Abstracts (first author)
Boys and girls and plant-eaters: Is herbivory sex-biased in Mercurialis perennis?PDF
Sex-biased herbivory has been implicated as one of the driving forces in the evolution of dioecy. Different partitioning of resource sources and sinks in male and female plants allows different defense strategies. Along with constitutive and induced defences, plants can tolerate herbivore damage to a certain extent, and can ameliorate the pressure through changes in phenology and life history. Gender-dimorphic species of genus Mercurialis are informative model systems in addressing questions in plant evolutionary ecology, including interactions with herbivores. For Mercurialis annua, the most commonly studied species of the genus, herbivore prefference for male plants has been demonstrated in experimental conditions. The aim of our study was to explore the pattern of herbivore damage in natural populations of Mercurialis perennis, a dioecious perennial herb with wide geographic and altitudinal distribution. Plants were sampled from a range of habitats in Serbia. Damage to leaf area was scored and used as an estimate of herbivore load. Herbivore damage was examined in relation to plant gender, altitude, plant height and reproductive allocation. Our results do not confirm the pattern of male-biased herbivory in natural conditions. The variance of herbivore damage between the sexes among the habitats was large, with highly significant effect of site, and non significant effects of sex and sex-site interaction. In a montane population, herbivore damage was male-biased, but without statistical significance. Studied populations showed male-biased sexual size dimorphism. The study of Mercurialis perennis offers a promising approach to better understanding the effect of plant gender on general vigor, tolerance and resistance to herbivores.