Nectar replenishment maintains the neutral effects of nectar robbing on female reproductive success of Salvia przewalskii (Lamiaceae), a plant pollinated and robbed by bumble bees.
It has been suggested that the dynamics of nectar replenishment could differ for flowers after being nectar robbed or visited legitimately, but further experimental work is needed to investigate this hypothesis. This study aimed to assess the role of nectar replenishment in mediating the effects of nectar robbing on pollinator behaviour and plant reproduction.



Plant-robber-pollinator interactions in an alpine plant, Salvia przewalskii , were studied. It is pollinated by long-tongued Bombus religiosus and short-tongued B. friseanus , but robbed by B. friseanus . Nectar production rates for flowers after they were either robbed or legitimately visited were compared, and three levels of nectar robbing were created to detect the effects of nectar robbing on pollinator behaviour and plant reproduction.



Nectar replenishment did not differ between flowers that had been robbed or legitimately visited. Neither fruit set nor seed set was significantly affected by nectar robbing. In addition, nectar robbing did not significantly affect visitation rate, flowers visited within a plant per foraging bout, or flower handling time of the legitimate pollinators. However, a tendency for a decrease in relative abundance of the pollinator B. religiosus with an increase of nectar robbing was found.



Nectar robbing did not affect female reproductive success because nectar replenishment ensures that pollinators maintain their visiting activity to nectar-robbed flowers. Nectar replenishment might be a defence mechanism against nectar robbing to enhance reproductive fitness by maintaining attractiveness to pollinators. Further studies are needed to reveal the potential for interference competition among bumble bees foraging as robbers and legitimate visitors, and to investigate variation of nectar robbing in communities with different bumble bee species composition.
Key Laboratory of Aquatic Botany and Watershed Ecology, Wuhan Botanical Garden, Chinese Academy of Sciences, Wuhan 430074, China.|Jiangxi Provincial Key Laboratory of Soil Erosion and Prevention, Jiangxi Institute of Soil and Water Conservation, Nanchang 330029, China.
Zhong-Ming
ZM
Ye
Institute of Ecology and Environmental Science, Nanchang Institute of Technology, Nanchang 330099, China.
Xiao-Fang
XF
Jin
Key Laboratory of Aquatic Botany and Watershed Ecology, Wuhan Botanical Garden, Chinese Academy of Sciences, Wuhan 430074, China.
Qing-Feng
QF
Wang
Key Laboratory of Aquatic Botany and Watershed Ecology, Wuhan Botanical Garden, Chinese Academy of Sciences, Wuhan 430074, China.
Chun-Feng
CF
Yang
Department of Biology, University of Maryland, College Park, MD 20742, USA.
David W
DW
Inouye
D000818:Animals; D001516:Bees / Q000502:physiology*; D002681:China; D005247:Feeding Behavior; D020387:Food Chain; D057048:Plant Nectar / Q000378:metabolism*; D054817:Pollination; D012098:Reproduction; D027544:Salvia / Q000502:physiology*
D057048:Plant Nectar
Bombus; Salvia przewalskii; bumble bee; geitonogamous mating; nectar replenishment; nectar robbing; pollination; pollinator behaviour