The impact of an extreme weather event on butterfly community activity, use of shelter and shade.

This data set was collected from a nature reserve in Bedfordshire, UK, on 19th July 2022 to assess the impact of an extreme weather event on a butterfly community and the ability of simple management solutions to buffer some of the negative impacts. These management solutions included interspersing patches of scrub in amongst grassland and building artificial banks of varying aspects and slopes, each of which provide shelter and shade. The surveys on July 19th were carried out to specifically assess how butterflies were affected by the hottest day on record in the UK. Five subsequent survey days gathered data under lower, more normal, temperatures for comparison. Each day a morning and afternoon survey were carried out. Recorders walked up and down the study site in parallel lines, getting within 10 m of all locations, and waving a butterfly net to flush out any insects. The starting point for each survey was varied to ensure recorders were not at the same location at the same time each survey. Any butterfly seen within 10 m was recorded and, if possible, captured using a butterfly net. For each butterfly, we recorded the species, whether it was active (flying, nectaring or interacting with another animal) or inactive (resting or basking) when first spotted, whether or not it was located in shade, and whether or not it was within 5 m of a butterfly bank or scrub, both of which provided shelter. If the butterfly was caught, we recorded its body temperature by touching a fine (0.25 mm) mineral-insulated type K thermocouple with hand-held indicator (Tecpel Thermometer 305B) to its thorax, as well as recording air temperature at waist height in the shade at the same location. During surveys, the area of each shade patch encountered was estimated by eye, to account for the size and location of these changing with the position of the sun. The area of all patches of shade was summed to give a total within the survey area for each survey.