Biology Reference
In-Depth Information
Chapter 8
ECOLOGICAL AND EVOLUTIONARY ASPECTS
OF FLORAL NECTARS IN MEDITERRANEAN
HABITATS
THEODORA PETANIDOU
Laboratory of Biogeography and Ecology, Department of Geography, University of the Aegean,
81100 Mytilene, Greece
1
NECTAR SECRETION IN MEDITERRANEAN
HABITATS
Owing to its superb sweet taste, nectar has, since antiquity, been considered
the drink of the gods, which underlines its importance as a major daily al-
lurement for insects to visit flowers. This is because nectar is the major
source of energy to pollinators, providing them with sugars, other nutritious
substances such as amino acids, and possibly minerals. Furthermore, nectar
generally constitutes the only form of water intake for such pollinators.
Unlike pollen, the other prime reward for pollinators, nectar functions
solely as a reward and secretion can continue after its removal (Proctor et al.,
1996). Even if the magnitude of its importance has been questioned for some
areas like the Mediterranean (Herrera, 1985; Petanidou & Vokou, 1990;
Petanidou & Lamborn, 2005), nectar still constitutes an irreplaceable and
unique attractant for pollinators within flowering plant communities (Proctor
et al., 1996), and as such is likely to be subject to selection pressures imposed
by pollinators (Petanidou, 2005; Petanidou et al., 2006). Consequently,
nectar may differ greatly among phylogenetically related plants pollinated
by different animals (Pyke & Waser, 1981; Baker & Baker, 1982), even
though genetic (Percival, 1961; Baker & Baker, 1983) and ecological con-
straints (Corbet, 1990; Petanidou & Smets, 1996; Petanidou et al., 1999, 2000;
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