Biology Reference
In-Depth Information
7
6
5
Pollen-Foraging Threshold
4
3
Foraging Threshold
2
1
0
0
5
10
15
20
25
30
35
Age (Days)
Theoretical Nectar-Forager
Trajectory
Knockdown Phenotype
Initiated
Vg-Knockdown Trajectory
Theoretical Pollen-Forager
Trajectory
Figure 7.5.
A model for the action of Vg in foraging division of labor. Very
young bees are unable to forage. h ey must pass through an initial maturation
phase during which l ight muscles develop and the cuticle hardens. During this
phase (gray) workers are primed for their future foraging specialization by titers
of the protein vitellogenin (Vg). Vg titers above the pollen threshold prime
workers for pollen foraging (dark gray), while workers with lower preforaging
titers (light gray) are primed for nectar foraging. In workers, Vg suppresses the
transition from nest tasks to foraging activity when its titer remains above the
foraging threshold level. Below this threshold, the probability of initiating
foraging is increased. h is model explains the Vg-knockdown phenotype
observed by Nelson and colleagues (Section 7.5.2). Ribonucleic acid
interference-mediated knockdown of vitellogenin results in workers that mature
with vitellogenin titers that are below both the pollen and foraging thresholds.
h ese workers forage precociously and preferentially collect nectar. From Nelson
et al. 2007. “h e gene vitellogenin has multiple coordinating ef ects on social
o r g a n i z a t i o n . ”
PLoS Biology
5(3): e62, doi: 10.1371/journal.pbio.0050062,
673-677, Fig. 5.
