Colour preferences of flower-naive honeybees

Abstract

Flower-naive honeybees Apis mellifera L. flying in an enclosure were tested for their colour preferences. Bees were rewarded once on an achromatic (grey, aluminium or hardboard), or on a chromatic (ultraviolet) disk. Since naive bees never alighted on colour stimuli alone, a scent was given in combination with colour. Their landings on twelve colour stimuli were recorded. Results after one reward ("first test") were analysed separately from those obtained after few rewards ("late tests"). 1) After pre-training to achromatic signals, bees preferred, in the first test, bee-uv-blue and bee-green colours. With increasing experience, the original preference pattern persisted but the choice of bee-blue and bee-green colours increased. 2) Neither colour distance of the test stimuli to the background or to the pre-training signal, nor their intensity, nor their green contrast, accounted for the colour choice of bees. Choices reflected innate preferences and were only associated with stimulus hue. 3) Bees learned very quickly the pre-trained chromatic stimulus, the original colour preferences being thus erased. 4) Colour preferences were strongly correlated with flower colour and its associated nectar reward, as measured in 154 flower species. 5) Colour preferences also resemble the wavelength dependence of colour learning demonstrated in experienced bees.

Cognition in Invertebrates

“…In honeybees, a similar result was found with respect to color preferences. Honeybees whose visual experience was strictly controlled in a flight cage in which no rewards were provided on colored targets showed consistent preferences for some dominant wavelengths when presented with such targets in their first active foraging flight (Giurfa et al, 1995). Colors preferred by naïve bees were human-blue and human-yellow, which correspond to those hues that experienced bees learn faster and better when trained with a single color/sucrose reward association (Menzel, 1967).…”

“…Colors preferred by naïve bees were human-blue and human-yellow, which correspond to those hues that experienced bees learn faster and better when trained with a single color/sucrose reward association (Menzel, 1967). However, all other hues which are originally not chosen rapidly become preferred if they are explicitly paired with sucrose reward (Giurfa et al, 1995).…”

Getting to the start line: how bumblebees and honeybees are visually guided towards their first floral contact

“…While bumblebees and honeybees have similar colour vision (Peitsch et al, 1992), they differ in that honeybees have a highly developed communication system: experienced honeybees communicate the location of food sources to inexperienced bees (von Frisch, 1967). Nonetheless, honeybees (A. mellifera) with controlled prior experience (''neutral pre-training'') do have colour preferences (Giurfa et al, 1995) for wavelengths of 410 nm (''bee-uv-blue'') and 530 nm (''bee-green''): the same colours that are learned most easily (Menzel, 1967). Bumblebees have, at most, a primitive communication system (Dornhaus and Chittka, 1999, 2001) and individuals rely much more on their own efforts to find food.…”

“…It can be traced to the writings of Manning (1956, p. 198) (…''it is necessary for a plant to attract bees in the first place, before they are 'aware' of the food supply…'') and Free and Butler (1959, p. 106) (''Little work has been done to discover those features of flowers to which bees react on their very first foraging flights, and such an investigation would be well worth undertaking''). Giurfa et al (1995) trace the question back to none other than Charles Darwin (1876). What is new is that now there are some answers.…”

“…One possible solution is to use the term ''pre-functional'' (Hogan, 1994)-in our case, the behaviour that occurs prior to functional experience with flowers. A similar tack is to characterize the bees themselves as ''flower-naïve'' (Giurfa et al, 1995) or ''foraging-naïve'' (Milet-Pinheiro et al, 2012). We will adopt these expressions because they have the advantage that they avoid any implication that no experience whatsoever is necessary for the development of behaviour.…”