Figure 2.

Building on the geometric framework of Smith & Evans [83], a heuristic graphical representation of a response surface highlighting interactions between vibratory and visual signal components of the courtship display of the wolf spider, Schizocosa crassipes [37]. Empirical data demonstrate that females respond to variation in brush size only in the presence, versus absence, of vibratory signalling [37]. This geometric visualization bears similarity to the multidimensional response surface methodology [e.g. 1], but rather than linking fitness to trait values to measure evolutionary responses to selection, here we plot behavioural responses as a function of trait (signal) values [84].