https://vegfrreceptor.com/inde....x.php/qualitative-ne
We investigated the rheotaxis of guppies above buffer waterfalls within the Aripo and Turure streams in Trinidad-the later on having been introduced in 1957 from a below-waterfall population in another drainage. We predicted that, due to strong choice against downstream emigration, these two above-waterfall populations should show strong good rheotaxis. Matching these expectations, both populations expressed large degrees of good rheotaxis, possibly reflecting contemporary (fast)