Appendix methods
We collected data on larval social behaviour from Brown (1981) in
binary, categorical and continuous formats. Brown provides the clutch
size range of each Heliconiini species, which we used as a proxy for our
categorical and continuous data on larval gregariousness. Categorical
social behaviour was recorded as four levels (solitary, G1, G2, G3), as
explained in the main methods. We calculated the median clutch size from
the ranges given in Brown (1981), these median clutch sizes were then
used for the continuous data. We performed additional transition rate
analyses on these categorical and continuous data.
Before testing for evolutionary relationships between larval social
behaviour and various host plant traits, we performed a count on the
host data to reveal how many different larval species use each plant as
a host. Using these count data, we omitted hosts used by fewer than four
separate larvae to create a more robust test for larval social behaviour
against individual host species. We also used these count data to
determine which hosts are used more frequently by larvae (Table A5).