Data from: Tolerance to deer herbivory and resistance to insect herbivores in the common evening primrose (Oenothera biennis)

The evolution of plant defence in response to herbivory will depend on the
fitness effects of damage, availability of genetic variation, and
potential ecological and genetic constraints on defence. Here we examine
the potential for evolution of tolerance to deer herbivory in Oenothera
biennis while simultaneously considering resistance to natural insect
herbivores. We examined: i) the effects of deer damage on fitness; ii) the
presence of genetic variation in tolerance and resistance; iii) selection
on tolerance; iv) genetic correlations with resistance that could
constrain evolution of tolerance; and v) plant traits that might predict
defence. In a field experiment, we simulated deer damage occurring early
and late in the season, recorded arthropod abundances, flowering
phenology, and measured growth rate and lifetime reproduction. Our study
showed that deer herbivory has a negative effect on fitness, with effects
being more pronounced for late-season damage. Selection acted to increase
tolerance to deer damage, yet there was low and non-significant genetic
variation in this trait. In contrast, there was substantial genetic
variation in resistance to insect herbivores. Resistance was genetically
uncorrelated with tolerance, whereas positive genetic correlations in
resistance to insect herbivores suggest there exists diffuse selection on
resistance traits. In addition, growth rate and flowering time did not
predict variation in tolerance, but flowering phenology was genetically
correlated with resistance. Our results suggest that deer damage has the
potential to exert selection because browsing reduces plant fitness, but
limited standing genetic variation in tolerance is expected to constrain
adaptive evolution in O. biennis.