Mutualistic interactions are often subject to exploitation by species that are not directly involved in the mutualism. Understanding which organisms act as such 'third-party' species and how they do so is a major challenge in the current study of mutualistic interactions. Here, we show that even species that appear ecologically similar can have contrasting effects as third-party species. We exp...

1. Pollinator declines caused by forage habitat loss threaten insect pollination services. Pollinating insects depend on adequate floral resources, and their ability to track these resources. Variability of these resources and the effect on insect foraging choice is poorly understood. 2. We record patterns of visitation to six wildflower species and test the hypotheses that: pollinators prefere...

The paradox of secondary metabolites, toxic defence compounds produced by plants, in nectar and fruits is well known. Deterrence of feeding by nectarivorous and frugivorous birds is better understood than the effect of these chemicals on the digestive performance of birds. Digestive parameters such as transit time and sugar assimilation are important in assessing nutrient utilization and deterr...

Mango nectar is a commercially familiar and preferred product. The traditional processing of mango nectar has been by thermal processing which resulted in the alteration of the flavour of the product due to the effect of high temperature. The thermal processing of the nectar also resulted in the production of byproducts of non-enzymatic browning such as 5hydroxy methyl furfural (HMF). These pro...

Floral nectars of bird-pollinated plants are relatively dilute. One hypothesis proposed to explain this concerns the difficulty for birds of drinking nectar of high viscosity. We examined the effects of viscosity, separately from those of sugar concentration, on feeding by captive whitebellied sunbirds (Cinnyris talatala). Viscosities of artificial nectar (sucrose solutions ranging in concentra...

We examine the suitability of ornithophilous flowers and sphingophilous flowers in Ipompsis and Aquilegia for nectar foraging by the hummingbird Selasphorus rufus. In S. rufus, bill length averages 18.9 mm in females and 17.3 mm in males. Maximal tongue extension approximates bill length, suggesting that birds can feed from floral tubes up to 33.5 mm in length. However, their ability to do so i...

Systemic neonicotinoid insecticides used in urban arboriculture could pose a risk to bees and other pollinators foraging on treated plants. We measured uptake and dissipation of soil-applied imidacloprid and dinotefuran in nectar and leaves of 2 woody plant species, a broadleaf evergreen tree (Ilex × attenuata) and a deciduous shrub (Clethra alnifolia), to assess concentrations to which pollina...

Unlike most other bees, the long-tongued orchid bees ingest nectar using suction feeding. Although long tongues allow exploitation of flowers with deep spurs, the energy intake rate is optimal at 10-20% lower nectar sugar concentrations compared to that of lapping bees. This constraint might be compensated by a higher digestive throughput. Additionally, orchid bees might evaporate water from re...

High blood glucose levels caused by excessive sugar consumption are detrimental to mammalian health and life expectancy. Despite consuming vast quantities of sugar-rich floral nectar, nectar-feeding bats are long-lived, provoking the question of how they regulate blood glucose. We investigated blood glucose levels in nectar-feeding bats (Glossophaga soricina) in experiments in which we varied t...

Spatiotemporal variation in nectar distribution is a key factor affecting pollinator movements between flowers and plants within a population. Pollinators having systematic searching ability can flexibly respond to the reward condition of floral patches, and they tend to revisit rewarding patches. However, foraging behaviour may be influenced by the nectar distribution within populations. To ev...