Extrafloral Nectaries

Extrafloral nectaries have been reported from over 90 families of flowering plants and ferns (Koptur 1992), mostly from tropical and subtropical regions. Plants producing extrafloral nectar are known to suffer less from herbivory (Rezende et al. 2014). There is considerable variation in extrafloral nectary morphology and visitor spectra of ants and other insects (Oliveira and Brandao 1991; Brewitt et al. 2015).

Plants/Extrafloral Nectaries
Schwitzke et al. (2015) - Leea manillensis (Leeaceae) is a large erect shrub with height up to 6 m, terminal inflorescences, and large stipular structures that enclose the next generation of shoots. It is distributed widespread throughout the Philippines and parts of Southeast Asia (Molina et al. 2013). The species is shade-tolerant, growing in the understory, as well as in forest gaps (and edges) in primary and secondary forests, with especially high abundances in bright, young-aged secondary growth forests.

Our results show that Leea manillensis consists of a highly variable system, shaped by a number of factors. We could confirm that it has mutualistic interactions with ants attracted by extrafloral nectaries and food bodies. Ants provided a certain degree of protection. However, the indirect defence mechanism via ants turned out to be very fragile, dependent on different conditions that influenced the magnitude of the beneficial effect of ants on plants (see also Rico-Gray et al. 2012). We found no evidence of any specific relationship between Leea and the attracted ants. Meng et al. 2011 describe similar conditions in the species Leea glabra (Leeaceae) growing in South China. The broad range of ant species observed to visit the extrafloral nectaries is consistent with a pattern typically found in many facultative ant–plant associations and indicating a low specificity (Fiala et al. 1994; Kessler and Heil 2011). Not only did we find a broad range of ant species, but also a high intraspecific variability in the abundance of ants assembling at the extrafloral nectaries. Only 36 % of the observed shoots showed a permanent presence of ants perhaps due to varying EFN production of the plants.