Plant-hummingbird interactions and temporal nectar availability in arestinga from Brazil

Abstract

Hummingbirds are the most important and specialized group of pollinating birds in the Neotropics and their interactions with plants are key components to many communities. In the present study we identified the assemblage of plants visited by hummingbirds and investigated the temporal availability of floral resources in an area of restinga, sandy plain coastal vegetation associated with the Atlantic forest, in Southeastern Brazil. We recorded flower and nectar features, flowering phenology and interactions between plants and hummingbirds and estimated the amount of calories produced per hectare from June 2005 to August 2006. Ten plant species were visited by two hummingbirds, Amazilia fimbriata and Eupetomena macroura. Resource availability was highly variable among plant species and over time. Nectar volume and concentration per flower were similar to other Neotropical hummingbird-visited plant assemblages. The estimated nectar resource availability between months varied from 0.85 to 5.97 Kcal per hectare/day, demanding an area between one and 6.8 ha to support a single hummingbird. Our study reports an unusual tropical setting where almost all interactions between hummingbirds and plants were performed by a single hummingbird species, A. fimbriata. Hence, the variable nectar availability is probably influencing hummingbird movements, its foraging area, and consequently plant pollination.

A Semivolatile Floral Scent Marks the Shift to a Novel Pollination System in Bromeliads

“…The low amount of nectar in flowers of Cryptanthus spp. (no more than 10 mL; our data and Siqueira and Machado 7 ) when compared to hummingbird-pollinated taxa across the Bromeliodeae clade, [46][47][48][49][50][51][52] together with the fact that the most effective pollinators (i.e., male euglossine bees) primarily forage for scent, indicate that nectar is a plesiomorphic trait that might gradually be suppressed across the evolutionary history of the recently evolved Cryptanthus lineage. 8 Perfume flowers have appeared independently in several Neotropical families under distinct evolutionary/ecological contexts.…”

The potential indirect effects among plants via shared hummingbird pollinators are structured by phenotypic similarity

“…This pattern can also be found in tropical communities dominated by few hummingbirds with similar bill morphology. In these systems, most flowers have accessible short corollas and resource availability (floral abundance and nectar) regulates hummingbird visitation (Feinsinger 1978, Fonseca et al 2015. However, when hummingbirds and flowers have diverse morphologies, floral barriers arise and phenotypic match regulates the interactions (Snow and Snow 1972, Murray et al 1987, Maglianesi et al 2014).…”

The silence of prey: Hummingbirds do not respond to potential ambush predators on flowers

“…present a high intrapopulation variation of nectar, forcing hummingbirds to expand their foraging range and raise visitation rates (Fonseca et al . 2015). It is important to note that our study was conducted in a period of resource scarcity, when only a small amount of plants was flowering throughout the study period, which may be a factor that enhances Heliconia spp.…”