Figure 1.

Schematic diagram of the methods for (a) no selection and (b) selection treatments at both the low and high migration rates over the first four generations of the seven‐generation experiment. Blue arrows indicate when two (low) or 20 (high) rph2 ^rr females were added to each generation; purple arrows indicate the point at which all adult beetles were removed from jars after 2 weeks of mating and oviposition, leaving only eggs and larvae (as indicated by the grey flour) in the jars. Green arrows indicate when 200 beetles were transferred into a fresh culture jar. Orange arrows in the selection treatments (b) indicate when all beetles from generation 3 were transferred into a fresh culture jar for exposure to a 48‐hr PH ₃ fumigation (orange box). These steps repeat from generation 4 to generation 7 with an additional 48‐hr PH ₃ fumigation at generation 6 in the selection treatments