Histological comparisons of parasitism by Schistonchus spp. (Nemata : Aphelenchoididae) in neotropical Ficus spp.

Syconia (enclosed infructescences) infested with host-specific species of S chistonchus (Aphelenchoididae) were collected from six species of Ficus (Mo raceae) native to Florida or Panama. They were sectioned and histologically examined to assess the effects of parasitism. Parasitism by Schistonchus s pp. was associated with hypertrophied cells, tissue necrosis, and the prese nce of an exudate in all species. Occasional hypertrophy of the outer epide rmal cells occurred on seed florets, wasp florets, and on the endothecial c ells of male florets in F. aurea (subgenus Urostigma) from Florida. Aberrat ions of the inner mesocarp occurred under the hypertrophied cells on seed f lorets. In F. laevigata (subgenus Urostigma) from Florida, Schistonchus sp. infested immature male florets and was associated with hypertrophy of endo thecial cells, epidermal cells of the anther filaments, and anthers. Schist onchus sp. also caused aberrations of the anther filament, anthers, and pol len. Ficus poponoei (subgenus Urostigma) and F. glabrata (subgenus Pharmaco sycea), both from Panama, had hypertrophied outer epidermal cells on seed f lorets. Ficus poponoei also had Schistonchus sp. within the pedicel of an a borted floret, with hypertrophy of the cortical parenchyma. Ficus trigonata (subgenus Urostigma) from Panama had hypertrophy of the outer epidermis of seed florets. When the outer epidermis on these florets was missing, the i nner mesocarp was hypertrophied. Ficus maxima (subgenus Pharmacosycea) from Panama had hypertrophy on the outer epidermis of seed and aborted florets. Schistonchus spp. were not found in wasp larvae or pupae in any of the Fic us spp. examined. Hypertrophy was never observed in the absence of Schiston chus spp.