Are breeding system and florivory associated with the abundance of Tillandsia species (Bromeliaceae)?

Abstract

Plant species abundance is partly determined by reproductive success and the factors that limit this success. We studied the flowering phenology, breeding systems and florivory in a community of seven epiphytic Tillandsia spp. in a tropical dry forest in central Mexico. Flowering periods were distributed throughout the year, and corolla sizes suggested that most species share pollinators. The most common breeding system was self-incompatibility (Tillandsia achyrostachys, T.caput-medusae and T.hubertiana), T.lydiae was infertile, T.circinnatioides was partially self-compatible and T.recurvata and T.schiedeana were self-compatible with high autonomous self-pollination. Floral morphology suggests that delayed selfing occurs in the autonomous self-pollinated species, and separation between stigma and stamens could result in self-pollination in the remaining species being avoided. Less than 5% of the inflorescences in the most abundant species (T.recurvata) suffered damage by florivores, but >40% of inflorescences were damaged in the other species. In damaged inflorescences, fruit set decreased by up to 89%. Our data show that the dominant species (T.recurvata) is autogamous and its reproductive success is slightly reduced by resource constraints and florivory. In the less abundant species, resource limitation and florivory dramatically reduced reproductive success, but the strength of these limiting factors is season dependent.