Datasets and scripts from: Sensory-based quantification of male colour patterns in Trinidadian guppies reveals no support for parallel phenotypic evolution in multivariate trait space

Parallel evolution, in which independent populations evolve along similar
phenotypic trajectories, offers insights into the repeatability of
adaptive evolution. Here, we revisit a classic example of parallelism,
that of repeated evolution of brighter males in the Trinidadian guppy
(Poecilia reticulata). In guppies, colonisation of low predation habitats
is associated with emergence of ‘more colourful’ phenotypes since
predator-induced viability selection for crypsis weakens while sexual
selection by female preference for conspicuousness remains strong. Our
study differs from previous investigations in three respects. First, we
adopt a multivariate phenotyping approach to characterise parallelism in
multi-trait space. Second, we use ecologically-relevant colour traits
defined by the visual systems of the two selective agents (i.e. guppy,
predatory cichlid). Third, we estimate population genetic structure to
test for adaptive (parallel) evolution against a model of neutral
phenotypic divergence. We find strong phenotypic differentiation that is
inconsistent with a neutral model but very limited support for the
predicted pattern of greater conspicuousness at low predation. Effects of
predation regime on each trait were in the expected direction, but weak,
largely non-significant, and explained little among-population variation.
In multi-trait space, phenotypic trajectories of lineages colonising low
from high predation regimes were not parallel. Our results are consistent
with reduced predation risk facilitating adaptive differentiation,
potentially by female choice, but suggest that this proceeds in
independent directions of multi-trait space across lineages.
Pool-sequencing data also revealed SNPs showing greater differentiation
than expected under neutrality, among which some are found in genes
contributing to colour pattern variation, presenting opportunities for
future genetic study.