The effects of herbivory on plant fitness have been assessed in terms
of seed or fruit production whereas the effects on male reproductive s
uccess have received much less attention. This female-biased approach
has been based on the assumption that the male and female reproductive
success in plants are correlated with each other and that the effects
of environmental Factors on female and male function are equal or at
least parallel. However, several studies have suggested that male and
Female reproductive success are not closely related and they may even
be negatively correlated. Here we review the literature and also prese
nt an experimental study of the effect of herbivory on pollen-tube gro
wth rates. The literature reviewed shows that the effects of herbivory
on plant fitness may vary in relation to the fitness measures used an
d that herbivory may have differential effects on Female and male repr
oductive functions. These differential effects may have evolutionary c
onsequences, as well as consequences for estimating the selective effe
cts of herbivory. Our experiment with Lobelia siphilitica showed that
removal of 50% of the leaves during flower development caused a signif
icant reduction in pollen-tube growth rates. We suggest that assessmen
t of both male and female fitness components will give more accurate e
stimates of the effects of herbivory on total plant reproductive succe
ss. Consequently. the role of herbivory as a selective force can be mo
re accurately estimated.