ARANDA RICKERT adriana Marina
congresos y reuniones científicas
Extrafloral nectar-mediated interactions along an elevational gradient in semiarid northwest Argentina
Simposio; XXIII Simpósio de Mirmecologia - An international ant meeting; 2017
Institución organizadora:
Universidade Federal do Paran√°
Extrafloral nectaries (EFNs) that reward aggressive ants and other arthropods with a sugary secretion are one of the best documented indirect defence strategies in plants. As other interspecific interactions, they can vary geographically along known gradients in biotic or abiotic factors. While few studies examined the variation of EFN-mediated interactions along latitudinal gradients, similar studies along elevational gradients are scarce. Here, we explore possible factors that drive the altitudinal distribution of EFN-ant interaction in an arid mountain base habitat of La Rioja, Northwest Argentina, covering an elevational gradient of 1100 m (from 800 to 1900 m asl). We surveyed the EFN plants (taxonomic diversity, cover, and abundance), EFN consumer ants (taxonomic diversity and abundance), total vegetation cover and plant species richness, and climatic variables (temperature and % humidity, this last one as a proxy for precipitation). We found that temperature decreases and % humidity increases from the base to the top, while total vegetation cover and plant species richness increase with higher altitudes. On the other side, EFN plant diversity, abundance as well as number of EFN ant-plant interactions show a distinct pattern, with peak values at mid-elevations (1400 to 1600 m asl). Ant abundance and diversity follow a similar altitudinal pattern. Our results show that EFN plant-ant interactions along an elevational gradient follow a hump-shaped distribution pattern, and suggest that this pattern could be a result of a lower herbivore pressure both in drier and more humid elevations, and /or a higher abundance of nectarivorous ants at mid-elevations (PIP 2014-2016GI CONICET, PUE0125 CONICET).