Plant-Pollinator interactions along an elevational gradient of the oceanic high-mountain volcano (El Teide, Canary Islands )

Flower-visiting animals were observed on the plant species from 15^th May to 15^th August, for two consecutive years (2014 and 2015), coinciding with the flowering of all plant species in the different elevational communities. The censuses were carried out between 9:00 and 19:00 h, avoiding the beginning and the end of the day, with usually low temperatures and little insect activity in this high mountain environment, and also avoiding windy days. All plant species were censused 7-8 hours per locality and year, throughout the flowering phenology of each plant species, to maximize the possibility of detecting different floral visitors. Each census lasted 15 minutes, during which the observer remained facing the plant, registering all insects contacting the flowers as well as, whenever possible, the number of flowers contacted per individual. We recorded a plant-pollinator interaction when an insect maintained contact with the reproductive organs of a flower for more than 1 second. Thus, all flower-visiting insects that feed on flowers were recorded, regardless of the efficacy of their visit. Insects were either identified in the field or collected for later identification in the laboratory. During the entire study period, a total of 868 observation hours were spent during 57 observation days.