Bats and bees are pollinating Parkia biglobosa in The Gambia

Abstract

A pollination experiment was conducted with Parkia biglobosa (Fabaceae) in The Gambia. P. biglobosa is integrated in the farming systems and produces fruit pulp and seeds used in cooking. The species is bat-pollinated, and in areas with few bats the main pollinators are assumed to be honey bees. A higher rate of effective pollination will in many instances increase fruit production, and the aim of this study was to investigate pollination efficiency of different pollinators. Access of flower visiting animals to flowers was controlled by nets with differently sized mesh, using five trees as replicates. The pollinators' identity, efficiency, and relative effect were determined. Bats, honey bees, and stingless bees were able to pollinate the species. Bat-visited capitula produced more pods, but not significantly more than honey bees. Honey bees were more efficient than stingless bees, resulting in significantly less aborted seeds. The treatment which excluded all flower visitors developed no mature pods, indicating that P. biglobosa was not autonomous autogamous, apomictic, or parthenocarpic, while the treatment with confined honey bees showed that geitonogamy is possible. Sugar content of fruit pulp was analysed and a positive correlation between number of seeds per pod and the sugar content was found. Improved pollination success may thus result in sweeter fruits. We conclude it is important to strive against a pollinator-friendly environment in order to attract bats and bees. Furthermore, we suggest beekeeping in the vicinity of P. biglobosa as a way to increase yield.

Genetic conservation in Parkia biglobosa (Fabaceae: Mimosoideae) - what do we know?

“…biglobosa is a monoecious species. The inflorescence, well described by Hopkins (1983), Ouedraogo (1995) and Lassen et al (2012), has bright red flowers, forming a capitulum in a large apical ball and a basal constricted receptacle. Different types of flowers are found in the hermaphroditic capitulum.…”

“…Controlled pollination studies have shown that forced self-pollination results in healthy seeds, however, a certain proportion of seeds per pod were aborted. Hence, self-fertilization is possible, probably through geitonogamy (Lassen et al, 2012). Based on controlled crossing experiments, Ouedraogo (1995) estimated a selfing rate of 5 %.…”

“…packages of 16 or 32 pollen grains (Baker and Harris, 1957). Polyads probably confer a selective advantage as they provide an efficient way for animal-mediated pollen transport (Kenrick and Knox, 1982), and honey bees are very efficient carriers of polyads compared to other insects pollinating P. biglobosa (Lassen et al, 2012). A single pod may contain up to 24 seeds (Ouedraogo, 1995), but commonly the number is lower; 16.5±5.2 seeds per pod were reported by Lassen et al (2014).…”

Improved management of fruit trees in West African parklands

“…Koptur 1984;Roubik 2002), but knowledge on parkland tree species is scarce. Studying P. biglobosa, Lassen et al (2011) found that presence of major pollinators (bats, bees) was critical for successful development of pods and for reducing the number of aborted seed in pods. The authors find a positive correlation between the number of seeds per pod and the sweetness of the pulp, indicating that improved pollination also improves the fruit quality.…”

Floral resource partitioning by ants and bees in a jambolan Syzygium jambolanum (Myrtaceae) agroforestry system in Brazilian Meridional Amazon

“…For human cultivated plants, conservative estimates indicate that pollination represents annually about $200 billion dollars in benefits (Costanza et al 1997;Velthuis and VanDoorn 2006;Gallai et al 2009). Thus, the decrease in availability of pollinators limits the quantity and quality of fruits (Wallace and Lee 1999;De-Marco and Coelho 2004;Lassen et al 2011), resulting directly in economic loss (Vianna et al 2007). Pollen and nectar are important carbohydrates and proteins resource for pollinators although these high energy supplies are limited in time and space (Brown et al 1981;Ramalho et al 1991;Galen and Geib 2007;Tiple et al 2009).…”