Biology Reference
In-Depth Information
long-tongued bees as a result of colonization by honeybees, although they
found no effect on short-tongued bees. In New Caledonia, unique systems of
pollination mutualism have been endangered by the introduction of honey-
bees (Kato & Kawakita, 2004).
Mediterranean habitats are known for their high solitary bee diversity
(O'Toole & Raw, 1991; Petanidou & Ellis, 1993; Michener, 2000; Petanidou
& Lamborn, 2005), which in turn is associated with high nectar niche diver-
sity, especially in low scrub systems (Potts et al., 2004). Because very few
Mediterranean species secrete copious nectar, with the majority producing
relatively little, invasions by bumblebees will affect the diversity of medium-
to long-tongued solitary bees negatively, as has happened in Israel (Dafni &
Shmida, 1996). Similarly, under the pressure of intense beekeeping it is ex-
pected that the diversity of solitary bees as a whole will decline. Introduced
bees are widespread, and because of this, deleterious effects are expected to
occur on a large scale, and in some areas may be irretrievably severe. In this
respect, areas managed almost solely by uncontrolled grazing (or rather,
overgrazing) and intense beekeeping, especially in the East Mediterranean,
are a priority risk (Rackham & Moody, 1992; Petanidou et al., 2001). They
encompass not only marginal and wild habitats, but also abandoned agricul-
tural lands, frequently terraced slopes, and hills that are nowadays
unprofitable for primary production. That these areas are frequently isolated,
and often on islands, may be an even worse omen (Roubik & Wolda, 2001).
REFERENCES
Adler, L.S. (2000a). The ecological significance of toxic nectar.
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Adler, L.S. (2000b). Alkaloid uptake increases fitness in hemiparasitic plant via reduced her-
bivory and increased pollination.
American Naturalist
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156
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Baker, H.G. (1977). Non-sugar chemical constituents of nectar.
Apidologie
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Baker, H.G., & Baker, I. (1973a). Amino acids in nectar and their evolutionary significance.
Nature
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Baker, H.G., & Baker, I. (1973b). Some anthecological aspects of the evolution of nectar-
producing flowers, particularly amino acid production in nectar. In: V.H. Heywood (Ed.),
Taxonomy and ecology
(pp. 243-264). London: Academic Press.
Baker, H.G., & Baker, I. (1978). Chemical aspects of the pollination biology of woody plants
in the tropics. In: P.B. Tomlinson, & M.H. Zimmermann (Eds.),
Tropical trees as living
systems
(pp. 57-83). Cambridge: Cambridge University Press.
Baker, H.G. & Baker, I. (1982). Chemical constituents of nectar in relation to pollination
mechanisms and phylogeny. In: M.H. Nitecki (Ed.),
Biochemical aspects of evolutionary
biology
(pp. 131-172). Chicago: University of Chicago Press.
Baker, H.G. & Baker, I. (1983). Floral nectar sugar constituents in relation to pollinator type.
In: C.E. Jones, & R.J. Little (Eds.),
Handbook of experimental pollination biology
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