Not Only Hummingbirds: Reproductive Biology and Pollinators of the High-Andean Endangered Puya raimondii (Bromeliaceae)

Puya raimondii, an endangered high-Andean species, exhibits life-history traits that may strongly influence its reproductive strategy; however, its reproductive biology remains poorly understood. Here, we assessed its floral biology, breeding system, and pollination ecology through field observations and controlled pollination experiments. Flowers are incompletely protogynous and herkogamous, with subsequent androecium development leading to contact between anthers and receptive stigma, enabling autonomous self-pollination. Consistent with this mechanism, P. raimondii was found to be self-compatible and capable of autonomous reproduction. The fruit set was high in both populations studied, likely supported by extended floral longevity, abundant nectar and pollen rewards, and a generalized bird pollination system. Hummingbirds were the most frequent visitors; however, passerine birds, including Diglossa brunneiventris, as well as bees, also contributed to pollination to a different extent. These findings indicate that P. raimondii combines reproductive assurance through selfing with the ecological benefits of generalized pollination. This dual strategy may enhance reproductive success under the variable and pollinator-limited conditions of high-Andean ecosystems, highlighting the importance of further ecological and reproductive studies to inform conservation efforts for this endangered species.