Fig 1.
Colour images of the flowering plants used in the current experiment.
Species names appear in Table 1.
Table 1.
Effect of ambient temperature on ΔT for the 30 sampled flower petals.
Fit type indicates the kind of model that best fitted the data: non-linear (GAM) or linear (GLS). Significance of all models was evaluated at α = 0.05. Details of each fit are available in Figs 5–10. Flower shape is abbreviated as Boat shape (BS), Open (O), Open tubular (OT), tubular (T) and flower colours in the hexagon colour space are abbreviated as BLUE (G), BLUE-GREEN (BG), GREEN (G), UV-GREEN (UG), ULTRAVIOLET (UV) and UV-BLUE (UB), as defined by [74]. Colour in the table represents non-significant (NS, green), significant non-linear relationship (magenta), significant linear positive (warm-yellow) and significant linear negative (cool-blue). * indicates a short flowering time (ca. 5–9 hours). Species 4 has two parts (4a and 4b) measured and analysed individually.
Fig 2.
Equipment set up in the field to collect flower temperature readings.
Inset shows the TSM sensor attached to a petal surface.
Fig 3.
Non-linear, 3-parameter logistic model (solid black) describing the probability of bees choosing a warm nectar feeder rather than an ambient temperature feeder (y-axis) at different ambient temperatures (x-axis) and 95% confidence region (blue shaded area).
Circles represent the data collected by [52].
Fig 4.
Predicted effect of ambient temperature (x-axis) on ΔT (primary y-axis: left-hand side) and on bee preference for warmer nectar reward (secondary y-axis: right-hand side).
The model for ΔT is represented by the solid red line along with its 95% confidence region (shaded blue region). The solid green line represents the preference model along with its 95% confidence region (shaded orange region). Species numbers correspond to those in Table 1. Black, dotted lines indicate ΔT values of -1 and 1°C. Refer to Methods sections for details of the bee preference function.
Fig 5.
Predicted effect of ambient temperature (x-axis) on ΔT (primary y-axis: left-hand side) and on bee preference for warmer nectar reward (secondary, y-axis: right-hand side).
The model for ΔT is represented by the solid red line along with its 95% confidence region (shaded blue region). Solid green line represents the preference model along with its 95% confidence region (shaded orange region). Species numbers correspond to those in Table 1. Black, dotted lines indicate ΔT values of -1 and 1°C. Refer to Methods sections for details of the bee preference function.
Fig 6.
Predicted effect of ambient temperature (x-axis) on ΔT (primary y-axis: left-hand side) and on bee preference for warmer nectar reward (secondary, y-axis: right-hand side).
The model for ΔT is represented by the solid red line along with its 95% confidence region (shaded blue region). Solid green line represents the preference model along with its 95% confidence region (shaded orange region). Species numbers correspond to those in Table 1. Black, dotted lines indicate ΔT values of -1 and 1°C. Refer to Methods sections for details on the bee preference function.
Fig 7.
Predicted effect of ambient temperature (x-axis) on ΔT (primary y-axis: left-hand side) and on bee preference for warmer nectar reward (secondary, y-axis: right-hand side).
The model for ΔT is represented by the solid red line along with its 95% confidence region (shaded blue region). Solid green line represents the preference model along with its 95% confidence region (shaded orange region). Species numbers correspond to those in Table 1. Black, dotted lines indicate ΔT values of -1 and 1°C. Refer to Methods sections for details on the bee preference function.
Fig 8.
Predicted effect of ambient temperature (x-axis) on ΔT (primary y-axis: left-hand side) and on bee preference for warmer nectar reward (secondary, y-axis: right-hand side).
The model for ΔT is represented by the solid red line along with its 95% confidence region (shaded blue region). The solid green line represents the preference model along with its 95% confidence region (shaded orange region). Species numbers correspond to those in Table 1. Black, dotted lines indicate ΔT values of -1 and 1°C. Refer to Methods sections for details on the bee preference function.
Fig 9.
Predicted effect of ambient temperature (x-axis) on ΔT (primary y-axis: left-hand side) and on bee preference for warmer nectar reward (secondary, y-axis: right-hand side).
The model for ΔT is represented by the solid red line along with its 95% confidence region (shaded blue region). The solid green line represents the preference model along with its 95% confidence region (shaded orange region). Species numbers correspond to those in Table 1. Black, dotted lines indicate ΔT values of -1 and 1°C. Refer to Methods sections for details on the bee preference function.
Fig 10.
a) A representative phylogenetic distribution of flowering plants in our sample following the method of [84] and [85]. A square (solid) represents the relationship between ΔΤ and ambient temperature i.e. NS (non-significant, green), NL (non-linear, magenta), LN (linear negative, blue), LP (linear positive, yellow), and a solid circle represents the hue of the flower colour distribution in bee hexagon colour space following [74]. The colours of these symbols are meant only to be distinguishable and to indicate an approximate radial angle (inset hexagon) consistent with current knowledge of bee colour processing. The short abbreviations represent flower shape (see detail in Table 1 Material and Method section). Frequency of ‘hue’ category uses definitions for bee pollinator perception as defined for the hexagon colour space [74]. b) The histogram represents the hexagon sector of our sample data, whereas the red line represents the global pattern of flower colour distribution in each hexagon sector [32,33,86]. Hue = Hue in hexagon sector, shape = flower shape.
Table 2.
Cross-tabulation of sampled flowers by type and shape (upper half), and by type and hexagon sector (lower half).
Data expressed as a frequency of observations. Non-significant relationship between the variables (NS), non-linear relationship between predictor and response variable (NL), negative linear relationship (LN), positive linear relationship (LP). Shape of the flower abbreviated as Boat shape (BS), Open (O), Open tubular (OT), tubular (T) whereas flower colours in hexagon colour space are abbreviated as BLUE (G), BLUE-GREEN (BG), GREEN (G), UV-GREEN (UG), ULTRAVIOLET (UV) and UV-BLUE (UB) as defined by [74].
Fig 11.
Distribution of measured flower samples in Australia based on type of relationship (details on Table 1) between ΔΤ and ambient temperature.
a) Non-Significant (NS) flowering plants species distribution, b) Non-Linear (NL) flowering plants species distribution, c) Linear-Positive (LP) flowering plants species distribution, or d) Linear-Negative (LN) flowering plants species distribution. Data sources: all the species data co-ordinates have been downloaded from the Global Biodiversity Information Facility (GBIF) (https://www.gbif.org) using the ‘dismo’ package and plotted using “maps” packages in R Version 1.1.423, 2017 [78].