Honeybee Pollinators Use Visual and Floral Scent Cues to Find Apple (Malus domestica) Flowers

Abstract

Apple flowers of most varieties require pollinator-mediated cross-pollination. However, little is known about the cues used by pollinators to find the flowers. We used bioassays to investigate the importance of visual and olfactory cues for the attraction of honeybee pollinators to apple flowers. Chemical–analytical and electrophysiological approaches were used to determine floral scents and investigate antennal responses of honeybees to scents from flowering twigs. Bioassays showed that visual and olfactory cues were equally important for the attraction of honeybees to apple flowers. Floral scents were dominated by aromatic components, mainly benzyl alcohol, and the antennae of honeybees responded to a large number of components, among them to benzyl alcohol, linalool, and indole. Our study aims to better understand how this important fruit crop communicates with its main pollinators. This knowledge might be used to improve the attractiveness of apple flowers to pollinators to optimize fruit sets.

Olfactory and Visual Floral Signals of Hedera helix and Heracleum sphondylium Involved in Host Finding by Nectar-Foraging Social Wasps

“…Our finding that olfactory floral signals are more important than visual ones for vespine wasps during their search for food plants is in agreement with several studies on the host location of different floral visitors (Hodgkison et al, 2007;Raguso, 2008b;Primante and Dötterl, 2010;Dötterl et al, 2011;Johnson et al, 2011;De Vega et al, 2014) and of wasps in specialized associations (e.g., Ayasse et al, 2003;Brodmann et al, 2008;Shuttleworth and Johnson, 2009a;Burger et al, 2017). In some other diurnal systems, however, visual signals are similar to (Milet-Pinheiro et al, 2012;Rachersberger et al, 2019) or more attractive than (Barragán-Fonseca et al, 2020) olfactory floral signals for attracting pollinators from a distance. Wasps are only rarely attracted by visual traits alone to wasp-favored flowers (but see Brodmann et al, 2012), which often appear in cryptic colors similar to the background vegetation (Shuttleworth and Johnson, 2012).…”

Overview of Bee Pollination and Its Economic Value for Crop Production

“…Because pollination is so important to plants, they adapt to be more appealing to pollinators [124,125]. Plants possess several means to attract bees, including flower color [126,127], flower motion as in the case of bumble bees [128], the type of plant cells (e.g., conical epidermal cells) as in bumble bees [129], visual and olfactory cues as in honey bees and apple pollination [130] and the production of nectar and pollen grains [131,132], as shown in Figure 1. Thus, plants play an important role in influencing the visitation rate of their pollinators [133].…”

It Is Not All about Being Sweet: Differences in Floral Traits and Insect Visitation among Hybrid Carrot Cultivars

“…Generally, there are many visual and olfactory floral traits, including morphology, colour, nectar composition, and floral volatiles, which separately or collectively make one flower easily distinguishable from another to a pollinator [ 16 , 17 , 18 ]. Furthermore, some pollinators such as honey bees are opportunistic foragers, whose tendencies for innate responses can be altered by learning, mainly via olfactory conditioning [ 19 , 20 ].…”