Geographical Patterns in the Architecture of Neotropical Flower-visitor Networks of Hummingbirds and Insects

摘要

Geographical variations in environmental factors can affect species diversity andconsequently influence the structure of interspecific ecological interactions.Relationships between flowering plants and animal flower visitors are among the mostimportant ecological interactions and can structure and maintain ecological diversity indifferent environments. Additionally, many animal and plant species participate in theseinteractions, which shape the specific characteristics of these communities, in terms ofboth the responses of the interacting species involved and environmental differences.Therefore, in the present study we investigated geographical and environmental effects onthe architecture of Neotropical flower-visitor networks of vertebrates and invertebrates.To this end, we used data regarding interaction networks available in the literature andconstructed binary interaction networks of plants and plant-visitors (hummingbirds andinsects) and tested the effects of altitude, latitude, vegetation type and number of plantfamilies on the structure of these networks. In total, we analyzed 55 networks offlower-visitor interactions with 746 species of flower-visiting animals and 1,185 speciesof plants, totaling 5,463 distinct plant-animal interactions. In general, the architectureof flower-visitor networks varied along latitudinal and altitudinal gradients, with morepronounced effects for flower-insect networks in which latitude influenced network size,modularity, and nestedness, and altitude influenced network size and connectance.Flower-hummingbird networks in open vegetation (grassland) were more modular than networksin other environments. The number of plant families positively influenced the size ofinsect and hummingbird networks, and positively affected connectance and nestedness andnegatively affected modularity in the flower-insect networks. So, the patterns we foundindicate that plant-visitor interactions in flower-insect and flower-hummingbird networksare differently affected by geographical and plant-related factors, possibly due to thedifferences in taxonomic and functional groups involved in these interactions.