Data from: Food fight: sexual conflict over free amino acids in the nuptial gifts of male decorated crickets

In decorated crickets, Gryllodes sigillatus, the spermatophore that a male
transfers at mating includes a gelatinous spermatophylax that the female
consumes, delaying her removal of the sperm-filled ampulla. Male
fertilization success increases with the length of time females spend
feeding on the spermatophylax, while females may benefit by prematurely
discarding the spermatophylaxes of undesirable males. This sexual conflict
should favour males that produce increasingly appealing spermatophylaxes,
and females that resist this manipulation. To determine the genetic basis
of female spermatophylax feeding behaviour, we fed spermatophylaxes to
females of nine inbred lines and found that female genotype had a major
influence on spermatophylax feeding duration. The amino acid composition
of the spermatophylax was also significantly heritable. There was a
positive genetic correlation between spermatophylax feeding duration and
the gustatory appeal of the spermatophylax. This correlation suggests that
genes expressed in males that produce more manipulative spermatophylaxes
are positively linked to genes expressed in females that make them more
vulnerable to manipulation. Outbred females spent less time feeding on
spermatophylaxes than inbred females, and thus showed greater resistance
to male manipulation. Further, in a nonspermatophylax producing cricket
(Acheta domesticus), females were significantly more prone to feeding on
spermatophylaxes than outbred female Gryllodes. Collectively, these
results suggest a history of sexually antagonistic coevolution over the
consumption of nuptial food gifts.