Composition of Extrafloral Nectar Influences Interactions between the Myrmecophyte Humboldtia brunonis and its Ant Associates

Thousands of plant species throughout tropical and temperate zones secrete extrafloral nectar (EFN) (see www.biosci.unl.edu/emeriti/keeler/extrafloral/worldlistfamilies.htm) to attract ants, whose presence leads to an indirect defence against herbivores (Chamberlain & Holland 2009, Heil 2008, Heil & McKey 2003, Rico-Gray & Oliveira 2007). Although termed ‘extrafloral’ because the nectar is not involved in pollination, EFN can also be secreted within the inflorescences (Bentley 1977, Holland et al. 2010, Martins 2009). Because ants tend to defend reliable food sources against all types of putative competitors, it has been hypothesized that the presence of extrafloral nectaries close to flowers may lead to competition among ants and pollinators, or even to direct ant–pollinator conflicts. Such antagonistic interactions would reduce the access of pollinators to flowers and, thereby, may cause significant ‘ecological costs’ of indirect, ant-mediated defences (Heil 2002).

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Catalpa bignonioides alters extrafloral nectar production after herbivory and attracts ant bodyguards

Oecologia ◽

10.1007/s00442-002-1110-6 ◽

2003 ◽

Vol 134 (2) ◽

pp. 210-218 ◽

Cited By ~ 82

Author(s):

J. Ness

Keyword(s):

Extrafloral Nectar ◽

Nectar Production

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Genetic and clonal diversity of the endemic ant-plant Humboldtia brunonis (Fabaceae) in the Western Ghats of India

Journal of Biosciences ◽

10.1007/s12038-010-0031-5 ◽

2010 ◽

Vol 35 (2) ◽

pp. 267-279 ◽

Cited By ~ 6

Author(s):

Suma A. Dev ◽

Megha Shenoy ◽

Renee M. Borges

Keyword(s):

Western Ghats ◽

Clonal Diversity ◽

Western Ghats Of India ◽

Humboldtia Brunonis ◽

The Western Ghats

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Seasonal Extrafloral Nectar Production by Laguncularia racemosa (L.) C.F. Gaertn (Combretaceae) in Southeast Brazil

International Journal of Botany ◽

10.3923/ijb.2011.122.125 ◽

2010 ◽

Vol 7 (1) ◽

pp. 122-125 ◽

Cited By ~ 2

Author(s):

Ronaldo Bastos Francini ◽

Elaine dos Santos Rovati

Keyword(s):

Laguncularia Racemosa ◽

Extrafloral Nectar ◽

Nectar Production ◽

Southeast Brazil

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Extrafloral nectaries in Combretaceae: morphology, anatomy and taxonomic significance

Bothalia ◽

10.4102/abc.v34i2.426 ◽

2004 ◽

Vol 34 (2) ◽

pp. 115-126 ◽

Cited By ~ 5

Author(s):

P. M. Tilney ◽

A. E. Van Wyk

Keyword(s):

Species Level ◽

Extrafloral Nectaries ◽

Small Cells ◽

Extrafloral Nectar ◽

Taxonomic Significance ◽

Sugar Composition ◽

Separate Species ◽

The Family

Extrafloral nectaries (EFNs) in members of the Combretaceae are nectaries not involved with pollination and occurring on vegetative structures; they are believed to attract ants to protect plants against herbivorv by other insects. In the Combretaceae EFNs are reported in species of Terminalia L. and Pteleopsis Engl., putative EFNs in Meiostemon Exell Stace and Quisqualis L., and an absence of EFNs in Combretum Loefl. and Lumnitzera Willd. EFNs in the family are generally spherical in shape and may be raised, level with the surface or somewhat concave. They are similar in the Terminalia and Pteleopsis species where they display varying degrees of internal zonation and are composed of small cells; those species observed in the field were all found to have functional EFNs. In Meiostemon tetrandrum (Exell) Exell Stace, Quisqualis indica L.. Q. littorea (Engl.) Exell and Q. paviflora Gerrard ex Sond.. apparent EFNs lack internal zonation and are composed of enlarged cells; confirmation is required as to whether these are functional . The formation of EFNs appears to be highly flexible. They are usually essentially associated with new growth but their occurrence is sporadic and they do not appear on every leaf or every' branch of a plant. The distribution of EFNs on leaves, when present, is of taxonomic significance to separate species of Pteleopsis and Terminalia: otherwise the presence or absence and distribution of EFNs are too variable and sporadic in occurrence to be of taxonomic significance at the species level. Indiscriminate use of the terms gland and domatium instead of EFN. and possible confusion with damage caused by other organisms, has probably contributed to many of these structures not previously being recorded as EFNs. Floral and extrafloral nectar samples of T. phanerophlebia Engl. Diels differed in sugar composition.

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