Data from: Mating competition among females: testing the distinction between natural and sexual selection in an insect

In species where females compete for mates, the male often provides the
female with resources in addition to gametes. A recently suggested
definition of sexual selection proposed that if females only benefit from
additional resources that come with each mating and not additional
gametes, female intrasexual competition for mating opportunities would
result in natural selection rather than sexual selection. The nuptial
gift-giving bushcricket Kawanaphila nartee has dynamic sex roles and has
been a textbook example of sexual selection acting on females via mating
competition. We investigated whether females of this species gain fitness
benefits from nuptial gifts, additional ejaculates, or both, by
controlling the number of matings and whether the female was allowed to
consume the nutritious gift (spermatophylax) at mating. We found that egg
production per day of life increased with the number of additional
matings, both with and without spermatophylax consumption, but consuming
the spermatophylax had an additional positive effect on the number of
eggs. These effects were particularly strong in females with shorter
lifespans. We discuss how the recently suggested definition of sexual
selection applies to nuptial feeding insects, and conclude that both
natural and sexual selection influence mating competition in K. nartee
females.