by Whit Gibbons
August 8, 2004
are amazing creatures in many ways. We know this because of the excellent
research by behavioral scientists and geneticists who have learned so
much about them. Especially intriguing are the colonial attributes of
honeybees, in which the workers, all females, will defend their colony
to the death, communicate with each other about where the nearest pollen
is, and tend the hive and developing young. Males (aka drones) are viewed
almost as a by-product whose sole function is to mate with the queen.
But a recent study in Australia (honey bees have been introduced on every
warm continent) indicates that which particular males breed with the queen
can make a difference in how hive temperature is controlled.
Being social insects, honeybees operate in a super-organism mode, each
individual operating in the best interest of the hive. Thus, members of
the colony operate in unison to maintain the hive as close to the preferred
temperature of 95 degrees as possible. In hot weather the bees wave their
wings to cool the hive. In cold weather they warm the hive by huddling
together to generate heat from their bodies. As environmental temperatures
may rise or fall slowly or rapidly, depending on the season and local
weather conditions, honeybees must be in a constant state of readiness
to act as a group to raise or lower the temperature in the hive.
by Julia C. Jones and colleagues at the University of Sydney was an impressive
mix of behavioral observations and DNA analyses demonstrating that multiple
matings by the queen, rather than the choice of only a single drone to
mate with, are in the best interest of the hive. The experiments were
conducted on pairs of hives having the same number of bees but differing
genetically. One hive consisted of worker bees that were all the offspring
of a single queen and single drone. The behavior of the hive with uniform
genetic parentage was compared to that of another in which the queen had
had multiple mates. Hence the workers in the second hive were of mixed
researchers found in regard to temperature regulation was that worker
bees in both hives maintained the hive temperature at the preferred temperature.
However, they differed in that the temperature over time in the mixed
genetic hive was relatively invariable compared to the uniform genetic
hive. In other words, the uniformly genetic individuals eventually got
the hive to the proper temperature but their response time lagged behind
that of the genetically diverse hive.
for the differing responses is that individual bees, just like people,
vary in their internal thermostats. That is, some individuals will take
action to regulate their surrounding temperature when their body is slightly
warmer or cooler than that to which another individual might respond.
We see this all the time in office buildings and other places where groups
congregate. Someone always thinks the room is too cold or too hot in contrast
to another who thinks the opposite. Bees are apparently the same way,
although their focus is on what is best for the hive, not themselves as
are genetically similar, they are more likely to respond to a need to
begin "regulating the thermostat of the hive" at the same temperature.
This means they all begin to operate at about the same time. In the genetically
diverse hive, individuals respond at different temperature levels. Thus
some begin the cooling process of fanning the hive on a hot day at slightly
lower temperatures than other individuals that pick up the call to duty
a little later. The temperature of a hive is kept at a more uniform level
because individual bees are responding across a wider gradient of temperatures.
To confirm the relationship between genetics and behavior, the researchers
did DNA tests in a mixed genetic hive. They removed some workers that
began fanning at one temperature and some that began fanning at other
temperatures. Sure enough, individuals that began fanning at a given temperature
were more likely to have the same father than those fanning at other temperatures.
findings are indeed captivating. But consider the scientific complexity
involved in conducting such a study. The scientists are as impressive
as the bees.
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