势类群有3科：棘跳虫科（Onychiuridae）（占土壤昆虫总个体数的32.756%）、鳞跳虫科（Tomoceridae）（18.869%）和节跳虫科（Isotomidae）（18.178%）。土壤昆虫个体数和类群数，随着豚草生长季的推进而增加，8月达到最高值。豚草降低了土壤昆虫的个体数量和群落多样性，根据逐月方差分析和多重比较，8月和9月对照样地土壤昆虫个体数量和多样性指数均显著高于豚草样地。豚草表现出对某些土壤昆虫类群的驱避作用，步甲科（Carabidae）成虫、拟花萤科（Dasytidae）幼虫、叶蝉科（Jassidae）、阎甲科（Histeridae）和管蓟马科（Phloeothripidae）在豚草整个生长季从未在豚草样地中出现。豚草对于土壤昆虫的抑制作用在豚草纯群落和植物生长旺季更为明显。土壤昆虫的垂直分布具有明显的表聚性。

Community structure and dynamics of soil insects in a ragweed habitat

Profile sampling method,macro-group classification method,and statistical method were used to study the community structure and dynamics of soil insects in ragweeds Ambrosia artemisiifolia and A.trifida habitats.Forty-six families of soil insects (adults and larvae were separately counted) belonging to 12 orders were collected.On the level of order, the individual number of Collembola was absolutely dominant (amounting to 80.879% of the total individual number of soil insects),followed by Hymenoptera (8.765%),Coleoptera larvae (3.951%), and Diptera larvae (3.093%), while the rest orders together amounted to 3.312% of the total. Among the 46 families, three families, i.e., Onychiuridae (amounting to 32.756% of the total individual number of soil insects), Tomoceridae (18.869%), and Isotomidae (18.178%), were dominant. The number of individuals and groups of soil insects increased with the proceeding of growth season and attained the maximum value in August. Ragweeds reduced the individual number and community diversity of soil insects. According to the results of monthly ANOVA and LSD, in August and September the individual number and diversity indices of soil insects in the control plot without ragweeds were significantly higher than those in ragweed plots. Ragweeds showed expellant effects on some groups of soil insects, and in the whole growth season of ragweeds, Carabidae adults, Dasytidae larvae, Jassidae, Histeridae, and Phloeothripidae were never found in ragweed habitats. The restrictive impacts of ragweeds on soil insects were more remarkable in pure ragweed community and in the bloom of plant growth. Vertically, soil insects aggregated mainly in surface soil profile.