Do honeybees (Apis mellifera) differentiate between different pollen types?

Abstract

Bees receive nectar and pollen as reward for pollinating plants. Pollen of different plant species varies widely in nutritional composition. In order to select pollen of appropriate nutritional quality, bees would benefit if they could distinguish different pollen types. Whether they rely on visual, olfactory and/or chemotactile cues to distinguish between different pollen types, has however been little studied. In this study, we examined whether and how Apis mellifera workers differentiate between almond and apple pollen. We used differential proboscis extension response conditioning with olfactory and chemotactile stimulation, in light and darkness, and in summer and winter bees. We found that honeybees were only able to differentiate between different pollen types, when they could use both chemotactile and olfactory cues. Visual cues further improved learning performance. Summer bees learned faster than winter bees. Our results thus highlight the importance of multisensory information for pollen discrimination.

Pollen defenses negatively impact foraging and fitness in a generalist bee (Bombus impatiens: Apidae)

“…Yet these generalist bees spent time foraging in cucurbit flowers, presumably for nectar 37,41,49 . This foraging behaviour is important because it suggests that bees recognize cucurbit flowers as a nectar source, but distinguish that the pollen should be avoided, likely using multi-sensory cues 15,50 . This collection avoidance means that as bees fail to groom pollen attached to their body into their corbiculae, more is available for transport and pollination, and in www.nature.com/scientificreports www.nature.com/scientificreports/ fact, bumble bees have been found to deposit the most pollen on a per visit basis in cucurbit systems, as compared to squash and honey bees 37 .…”

Pollen report: Quantitative review of pollen crude protein concentrations offered by bee pollinated flowers in agricultural and non-agricultural landscapes

“…While it is clear that increased protein supply can be beneficial to developing larvae and insufficient protein supply can result in larval malnutrition with clear adverse effects (Tasei and Aupinel 2008, Brodschneider and Crailsheim 2010, Di Pasquale, Salignon et al 2013, Hass, Brachmann et al 2018, there is only limited support for a simple relationship between crude protein concentration and bee fitness (Babendreier, Kalberer et al 2004, Tasei and Aupinel 2008, Brodschneider and Crailsheim 2010, Di Pasquale, Salignon et al 2013. It is likely that in addition to protein content, other quality markers such as lipid content, amino acid composition and secondary metabolites might play an important role in determining pollen quality for bees (Maurizio and Grafl 1980, Day, Beyer et al 1990, Pernal and Currie 2000, Tasei and Aupinel 2008, Nicolson and Human 2013, Nicholls and Hempel de Ibarra 2017, Hass, Brachmann et al 2018, Ruedenauer, Wöhrle et al 2018. In contrast to nectar quality (sugar concentration), there is only some evidence that bees can reliably separate high from low quality pollen and adjust their collecting behavior according to their needs (Nicholls and Hempel de Ibarra 2017).…”

“…Given that pollen is the main protein source for bees' offspring, crude protein concentration in pollen is directly linked to the amount of protein bees can extract from their habitat and has traditionally served as a proxy for pollen quality (T'ai, Cane et al 2000, Roulston and Goodell 2011, Vaudo, Tooker et al 2015). However, most of the evidence supporting the importance of crude protein concentration for the fitness of bees (Brodschneider and Crailsheim 2010) and their ability to adjust their individual (Ruedenauer, Spaethe et al 2015, Ruedenauer, Wöhrle et al 2018 or collective response according to their protein requirements (Fewell andBertram 1999, Pernal andCurrie 2001) stems from social bees.…”

A matter of taste: the adverse effect of pollen compounds on the pre-ingestive gustatory experience of sugar solutions for honeybees

“…It appears that no single nutrient type, other than sugar, is sufficient alone in reinforcing the conditioned response to a neutral odour. Similarly, when discriminating between the nutritional quality of pollen samples using taste, the presence of sugar for reinforcement seems to be required (Ruedenauer et al 2015 , 2018 ). Our present findings further suggest that the strength of learning is contingent on how strongly sucrose masks the presence of distasteful compounds.…”