Les abelles, a l'igual que les persones i altres animals, comparteixen els mateixos trets distintius de les emocions negatives. L'estrés, la depressió i l'ansia són presents també en l'estat d'ànim de les abelles, com una propensió a veure l'ampolla mig buida. Els investigadors de la Universitat de Newcastle van arribar a aquesta conclusió després de sotmetre a diferents grups d'abelles a situacions agradables i adverses. Les abelles "maltractades" es mostraven més hostils i una predisposició més negativa a la captació de les sensacions gustatives i olfactòries de les recompenses ofertades pels investigadors.
We have shown that the emotional responses of bees to an aversive
event are more similar to those of humans than previously thought,"
said Geraldine Wright of Newcastle University. "Bees stressed by a
simulated predator attack exhibit pessimism mirroring that seen in
depressed and anxious people."
"In other words," added study first author Melissa Bateson, "the stressed bee's glass is half empty."
But, they say, that isn't the same as saying that bees consciously
experience emotions in the way that we do. On that point, the jury is
still out.
To find out how bees view the world, the researchers set them up to
make a decision about whether an unfamiliar scent portended good or bad
things. First, the bees were trained to connect one odor with a sweet
reward and another with the bitter taste of quinine. The bees learned
the difference between the odors and became more likely to extend their
mouthparts to the odor predicting sugar than the one predicting quinine.
Next, the researchers divided the bees into two groups. One group
was shaken violently for one minute to simulate an assault on the hive
by a predator such as a honey badger. The other group was left
undisturbed. Those bees were then presented with the familiar odors and
some new ones created from mixes of the two.
Agitated bees were less likely than the controls to extend their
mouthparts to the odor predicting quinine and similar novel odors, the
researchers found. In other words, the agitated bees behaved as if they
had an increased expectation of a bitter taste, the researchers said,
demonstrating a type of pessimistic judgment of the world known as a
"cognitive bias."
"What we have shown is that when a honeybee is subjected to a
manipulation of its state that in humans would induce a feeling of
anxiety, the bees show a similar suite of changes in physiology,
cognition, and behavior to those we would measure in an anxious human,"
Wright said. "In terms of what we are able to measure, a shaken
honeybees is no less 'anxious' than a lonely dog or a rat in a barren
cage."
The researchers say they don't expect the findings will be unique to
honeybees among invertebrates. They would in fact expect to see the
same thing in any animal that needs to change its behavior in the face
of potential dangers.
The findings suggest that it may be possible to study bees as a
model for emotion in invertebrates. "If some scientific research on
emotion could be conducted in insects, this would lead to a reduction
in the numbers of sentient vertebrate animals used in research,"
Bateson said. "Thus our research potentially has important implications
for animal welfare."
Science Daily
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