Data from: Experimental evolution of a pheromone signal

Sexual signals are important in speciation, but understanding their
evolution is complex, as these signals are often composed of multiple,
genetically interdependent components. To understand how signals evolve,
we thus need to consider selection responses in multiple components and
account for the genetic correlations among components. One intriguing
possibility is that selection changes the genetic covariance structure of
a multicomponent signal in a way that facilitates a response to selection.
However, this hypothesis remains largely untested empirically. In this
study, we investigate the evolutionary response of the multicomponent
female sex pheromone blend of the moth Heliothis subflexa to 10
generations of artificial selection. We observed a selection response of
about 3/4s of a phenotypic standard deviation in the components under
selection. Interestingly, other pheromone components that are
biochemically and genetically linked to the components under selection did
not change. We also found that after the onset of selection, the genetic
covariance structure diverged, resulting in the disassociation of
components under selection and components not under selection across the
first two genetic principal components. Our findings provide rare
empirical support for an intriguing mechanism by which a sexual signal can
respond to selection without possible constraints from indirect selection
responses.