Figure 4.

Percentage of Ts in relation to the structure of the habitat. (A) In the fluctuating habitat (tanks F I to F IV), the lack of shelters suitable for territories dramatically reduces the number of Ts (arrows). Highly structured habitats, however, can sustain significantly more Ts. (B) Stable habitat conditions (tanks S I to S II) show less variation in the proportion of Ts, although it appears to increase over time when more and more NTs turn T with only a few Ts losing their territories (arrow).