Flower morphology, nectar features, and hummingbird visitation to Palicourea crocea (Rubiaceae) in the Upper Paraná River floodplain, Brazil

Abstract

We investigated flower morphology, nectar features, and hummingbird visitation to Palicourea crocea (Rubiaceae), a common ornithophilous shrub found in the riparian forest understory in the Upper Paraná River floodplain, Brazil. Flowers are distylous and the style-stamen dimorphism is accompanied by other intermorph dimorphisms in corolla length, anther length, and stigma lobe length and form. We did not observe strict reciprocity in the positioning of stigma and anthers between floral morphs. Flowering occurred during the rainy season, October to December. Nectar standing crop per flower was relatively constant throughout the day, which apparently resulted in hummingbirds visiting the plant throughout the day. Energetic content of the nectar in each flower (66.5J) and that required daily by hummingbird visitors (up to 30kJ) would oblige visits to hundreds of flowers each day, and thus movements between plants that should result in pollen flow. Three hummingbird species visited the flowers: the Gilded Sapphire (Hylocharis chrysura), the Black-throated Mango (Anthracothorax nigricollis), and the Glittering-bellied Emerald (Chlorostilbon aureoventris). The frequency of hummingbird visitation, nectar features, and the scarcity of other hummingbird-visited flowers in the study area, indicate that P. crocea is an important nectar resource for short-billed hummingbirds in the study site.

Might Heterostyly Underlie Spider Occurrence on Inflorescences? A Case Study ofPalicourea rigida(Rubiaceae), a Common Shrub from Brazilian Cerrado

“…Such characteristics are usually related to the prey abundance on inflorescences, since they are largely responsible for attracting pollinators and phytophagous [30][31][32]. However, we should note that P. rigida, like many other of Rubiaceae family [33], is an ornithophilous species that is primarily pollinated by hummingbirds, with insects such as bees, moths, and flies only occurring as occasional visitors [21]. For example, [14] compared inflorescences of an ornithophilous species (Palicourea guianensis, Rubiaceae) with a species pollinated by bees and butterflies (Lantana camara, Verbenaceae) and found that the ornithophilous one had much lower density of insects and spiders than the one pollinated by insects.…”

Feeding behavior by hummingbirds (Aves: Trochilidae) in artificial food patches in an Atlantic Forest remnant in southeastern Brazil

“…One of the factors determining aggressive behavior in hummingbirds is body size; the bigger and heavier the hummingbird is, the more dominant it is (Antunes 2003, Loss and Silva 2005, Mendonça and dos Anjos 2006, Rodrigues et al 2009). In this study, small and light hummingbird species were expelled from the food patches by the bigger and heavier species, except for Phaethornis spp.…”

“…Typical behaviors exhibited by territorial hummingbirds are "perching near the food resource" (Loss andSilva 2005, Longo andFischer 2006), inter-and intraspecific attacks (Loss and Silva 2005), and intense vocalizations and visual displays (Mendonça and dos Anjos 2006). Since the energetic cost of defending a territory can be up to three times higher than the cost of non-aggressively foraging (Gill and Wolf 1975), it is expected that individuals will engage in resource defense only when the fitness benefits of territoriality outweigh its costs (Brown 1964).…”

Atypical distyly in Psychotria goyazensis Mull. Arg. (Rubiaceae), an intramorph self-compatible species

“…In recent decades, the number of studies on heterostyly and phenology of heterostylous species in the cerrado has been increasing (Monteiro et al 1991;Coelho & Barbosa 2003;Coelho & Barbosa 2004;Consolaro et al 2005;Toledo et al 2007;Lenza et al 2008;Oliveira 2008;Consolaro et al 2009;Machado et al 2010;Consolaro et al 2011) and could be compared to those conducted in the Atlantic Forest (Passos & Sazima 1995;Lopes & Buzato 2005;Castro & Oliveira 2002;Castro et al 2004;Teixeira & Machado 2004a, 2004bRossi et al 2005;Pereira et al 2006;Mendonça & Anjos 2006;Virillo et al 2007, Fonseca et al 2008. To increase understanding of the heterostyly system in the cerrado, this study aimed to investigate the phenology, distylous features, reproductive biology and fl oral visitors of Psychotria goyazensis Mull.…”