Host-specificity and Hyperparasitoids of Three New Costa Rican Species of Microplitis Foerster (Hymenoptera: Braconidae: Microgastrinae), Parasitoids of Sphingid Caterpillars

Three new species of parasitoid wasps (Braconidae: Microgastrinae) from Costa Rica are described: Microplitis espinachi Walker, n. sp.; Microplitis figueresi Walker, n. sp. and Microplitis marini Whitfield, n. sp. Two parasitoids of Sphingidae are redescribed for comparison with the three new species: Microplitis ceratomiae Riley and Microplitis chacoensis (Cameron) (=Microplitis ayerzai Brethes, New Synonymy). The ichneumonid wasp Acrolyta stroudi Gauld, n. sp., and the chalcidid wasp Conura convergea Delvare, n. sp. are also described; both are hyperparasitoids of prepupae in newly spun cocoons of M. espinachi and M. figueresi. The mesochorine ichneumonid hyperparasitoid Mesoschorus angustistigmatus Dasch, a hyperparasitoid of M. espinachi and M. espinachi larvae while still inside the caterpillar, is redescribed. The seasonal biology and host specificity of the Microplitis and associated hyperparasitoids is discussed in the context of the extensive caterpillar and parasitoid inventory data for the Area de Conservacion Guanacaste (ACG) in northwestern Costa Rica. M. espinachi is a dry forest parasitoid of Agrius cingulata, Sphinx merops and nine species of Manduca (all Sphingidae), all when in the most open and insolated habitats and on a variety of host plants; it does not search for other common species of Manduca or other Sphingidae in slightly shadier microhabitats a few meters away. The extremely similar M. figueresi parasitizes Erinnyis ello and Erinnyis crameri (Sphingidae) in slightly shadier older woody succession (only a few meters from the microhabitat occupied by M. espinachi), and conspicuously does not parasitize Erinnyis oenotris or the tens of other species of sphingid caterpillars in the same habitat. M. figueresi finds E. ello on seven different species of food plants, and E. crameri on two others (but does not parasitize E. crameri on an insolated third). Neither species of Microplitis extends from the ACG dry forest into the contiguous cloud forest or rain forest, even though their host caterpillars do. While E. ello is a common pest in commercial cassava plantations, M. figueresi does not appear to have followed this host into this highly insolated habitat. Both species are highly univoltine and pass the last two thirds of the rainy season and six-month dry season in an extremely tough silk cocoon in the litter. In the ACG, M. marini is a parasitoid of only Xylophanes tersa in very insolated low herbaceous vegetation in mid-elevation rainforest and lower elevation cloud forest, and does not parasitize at least 15 other species of Xylophanes in the adjacent forest understory. (Resume d'auteur)