To measure wing length, the right wing of each specimen was removed by cutting near the tegula using the tip of a small metal syringe (8 mm BD 3/10 ml/cc Insulin Syringe, Becton, Dickinson and Company, Franklin Lakes, NJ). Each wing was placed flat on a glass slide (VWR Micro Slides, Cat. No. 48300-037, VWR International LLC, Radnor, PA). All flies were stored in 80% ethanol prior to and during wing removal. Up to 10 female and 10 male wings on slides were arranged and fixed to the slide using a protein fixative (ClearMount Mounting Solution, LifeTechnologies, Frederick, MD) and slide cover (VWR Plastic Cover Slip, Cat. No. 48376-049, VWR International LLC). Additionally, the whole abdomen melanization of each specimen was recorded as ‘light’, ‘medium’, or ‘dark’. This was a subjective assessment and lab-reared summer morphs were used as the baseline ‘light’ category. All slides were then photographed at identical magnification parameters (Leica S6D and Microscope Camera MC120 HD, using the Leica Application Suite V 4.6.0, Leica Microsystems Inc., Buffalo Grove, IL) and measured using ImageJ (imagej.nih.gov/ij/). Two length measurements were made for each wing along the IV vein, as described in Shearer et al. (2016) (link). For analysis, these two lengths were summed and considered as total wing length.