Young honeybees show learned preferences after experiencing adulterated pollen

Rocío Lajad,Andrés Arenas,Emilia Moreno

doi:10.1038/s41598-021-02700-6

Abstract

Pollen selection affects honeybee colony development and productivity. Considering that pollen is consumed by young in-hive bees, and not by foragers, we hypothesized that young bees learn pollen cues and adjust their preferences to the most suitable pollens. To assess whether young bees show preferences based on learning for highly or poorly suitable pollens, we measured consumption preferences for two pure monofloral pollens after the bees had experienced one of them adulterated with a deterrent (amygdalin or quinine) or a phagostimulant (linoleic acid). Preferences were obtained from nurse-aged bees confined in cages and from nurse bees in open colonies. Furthermore, we tested the bees’ orientation in a Y-maze using a neutral odour (Linalool or Nonanal) that had been previously associated with an amygdalin-adulterated pollen. Consumption preferences of bees, both in cages and in colonies, were reduced for pollens that had been adulterated with deterrents and increased for pollens that had been supplemented with linoleic acid. In the Y-maze, individuals consistently avoided the odours that they had previously experienced paired with the deterrent-adulterated pollen. Results show that nurse-aged bees associate pollen-based or pollen-related cues with either a distasteful/malaise experience or a tasty/nutritious event, leading to memories that bias their pollen-mediated response.

Highlights

In the field, pollen selection might be based on the foragers’ innate preferences[27,28,29,30] to pollen-based cues and on their previous experience with neutral cues associated to pollen sources (: pollen-related cues[31,32,33])
We investigated the ability of young honeybees to learn and memorize pollen cues according to changes in resource quality
B. napus pollen adulterated with linoleic acid did not affect the Standardized Consumption (SC) of nurse-aged bees (Control—Linoleic acid: t-ratio = 0.339; P = 0.9863; Fig. 2A) and no differences were detected between Amygdalin and Quinine (t-ratio = − 1.459; P = 0.4738)

Summary

Introduction

Pollen selection might be based on the foragers’ innate preferences[27,28,29,30] to pollen-based cues (i.e., pollen odour, colour, and taste) and on their previous experience with neutral cues associated to pollen sources (: pollen-related cues[31,32,33]). We tested whether nurse-aged bees confined in cages could learn to discriminate between two pure pollens: one that they had previously experienced adulterated with amygdalin, quinine, or linoleic acid and another one that they had experienced unadulterated. We predicted that bees would discriminate between pollens using learned pollen-based cues They would prefer less those that had been paired with the deterrent substances and would prefer more those that had been supplemented with linoleic acid. We tested whether nurse-aged bees could associate a neutral cue (namely an olfactory cue) with pollen (adulterated or not) and, in turn, use that cue to predict resource suitability. We assessed whether the learned preferences for pollen-based cues studied in experiment 1 (i.e., using caged nurse-aged bees and only two types of pollen) could be observed in the social context of the hive and with a wider range of pollens

Methods

Results

Conclusion