Sucking or lapping: facultative feeding mechanisms in honeybees (Apis mellifera)

Abstract

Nectarivorous insects generally adopt suction or lapping to extract nectar from flowers and it is believed that each species exhibits one specific feeding pattern. In recent literature, large groups of nectarivores are classified as either ‘suction feeders', imbibing nectar through their proboscis, or ‘lappers', using viscous dipping. Honeybees ( Apis mellifera ) are the well-known lappers by virtue of their hairy tongues. Surprisingly, we found that honeybees also employ active suction when feeding on nectar with low viscosity, defying their classification as lappers. Further experiments showed that suction yielded higher uptake rates when ingesting low-concentration nectar, while lapping resulted in faster uptake when ingesting nectar with higher sugar content. We found that the optimal concentration of suction mode in honeybees coincided with the one calculated for other typical suction feeders. Moreover, we found behavioural flexibility in the drinking mode: a bee is able to switch between lapping and suction when offered different nectar concentrations. Such volitional switching in bees can enhance their feeding capabilities, allowing them to efficiently exploit the variety of concentrations presented in floral nectars, enhancing their adaptability to a wide range of energy sources.

Mutualisms and (A)symmetry in Plant–Pollinator Interactions

“…For example, bees, which consume nectar via dipping their tongue, typically feed on nectar with 50-60% sugar concentration, whereas butterflies and birds, which feed via suction, typically feed on nectar with 35% sugar concentration, likely because nectar viscosity quickly decreases uptake via suction 30 . Intriguingly, honeybees can switch between suction and lapping, depending on the sugar content and viscosity, which increases their foraging efficiency 31 . Eusocial pollinators like honeybees and bumblebees store collected nectar in nests, which requires foragers to regurgitate nectar from crops.…”

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

“…In the centre of glossa, a humour-filled cavity is formed by the sheath, muscular rod, and thin membranes. The honey bees are described to have two feeding modes, namely lapping and suction [ 10 ]. For the lapping mode, the glossa moves forward and backward with glossal hairs erecting rhythmically to load the nectar ( Figure 1 f).…”

“…For the lapping mode, the glossa moves forward and backward with glossal hairs erecting rhythmically to load the nectar ( Figure 1 f). For the suction mode, the glossa stays still through the proboscis tube, and the nectar is sucked up by the cibarial pump, generating flows across the glossa surface [ 10 ].…”

“…The mouth parts of a honey bee are comprised of a pair of galeae, a pair of labial palpi, and a glossa [ 6 ]. The honey bee performs two feeding modes, namely lapping and suction [ 10 ]. While lapping, the honey bee drives its segmented tongue (glossa) coated in dense hairs back and forth to load nectar.…”

“…Next the brush-like glossa is filled with nectar and retracts to the mouth parts to load nectar. While sucking, the glossa extends out of the proboscis tube, directly sucking with the glossa keeping still [ 10 ].…”