Energy saving strategies of honeybees in dipping nectar

Nectar Feeding by a Honey Bee's Hairy Tongue: Morphology, Dynamics, and Energy-Saving Strategies

Simple Summary

This paper reviews the interdisciplinary research on nectar feeding behaviour of honey bees ranging from morphology, dynamics, and energy-saving strategies, which collects a range of knowledge of feeding physiology of honey bees and may inspire the design paradigms of next-generation multifunctional microfluidic transporters.

Abstract

Most flower-visiting insects have evolved highly specialized morphological structures to facilitate nectar feeding. As a typical pollinator, the honey bee has specialized mouth parts comprised of a pair of galeae, a pair of labial palpi, and a glossa, to feed on the nectar by the feeding modes of lapping or sucking. To extensively elucidate the mechanism of a bee’s feeding, we should combine the investigations from glossa morphology, feeding behaviour, and mathematical models. This paper reviews the interdisciplinary research on nectar feeding behaviour of honey bees ranging from morphology, dynamics, and energy-saving strategies, which may not only reveal the mechanism of nectar feeding by honey bees but inspire engineered facilities for microfluidic transport.

Drag Reduction in a Natural High-Frequency Swinging Micro-Articulation: Mouthparts of the Honey Bee

Worker-bee mouthparts consist of the glossa, the galeae and the vestigial labial palp, and it is these structures that enable bees to feed themselves. The articulation joints, 60∼70 µm in diameter, are present on the tip of the labial palp and are covered with olfactory sensilla, allowing movements between the segments. Using a specially designed high-speed camera system, we discovered that the articulation joint could swing in the nectar at a frequency of ∼50 Hz, considerably higher than the usual motion frequency of mammalian joints. To understand the potential drag reduction in this tiny organ, we examined its microstructure and also its surface wettability. We found that chitinous semispherical protuberances (4∼6 µm in diameter) are uniformly scattered on the surface of the joint and, moreover, that the surface is hydrophobic. We proposed a hydrodynamic model and revealed that the specialized surface can effectively reduce the mean equivalent friction (Ff) by ∼10%, through the use of protuberances immersed in the liquid feed. Theoretical results indicated that the dimensions of such protuberances are the predominant factor in minimizing Ff, and that the natural dimensions of the protuberances are close to the theoretical optimum at which friction is at a minimum. These discoveries may inspire the design of high-frequency micro-joints for engineering applications, such as in micro-stirrers.