Biology Reference
In-Depth Information
Queen and worker larvae are fed proteinaceous secretions from hypo-
pharyngeal glands in the heads of the nurse bees. Food fed to queens is
ot en called royal jelly, while food fed to workers is called worker jelly.
Most of the proteins produced by the hypopharyngeal glands of nurse
bees belong to a family called major royal jelly proteins. h e glandular
food appears to be the same for worker jelly and royal jelly, except that
more sugar is added to the queen food initially.
Here it is important to note that for decades apicultural researchers
have led a quest to i nd a special substance that is added only to the food
of queens that is responsible for “unlocking” a developmental program
or throws a developmental switch that results in the production of the
queen phenotype. h is quest has had many twists and turns. h e most
recent special substance, royalactin, was proposed by Masaki Kamu-
kura to be one of the major royal jelly proteins found in brood food. In
an elegant study, he showed that royalactin is necessar y to make a queen.
However, although it may be necessary for developing a queen, it does
not qualitatively dif erentiate queen from worker development because
it is fed in the same proportion to developing worker larvae. Today, at er
at least 60 years of the quest, the only consistent and independently con-
i rmed result is that the food of worker and queen larvae dif ers in the
amount of sugar it contains.
Gene Robinson and I, along with his student Naomi Arensen, stud-
ied the feeding behavior of individual nurse bees when they had a
choice to feed worker or queen larvae. We found that individuals
switched readily between the two larval types in successive feeding
bouts. I i nd it dii cult to believe that individual nurse bees, with thou-
sands of larvae to feed, dif erentially control the composition of the
glandular secretions they feed to queen and worker larvae in successive
feeding bouts. It is easy to believe that nurse bees dif erentially add nec-
tar or honey (sources of sugar) to the food of queen and worker larvae.
Sugar acts as a phagostimulant, causing the larvae to eat more, but it
also probably increases metabolism and the production of juvenile hor-
mone (JH), a growth-regulating hormone found in all insects. During
the i rst two days of larval development, the queen larvae respond to the
extra sugar in their food with elevated respiration but do not grow faster
