Biology Reference
In-Depth Information
Mary Jane West-Eberhard. h e original manifestation postulated that
high- and low-strain bees were frozen in dif erent parts of a gonotropic
cycle of ancient origins in insects (Figure 7.3). Our thoughts were about
the mosquito, where newly emerged adults forage for nectar from l ow-
ers to sustain themselves with carbohydrates for energy and then
switch to foraging for protein by seeking blood meals. Associated with
this is a change in behavior and presumably a change is sensory sensi-
tivity. As protein foragers, mosquitos l y at dawn and dusk and orient
to infrared radiation and carbon dioxide. At er females take a blood
meal, they seek low, dark places where they sit, digest their food, and
make vitellogenin and eggs. When they have an egg load, they l y again
and seek water vapor, where they lay their eggs on the water. h en they
begin the cycle again. Our original, naive idea for the honey bee was
that nectar foragers were stuck in the carbohydrate self-maintenance
part of the cycle, while pollen foragers were stuck in the reproductive,
protein-foraging part. It is important to note that many insects appar-
ently do not cycle; instead, they display a sequence of ovary maturation
with accompanying changes in behavior with age.
Nectar Foraging
Oviposition
a
Self-Maintenance
b
Pollen Foraging
Reproduction
Figure 7.3.
Early conceptual model of the reproductive-ground-plan hypothesis.
Many insects change behavior as they cycle through reproductive states
involving the availability of eggs in the ovary. Oviposition resets the cycle. We
hypothesized for the honey bee that nectar foragers are stuck in stage
a,
while
pollen foragers are stuck in
b.
Although the actual situation is certainly not this
simple, the model provided testable hypotheses.
