Effects of nectar robbing on male and female reproductive success of a pollinator-dependent plant.
OBJECTIVE
Nectar robbers affect host fitness in different ways and by different magnitudes, both directly and indirectly, and potentially constitute an important part of pollination interactions. The aim of this study was to assess the effect of nectar robbing on several variables that characterize the reproductive success of Lonicera etrusca, a pollinator-dependent plant with long, tubular flowers that produce abundant nectar.


METHODS
Using fluorescent powder dye as a proxy for pollen, the distance of pollen dispersal was compared for robbed and non-robbed flowers. Artificial nectar robbing treatments were applied to test its effects on four additional measures of reproductive success, namely the quantity of pollen exported, fruit set, seed/ovule ratio and seed weight.


RESULTS
Nectar robbing was not found to have any significant negative consequences on female and male components of reproductive success as determined through the five variables that were measured.


CONCLUSIONS
Although L. etrusca exhibits high levels of nectar robbing and nectar robbers are common floral visitors, no evidence was found of detrimental changes in the components of reproductive success. A combination of morphological and ecological mechanisms is proposed to explain how plants may compensate for the energetic loss caused by the nectar robbers.
Department of Plant Biology, University of Vigo, Campus Lagoas-Marcosende, 36310 Vigo, Spain srojas@uvigo.es.
Sandra V
SV
Rojas-Nossa
Department of Plant Biology, University of Vigo, Campus Lagoas-Marcosende, 36310 Vigo, Spain.
José María
JM
Sánchez
Department of Plant Biology, University of Vigo, Campus Lagoas-Marcosende, 36310 Vigo, Spain.
Luis
L
Navarro
D005638:Fruit; D031239:Lonicera / Q000502:physiology*; D056771:Ovule / Q000502:physiology; D057048:Plant Nectar; D011058:Pollen / Q000502:physiology*; D054817:Pollination; D012098:Reproduction; D012639:Seeds / Q000502:physiology; D013030:Spain
D057048:Plant Nectar
Lonicera etrusca; floral larceny; floral visitor behaviour; fruit set; nectar robber; plant mating sytems; plant–animal interactions; pollen donation; pollination; reproductive success; seed weight; seed/ovule ratio