Plant secondary metabolites (PSMs), such as alkaloids, are often found in many parts of a plant, including flowers, providing protection to the plant from various types of herbivores or microbes. PSMs are also present in the floral nectar of many species, but typically at lower concentrations than in other parts of the plant. Nectar robbers often damage floral tissue to access the nectar. By doing so, these nectar robbers may initiate an increase of PSMs in the floral nectar. It is often assumed that it takes at least a few hours before the plant demonstrates an increase in PSMs. Here, we addressed the question of whether PSMs in the floral tissue are immediately being released into the floral nectar following nectar robbing. To address this research question, we investigated whether there was an immediate effect of nectar robbing by the Palestine Sunbird (Nectarinia osea) on the concentration of nectar alkaloids, nicotine and anabasine, in Tree Tobacco (Nicotiana glauca). We found that the concentration of anabasine, but not nicotine, significantly increased in floral nectar immediately following simulated nectar robbing. These findings suggest that nectar robbers could be ingesting greater amounts of PSMs than they would if they visit flowers legitimately. As a consequence, increased consumption of neurotoxic nectar alkaloids or other PSMs could have negative effects on the nectar robber.
Bibliographical noteFunding Information:
Acknowledgement We would like to thank the staff at the Oranim Botanical Garden: Oren Azar, Yoni Gal, and Muky Gross, who helped to prepare and maintain the Nicotiana glauca plot. RLK was supported in part by a Haifa University Presidential post-doctoral fellowship and by Israel Science Foundation (ISF). This study was funded by an ISF grant number 1338/11 awarded to SM.
- Secondary metabolites
ASJC Scopus subject areas
- Ecology, Evolution, Behavior and Systematics