Environment-dependent Intralocus Sexual Conflict in a Dioecious Plant

Intralocus sexual conflict is a form of conflict that does not involve direct interactions between males and females. It arises when selection on a shared trait with a common genetic basis differs between the sexes. Environmental factors, such as resource availability, may influence the expression and evolutionary outcome of such conflict. We quantified the genetic variance-covariance matrix, G, for both sexes of Silene latifolia for floral and leaf traits, as well as the between-sex matrix, B. We also quantified selection on the sexes via survival for 2 yr in four natural populations that varied in water availability. Environment-dependent intralocus sexual conflict exists for specific leaf area, a trait that is genetically correlated between the sexes. Males experienced significant negative selection, but only in populations with relatively limited water availability. Females experienced weakly positive or significant stabilizing selection on the same trait. Specific leaf area is genetically correlated with flower size and number, which are sexually dimorphic in this species. The extent of intralocus sexual conflict varied with the environment. Resolution of such conflict is likely to be confounded, given that specific leaf area is highly genetically integrated with other traits that are also divergent between the sexes.