The distribution of the scale insect Saissetia coffeae in old-growth rainforest continuous with abandoned agricultural fields

Abstract. Saissetia coffeae (Homoptera: Coccidae) is a scale insect that inhabits the fern Lomariopsis fendleri (Filicales: Lomariopsidaceae) at La Selva Biological Station (Heredia Province, Costa Rica). Because this parasite is common on agricultural plants, I wanted to determine whether the distribution of S. coffeae within old-growth forest was affected by proximity to abandoned agricultural fields, which are in some places contiguous with the primary forest at La Selva. I examined L. fendleri individuals along a forest transect that began in an abandoned plantation field. I found that distance from the abandoned plantation field affected the number of S. coffeae individuals per fern, and that ants were present on all but one of the scale-infested plants I found. Further investigation of the pattern of scale distribution at La Selva may help understand the mode of dispersal and relationship to specific ant or plant species.