【目的】 黑豆蚜Aphis fabae Scopoli和豌豆蚜Acyrthosiphon pisum（Harris）是豆科作物上的两类重要害虫，常在同种豆科植物上混合发生，但目前尚不明确2种蚜虫的种间竞争及密度效应。【方法】 通过设置异种密度为单头、5头和10头，研究不同异种共存密度对单头豌豆蚜与黑豆蚜生长发育及生殖的影响；异种预侵染后，研究对另一种蚜虫生殖的影响。【结果】 在单头和5头异种竞争条件下，2种蚜虫各龄若蚜的发育历期及1龄若蚜-成蚜的总发育历期均与对照差异不显著。在单头异种竞争条件下，2种蚜虫所得成蚜体重均与对照无显著差异；在5头异种竞争条件下，豌豆蚜成蚜体重显著低于对照，而黑豆蚜显著高于对照。在5头异种共存竞争条件下，黑豆蚜的生殖力无显著变化，而异种高密度共存竞争（5头和10头）对豌豆蚜的生殖力具有明显不利影响。当2种蚜虫共存于活体植株上，豌豆蚜的首日产蚜量显著低于理论值，而黑豆蚜略高于理论值。在异种预侵染条件下，豌豆蚜的日均产蚜量显著低于对照，而黑豆蚜的日均产蚜量略高于对照。【结论】 黑豆蚜较豌豆蚜具有明显的竞争优势。这一研究结果对明确2种蚜虫在豆科作物上的群落演替规律及制定科学合理的防治措施具有重要指导意义。

[Objectives]  To determine the effects of density on the degree of interspecific competition between Aphis fabae Scopoli and Acyrthosiphon pisum (Harris), two important pests of leguminous crops that are usually sympatric on a same crop. [Methods]  The effects of different numbers of heterogonous species on the development and reproduction of A. fabae and A. pisum were determined, as was the effect of densities of 1, 5 or 10 A. fabae on A. pisum, and vice versa. In addition, the effects of pre-infestation by one species on the reproduction of the other were measured. [Results]  The developmental time of each instar and the duration required for 1st instar-to-adult of A. fabae and A. pisum were similar to those of the control (no competition) irrespective of whether there was one, or 5, heterogonous species present. When only a single heterogonous species was present, the weights of adult A. fabae and A. pisum were not significantly different from those of the control; however, when 5 heterogonous species were present the weights of adult A. pisum were significantly lower than the control and the weights of A. fabae were significantly higher than control. Reproduction of A. fabae was not significantly changed when 5 A. ptisum were present, whereas the presence of 5 or 10 A. fabae adversely affected the reproduction of A. pisum. When sympatric on live plants, first day nymph production of A. pisum was significantly lower than the theoretical value, whereas that of A. fabae was higher than the theoretical value. Pre-infestation by a heterogonous species caused reproduction of A. pisum to be significantly lower than that of the control, whereas reproduction of A. fabae was higher than that of the control. [Conclusion]  A. fabae is competitively superior to A. pisum. These results lay a solid foundation for further evaluating interspecies succession of these two aphids on leguminous crops, and for designing effective methods to control them.