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The Complexity of Background Clutter Affects Nectar Bat Use of Flower Odor and Shape Cues.

Muchhala N, Serrano D - PLoS ONE (2015)

Bottom Line: Chiropterophilous plants depend on these bats for their reproduction, thus they also benefit if their flowers can be easily located, and we would expect that floral traits such as odor and shape have evolved to maximize detection by bats.Results demonstrate that bats visit either flower indiscriminately with simple backgrounds, with no significant difference in terms of whether they visit the training-flower odor or training-flower shape first.In more complex backgrounds, nectar bats depend more heavily on olfaction during foraging bouts.

View Article: PubMed Central - PubMed

Affiliation: Department of Biology, University of Missouri St. Louis, St. Louis, Missouri, United States of America.

ABSTRACT
Given their small size and high metabolism, nectar bats need to be able to quickly locate flowers during foraging bouts. Chiropterophilous plants depend on these bats for their reproduction, thus they also benefit if their flowers can be easily located, and we would expect that floral traits such as odor and shape have evolved to maximize detection by bats. However, relatively little is known about the importance of different floral cues during foraging bouts. In the present study, we undertook a set of flight cage experiments with two species of nectar bats (Anoura caudifer and A. geoffroyi) and artificial flowers to compare the importance of shape and scent cues in locating flowers. In a training phase, a bat was presented an artificial flower with a given shape and scent, whose position was constantly shifted to prevent reliance on spatial memory. In the experimental phase, two flowers were presented, one with the training-flower scent and one with the training-flower shape. For each experimental repetition, we recorded which flower was located first, and then shifted flower positions. Additionally, experiments were repeated in a simple environment, without background clutter, or a complex environment, with a background of leaves and branches. Results demonstrate that bats visit either flower indiscriminately with simple backgrounds, with no significant difference in terms of whether they visit the training-flower odor or training-flower shape first. However, in a complex background olfaction was the most important cue; scented flowers were consistently located first. This suggests that for well-exposed flowers, without obstruction from clutter, vision and/or echolocation are sufficient in locating them. In more complex backgrounds, nectar bats depend more heavily on olfaction during foraging bouts.

No MeSH data available.


Related in: MedlinePlus

Main effect of background.Number of visits, of the 40 total, to the flower with the training-flower scent (versus the one the training-flower shape) for simple and complex backgrounds.
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pone.0136657.g002: Main effect of background.Number of visits, of the 40 total, to the flower with the training-flower scent (versus the one the training-flower shape) for simple and complex backgrounds.

Mentions: Results of the GLM are summarized in Table 1. The bat species (Anoura caudifer or A. geoffroyi) and scent type (banana or dimethyl disulfide) used in the experiments did not significantly affect results. Background type showed a significant main effect: in simple backgrounds, bats visited the two flowers in similar proportions, while in complex backgrounds, bats visited the flower with the training-flower odor approximately twice as frequently as the flower with the training-flower shape (Fig 2). Trial number also showed a significant main effect: bats visited more scented flowers in the second set of twenty visits, after the 10-minute break, than in the first set of twenty visits (Fig 3). This increase in visits to scented flowers was particularly large in complex backgrounds and less apparent in simple backgrounds. Finally, there was a marginally significant interaction between background type and scent used: for the experiments with dimethyl disulfide there was a much steeper increase in reliance on scent in complex versus simple backgrounds than for the experiments with banana scent (Fig 4). None of the other two-way interactions were statistically significant, nor were the three-way or four-way interactions.


The Complexity of Background Clutter Affects Nectar Bat Use of Flower Odor and Shape Cues.

Muchhala N, Serrano D - PLoS ONE (2015)

Main effect of background.Number of visits, of the 40 total, to the flower with the training-flower scent (versus the one the training-flower shape) for simple and complex backgrounds.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4596802&req=5

pone.0136657.g002: Main effect of background.Number of visits, of the 40 total, to the flower with the training-flower scent (versus the one the training-flower shape) for simple and complex backgrounds.
Mentions: Results of the GLM are summarized in Table 1. The bat species (Anoura caudifer or A. geoffroyi) and scent type (banana or dimethyl disulfide) used in the experiments did not significantly affect results. Background type showed a significant main effect: in simple backgrounds, bats visited the two flowers in similar proportions, while in complex backgrounds, bats visited the flower with the training-flower odor approximately twice as frequently as the flower with the training-flower shape (Fig 2). Trial number also showed a significant main effect: bats visited more scented flowers in the second set of twenty visits, after the 10-minute break, than in the first set of twenty visits (Fig 3). This increase in visits to scented flowers was particularly large in complex backgrounds and less apparent in simple backgrounds. Finally, there was a marginally significant interaction between background type and scent used: for the experiments with dimethyl disulfide there was a much steeper increase in reliance on scent in complex versus simple backgrounds than for the experiments with banana scent (Fig 4). None of the other two-way interactions were statistically significant, nor were the three-way or four-way interactions.

Bottom Line: Chiropterophilous plants depend on these bats for their reproduction, thus they also benefit if their flowers can be easily located, and we would expect that floral traits such as odor and shape have evolved to maximize detection by bats.Results demonstrate that bats visit either flower indiscriminately with simple backgrounds, with no significant difference in terms of whether they visit the training-flower odor or training-flower shape first.In more complex backgrounds, nectar bats depend more heavily on olfaction during foraging bouts.

View Article: PubMed Central - PubMed

Affiliation: Department of Biology, University of Missouri St. Louis, St. Louis, Missouri, United States of America.

ABSTRACT
Given their small size and high metabolism, nectar bats need to be able to quickly locate flowers during foraging bouts. Chiropterophilous plants depend on these bats for their reproduction, thus they also benefit if their flowers can be easily located, and we would expect that floral traits such as odor and shape have evolved to maximize detection by bats. However, relatively little is known about the importance of different floral cues during foraging bouts. In the present study, we undertook a set of flight cage experiments with two species of nectar bats (Anoura caudifer and A. geoffroyi) and artificial flowers to compare the importance of shape and scent cues in locating flowers. In a training phase, a bat was presented an artificial flower with a given shape and scent, whose position was constantly shifted to prevent reliance on spatial memory. In the experimental phase, two flowers were presented, one with the training-flower scent and one with the training-flower shape. For each experimental repetition, we recorded which flower was located first, and then shifted flower positions. Additionally, experiments were repeated in a simple environment, without background clutter, or a complex environment, with a background of leaves and branches. Results demonstrate that bats visit either flower indiscriminately with simple backgrounds, with no significant difference in terms of whether they visit the training-flower odor or training-flower shape first. However, in a complex background olfaction was the most important cue; scented flowers were consistently located first. This suggests that for well-exposed flowers, without obstruction from clutter, vision and/or echolocation are sufficient in locating them. In more complex backgrounds, nectar bats depend more heavily on olfaction during foraging bouts.

No MeSH data available.


Related in: MedlinePlus