Bumble bee preference for flowers arranged on a horizontal plane versus inclined planes

Abstract

Summary 1.Determining factors affecting pollinator visitation is the key to understanding the reproductive success of animal-pollinated plants. The inclination of the ground where plants grow, which has been little studied, could be one such factor. There may be differences in foraging performance when visiting flowers on horizontal planes compared with flowers on inclines planes. And if this is the case, pollinators may have a preference for horizontal or inclined planes. To test these possibilities, a series of laboratory experiments with bumble bees and arrays of artificial flowers were conducted. 2. In the first experiment, bees were presented with a pair of floral arrays, one on a horizontal plane and one sloping. The bees preferred visiting flowers on the horizontal array. 3. In the second experiment, bees were allowed to forage on a flower array tilted at various angles ranging from 0 ° (horizontal) to 90 ° (vertical). It was found that their foraging performance decreased with increasing angles, showing a 9·1% reduction from 0 ° to 90 ° arrays. This reduction was caused by an increased travel time between flowers, when moving upslope or downslope. 4. These results suggest that plants growing on steep slopes may be less preferred by pollinators. Future studies are needed to clarify how slopes affect pollinator behaviour in field conditions and the ecological influences on plant reproduction.

The innate responses of bumble bees to flower patterns: separating the nectar guide from the nectary changes bee movements and search time

“…Like Leonard and Papaj (2011), we presented our flowers horizontally. This is a normal position for many flowers (Giurfa et al 1999), and is used in other studies of bumble bee floral orientation (e.g., Spaethe et al 2001). Makino (2008 also demonstrated that bumble bees prefer foraging on a horizontal as compared to a sloping array and had decreased foraging performance on a vertical as compared to a horizontal array.…”

Disentangling confusions in inflorescence morphology: Patterns and diversity of reproductive shoot ramification in angiosperms

“…Coen & Nugent, 1994; Singer et al, 1999; Tucker & Grimes, 1999; Kellogg, 2000, 2007; Penin et al, 2002, 2005; Schmitz & Theres, 2005; Tooke et al, 2005; Vollbrecht et al, 2005; Benlloch et al, 2007; Bortiri & Hake, 2007; Conti & Bradley, 2007; Prusinkiewicz et al, 2007; Rebocho et al, 2008; Souer et al, 2008; Dumonceaux et al, 2009) and what forms are selected by pollination biological factors (e.g. Waddington, 1979; Waddington & Heinrich, 1979; Wyatt, 1982; Fishbein & Venable, 1996; Friedman & Harder, 2004; Harder et al, 2004; Jordan & Harder, 2006; Ishii et al, 2008; Makino, 2008; Classen‐Bockhoff, 2009), or by other aspects of reproductive biology (Campbell, 1989; Diggle, 2003) or climate (Stebbins, 1973; Prusinkiewicz et al, 2007). Prusinkiewicz et al (2007) discuss inflorescence morphospace and show which ramification patterns in inflorescences are common and which do not occur in nature.…”

Flower patterns improve foraging efficiency in bumblebees independent of nectary guidance

“…While the exclusively horizontal presentation of our artificial flowers was not representative for all flower types visited by bumblebees, their size and general shape fell well within the natural range of flowers bumblebees typically forage from (Dafni & Kevan 1997, Dafni et al 1997). Moreover, choice experiments suggest that bumblebees prefer horizontally arranged flowers (Makino 2008), from which they also learn cues more flexibly (Wolf et al 2015), so that this type of flower is highly relevant for bumblebees. The colour contrast and spatial resolution of the patterns in our experiments were designed to ensure reliable detection by the bumblebees.…”