i) Many origins of gregarious larvae in Heliconiini
Overall, we recorded 23 gregarious species (Figure 1A), out of the 75
Helicoiniini included in Kozak et al. (2015). Our model estimated there
have been seven independent transitions to gregariousness across the
Heliconiini phylogeny (under the ‘all rates different model’, model
comparison: X2(1) = 4.812, p = 0.028,
transition rate = 0.024)). Despite this pattern of convergent evolution,
the phylogenetic signal of social behaviour is estimated to be very
strong (λ = 1), likely reflecting the general tendency for transitions
to occur at the base of specious clades. Transitions between solitary
and gregarious states are most likely to occur at different rates, with
11 reversals from gregarious larvae back to solitary larvae across the
phylogeny (transition rate = 0.078). This dynamic turnover of social
behaviour suggests Heliconiini oviposition behaviour is likely
responding to a range of selection pressures.