Meeting Abstract
The sensory drive hypothesis has been supported by many previous studies that show animals to preferentially approach colors that are also used as sexual signals. Studies in fish have shown modifications in such preferences depending on the ambient water color. Turbidity alters ambient color and organisms may compensate for visual obscurity in turbid environments through shifts in visual sensitivity towards higher wavelengths. Here, we asked whether zebrafish from more turbid habitats developed an increased preference for a prominent body color blue (on their stripes) or a presumed habitat color green, and whether relaxed selection on domesticated zebrafish has altered this preference. We subjected zebrafish from 4 populations (3 wild & 1 hatchery reared) to a dichotomous choice task (blue vs green door). We found the wild fish to show a clear preference for green over blue, while the domesticated fish entered green and blue doors equally often. The preference for green was strongest in fish from a turbid stagnant water population. Wild fish may tend to associate the green color with features of the natural habitat consisting of vegetation or with the diet consisting of microalgae and zooplanktons. This indicates that vegetation/food color and not turbidity might influence development of visual preference in wild zebrafish. Domestication has eliminated the preference, perhaps explaining why other zebrafish studies yield conflicting results on color preferences. These results are also suggestive of zebrafish offering an intriguing example where a color signal does not drive visual preferences.
