[Spatial and temporal niches of Aphis gossypii and its predatory enemies]

The research results showed that Aphis gossypii had a narrow temporal niche breadth and a wide spatial niche breadth. This implied that the occurrence of A. gossypii population had the characteristics of obvious peak-period and whole-plant damage. The temporal-dynamic spatial niche breadthes of A. gossypii had no relativity to its own population densities. This implied that the damage of A. gossypii was complicated. Among the predatory enemies, Erigonidium graminicola and Propylaea japonica had wider temporal and spatial niche breadthes than other predatory enemies, and it meant that the above two enemies had longer period of occurrence and wider range of distribution. The temporal x spatial niche overlap of the predatory enemies with A. gossypii was in order of Theridium octomaculatum > P. japonica > E. graminicola > total of other enemies > Geocoris ochropterus > Misumenops tricuspidatus > Orius minutes, and the other was consistent with that of relational grades of A. gossypii and its predatory enemy populations. This result showed that the sympatry and synchronism of predatory enemies with A. gossypii had close relation to the predatory effect of the natural enemies.