Biology Reference
In-Depth Information
captured, feral AHB colonies for comparisons. Defensive behavior was
measured by waving a 5-by-6-centimeter black leather patch at the end
of a meter stick in front of the entrance. h e time it took for the i rst bee
to sting the patch and the total number of stingers in the patch at er
one minute were recorded (Figure 3.7). Worker honey bees have barbed
stingers and leave the sting apparatus and their intestines behind when
they sting, the ultimate self-sacrii ce. Dark colors and movement are
both stimuli that release stinging behavior in bees.
Africanized colonies (100 percent AHB) responded eight times faster
and deposited more than i ve times as many stings as European colo-
nies. h is was consistent with the i ndings of many other studies. We
would expect the hybrid colonies where workers had EHB mothers and
AHB fathers (50 percent Africanized) to be intermediate in response,
but the hybrid colonies gave nearly the same defensive behavior re-
sponse as AHB colonies, demonstrating genetic dominance for the
AHB high defensive behavior trait. Times to sting the patch for the
colonies with 25 percent hybrid bees were signii cantly faster than ex-
pected on the basis of genetic dominance and the genotypic mixture of
bees, demonstrating behavioral dominance for that trait. Stingers were
removed from the patches and analyzed for enzyme markers. h e EHB
and AHB fathers used to instrumentally inseminate the EHB queens
had distinct genetic (allozyme) markers. We could distinguish which
stingers came from EHB and which came from EHB X AHB hybrid
crosses. Africanized hybrid stingers were always overrepresented rela-
tive to the proportional representation of workers in the hive, which
suggests that the original owners of the stingers had lower response
thresholds to the dark color and movement. As the proportion of AHB
increased in hives, the number of stingers increased, and more EHB were
stimulated to sting. When a worker stings, she releases an alarm phero-
mone composed primarily of isopentyl acetate. h is compound smells
like banana oil and is a strong releaser of stinging behavior. By stinging
the patch, the bees altered the stimulus environment and the behavior
of their nestmates, making them more likely to respond and sting—a
correlation between the response and the stimulus environment.
