Functional Structure and Patterns of Specialization in Plant-Pollinator Relationships of an Agroecosystem in Valle del Cauca, Colombia

Hymenoptera is the main group of pollinators in agricultural systems and play a key role in food production. However, little is known about pollination networks and the dependence of plants on pollinators in tropical agroecosystems. The objectives of this study were i) to describe the plant-pollinator network associated with an agroecosystem, and ii) to evaluate the influence of morphological traits of the species on pollination. To do so, we conducted the fieldwork in an agroecosystem in Valle del Cauca, Colombia, between January and February 2017. We invested 96 h of observation and quantified interactions between pollinators and flowers; we estimated the average of visit duration per pollinator, the floral abundance, and measured the main morphological traits of plants and pollinators. For plants, we measured the length of corolla, and for pollinators, body mass and tongue length. We found that 17 species of pollinator visited eight plant species (five agricultural plants and three weeds). Our results suggest that the network is specialized (H-2' = 0.8), had a low degree of nestedness (NODF = 10.4), and that plants were specialized and highly dependent on pollinators (75 % spp. d' > 0.7). Also, we found that floral abundance and body mass of Hymenoptera influence the length of visit, which might affect the quality of pollination. This study reveals that ecological specialization and functional complementarity of Hymenoptera influence pollination in agroecosystems.