Data from: Intraspecific variation in color and carotenoids across environmental extremes in an African Cichlid

Human activities frequently alter environmental conditions and affect the
use of sexually selected traits like color in animals. However, the
effects of environmental stressors are unlikely to be uniform across
populations that experience different environments or between sexes. We
aimed to understand the underlying genetic, environmental, and
gene-by-environment contributions to color expression in males and females
of a sexually dimorphic fish. Pseudocrenilabrus multicolor is a
haplochromine cichlid found in environments that vary dramatically,
particularly with respect to oxygen and turbidity levels. We reared fish
from one swamp (hypoxic, clear) and one river (normoxic, turbid)
population in a split-brood design (hypoxic/normoxic x clear/turbid) then
quantified color and carotenoid concentrations. As expected in this
sexually dimorphic species, females were far less colorful than males. In
males, hypoxia and turbidity were drivers of traits associated with color,
suggesting that color was modified under energetically or visually
unfavorable conditions. Males in the hypoxic treatment from both
populations were not as bright as males reared under normoxic conditions,
which corresponds to results observed in wild fish. Males reared in turbid
conditions were also marginally less bright along the ventral surface than
males reared in clear water. Rearing under turbid conditions reduced
carotenoid concentrations in male skin, but carotenoids were not
correlated with spectral characteristics of male color. We did not find
effects of population on color traits, suggesting that differences in
color between wild populations are due to plastic rather than fixed
genetic effects. Overall, we provide evidence that hypoxia and turbidity
affect signaling traits, though the consequences for mating success remain
to be determined.