Biased sex rations in Spanish populations of Pistacia lentiscus (Anacardiaceae): the possible role of herbivory

Sex ratios in two populations of the Mástic tree (Pistacia lentiscus) were determined and the degree of insect herbivory on leaves was estimated for each sex. The populations were female biased, consistingof60% to70% females. However, no differences in the degree of insect damage on leaves was found between male and female trees. Similarly, no sex-related differences in leaf nitrogen content, which is known to be an important determinant of food quality, were found. Our fíndings suggest that insect herbivores are not responsible for the female biased sex ratios in mástic tree populations.