Extra-floral nectaries of Opuntia sulphurea. Photo: Marina Alma.
Many plant species offer feeding resources (usually nectar) or nesting sites for ants, which in turn defend plants from herbivore attacks. With Marina Alma (former lab member), Rodrigo Pol (colleague at IADIZA) and Luis (Lucho) Pacheco (colleague at Universidad Mayor de San Andrés, La Paz, Bolivia) we observed ants visiting what seemed extra-floral nectaries in the cactus Opuntia sulphurea. This cactus species has a broad latitudinal distribution, from Mendoza in Argentina to La Paz in Bolivia; it also has a broad altitudinal distribution in the Andes. These facts led us to wonder about the outcome of the ant-plant interaction and its geographic variation: do ants visiting the extra-floral nectaries defend this plant species from insect herbivores, and does the outcome of this interaction vary throughout the geographic distribution of this plant species? We just published a paper in Biotropica reporting the results of a study (actually, Marina’s undergraduate thesis) evaluating this question. We conducted ant-exclusion experiments close to the southern (Mendoza) and northern (La Paz) latitudinal limits of O. sulphurea, and at two contrasting elevations. Our results indicate that ants do not benefit the plant in terms of herbivore damage or fruit and seed production, a result that was latitudinally and altitudinally consistent. Thus, this plant is apparently offering free meals for the ants, with no apparent benefit (nor detriment).
Vero moved to start a new post-doc at the University of Río Negro, in the southern city of El Bolsón, Chubut. She’ll surely enjoy cooler temperatures there than in Mendoza. Good luck Vero!
Former lab’s doctoral student Jimena Dorado (left) and current lab’s post-doc Natalia Schroeder (right) will soon become CONICET assistant researchers. As such, they will continue being involved in our group’s activities. Congratulations Jime and Nati!
Nati, with Daniela Rodriguez (IADIZA) and Valeria Aschero (IANIGLA, and former lab member), gave a talk on the scientific inquiry process to participants of the 
Guadalupe Peralta was awarded a CONICET post-doc fellowship to work on responses of plant-pollinator networks to changes in the abundance of pollinators. She will be supervised by Diego and by 
Micaela Santos has been awarded a CONICET doctoral fellowship to work on habitat and interaction networks in fragmented landscapes. She will be supervised by Diego and by Luciano Cagnolo (CONICET-UN Córdoba). Welcome Mica!
Ecological Interactions Lab 