DOI: 10.5061/dryad.8w9ghx3vg
title: A thermal performance curve perspective explains decades of disagreements over how air temperature affects the flight metabolism of honey bees

description: While multiple studies have shown that honey bees and some other flying
 insects lower their flight metabolic rates when flying at high air
 temperatures, critics have suggested such patterns result from poor
 experimental methods as, theoretically, air temperature should not
 appreciably affect aerodynamic force requirements. Here, we show that
 apparently contradictory studies can be reconciled by considering the
 thermal performance curve of flight muscle. We show that prior studies
 that found no effects of air temperature on flight metabolism of honey
 bees achieved flight muscle temperatures that were near or on equal,
 opposite sides of the thermal performance curve. Honey bees vary their
 wing kinematics and metabolic heat production to thermoregulate, and how
 air temperature affects the flight metabolic rate of honey bees is
 predictable using a non-linear thermal performance perspective of honey
 bee flight muscle.
description: # A thermal performance curve perspective explains decades of
 disagreements over how air temperature affects the flight metabolism of
 honey bees [Access this dataset on
 Dryad](https://doi.org/10.5061/dryad.8w9ghx3vg∴) The data in this file
 come from published data (i.e., Heinrich, 1980; Harrison et al., 2001;
 Woods et al., 2005; Glass and Harrison, 2022) and a new dataset presented
 in the main body of the manuscript, which used the honey bee, Apis
 mellifera. Each study has its separate tab. We digitally extracted data
 from the figures of the Heinrich, Harrison et al., Woods et al. studies,
 as these datasets were inaccessible (Heinrich, 1980; Harrison et al.,
 2001; Woods et al., 2005). Methods for these published studies can be
 found in each published article, the references for which can be found in
 the list in the main article. From these previously published studies, we
 report the free-flying, mass-specific metabolic rates (mW/g) of unloaded
 bees and their achieved flight muscle temperatures (degrees Celsius) when
 flown at different air temperatures. We only included unloaded bees
 weighing &lt; 98 mg in this analysis, which delineation is based on
 extrapolated values from Woods et al., 2005 (i.e., 90 +/- 8.8 mg; mean +/-
 S.D., n = 78). By only including bees that weighed &lt; 100 mg, we also
 ensured the exclusion of bees transitioning from the role of brood care to
 foraging, which still carry significant hindgut content that can affect
 flight performance and metabolism (Glass et al., 2021; Glass and Harrison,
 2022). ## Description of the data and file structure Each study listed
 above has its tab. The Heinrich 1980 study only reported the sample sizes
 and the mean S.D. for flight metabolism of bees flying at either 20 or 42C
 air temperature. We report the flight muscle temperature, Tthorax (C),
 mass-specific metabolic rates as spFRM (mW/g), and calculated all other
 statistical values based on Heinrich's reported values. The Harrison
 et al. 2001 tab included digitally extracted values for flight muscle
 temperatures, Tthorax (C), and mass-specific flight metabolic rates, spFMR
 (mW/g), for 'winter bees' flying at 24C air temperature. The
 Woods et al. 2005 tab included digitally extracted values for flight
 muscle temperatures, Tthorax (C), and mass-specific flight metabolic
 rates, spFMR (mW/g), for honey bees flying across a range of air
 temperatures from ~18 to 39C, Tair (C). The Glass & Harrison 2022 data
 tab reports the mass-specific flight metabolic rates, spFMR (mW/g), air
 temperature, Tair (C), and flight muscle temperatures, Tthorax (C), of
 honey bees flying in low-density gas mixtures. The values represent the
 maximal flight metabolic rates for every half-degree change in flight
 muscle temperature. "This study" tab shows the new data
 presented in our article. On this tab, we report the air temperature, Tair
 (C), flight muscle temperatures, Tthorax(C), and mass-specific flight
 metabolic rates, spFMR (mW/g), for honey bees flying across a range of air
 temperatures (i.e., 20, 30, or 40C).