Biology Reference
In-Depth Information
matings, and the fact that a queen stores roughly 5 to 6 million sperma-
tozoa in her spermatheca, while individual males produce about 6 mil-
lion. However, it was subsequently shown that queens mate with many
males. h erefore, a colony consists of a large number of subfamilies of
workers because potentially all the fathers contribute sperm to the eggs
of the queen (Figure 3.2). Worker honey bees with the same father share
75 percent of their genes in common (they are called super sisters be-
cause they inherit the entire genome of the father), while diploid species
share just 50 percent (full sisters). Half sisters of diploid species share
just 25 percent of their genes in common, the same as half sisters of
haplodiploid species.
Beginning in the 1950s, many believed that the sperm loads of the
dif erent males clumped together in the spermatheca and were not uni-
formly distributed. Researchers thought that the sperm were used in
batches belonging to individual males. If this were true, it would reduce
the number of subfamilies in a colony and the amount of genetic varia-
tion at any given time. One argument for sperm clumping was based
on the observation that spermatozoa in a dissected, full spermatheca
appear to be arranged in “whorls” when they are viewed under a mi-
croscope, giving the appearance that they had entered in bundles, like
packages of spaghetti.
h e other main piece of evidence used to support the sperm-clumping
idea was an article published in the mid-1950s by Stephen Taber. He
raised virgin queens that were homozygous for a recessive mutation,
called cordovan, that changes the black color of the bee to a light
brownish color. h e head, antennae, thorax, and legs of honey bees are
normally black, but the abdomen may be striped with yellow and
black. Dif erent strains of bees found in dif erent parts of Europe, the
evolutionary home of the bees that were originally brought into North
America, vary in the amount of yellow found on the abdomen. He put
the queens in small hives, called mating nuclei, where they made mat-
ing l ights and mated with the males from hives in the general vicinity.
Some of the males were sons of other queens that carried the mutation,
while others were wild type. h e of spring of a cordovan male were eas-
ily distinguished by their color; those of wild-type males were black
