Fig. 4.

Dose response curves (a) and synergy (b) of the attraction of male Caenorhabditis elegans to two different mating pheromones. The assays were as described in Fig. 2. Panel (a) shows that there can be points of maximal attraction and that caution needs to be used to avoid adding too much material in a bioassay. The blue and red arrows in (a) indicate the concentrations tested in (b), which shows the results of adding together two pheromones at concentrations that each alone would produce no activity but that together produce a large response. All of these very interesting biological stories can cause great confusion in an AGF study. Reproduced from Srinivasan et al. (2008).