A Sensory Bias Has Triggered the Evolution of Egg-Spots in Cichlid Fishes (original) (raw)
Figure 2
Female preference tests in Pseudocrenilabrus multicolor using computer animated stimuli.
(A) The experimental set-up consists of an iMac computer behind an experimental aquarium (60×30×30 cm). Two animations are shown simultaneously (in this case a conspecific male and a heterospecific, Astatotilapia burtoni; see [B]). (B) Results from the ‘benchmark’ experiment, in which P. multicolor females were given the choice between a conspecific and a heterospecific (A. burtoni) male. The females reacted significantly more often with the animated image showing a conspecific male. (C) Results from the ‘red fringe’ experiments, in which P. multicolor were left the choice between a male with and one without the red fringe on the tip of the anal fin. We could not detect any difference in female response, which is also backed-up by two-way choice experiments with live fish (see Figure S1). (D) Results from the ‘egg-spot’ experiment, in which P. multicolor females could choose between a natural male and a male bearing an in- silico egg-spot. Females showed a significant preference for the male with the artificial egg-spot. Arrowheads indicate the minute differences between the images presented to the females.