Supplemental data for: Parallel shifts in flight-height associated with altitude across incipient Heliconius species

Vertical gradients in microclimate, resource availability and interspecific interactions are thought to underly stratification patterns in tropical insect communities. However, only a few studies have explored the adaptive significance of vertical space use during the early stages of reproductive isolation. We analysed flight-height variation across speciation events in Heliconius butterflies representing parallel colonisations of high-altitude forest. We measured flight-height in wild H. erato venus and H. chestertonii, parapatric lowland and mountain specialists respectively, and found that H. chestertonii consistently flies at a lower height. By comparing our data to previously published results for the ecologically equivalent H. e. cyrbia (lowland) and H. himera (high-altitude), we found that the species flying closest to the ground are those that recently colonised high-altitude forests. We show that these repeated trends largely result from shared patterns of ecological selection ..., We characterised the local forest structure by measuring the trunk diameter at breast height (m) and the average distance (m) between neighbouring trees of common tree species along 15–20m sections of the trails used for collecting butterflies. For the tallest trees, we measured the angle of elevation to the treetop with a clinometer. The tangent of this angle was then multiplied by the distance to the tree from the point of observation to estimate height. Shorter trees were measured using measuring tapes.
We measured the height (m) of all the Passiflora (Passifloraceae) hostplants that were visually identified along the trails used to collect butterflies. We also measured the height (m) of the flowering plants that butterflies were observed feeding from at least once. 
In our study, flight-height is defined as the length of the line perpendicular to the ground level from the point where individuals were first observed, as estimated with a measuring tape. Each measured individual (H. e...., , # Supplemental data for: Parallel shifts in flight-height associated with altitude across incipient Heliconius species

## Description of the Data and file structure

This data set consists of CSV tables with raw data for the manuscript by the title and a .Rmd file with the annotated scripts used in the analyses. The tables are labeled S1-S4.

S1 includes the taxonomic identity of plant species (hosts or flowering plants) used by butterflies in the study and their heights (meters).

S2 contains forest density data measured as \"Diameter at the breast height\" (DBH), \"Average distance between neighbouring trees\" (ADNT, in meters) for trees measured at dry-high-altitude (DHA, in meters) or wet-low-altitude (WLA, in meters)

S3 contains forest vertical structure data measured as height of trees measured at the canopy, undercanopy or scrub at dry-high-altitude (DHA, in meters) or wet-low-altitude (WLA, in meters)

S4 contains flight-height (meters) data for butterflies of the four species con...