Figure 5

Schematic representation (graphical model) of the population-level phenomena regarding the shift of preferences for the primary host, the sequestration of chemical defenses, and the ontogenetic colour change in Lycorma delicatula. (A) - individual trajectories of accumulation of defenses in bodies of insects from a hypothetical population of the lanternflies, who preferentially switch to defense-providing tree of heaven approximately around the transition between instar 3 and instar 4. Each trajectory line changes from black (indicating instars 1, 2 and 3), to red (indicating instar 4) to brown (indicating adult), Each individual starts increasing (sequestering) chemical defenses as soon as it starts feeding on the primary host. Because this moment is different for each individual, the individual trajectories show increases of accumulated defensive compounds at different time, but most of the individuals end up on the primary host around the time of instar 4. Summarizing the individual trajectories in the whole population results in the figure representing changes of the proportion of instar 4 individuals (red) and adults (brown) in the population over time (B), as well as the proportion of unpalatable (defended) individuals in the population over time (C) assuming for simplicity that “unpalatability” happens when the amount of accumulated defensive compounds reaches a certain hypothetical threshold (shown as green-shaded horizontal bar in A).