Relaxation dynamics of a flexible rod in a fluid

Optimal kinematics of the bee tongue for viscous fluid transport

“…1B inset on the right). 14,29 The deflected tongue hair recovered to its equilibrium position driven by the elastic recoil and was slowed down through viscous dissipation (Fig. 1E).…”

“…1E). 29 Finally, the tongue hair was fully unfolded at t = T with d(T) = d m . 14,29 Since the erection of tongue hairs occurs only in the tongue retraction phase, the duration of retraction T 2 plays a significant role in the nectar capture process.…”

“…29 Finally, the tongue hair was fully unfolded at t = T with d(T) = d m . 14,29 Since the erection of tongue hairs occurs only in the tongue retraction phase, the duration of retraction T 2 plays a significant role in the nectar capture process. [29][30][31] Specifically, at a relatively short retraction time, T 2 is smaller than the hair unfolding time T. The tongue hairs might have a limited time to deploy fully before the tongue completely retracts out of the liquid, which results in the shrinkage of the tongue diameter, thus possibly impeding the energy intake rate.…”

“…14,29 Since the erection of tongue hairs occurs only in the tongue retraction phase, the duration of retraction T 2 plays a significant role in the nectar capture process. [29][30][31] Specifically, at a relatively short retraction time, T 2 is smaller than the hair unfolding time T. The tongue hairs might have a limited time to deploy fully before the tongue completely retracts out of the liquid, which results in the shrinkage of the tongue diameter, thus possibly impeding the energy intake rate. Inversely, the tongue hairs can be fully erected before the tongue retracts with a longer duration for retraction, and T 2 becomes significantly larger than T. However, this would increase the duration of feeding, thus decreasing the energy intake rate.…”

Effects of tongue hair flexural deformation on viscous fluid transport by bees

“…After full immersion in the nectar pool, the bee retracts the tongue with the tongue hairs deploying so that the distance between the tip of the hairs and the glossa, d(t), increases [12]. When the tongue retracts from the nectar at t = T R = constant (about 0.1-0.15 s), the distance between the tip of the hairs and the glossa is thus d(T R ), and the bee loads the nectar into the mouthparts for further swallowing [13][14][15]. Most investigations about the feeding mechanism of bees have focused on the kinematics and structural characteristics of bee tongues under the static tongue hair assumption, while a bee tongue has a dynamic hairy surface that should inevitably unfold in viscous fluid for nectar infiltration [16][17][18].…”