Modelling the distribution of Ornidia obesa Fabricius, 1775 (Diptera: Syrphidae) in the neotropical region

Ornidia obesa Fabricius, 1775 (Diptera: Syrphidae) is presumably an endemic Neotropical species that has spread extensively in the Pacific and across the Orient to the east coast of Africa, probably promoted through human activities (Thompson 1991). The species is well adapted to open spaces and is found near human-inhabited areas. The adults are pollinators of a great variety of flowers and feed on pollen and nectar, without showing much specificity regarding the plants they visit. The larvae breed in a variety of decaying plant materials ranging from exuding tree sap to decaying flowers, fruits, and stems of non-woody plants. In order to predict the distribution of O. obesa in the Neotropical region and understand the potential effect of environmental variables driving this distribution, we have catalogued distributional information from Val (1972), Thompson (1991), and data from specimens housed in various entomological collections in Colombia and Puerto Rico. All calculations and analyses of the potential distribution of O. obesa were done using maximum entropy ecological niche modeling in MAXENT. A probability model was created and an exploratory map was produced. Accordingly, we predict the presence of O. obesa in the northern region of Costa Rica; in Colombia, Venezuela, and Brazil; and in southern Mexico – in each case with probabilities of occurrence of 54-78%.