A dataset of tropical and temperate butterflies.

Methods of data collection: Neotropical data were collected in Panama from February to June 2020 and from October 2021 to March 2022 during both wet (May to December) and dry (January to April) seasons (Supplementary Fig. 1, Supplementary Table 1) (Leigh, 1999). Temperate data were collected in the Czech Republic and Austria between April and August 2021 and in the UK between April and September 2009 and May and September 2018 (Supplementary Fig. 1, Supplementary Table 1) (Bladon et al., 2020). Data collection took place between 7:30 and 17:30. Neotropical field sites included lowland scrub and managed urban green spaces, secondary semi-deciduous lowland tropical forest, mountain rainforest and management agroforestry (Supplementary Table 1). Temperate field sites included calcareous meadows, grassland meadows, alpine/montane grassland, encroaching scrub, secondary forest, and exposed ground (Supplementary Table 1).

Butterfly body temperature and morphological measurements

Butterflies were captured with butterfly nets when encountered (without chasing) and data were collected following the protocol used by Bladon et al. (2020), as follows. Once in the net, and within 10 seconds, a temperature reading of the butterfly’s thorax (body temperature, Tb) was taken using a thermocouple (0.5 mm diameter) and handheld indicator (Tecpel Thermometer 305B, TC Direct, Uxbridge, UK). Air temperature (Ta) was taken at waist height where the butterfly was caught, with the thermocouple shaded from the sun. If the butterfly was resting on a substrate before capture, the temperature of the air 1 cm above where it was sat was recorded with the thermocouple (microclimate temperature, Tm). The butterfly was identified to species or subspecies. In the case of butterflies from the tropical Calephelis genus it was not possible to identify individuals to species, so data from these butterflies were aggregated to genus level. Forewing length (in mm) from the tip of the wing to the point where it meets the thorax was measured using callipers (at the Panama and UK sites only).

Description of each column: Species: species name Site: location of capture of the butterfly Date: date of capture of the butterfly Family: family the butterfly belongs to Activity: what the butterfly was doing when it was first encountered (nectaring, flying, resting, basking, interacting with other/same species). Tair.perch: if the butterfly was first encountered while on a perch, this is the temperature 1cm above the perch. All temperatures are in Celcius. Tbody: temperature of the thorax of the butterfly within 10 seconds of capture Tair: air temperature recorded at waist height in shade in the location the butterfly was first encountered Tperch: if the butterfly was first encountered while on a perch, this is the temperature of the surface of the perch Region: tropical (from Panama) or temperate (from Europe) Mean.winglength.mm: mean wing length of the species (one value per species) in mm Colour: the dominant wing colour of the butterfly Colour.value: the wing colour converted to a scale from 1 (white) to 6 (black) Sexual.dimorphism.in.colour: A Y (yes) or N (no) for whether that species has males and females having different dominant wing colours (so that their colour would be different between sexes) Migratory: A Y (yes) or N (no) for whether in the area of capture that butterfly species is known to be migratory Average.forewing.aspect.ratio: the average aspect ratio for the forewing of the butterfly (wing length divided by wing width) Subfamily: the subfamily the species belongs to Tribe: the tribe the species belongs to