Biology Reference
In-Depth Information
2.5.7.3 Nectar and Pollen Load Sizes
Karl von Frisch won the Nobel
Prize in Physiology or Medicine in 1973 for his work on the dance lan-
guage of the honey bee (Figure 2.11). He did many wonderfully simple
but elegant studies of foraging behavior, looking at the economics of for-
aging, as well as the communication system of honey bees, and showed
that bees that are of ered higher concentrations of sucrose solutions col-
lect larger loads. h e rate at which a bee imbibes sugar solution is also
correlated with sugar concentration. If the solution is more concentrated,
they collect it faster at a feeder, and the food is transferred faster to a re-
ceiver bee back at the nest when the forager returns. Foragers that are
more responsive to lower concentrations of sucrose will forage at artii cial
feeders with a more dilute sugar solution than will less responsive bees.
Pollen and nectar loads are not independent. h e nectar load size of
foragers increases with the concentration of the nectar collected. h e size
of pollen loads decreases with an increase in nectar load. We collect bees
at the hive entrance as they return from foraging, take them into the
Figure 2.10.
Tactile learning. A honey bee shows conditioned proboscis
extension response during tactile antennal conditioning. Associative-learning
assays for honey bees are based on standard classical conditioning models where a
stimulus one wants them to learn is paired with a reward. Conditioning is based
on the forward pairing of the conditioned stimulus (CS) with a reward. In tactile
learning, harnessed bees have their vision occluded by black paint and are
presented with a small copper plate with etched grooves, the CS. h eir antennae
are naturally active, scanning their surroundings. When the antennae touch and
move over the plate, the bees get information about the characteristics of the plate
from hairlike mechanoreceptors located on the tips of the antennae. At er the bee
scans for a few moments, a droplet of sucrose solution (of sui cient concentration
to exceed its response threshold) is touched to the antenna, an unconditioned
stimulus (US), eliciting a proboscis extension response. With the proboscis
extended, a droplet of sucrose is touched briel y to the tip of the proboscis, the
reward, and the bee is allowed to imbibe a small quantity. h e brass plate is then
withdrawn. h e sequence thus is CS-US-reward. h is sequence is repeated for a
number of trials. Usually at er a single or a few trials, the bee will respond by
extending the proboscis when it is presented only with the target; the US is no
longer needed. Photos by Jochen Erber. Reprinted from Page and Amdam 2007,
“h e making of a social insect: developmental architectures of social design,”
Bioessays
29:334-343, Fig. 2, with permission from John Wiley and Sons, UK.
