Two new species of Fabritius (Hymenoptera, Diapriidae), larval koinobiont endoparasitoids of the leaf-cutter ant (Fabricius) (Hymenoptera, Formicidae), from Panama.

Leaf-cutter ant nests attract a wide variety of guests and parasites due to considerable food resources, substrate and shelter available within nests. Limited information is known about their taxonomy, bionomics, and natural history, including interactions with the ants, and degree of host specificity of these symbionts. Here we describe two new species of Fabritius, 1974 (Diapriidae, Diapriinae, Diapriini) wasps which are koinobiont endoparasitoids of the larvae of a leaf-cutter ant, (Fabricius, 1804) (Myrmicinae, Attini) in Chiriquí, Panama. For both new species, Araúz & Fernández-Marín, and Araúz & Fernández-Marín, , we provide information on parasite-host interactions. The most abundant and frequent parasitoid type was solitary, while gregarious parasitoidism, where two or more wasps emerged from a single ant larva, was associated with certain times of the year. We provide an updated key to females of all species of , their geographic distribution, and host-parasite interactions. previously had been identified as parasitoids of several ant genera including some species, but our data indicate that some species of may be specialized on ants. Rates of parasitism suggest that the wasps have a negative effect on colonies and populations of the ants.