Figure legends
Figure 1 . A) The Heliconiini phylogeny, adapted from Kozak et
al. (2015), showing larval social behaviour (solitary = grey tip points,
gregarious = blue tips) and the number of separate Passifloraceae used
by each species as larval host plants (1-57 represented by increasing
tip point size). B) The frequency of solitary (grey bars) and gregarious
(blue bars) larvae which use each number of separate Passifloraceae host
species. The majority of gregarious species use < 20 hosts. C)
Image examples (with credit) of various Heliconiini larvae. Clockwise
from top-left: Agraulis vanilla , Heliconius hewitsoni ,Heliconius doris , Eueides isabella .
Figure 2 . The frequencies at which Passifloraceae with certain
traits are used by both solitary (grey bars and points) and gregarious
(blue bars and points) Heliconiini larvae. A) Larval use of host plants
separated by their main habitat. B) Larval use of hosts separated by
their vestiture (presence or absence of leaf trichomes). C) larval use
of host plants separated by their median mature leaf size.
Figure 3. Results from phylogenetic pathway analyses (PPA) in
which directional evolutionary relationships between traits are
estimated. Arrows show the direction of evolutionary interactions, the
values next to arrows display the pathway coefficient (strength of the
estimated relationship). Between categories of social behaviour,
negative coefficients (red arrows) indicate that a loss of the parent
trait precedes a gain of the child trait. Positive coefficients (blue
arrows) indicate that a transition to the parent trait precedes a
subsequent transition to the child trait. A) Output from the model
looking only at larval social behaviour, showing strong support for the
pathway in which initial solitariness precedes transitions to both
gregarious levels 1 and 2, which in turn occur before the evolution of
gregarious level 3. B) Output from the model including the degree of
larval host specialisation (number of host plants used). With host use
count as the parent trait, the negative coefficient indicates that a
decrease in the number of host plants used precedes a transition to
gregariousness.