稻田微蛛优势种形成的若干环境因子分析

ENVIRONMENTAL FACTORS ON ESTABLISHMENT OF DOMINANT MICRYPHANTID SPIDERS IN PADDY FIELD

草间小黑蛛(Erigone graminicolum)和食虫沟瘤蛛(Ummeliata insecticeps)都有较强的耐寒、耐饥能力和较大的捕食量,在-3—0℃时能存活3天左右,平均耐饥历期大于30天,对稻褐飞虱的平均最大捕食量分别为6.3头/天和6.1头/天;Holling模型分别为N_A(草)=0.9886N_0/(1+0.09N_0)和N_A(食)=1.0234N_0/(1+0.101N_0),它们的抗药能力相差无几。但它们对湿度要求不同,前者较后者耐干旱。草间小黑蛛耐干历期雌蛛为27.2天,雄蛛为9.7天;耐湿历期雌蛛为53.2天,雄蛛为46.2天。食虫沟瘤蛛耐干历期雌蛛为7.7天,雄蛛为4.2天;耐湿历期雌蛛为55.4天,雄蛛为49.0天。温度相同湿度不同时它们的竞争能力不同,湿度较小时草间小黑蛛取胜,湿度较大时食虫沟瘤蛛取胜。它们在稻田中成为优势种的条件,主要取决于稻田生境与周围环境的干湿状况。

Both Erigone graminicolum Sundevall and Ummeliata insecticeps (Boes et Str.) had comparatively strong cold and starvation resistance, and their insecticide resistance were similar. Their survival duration were 3 days under the temperature of-3-0℃, and the duration of their starvation resistance was more than 30 days. Their reacton of functional simulation model of captured brown planthopper (Nilaparata lugens) were NA(E. g.)= 0.9886 No/(l + 0.09 No) and NA(U. i.) =1.0234 No/(1+0.101 No) respectively. The former tended to adapt dry environment but the latter was found to adapt wet habitat. The competitive ability of E. graminicolum was higher than U. insecticeps under low humidity of the habitat (Relative humidity< 80%). U. insecticeps had higher competitive ability than E. graminicolum in the high humidity of environment (Relative humidity>90%). That Whether or not they become dominant in paddy field depends mainly on humidity of the babitat and surrounding environment.