Reproductive investment at stem and genet levels in male and female plants of the clonal dioecious shrub Ilex leucoclada (Aquifoliaceae)

Abstract

The sexual dimorphism of reproductive investment (measured as dry mass of reproductive tissues) at stem and whole plant (i.e., genet) levels in a dioecious clonal shrub, Ilex leucoclada (Maxim.) Makino., was examined over 2 consecutive years. Five patches in which different genets had already been distinguished using molecular markers in a previous study were selected, and the stem length, numbers of flowers and fruits, and sex of each stem were recorded. Fresh inflorescences and fruits were randomly sampled to estimate the reproductive investment of each stem. The male plants invested more resources in flowering at both the stem and genet levels than female plants, but females invested more resources than males when fruit masses were considered in addition to flower masses. The degrees of sexual dimorphism in reproductive investment at the stem and genet levels were similar, for both flowering alone and flowering plus fruiting. However, the reproductive investment was more restricted to large stems in female genets than in males. Inter-year fluctuations in reproductive investment were greater for females than males at both levels. These results suggest that patterns of reproductive investment should be examined simultaneously at multiple modular levels to obtain a thorough understanding of gender-associated variations in clonal plants.