Review of the Pollination System by Small Diverse Insects

Many studies have evaluated and categorized the pollination systems of plants in different regions. These studies resulted in the definition of new pollination systems, such as that by small diverse insects (SDI). Although SDI systems are frequent in tropical communities, we know little about the species of plants and pollinators that compose these systems. This study synthesized knowledge of SDI systems through a systematic review of the literature, in order to characterize the composition of plants and pollinator species related to this pollination system. Most studies of SDI systems were carried out in tropical rainforest communities, and used a variety of terminologies and concepts. We found 362 plant species assigned to the SDI system, distributed in 76 families and 35 orders. These species are mainly trees and have inconspicuous greenish flowers, and most are hermaphroditic or dioecious. Few studies provided information on the composition of pollinators, which encompassed small and large insects; beetles, wasp, flies, and bees were the most frequent groups. We suggest adoption of the term "pollination system by diverse insects" instead of "small diverse insects." We discuss conceptual aspects and questions for studies with this pollination system.