Ordano & Ornelas 2005 (Article) Tillandsia

The cost of nectar replenishment in two epiphytic bromeliads

Author(s):—M. Ordano & J.F. Ornelas

Publication:—Journal of Tropical Ecology 21: 541–547. (2005) — DOI

Abstract:—Animal-pollinated angiosperm plants that replenish removed nectar invest energy that can entail are productive cost. Here we investigated whether or not seed production is affected by replenishing nectar in hummingbird-pollinated Tillandsia multicaulis and T. deppeana (Bromeliaceae) in a montane cloud forest in eastern Mexico. These epiphytic plants respond strongly and positively to repeated nectar removal. The female reproductive cost was assessed in manually, cross-pollinated flowers with or without repeated nectar removal. Seed production from experimental flowers was then contrasted with those naturally exposed to pollination and nectar removal. Tillandsia deppeana set the same numbe of seeds of the same size regardless of whether or not it had to replenish nectar. Seeds were slightly smaller if the result of natural open pollination than from copious hand crossing. In contrast, T. multicaulis set about half as many seeds when it had to replenish than when it did not, indicating a substantial cost to replenishment. There was no difference in seed number of T . multicaulis between open and hand-augmented pollination. The contrasting results for plants that respond strongly and positively to repeated nectar removal suggest that the female reproductive costs of nectar replenishment can range from costly to beneficial, depending on the conditions of the plants and on the species

Keywords:—Bromeliaceae,cloudforest,epiphytes,hummingbirds,Mexico,nectarcost,nectarremoval,seedproduction, Tillandsia