Oenopia conglobata (Linnaeus) and Menochilus sexmaculatus Fabricius (Coleoptera: Coccinellidae) are important predators of the pistachio psyllid, Agonoscena pistaciae Burckhardt and Lauterer (Hemiptera: Psyllidae), a key pest of pistachio. The abundance of M. sexmaculatus has recently increased in pistachio orchards, while that of O. conglobata has declined. We designed laboratory experiments to (1) evaluate the potential for intraguild predation (IGP) between these two species, (2) detect any possible asymmetries in IGP interactions, and (3) characterize the sensitivity of IGP to varying densities of two extraguild (EG) prey, A. pistaciae and Aphis gossypii Glover (Hemiptera: Aphididae). We measured rates of IGP by fourth instar larvae and female adults (both starved for 12 h) on vulnerable immature life stages of the other species (eggs, first, and second instar larvae). IG and EG prey consumption were tallied after 12 h. All factors influenced rates of IGP, but species of IG predator, and life stage and density of EG prey, contributed the most variance. IGP decreased parabolically with increasing prey densities. IGP on eggs was higher than on first instars, which was higher than on second instars, suggesting palatability declined in later life stages. The larger M. sexmaculatus exhibited higher voracity than the smaller O. conglobata in both predation and IGP. Both species consumed more A. pistaciae than A. gossypii in all treatments, which may reflect either lower handling time or lower food value per prey.

开心果球果（Linnaeus）和天竺葵（Menochilus sexmaculatus Fabricius）（鞘翅目：Coccinellidae）是开心果的主要害虫-开心果木犀科，黄gon木（Agonoscena pistaciae Burckhardt）和Lauterer（半翅目：木犀科）的重要捕食者。阿月浑子果园中M. sexmaculatus的丰度最近有所增加，而球果O. conglobata的丰度却有所下降。我们设计了实验室实验，以（1）评估这两个物种之间的公会内捕食（IGP）的潜力，（2）检测IGP相互作用中任何可能的不对称性，以及（3）表征IGP对两个公会（EG）的不同密度的敏感性）猎物，黄连木和蚜虫格洛弗（半翅目：蚜科）。我们测量了四龄幼虫和成年雌性（均饿死了12小时）在其他物种（卵，第一龄和第二龄幼虫）的脆弱未成熟阶段的IGP发生率。IG和EG猎物的消费在12小时后达到了计算。所有因素都影响IGP的发生率，但IG掠食者的种类，EG猎物的生命周期和密度是最大的差异。随着猎物密度的增加，IGP呈抛物线下降。卵上的IGP高于第一龄幼虫，后者高于第二龄幼虫，表明在后期生命中适口性下降。较大M.六点始叶螨表现出比越小更高贪婪O.聚合性在两个捕食和IGP。两种物种消耗的黄连木霉比所有处理中的棉球菌都可能缩短处理时间或降低每个猎物的食物价值。