Biology Reference
In-Depth Information
3. Ge ne tic ef ects on the sensory-response system are stronger than
on foraging behavior. h is was expected because the sensory responses
lie between the action of genes and the behavior of the bees.
4. h e correlations between the causal links are mostly weak. h e
correlation between ovariole number and vitellogenin is not expected
to be strong because Vg titers are dynamic and, therefore, are subject to
large l uctuations depending on when they are measured during the
life history of the bee. h e model presented in Figure 7.5 suggests that
Vg in some way sets the system during a window of time soon at er
bees become adults; at erward, the response system is independent of
current blood titers. h e ef ect of Vg must work like this because forag-
ers have very little circulating Vg. h e correlation between Vg and su-
crose response suf ers the same dii culty, with the added problem that
sucrose responsiveness changes with age, perhaps because of declining
Vg and increasing JH, and nutritional state. h e relatively high correla-
tion between sucrose response and the concentration of nectar col-
lected in the i eld is, therefore, surprising if one considers how variable
and unpredictable the foraging environment can be on an hour-to-
hour basis. h e relatively low correlations of nectar load to nectar con-
centration and pollen load to nectar load are not surprising, given the
changing and unpredictable foraging environment.
9.3 Social Regulation of Pollen Hoarding
How can genotype (strain) explain so much of the phenotypic variation
at the colony level (stored pollen) and so little at the individual foraging
level? h e answer, of course, is captured by Maurice Maeterlinck's spirit
of the hive. It is a consequence of the stimulus-response relationships of
thousands of individuals who alter the stimulus environment through
their individual actions (Figure 9.3). Foragers collect loads of pollen
and nectar according to a loading algorithm that is determined by their
sensory-response system and stimuli from the nest and foraging envi-
ronment. h e pollen they collect contributes to the pollen intake of the
colony, which gets stored as pollen, consumed, and converted into brood.
Stored pollen is a negative pollen-foraging stimulus, while larvae provide
