Nectar features, diurnal and nocturnal pollinators, and male fitness in Qualea grandiflora (Vochysiaceae)

Nectar production in flowers has been associated with pollination systems and seen as part of plant reproductive strategies. But other factors may have a role on nectar features and its efficacy as reward. We investigated pollination system of Qualea grandiflora, the most widespread woody species of Cerrado, the Neotropical savannas in Central Brazil, focusing on nectar features, their relationship with nocturnal and diurnal pollinators and how nectar affects male fitness, measured through pollen removal. Qualea grandiflora flowers during rainy season; anthesis starts at dusk, with a slightly sweet scent, pollen release and receptive stigma. Flowers remained opened until next evening and were visited and pollinated by a wide range of nocturnal and diurnal animals. Hawk moths were more frequent and responsible for most Q. grandiflora male fitness. Nectar was secreted during the night and early morning, with maximum accumulated volume up to 20.9 μl. Sugar concentration (23.12%) and amount (1.79 mg) remained constant during flower lifespan. No signals of active nectar resorption were observed. Nectar sugar composition was sucrose dominant during the night, and sucrose and hexose rich during the day. Standing crop measurements indicated an important proportion of nectar intake by flower visitors. Qualea grandiflora seemed to synchronize its floral and nectar features with hawk moths. However, nectar composition encompasses general preferences by both diurnal and nocturnal pollinators, assuring a mixed pollination system which seems well adapted to the species continental-scale distribution.Fil: Potascheff, Carolina de M.. Universidade Estadual de Campinas; BrasilFil: de Brito, Vinícius L. G.. Universidade Federal de Uberlandia; BrasilFil: Galetto, Leonardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; ArgentinaFil: Sebbenn, Alexandre M.. Instituto Florestal de São Paulo; BrasilFil: Oliveira, Paulo E.. Universidade Federal de Uberlandia; Brasi

Stepping stones or stone dead? : fecundity, pollen dispersal and mating patterns of roadside qualea grandiflora mart. trees

Forest fragmentation may affect mating and pollen dispersal patterns through conversion of continuous forests into small, spatially isolated remnant patches and individual trees in an anthropogenic landscape. We investigated reproductive investment and success, pollen dispersal, mating system, and genetic diversity and spatial structure of Qualea grandiflora trees in two environmental contexts: a continuous natural Cerrado area and isolated individuals on roadsides. Roadside trees produced more flowers and more fruit than Cerrado trees. Pollen dispersal kernels were fat-tailed in both contexts, indicating long-distance dispersal, but in Cerrado the mean pollen dispersal distance (524.7 m) and the effective number of pollen donors per mother-tree (Nep = 12.7) were higher than for roadside trees (60.9 m, Nep = 4.6). The levels and structure of genetic diversity, outcrossing rates (tm > 0.98), and mating among relatives (tm−ts < 0.1) were similar in both environmental contexts. Allelic richness and number of private alleles were similar between the two environments. The fixation index was significantly lower in adults (minimum of 0.08) than in offspring (minimum of 0.23) in both contexts, suggesting selection against inbred individuals between offspring and adult stage. Our results indicate that the spatial isolation of roadside trees, by increasing the number of flowers produced, decreased pollinator movements, thereby reducing effective pollen flow and the number of pollen donors. All these results suggest that roadside trees can be used for harvesting seeds for recovery plans, and that these trees are a biological legacy, and reservoir of Q. grandiflora genetic diversity, from the original Cerrado forest20613551367CNPQ - Conselho Nacional de Desenvolvimento Científico e TecnológicoFAPESP – Fundação de Amparo à Pesquisa Do Estado De São PauloNão tem2014/17472-