Data from: female preference for super-sized male ornaments and its implications for the evolution of ornament allometry

It has been argued that disproportionately larger ornaments in bigger
males—positive allometry—is the outcome of sexual selection operating on
the size of condition dependent traits. We reviewed the literature and
found a general lack of empirical testing of the assumed link between
female preferences for large ornaments and a pattern of positive allometry
in male ornamentation. We subsequently conducted a manipulative experiment
by leveraging the unusual terrestrial fish, Alticus sp.
cf. simplicirrus, on the island of Rarotonga. Males in this
species present a prominent head crest to females during courtship, and
the size of this head crest in the genus more broadly exhibits the classic
pattern of positive allometry. We created realistic male models
standardized in body size but differing in head crest size based on the
most extreme allometric scaling recorded for the genus. This included a
crest size well outside the observed range for the study population
(super-sized). The stimuli were presented to free-living females in a
manner that mimicked the spatial distribution of courting males. Females
directed greater attention to the male stimulus that exhibited the
super-sized crest, with little difference in attention direct to other
size treatments. These data appear to be the only experimental evidence
from the wild of a female preference function that has been implicitly
assumed to drive selection that results in the evolution of positive
allometry in male ornamentation.