Biology Reference
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the sense in which it is used in quantitative genetics, but it is a measure
of the degree of genetic determination. h is is how we compared bees
from the high- and low-pollen-hoarding strains.
5.2.2 h e Social Phenotype
We selected for a single trait, the amount of pollen stored in the comb—
pollen hoarding. h is is a colony-level, social trait that is a consequence
of the interactions of tens of thousands of individuals in the nest. For-
agers collect pollen and store it in the comb. Nurse bees consume the
pollen and convert the pollen proteins into glandular secretions that
they feed to larvae. Assume that a queen lays about 1,500 eggs per day
during spring and summer; that a worker lives for 6 weeks, for 1 week
of which she is a nurse bee and 3 weeks a forager; and that about one-
third of foragers collect pollen. Larvae are fed for about 6 days. With
these assumptions, a colony will consist of about 10,000 pollen forag-
ers, 10,000 nurse bees, and 9,000 larvae consuming pollen being pro-
cessed through the nurse bees. h e pollen foragers are engaged in as-
sessing the amount of stored pollen and the number of young larvae
being fed, foraging, and performing recruitment dances to engage
other foragers in pollen collecting. h us the amount of stored pollen is
the result of a highly interactive social, regulatory network (Figure 5.1).
Pollen is stored near the brood. h e amount of stored pollen is regu-
lated (see Section 1.2 and Chapter 9), which makes it an ideal pheno-
type for selection (Figure 5.2). h e regulation of stored pollen results in
high repeatability of measurements and consequently higher heritabil-
ity because there is less measurement error and environmental “noise”
associated with the phenotype. h e amount of stored honey is not reg-
ulated. Bees will continue to store surplus honey as long as there are
empty cells in combs and nectar is available; therefore, the heritability
is much lower and usually is not statistically signii cant. We estimated
the amount of pollen stored in the combs of colonies by examining in-
dividual frames of combs containing pollen. We placed a wire grid over
the combs and counted the number of grid squares covering the areas
of stored pollen, from which we estimated the total area of stored pol-
len in the hive (Figure 5.2).
