Potential pollinators of understory populations of &lt;i&gt;Symphonia globulifera&lt;/i&gt; in the Neotropics.

Andre Sanfiorenzo,Manuel Sanfiorenzo,Bryan Finegan,Ronald Vargas Castro,Lisette Waits

doi:10.26786/1920-7603(2018)one

Abstract

One difference between the forest canopy and the understory is that animals pollinate the majority of understory species in the tropical wet forest. Pollinators active in the understory are also different from those in the forest canopy and are adapted to the mesic conditions underneath the canopy. We used video cameras to observe flowers of understory Symphonia globulifera (Clusiaceae) in tropical wet forests of Costa Rica. We quantified the timing, frequency and behaviour of flower visitors to explore their potential contribution to pollination. A total of 82 flower visits were observed during 105 h of observations. Flowers were visited by ten insect species and one hummingbird species; the most active time period was between 1200-1700 h followed by the time between 0500-1000 h. The time period with fewer visitors was 1700-2200 h, during this period we observed flowers visited in multiple instances by a bushcricket (Tettigoniidae). The most frequent flower visitors were the stingless bee Tetragonisca angustula and the hummingbird Phaethornis longirostris; both came in contact with anther and stigma during visits. We observed different flower visitors from those reported for canopy populations of S. globulifera. Insects predominated, in contrast to observations in canopy populations of S. globulifera, wherein perching birds predominated. We also documented the consumption of pollen by visiting insects. These findings highlight differences in flower visitors between the forest canopy and the understory for the same tree species and contribute to better understanding of the pollination ecology of understory tropical wet forest species.

Highlights

Tropical wet forests (TWF) are characterized by the immense diversity of taxa and complex vertical and horizontal structure
The flowers were visited by ten insect species and one hummingbird species (Tab. 1, Fig. 2)
In the forest understory, insects and hummingbirds were the most frequent flower visitors of S. globulifera, in contrast to canopy populations of S. globulifera in French Guyana, where perching birds are reported as the main pollinators (Gill et al 1998)

Summary

Introduction

Tropical wet forests (TWF) are characterized by the immense diversity of taxa and complex vertical and horizontal structure. One characteristic that differentiates TWF from other forest biomes is that animals pollinate the great majority of tree species (Bawa et al 1985; Dick et al 2008). Differences among pollinators regarding behaviour and homes-range size create variation in the distance pollen is transported. The pollinator communities can differ between the several forest strata (Dick et al 2008). Insects are the most important pollinator groups; vertebrates, such as birds and bats, serve as pollinators, but for a smaller fraction of TWF species (3-11%) (Dick et al 2008; Fleming et al 2009). Bees constitute the most important group in number and diversity of plant species pollinated (Bawa 1990)

Methods

Results

Discussion

Conclusion