Finding love: fruit fly males evolving under higher sexual selection are inherently better at finding receptive females

Courtship is an important component of male reproductive behaviour that
enables males to learn about the suitability of their mating partners.
Experimental evidence suggests that Drosophila melanogaster males can
learn to modify their courtship behaviour based on their prior experience
with unreceptive females. This courtship learning is expected to provide a
fitness advantage to males and could therefore evolve given suitable
heritable variation. We investigated the role of sexual selection in the
evolution of courtship learning ability of males, using populations of D.
melanogaster evolving under high and low levels of sexual selection for
over 170 generations. We exposed males from both types of population to
unreceptive females and then tested their ability to discriminate between
receptive and unreceptive females in a complex mating environment. After
being exposed to unreceptive females, males from both types of population
(1) courted females less (both receptive and unreceptive), (2) took longer
to initiate courtship, but took less time to start mating after initiating
courtship and (3) increased the proportion of courtship directed towards
receptive females, indicating the ability of both types of male to learn
from experience. We did not find any difference in the courtship learning
ability of males from the two types of population. However, males from
populations with higher levels of sexual selection were better able to
recognize and court receptive females, even when they were not previously
exposed to unreceptive females. Taken together, these results show that
sexual selection may not result in improved learning abilities but can
lead to the evolution of an improved innate ability of males to assess the
receptivity of females.