PT  - JOURNAL ARTICLE
AU  - Rachel H. Parkinson
AU  - Sébastien C. Kessler
AU  - Jennifer Scott
AU  - Alexander Simpson
AU  - Jennifer Bu
AU  - Adam Mahdi
AU  - Ashwin Miriyala
AU  - Geraldine A. Wright
TI  - Temporal responses of bumblebee gustatory neurons to sugars
AID  - 10.1101/2022.02.28.482341
DP  - 2022 Jan 01
TA  - bioRxiv
PG  - 2022.02.28.482341
4099  - http://biorxiv.org/content/early/2022/05/03/2022.02.28.482341.short
4100  - http://biorxiv.org/content/early/2022/05/03/2022.02.28.482341.full
AB  - The sense of taste permits the recognition of valuable nutrients and the avoidance of potential toxins. Models of gustatory coding propose that within modalities (e.g. sweet, bitter, etc.), taste ligands are not distinct stimuli. However, these models are based on data from mice or flies that have omnivorous, non-specialist diets. A specialist feeder might, however, be expected to have acuity within modality if stimulus resolution was critical to survival. Previously, we found that bumblebees have a specialized mechanism for sensing sugars whereby two gustatory receptor neurons (GRNs) within the galeal sensilla of the bees’ mouthparts exhibit burst of spikes. Here, we show that the temporal firing patterns of these GRNs separate sugars into four distinct groups that correlate with sugar nutritional value and palatability. We also identified a third GRN that responded to stimulation with relatively high concentrations of fructose, sucrose, and maltose. Sugars that were non-metabolizable or toxic suppressed the responses of bursting GRNs to sucrose. These abilities to encode information about sugar value are a refinement to the bumblebee’s sense of sweet taste that could be an adaptation that enables precise calculations of the nature and nutritional value of floral nectar.Competing Interest StatementThe authors have declared no competing interest.