2.3 Dispersal traits
Dispersal ability was measured for male D. carinulata since, in the field, they have been observed dispersing first and using pheromones to attract mixed-sex aggregations of reproductive adults (Cossé et al. 2005). After emergence as adults, males were randomly assigned to a density treatment and a mating treatment. Males assigned to the mated treatment were paired with a female from the same population for 24 hours. The males were thereafter reared in 0.24 L containers in groups of five (high density) or alone (low density). All males in each high-density container were of the same mating treatment. All containers received the same surplus amount of fresh tamarisk, regardless of how many beetles were in the container. Male beetles were weighed on the day of the dispersal trial.
We assessed dispersal of male beetles using tethered flight mills (Maeset al. 2014; Jones et al. 2016; Tanaka & Murata 2017; Dällenbach et al. 2018; Minter et al. 2018), similar in design to Maes et al. (2014) (Appendix S1). Between 6 and 23 days after eclosion, each beetle was given a one-hour flight trial to take any number of flights. Data from each trial was converted into four dispersal parameters: presence of at least one flight, number of flights, total flight distance, and average flight speed (Appendix S2).