Colour‐based foraging diverges after multiple generations under different light environments

Abstract

When the environment changes, sensory systems can adapt plastically or evolve genetically to the new surroundings, and traits and behaviours reliant on these sensory systems may also change, leading to altered evolutionary trajectories. We tested for differences in colour‐based foraging preferences of guppies (Poecilia reticulata) that lived for 6–10 generations under each of three light environments (green, lilac or control) to determine whether evolution under different light environments alters visually based behaviour. When tested in a common light environment, we found differences in pecking behaviour between treatments that were likely due to changes in the visual system. Pecking behaviour towards green stimuli was consistent across light treatments, possibly reflecting the importance of detecting green algae in the wild. The blue stimulus was only pecked at by fish from the control environments. Behaviour towards long wavelength stimuli varied, possibly due to the polymorphic nature of the long wavelength opsins. These results are consistent with one component of sensory drive but do not allow us to conclude whether these differences are due to plastic or evolved responses.

Geographic variation in opsin expression does not align with opsin genotype in Lake Victoria cichlid populations

“…To maximize RNA yield and minimize differences due to circadian variation in opsin expression (Halstenberg et al, ), all fish were euthanized in the early evening on the day of capture (~17:00–20:00). Though the time between fish capture and eye sampling was variable (most were captured in the early afternoon, but some were caught later, ~16:00), we do not expect this to have influenced the patterns we report here; recent work in guppies suggests that light‐induced changes in the visual system occur over longer time periods (>24 hr; Cole, Lynn, Kranz, & Endler, ). Sampling was conducted with permission of the Tanzania Commission for Science and Technology (COSTECH—No.…”

Colour biases in learned foraging preferences in Trinidadian guppies

“…Given that fish were raised under laboratory conditions, our findings are most likely explained by a genetic predisposition impacting colour learning. We cannot rule out developmental influences of the standardized rearing environment shaping the learning predisposition we observed, but we note robust preferences to peck on green over blue objects were observed in a feral guppy population raised across three different light environments (Cole et al, 2019). We studied only one guppy population, fish originating from the Paria river, meaning that we cannot make inferences about guppies broadly.…”

“…In comparison, green food such as algae makes up a sizeable proportion of many guppy's diets (Dussault & Kramer, 1981). Indeed, preferences for foraging on green versus other colours (including blue) were robust across feral guppies raised for several generations under different light conditions (Cole et al, 2019). Thus, learned associations may differ between blue and green food.…”