Variation in Nectar Volume and Sugar Concentration ofAllium ursinumL. ssp.ucrainicumin Three Habitats

Abstract

Floral nectar volume and concentration of ramson (Allium ursinum L. ssp. ucrainicum) were investigated in three different habitats, including two types of sessile oak-hornbeam association on brown forest soil with clay illuviation and a silver lime-flowering ash rock forest association on rendzina. Daily nectar production ranged from 0.1 to 3.8 μL per flower with sugar concentrations of 25 to 50%. Mean nectar volumes and concentrations showed significant differences between freely exposed flowers and covered flowers, which had been isolated from flower visitors 24 h prior to nectar studies. Both the amount and quality of nectar were affected by microclimatic conditions and soil properties and varied between populations at different habitats. In the silver lime-flowering ash rock-forest association mean nectar volumes and concentrations were lower than in a typical sessile oak-hornbeam association on three occasions, the difference being significant in two cases. During full bloom, the date of sampling did not have a profound effect on either nectar volume or concentration.

Landscape scale variation in nectar amino acid and sugar composition in a Lepidoptera pollinated orchid species and its relation with fruit set

“…Our study corroborates the results of earlier work in demonstrating that there is significant intraspecific variation in nectar volume and nectar sugar composition (Herrera, P erez & Alonso 2006;Farkas et al 2012), but it is the first to demonstrate high levels of intraspecific variation in nectar AA between-and within-individuals. Importantly, we found that the highest proportion of variation in nectar traits is situated within individuals.…”

“…This has resulted in the early prevailing notion that nectar chemistry is a relatively invariant species-specific trait (Wykes 1952;Percival 1961;Lanza et al 1995). During the past decade, however, evidence has accumulated that nectar sugar composition is highly variable, both among and within populations (Lanza et al 1995;Herrera, P erez & Alonso 2006;Farkas et al 2012), and there is also some evidence of intraspecific variability in AA composition (Lanza et al 1995;Gardener & Gillman 2001a;Nocentini et al 2012Nocentini et al , 2013. So far, nectar composition studies, and especially those focusing on AAs, have been typically based on small sample sizes.…”

“…Environmental gradients were expected to cause the observed differences in nectar composition between populations (Lanza et al 1995;Farkas et al 2012). Soil nutrient composition and acidity can affect nectar volume, concentration and composition through a variety of mechanisms, including altered metabolite availability or altered growth of plant tissues (Gardener & Gillman 2001b).…”

Phenotypic selection on nectar amino acid composition in the Lepidoptera pollinated orchid species Gymnadenia conopsea

“…Recently, evidence has accumulated, however, that both nectar sugar and AA composition are highly variable, not only among populations and among individuals within populations (Farkas et al , Nocentini et al ), but also among flowers within a plant individual (Herrera et al , Gijbels et al ). Yet, phenotypic selection on nectar traits can only occur at the level of an individual, and even if pollinators prefer a specific type of nectar, their selective potential on floral nectar is very likely to be strongly hampered by the variation in nectar composition among flowers within individuals.…”

Niches and radiations: a case study on the Andean sapphire‐vented puffleg Eriocnemis luciani and coppery‐naped puffleg E. sapphiropygia (Aves, Trochilidae)

“…We assessed specific ornithological gazetteers (Stephens and Traylor 1983, Paynter 1993 and the above cited publications to Table 1. For example, bird assemblages composition can respond to soil variations (Myers et al 2015), and it is reasonable to expect that such an influence is strong in nectarivorous birds, since soil characteristics have an effect not only on both the yield and sugar concentration of nectar (Kenoyer 1917, Shuel and Shivas 1953, Robacker et al 1983, Farkas et al 2012, Nickless et al 2017) but also on floral traits (Paiaro et al 2012), shaping the plant-pollinator interactions (Meindl et al 2013), and even constituting an important evolutionary force for plants , Yost et al 2012, Rajakaruna 2018). 1.2), which has proven to have better predictive power than other data with regards to precipitation patterns in mountainous areas (Karger et al 2017), for the tropical Andes.…”