Biology Reference
In-Depth Information
Leonhard, 1997; Hrassnigg et al., 2003). Proline obtained from plant nectars
by honeybees may also regulate the secretion of invertase that is required for
conversion of nectar to honey (Davies, 1978). Haemolymph proline is selec-
tively degraded during the initial stages or lift phase of flight (Brosemer &
Veerabhadrappa, 1965; Micheu et al., 2000). The metabolism of proline pro-
duces 71% of the levels of ATP that are produced by glucose. However, the
initial steps of glucose metabolism require the consumption of ATP, while
metabolism of proline does not. Thus, proline is a more efficient fuel in the
short run, while glucose is a far superior fuel in the long run. The accumula-
tion of both glucose and nectar presents insects with a dual action fuel:
proline for rapid, short-term bursts of energy production and a large amount
of glucose for extended flight (Carter et al., 2006).
Also deserving special mention is phenylalanine, the most abundant
amino acid in the nectars of 73 mainly bee-pollinated Mediterranean plant
species sampled by Petanidou et al. (2006). (Unfortunately, proline could not
Figure 2.
Possible stimulation of insect chemoreceptors by amino acids in various plant nec-
tars:
Gossypium hirsutum
(Hanny & Elmore, 1974);
Impatiens sultani
extrafloral nectar
(Smith et al., 1990);
Sarracenia purpurea
pitcher extrafloral nectar (Dress et al., 1997);
Lotus corniculatus
,
Trifolium pratense,
Scabiosa columbaria
(Rusterholz & Erhardt,
1998);
Agrostemma githago
(Gardener & Gillman, 2001b);
Glycine tomentella
,
Gly-
cine canescens,
and
Nicotiana langsdorffii
×
N. sanderae
var. LxS8 (Carter et al., 2006).
