Seed-feeding species of Megastigmus (Hymenoptera: Torymidae) associated with Anacardiaceae.
Four species of Megastigmus have been reported as phytophagous in seeds of the plant family Anacardiaceae: M. pistaciae, M. rhusi, M. thomseni and M. transvaalensis. All are Old World in origin. In this paper, we summarized known host and distribution data for each species, place M. rhusi as a junior subjective synonym of M. transvaalensis, diagnosed and illustrated all species, and provided a key to aid in the identification of females and, to some extent, males. Known host plant genera are: Pistacia, Rhus, Schinus, Ozoroa and Lannea. M. pistaciae and M. transvaalensis have been accidentally introduced into the New World. The former has long been established in California (USA) and is thought to be reported for the first time from Mexico; the latter is widely established, through host-shifting, in the states of Hawaii, California, Florida, and in Brazil and Argentina.