SOYBEAN and BEES

• Nectar secretion via trichomes excludes an apoplastic transport for the respective species,
owing to apoplastic barriers in the external cells walls in the stalk and intermediate
cells of the trichomes (Fahn, 1988; Kuo and Pate et al., 1985);
• Vesicles are common in nectariferous tissues (Fahn, 1988; Kuo and Pate et al., 1985);
• Secreted nectars are characterized by a wide range of concentrations and sucrose: hexose
ratios (Baker and Baker, 1975; Baker and Baker, 1982) and, therefore, cannot be
produced only by a passive flow or transport mechanisms exclusively driven by sucrosecleaving
enzymes;
• Non-carbohydrates such as lipids and proteins are likely to be synthesized in the
nectariferous tissue and then must enter the prenectar before its secretion (Nicolson et
al., 2007; Kram et al., 2008);
• Nectar secretion depends on several fast-acting control mechanisms, which cannot result
solely from passive source sink relationships.
Bee general orientation
Generally speaking, when approaching blossoms, honeybees are firstly attracted by their
color and/or the form. These cues are then used for successful revisits. According to Hsu and
Young (2012), the bees receives visual cues through two types of parallel channels located
behind the retina. The first channel is used for colors; the other is a monochrome channel
directed to the orientation and edge of an item in their visual field. In the integration process
of these channels, the priority and interaction between them are significant, as these chromatic
and achromatic signals coexist naturally.
Hsu and Young (2012) trained bees to detect form and color, afterwards tested for its ability
to differentiate combinations of opposite patterns. The bees choose the correct color but the
wrong form pattern in the above experiment as well as for other manipulations. The effect of
the color training for the blue reward pattern differed from that of the green reward pattern.
The color pattern choices tended to be more correct if blue was the target during the training
process, indicating that the chromatic signal was the main cue in pattern discrimination.
The authors concluded that color tended to be the decisive factor in a conflicting situation.
In addition, the color blue was preferred over green, indicating that color preference was
involved in bees’ visual recognition.
Honeybee visitation to a flower can be considered a two stage process. At first involves
orientation from a larger distance and then, secondarily, close-range orientation during
which the bee alights and probes for nectar. Von Frisch (1967) established that bees are
66 SoybeAn and bees