Insect sociality plays a major role in a highly complex flower-visiting network in the neotropical savanna

Abstract

Mutualistic networks between plants and their flower visitors provide information about the ecological dynamics and coevolutionary processes shaping species interactions. Sociality in insects has recently been considered a predictor for topological patterns in such networks. However, the effects that social and solitary species impose upon network topologies are still poorly understood. We evaluated the effects of social and solitary species within a tropical savanna flower visitor insect network in southeastern Brazil. We recorded a highly complex flower visitor network, with Hymenoptera as the most abundant and rich insect order in the samples. A total of 172 (48%) species were characterized as generalists and 183 (52%) as peripherals. Social species (54, ~ 15%) were the most abundant and solitary species (301, ~ 85%) represented the higher richness for all taxonomic groups. Most social species (~ 87%) and 41% of the solitary species were generalists. Social species played central roles in network structure, representing the most species with higher abundance and intensity of interaction with visited flowers. Finally, the sociality of Vespidae and Apidae is explained by different sets of metrics, which may reflect their different behaviors.