Fig 1.
Facial colour patterns and four types of models of Neolamprologus pulcher, and their presentation in experiments.
(a): facial colour pattern of four individual fish. (b): preparation of four types of digital-models; (FfFb): familiar neighbour, (FfSb): familiar neighbour’s face on stranger body, (SfSb): stranger and (SfFb): stranger’s face on familiar neighbour body. (c): monitor display exhibiting moving models in an experimental tank. (d): typical reaction of fish just after noticing an emerging model; (1) distance of fish approaching a site for watching model, and (2) distance between site of fish watching model and model on screen.
Fig 2.
Time of watching models by Neolamprologus pulcher when presented four types of digital models.
(FfFb): familiar neighbour, (FfSb): familiar neighbour’s face on stranger’s body, (SfSb): stranger, (SfFb): stranger’s face on familiar neighbour’s body. Median, box (showing 25% and 75%) and ranges are shown. **p < 0.01, NS p > 0.05. (Wilcoxon signed rank test).
Fig 3.
Approaching distance and time to respond to models that initially emerged from behind a right solid block after noticing the models.
(a): approaching distance from site of noticing emerging models to site of watching the model [(1) shown in Fig 1D], (b): distance between the site of watching model and model on screen [(2) in Fig 1D], and (c): time from noticing the emerging model to stopping at the watching site. Median, box (showing 25% and 75%) and ranges are shown. *p < 0.05, NS p > 0.05. In (a) and (b), familiar face models (FfFb or FfSb) and unfamiliar face models (SfSb or SfFb) are compared. When both data are available in a fish, FfFb and SfSb are used. [Wilcoxon signed rank test in (a) and (b), and Mann Whitney U-test in (c)].