Gustatory sensitivity to amino acids in bumblebee mouthparts

Bees rely on amino acids from nectar and pollen for essential physiological functions. While nectar typically contains low (<1 mM) amino acid concentrations, levels in pollen are higher but variable (10-200 mM). Behavioural studies suggest bumblebees have preferences for specific amino acids but whether such preferences are mediated via gustatory mechanisms remains unclear. This study explores bumblebees' (Bombus terrestris) gustatory sensitivity to two essential amino acids found in nectar and pollen, valine and lysine, using electrophysiological recordings from gustatory sensilla on their mouthparts. Valine elicited a concentration-dependent response from 0.1 mM, indicating that bumblebees could perceive valine at concentrations found naturally in nectar and pollen. In contrast, lysine failed to evoke a response across tested concentrations (0.1-500 mM). The absence of lysine detection raises questions about the specificity and diversity of amino acid-sensitive receptors in bumbleb..., Bumblebee (Bombus terrestris audax) colonies were obtained from Biobest (Westerlo, Belgium) (n=2) and Koppert (Berkel en Rodenrijs, The Netherlands) (n=1). Colonies were maintained at the University of Sussex, U.K., housed either within a flight cage (73x73x65 cm) or connected to a feeding arena (40x40x35 cm) via a corridor (4x4x26 cm). Bees had ad libitum access to a nectar substitute (Biogluc, Biobest, Westerlo, Belgium) via both ground and suspended feeders, and finely ground honeybee collected pollen (Agralan, Swindon, U.K.), presented on chenille stems placed inside white plastic cups. Nectar was replenished as needed and pollen changed daily. Workers observed collecting pollen from the feeders were marked on the thorax with a small dot of white enamel paint (Humbrol, Hornby Hobbies Limited, Margate, U.K.). Only individuals observed collecting pollen at least once were used in testing (n=27).
Bumblebees (n=27) were caught in the feeding arena and left at 4 °C overnight to immobilis..., , # Data from: Gustatory sensitivity to amino acids in bumblebees

[https://doi.org/10.5061/dryad.bzkh189mq](https://doi.org/10.5061/dryad.bzkh189mq)

## Description of the data and file structure

These spreadsheets contain the data used in the paper. Each spreadsheet contains a full dataset related to the substance in the file name (Valine/Lysine/Sucrose). In Valine.csv and Lysine.csv, the initial exposure to 5mM sucrose prior to testing is included at the beginning of the dataset; following this, sensilla were exposed to water and increasing concentrations of the amino acid indicated (0.1-500 mM). Sensilla used to test 0.1-50 mM and 50-500 mM are from different bees; a unique sensillum ID is included to differentiate between them. Sensilla used to test 0.1-50 mM valine were then exposed to water again and sucrose (1-50 mM); for this reason the sensillum ID numbers of the Sucrose.csv spreadsheet are the same as for Valine (between 0.1 and 50 mM).

### Files and variables

#### File: Su...,