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and the queens continue to feed and gain weight for an additional two
days. Worker larvae are capped on the sixth day without surplus food
and lose weight when they spin their cocoon before pupation.
Until the fourth instar, queens and workers both have a full comple-
ment of ovariole primordia (clusters of cells that develop into ovarioles
in the pupal stage), enough to make 300 or more ovarioles. Elevated ti-
ters of JH in queens probably initiate changes in target tissues and
prime specii c tissues for worker-queen dif erentiation in response to
ecdysteroids, important growth hormones of insects. In addition, JH
protects the ovarioles from programmed cell death that begins in the
fourth and i t h larval instars, as shown by Ines Schmidt Capella and
Klaus Hartfelder. Programmed cell death is a normal part of develop-
mental processes where cells that are no longer needed, or are needed
for structure but do not need to be living cells, undergo programmed
death. In queens, most of the 300 or so ovarioles are rescued, while
most of them fail in workers. In the mid- to late i t h instar, an increase
of JH occurs in both workers and queens, resulting in an increase in
ecdysteroid hormones, and initiates metamorphosis and dif erentiation
between the worker and queen phenotypes.
It appears that the queen phenotype is the default. It is the easiest for
the workers to achieve when one considers the requirements. All that is
needed is to provide a large cell with food in excess and add sugar. h e
sugar in royal jelly is composed of fructose, glucose, and a small amount
of sucrose. Fructose is the majority sugar and is what is found in most
nectar and honey. It makes sense that development would be sensitive
to this nutritional component that is central to honey bee survival. To
make a worker requires the orchestration of a complex feeding pro-
gram: reduce sugar, feed unlimited food for two days and then regulate
(restrict) it, increase sugar content of food in the fourth instar, and
starve for the i nal day before moulting.
8.2 Nurses and Larvae Share Developmental Programs
Larval development is jointly controlled by the physiology and behav-
ior of the nurse bees and the developmental regulatory programs of
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