Extranuptial nectaries inCarapaAubl. (Meliaceae-Cedreloideae)

David Kenfack,Mathieu Gueye,Maurice Tindo

doi:10.5252/a2014n2a13

David Kenfack, Mathieu Gueye + Show 1 more

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https://doi.org/10.5252/a2014n2a13

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Journal: Adansonia	Publication Date: Dec 1, 2014
Citations: 4	License type: publisher-specific-oa

Affiliation: Smithsonian Institution, ForestGEO, University of Douala

Abstract

Ant-plant interactions mediated by special structures provided by plants such as domatia, extrafloral nectaries (EFNs) and food bodies, are very frequent in tropical ecosystems. To understand why ants are frequently encountered on most species of Carapa Aubl. (Meliaceae), we investigated the presence of extranuptial nectaries (ENNs) in all 27 species of the genus, spanning its entire distributional range in tropical Africa and America. We report for the first time in the genus the occurrence of extrafloral nectaries (at the base of the petiole, along the rachis of the pinnately compound leaf, on bracts) petaline nectaries (on the outer surface of petals), and pericarpial nectaries (on the surface of fruits), and confirm the presence of nectaries on leaflets in Carapa. Petiolar nectaries are the most common, occurring in 85% of the species. Nectaries were mainly active in young developing plant organs. Ants were observed foraging on exudates from these nectaries. The secretions from these glands help to explain the abundance of ants on Carapa trees. Although similar nectaries were also found in other members of the subfamily Cedreloideae, their position and frequency provide new characters for the identification of Carapa species in the field and the herbarium. As in other myrmecophilous plants, ENNs probably confer adaptive advantages to Carapa trees.

Highlights

Mutualistic interactions between plants and ants have developed probably since the mid-Cretaceous and are today very common, ranging from facultative non-specific relationships to obligatory specific and symbiotic associations (Hölldobler & Wilson 1990; Bronstein 1998; Solano & Dejean 2004)
EXTRANUPTIAL NECTARIES IN CARAPA extranuptial nectaries (ENNs) in Carapa include extrafloral nectaries (EFNs) on leaves, petaline nectaries on flowers and pericarpial nectaries in fruits (Fig. 2)
Petiolar nectaries occur on the abaxial surface of the swollen base of the petiole in 23 (85%) of the Carapa species examined. eir morphology varies among species, from pit (Fig. 1E) to flattened (Fig. 2D) or elevated (Fig. 1G)

Summary

INTRODUCTION

Mutualistic interactions between plants and ants have developed probably since the mid-Cretaceous and are today very common, ranging from facultative non-specific relationships to obligatory specific and symbiotic associations (Hölldobler & Wilson 1990; Bronstein 1998; Solano & Dejean 2004). Plant-produced rewards include domatia (hollow structures), food bodies (Fiala et al 1989; Dutra et al 2006), and extranuptial nectaries (Oliveira 1997; Koptur 2005), which are the focus of this paper. ENNs have been reported in over 4000 species of vascular plants, belonging to 745 genera and 113 families (Zimmermann 1932; Elias 1983; Koptur 1992; Keeler 2008). Ey may occur on leaflet surfaces, petioles, rachis, petals, sepals or fruits (Zimmermann 1932; Lersten & Rugenstein 1982; Elias 1983 ; Lersten & Pohl 1985; Schupp & Feener 1991; Puri 1999; Blüthgen & Reifenrath 2003; Mody & Linsenmair 2004; Díaz-Castestelazo et al 2004). In this paper, based on field observations and herbarium studies, we provide evidence of the presence of ENNs on numerous plant parts in Carapa. We focus only on the morphology and typology of the nectaries, without any histological or physiological scope, and include all 27 species currently recognized in the genus

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DISCUSSION