Floral Temperature and Optimal Foraging: Is Heat a Feasible Floral Reward for Pollinators?

Sean A Rands,Heather M Whitney,Frederick R Adler

doi:10.1371/journal.pone.0002007

Sean A Rands, Heather M Whitney + Show 1 more

Open Access

https://doi.org/10.1371/journal.pone.0002007

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Journal: PloS one	Publication Date: Apr 23, 2008
Citations: 89	License type: CC BY 4.0

Affiliation: University of Bristol, University of Cambridge

Abstract

As well as nutritional rewards, some plants also reward ectothermic pollinators with warmth. Bumble bees have some control over their temperature, but have been shown to forage at warmer flowers when given a choice, suggesting that there is some advantage to them of foraging at warm flowers (such as reducing the energy required to raise their body to flight temperature before leaving the flower). We describe a model that considers how a heat reward affects the foraging behaviour in a thermogenic central-place forager (such as a bumble bee). We show that although the pollinator should spend a longer time on individual flowers if they are warm, the increase in total visit time is likely to be small. The pollinator's net rate of energy gain will be increased by landing on warmer flowers. Therefore, if a plant provides a heat reward, it could reduce the amount of nectar it produces, whilst still providing its pollinator with the same net rate of gain. We suggest how heat rewards may link with plant life history strategies.

Highlights

Flowering plants rely on a wide range of pollinators, and employ a wide variety of tactics to attract them
Many of these pollinators are ectotherms, and are sensitive to changes in environmental conditions such as temperature, which might present problems to plants in colder climates–how can a plant attract any ectothermic pollinators when the environment is too cold for them to travel between flowers? some of these ectothermic pollinators, such as bumble bees (Bombus spp.), are able to control their body temperature to allow them some independence from the environmental conditions [4], allowing them to operate in environments that would otherwise be too cold [5]
All the results described here are specific to parameters derived for bumble bees, as described in the methods section

Summary

Introduction

Flowering plants rely on a wide range of pollinators, and employ a wide variety of tactics to attract them. The model we present (sketched in figure 1) considers the effects of floral temperature on net gain rate.

Results

Conclusion