不同抗性品种稻田捕食性节肢动物的群落结构

Community structure of predatory arthropods in different resistant variety rice fields

对3个类型稻田早、晚稻捕食性节肢动物群落调查,结果表明:共有捕食性节肢动物67种,丰富度以蜘蛛高于捕食性昆虫类;早稻高于晚稻;中抗品种高于抗虫和感虫品种。早稻以皿蛛科Linyphiidae的食虫沟瘤蛛UlmmeliatainsecticepesBoes.etStr.占优势,晚稻则以狼蛛科Lycosidae的相对丰盛度最高。早稻捕食性天敌数量动态以中抗品种峰期最长;感性样田中天敌平均密度与中抗样田差异不显著,与抗虫品种差异显著;捕食性节肢动物多样性随着品种抗性的增强呈降低趋势,优势度随着品种抗性的增强而增强。晚稻3个品种样田中天敌的平均密度差异不显著;各品种样田的多样性明显高于早稻,且波动幅度小于早稻,品种之间多样性差异较小,晚稻群落可能具有较高的稳定性。

Coummunity structures of the predatory arthropod in paddy fields with three resistant level varieties were investigated. The results showed that 67 species of predatory arthropod were collected, and richness of spiders was far higher than that of predatory insects. The richness of spiders in paddy field with medial resistant variety was significantly higher than that of higher resistant and susceptible varieties, and it was higher in early rice field than that in late rice field. Ulmmeliata insecticeps Boes. et Str. was the most dominant predatory spider species in early rice fields, however, the relative abundance of Lycosidae species was the highest in late rice fields. The dynamic peak phase of predatory arthropod with medial resistant variety was the longest among three resistant levels in early rice fields. Mean densities of predatory arthropod did not differ between susceptible and medial resistant variety, but it was significantly different between susceptible and higher resistant variety. In early rice fields, the dominance of predatory arthropod was increased with rising variety resistance, whereas diversity index was decreased. In late rice fields, mean density of natural enemies made no difference among three resistant level varieties. Not only was diversity index of predatory arthropod in late rice fields significantly higher than that in early rice fields, but the fluctuation in late rice fields was less than that in early rice fields, and diversity has little difference among different resistant level varieties. The results suggested that the community of predatory arthropod in late rice fields had higher stability.