Animal-pollinated angiosperm plants that respond positively to nectar removal by replenishment invest energy that can entail a reproductive cost. Here we use nectar removal manipulation to investigate whether nectar removal increases total nectar production in Moussonia deppeana (Gesneriaceae) and to see if this leads to lower seed production. We found that flowers strongly respond to increased nectar removal by producing 2–4 times as much additional nectar. Other nectar removal treatments had little effect on nectar production and rule out alternative explanations at the flower level. Compared with open-pollinated flowers, hand cross-pollination yielded similar seed production in flowers with experimentally increased nectar removal. Although flower-level effects of nectar replenishment on seed production were not detected in M. deppeana, costs of nectar replenishment need further study as tradeoffs between nectar production and seed production could be expressed at the plant level and/or as long-term effects.
Nectar removal effects on seed production in Moussonia deppeana (Gesneriaceae), hummingbird-pollinated shrub