Data from: Matching habitat choice could be brightness-based instead of hue-based in green–brown polymorphic grasshoppers

Some prey species have evolved background matching, that is, they resemble
their surrounding environment in terms of colour and/or brightness. When
prey populations inhabit patchy environments, they may even have evolved
specialised phenotypes: each phenotype matching a specific subset of
patches. To benefit from the match between their phenotype and this subset
of patches, individuals should preferentially select patches within that
subset, a process known as matching habitat choice. Matching habitat
choice is particularly beneficial to colour polymorphic prey populations,
as it reduces individual and population-level predation risk. We tested
for matching habitat choice in green-brown polymorphic grasshoppers using
experimental arenas lined with green-brown checkerboards. Because previous
work suggested that grasshoppers may distinguish green and brown solely
achromatically, individuals were tested on green-brown checkerboards that
were either achromatically-mismatched (different luminances and hues) or
achromatically-matched (same luminance, different hues). Grasshoppers
selected coloured microhabitats independently of their colour morph. They
preferred green patches on achromatically-mismatched checkerboards and
tended to prefer brown patches on achromatically-matched checkerboards. We
conclude that green-brown polymorphic grasshoppers do not engage in
matching habitat choice for hue, even though they likely distinguish green
and brown chromatically. We finally investigated the potential of the
preferred patches to provide increased concealment from their natural
predators. Both morphs were better concealed achromatically on the
preferred patches. Green-brown polymorphic grasshoppers may thus perform
matching habitat choice, though through brightness matching instead of hue
matching. Such brightness-based habitat choice could reduce predation risk
at long distances and under low-light conditions, highlighting the
importance of considering both hue and brightness in studies of habitat
choice for colour purposes.