[Niches analysis of three aphid populations on spring sowing maize]

Systematic analysis of aphid populations and niches patterns on spring sowing maize was carried out during 1998-1999 in the suburbs of Chongqing. The results indicated that there were three aphid populations Rhopalosiphum maidis Fitch., Rhopalosiphum padi Linn. and Sitobion avenae Fabricius distributed on the spring sowing maize. The mixed aphid populations traded off during the growth period of spring sowing maize, and two peaks of quantitative counts were shown at the mid and last ten days of May and the last ten days of June. In addition, the niches of aphid population were also discussed from one dimension (i.e., temporal or spatial) to two dimensions (i.e., temporal and spatial). Through the quantitative analysis of niche breadth and niche overlap, the highly temporal differentiation of M. avenae and the highly gathering character of R. maidis were all indicated. R. padi showed an indistinct differentiation, while R. maidi was a dominated population on the spring sowing maize.