Biology Reference
In-Depth Information
h e experiment discussed in the preceding paragraph only sug-
gested that the hybrid bees were more responsive to stimuli that release
stinging behavior. An alternative explanation is that they were more
likely to be guard bees at the entrance, and, therefore, more of them en-
countered sting-inducing stimuli. Guard bees sit at the entrance and
respond to stimuli, releasing an alarm pheromone that recruits bees
engaged in other activities into the task of colony defense. We collected
guards at the entrance to see whether AHB X EHB hybrids were more
likely to guard. We found no dif erence in the likelihood that an EHB or
a hybrid performed guard duty. Hence, they dif ered in their responses
to the sting-releasing stimuli.
3.8 Behavioral Plasticity and Colony Resilience
Colonies need to be able to respond to changes in the environment.
Behavioral l exibility of individual bees leads to the resilience of colonies,
the ability to respond and return to a “normal” state. So how plastic is
behavior, and how resilient are colonies to perturbation?
3.8.1 h ermal Regulation
Gene Robinson and I proposed that colony plasticity and resilience
could occur as a consequence of polyandry and genetic variation of
response thresholds of individuals. A broad distribution of response
thresholds might result in more appropriate, graded responses of col-
onies to perturbations of the stimulus environment (Figures 2.4C and
2.4D). Bees regulate the temperature of the brood nest where the
eggs, larvae, and pupae reside. When the temperature exceeds about
35 degrees Celsius, the bees collect water and initiate fanning, setting
up an evaporative cooler. When the temperature falls below 35 de-
grees Celsius, they cluster around the brood, providing insulation, and
vibrate their wing muscles and generate heat. If a colony is subjected
to an increasing ambient temperature, rather than all individuals
immediately initiating foraging for water and ventilating, it might be
best if those with the lowest response thresholds to elevated temper-
