Open Access
A quick tongue: older honey bees dip nectar faster to compensate for mouthpart structure degradation
Author(s) -
Jianing Wu,
Yue Chen,
Chuchu Li,
Matthew S. Lehnert,
Yunqiang Yang,
Shaoze Yan
Publication year - 2019
Publication title -
journal of experimental biology
Language(s) - English
Resource type - Journals
eISSN - 1477-9145
pISSN - 0022-0949
DOI - 10.1242/jeb.212191
Subject(s) - nectar , honey bees , biology , tongue , zoology , ecology , medicine , pollen , pathology
The western honey bee, Apis mellifera L. (Hymenoptera), is arguably the most important pollinator worldwide. While feeding, A. mellifera uses a rapid back-and-forth motion with its brush-like mouthparts to probe pools and films of nectar. Due to the physical forces experienced by the mouthparts during the feeding process, we hypothesized that the mouthparts acquire wear or damage over time, which is paradoxical, because it is the older worker bees that are tasked with foraging for nectar and pollen. Here, we show that the average length of the setae (brush-like structures) on the glossa decreases with honey bee age, particularly when feeding on high-viscosity sucrose solutions. The nectar intake rate, however, remains nearly constant regardless of age or setae length (0.39±0.03 µg/s for honey bees fed a 45% sucrose solution and 0.48±0.05 µg/s for those fed a 35% sucrose solution). Observations of the feeding process with high-speed video recording revealed that the older honey bees with shorter setae dip nectar at a higher frequency. We propose a liquid transport model to calculate the nectar intake rate, energy intake rate and the power to overcome viscous drag. Theoretical analysis indicates that A. mellifera with shorter glossal setae can compensate both nectar and energy intake rates by increasing dipping frequency. The altered feeding behavior provides insight into how A. mellifera, and perhaps other insects with similar feeding mechanisms, can maintain a consistent fluid uptake rate, despite having damaged mouthparts.