Data from: Similar preferences for ornamentation in opposite- and same-sex choice experiments

Selection due to social interactions comprises competition over matings
(sexual selection stricto sensu) plus other forms of social competition
and cooperation. Sexual selection explains sex differences in
ornamentation and in various other phenotypes, but does not easily explain
cases where those phenotypes are similar in males and females.
Understanding such similarities requires knowing how phenotypes influence
non-sexual social interactions as well, which can be very important in
gregarious animals, but whose role for phenotypic evolution has been
overlooked. For example, ‘mate choice’ experiments often found preferences
for ornamentation, but have not assessed whether those are strictly sexual
or are general social preferences. Using choice experiments with a
gregarious and mutually-ornamented finch, the common waxbill (Estrilda
astrild), we show that preferences for ornamentation in the opposite-sex
also extend to same-sex interactions. Waxbills discriminated between
opposite- and to same-sex individuals, but most preferences for colour
traits were similar when interacting with either sex. Similar preferences
in sexual and non-sexual associations may be widespread in nature, either
as social adaptations or as by-product of mate preferences. In either
case, such preferences may set the stage for the evolution of mutual
ornamentation and of various other similarities between the sexes.