【目的】 通过研究斯氏钝绥螨Amblyseius (Typhlodromips) swirskii和胡瓜新小绥螨Neoseiulus cucumeris这两种外来植绥螨种内和种间的捕食关系及适合度，为斯氏钝绥螨的释放应用前的风险评估及与胡瓜新小绥螨的联合释放技术提供理论依据。【方法】 在无共享猎物的条件下，分别为两种雌成螨提供同种和异种的卵、同种和异种的幼螨、同种和异种的若螨，测定其对同种和异种不同个体的捕食选择性及捕食量，并比较两种植绥螨捕食后的适合度（产卵率和存活率）的差异。【结果】 两种植绥螨互为捕食者，斯氏钝绥螨为集团内捕食者的几率高于胡瓜新小绥螨；两种植绥螨发生同类相残的几率无显著差异（χ²=0.118，df=1，P=0.732）。两种植绥螨对幼螨的捕食量显著高于对若螨、卵的捕食量（斯氏钝绥螨：F_2,114=66.27，P<0.000 1；胡瓜新小绥螨：F_2,114=50.39，P<0.000 1），而且两种植绥螨对异种幼螨和若螨的捕食量均显著高于对同种个体的捕食量。两种植绥螨捕食幼螨后的产卵率均显著高于捕食若螨后的产卵率（斯氏钝绥螨：t=5.774，df=26，P<0.000 1；胡瓜新小绥螨：t=3.334，df=26，P=0.002 6），斯氏钝绥螨捕食异种个体后的产卵率显著高于捕食同种个体后的产卵率（t=2.854，df=26，P=0.008 4）。两种植绥螨捕食不同发育阶段（幼螨和若螨）的存活率无显著差异；但斯氏钝绥螨捕食异种个体后的存活率显著高于捕食同种个体后的存活率（t=2.196，df=26，P=0.037 2）。【结论】 两种植绥螨更倾向于发生交互集团内捕食作用而非同类相残；两种植绥螨捕食幼螨比捕食若螨更利于产卵；对于斯氏钝绥螨，异种个体是比同种个体更适合的食物来源。

[Objectives]  To investigate conspecific and heterospecific predator-prey interactions between two exotic phytoseiid mites, Amblyseius (Typhlodromips) swirskii and Neoseiulus cucumeris in order to assess the risk of using A. swirskii, either alone, or in combination with other phytoseiid species, as a biocontrol agent. [Methods]  The prey preferences and predation rates of these two phytoseiid mites were determined by offering either conspecific or heterospecific eggs, larvae or protonymphs, to female adults. The effect of feeding on either conspecific or heterospecific prey on the fitness (oviposition rate and adult female survival) of females of each species was measured and compared. [Results]  A. swirskii and N. cucumeris both preyed on each other but A. swirskii was more likely to be the IG-predator than N. cucumeris. There was no significant difference in the likelihood of cannibalism by each species (χ²=0.118, df=1, P=0.732). Both species of predatory mites displayed statistically higher predation on larvae than on protonymphs or eggs (A. swirskii: F_2,114=66.27, P<0.000 1; N. cucumeris: F_2,114=50.39, P<0.000 1). Both phytoseiid predators preyed significantly more on heterospecific larvae and protonymphs than on conspecific larvae and protonymphs. The oviposition rate of females of both species was significantly higher when females fed on larvae than when they fed on protonymphs (A. swirskii: t=5.774, df=26, P<0.000 1; N. cucumeris: t=3.334, df=26, P=0.002 6) and A. swirskii had significantly higher oviposition rates after feeding on heterospecific larvae than conspecific larvae (t=2.854, df=26, P=0.008 4). There was no significant difference in the survival of the two species when they fed on either larvae or protonymphs. However, the survival of A. swirskii was significantly higher when fed heterospecific prey than when fed conspecific prey (t=2.196, df=26, P=0.037 2). [Conclusion]  A. swirskii and N. cucumeris preferentially engage in reciprocal IGP rather than cannibalism. Females of either species that fed on larvae laid more eggs than those that fed on protonymphs. Heterospecific prey appears to be more suitable than conspecific prey for A. swirskii.