Bee discovery may improve patient post-operative care
A University of Auckland study that proves bees navigate by building mental maps of familiar terrain has the potential
to improve post-operative care of patients.
Auckland scientists, Dr James Cheeseman, Dr Guy Warman and Dr Craig Millar have solved a long-standing biological
question about how honey bees navigate that has international implications.
It is already known that mammals navigate using cognitive maps – continuous mental maps of familiar terrain created
through experience and continually referenced and updated.
Until now, it was unclear whether insects also navigated in the same way or by different means. For decades it was
assumed bees navigated their way back to the hive by sun-compass.
The Auckland study team, led by Dr Cheeseman, from the University’s Faculty of Medical and Health Sciences and in
collaboration with neurobiologist Dr Randolf Menzel from the Free University of Berlin, tested the theory that displaced
bees rely only on the remembered direction home from familiar landmarks, referenced to the sun’s position.
“We reasoned that if bees relied on the sun to navigate, then a circadian shift should disrupt the bees’ ability to
locate their hive after release,” says Dr Cheeseman.
They caught the honey bees and anesthetised them for six hours, to shift their circadian clocks. Miniature transponders
were fixed to each bee’s thorax to enable the bees to be radar tracked from release.
“Initially clock-shifted bees tried to use their sun compass, but realised their mistake and were able to navigate back
to the hive as quickly as the control group bees,” says School of Biological Sciences, senior lecturer Craig Millar.
It had been assumed that the bee brain was too small to have a cognitive map, because it did not have enough neurons to
perform computational tasks.
“By giving the bees the equivalent of jet-lag for a couple of hours that tricked them into thinking it was a different
time of day, we were able to show that despite making a predictable mistake in direction on leaving the release site,
they quickly corrected the angle,” says Dr Cheeseman.
“The bees don’t get lost, so they must have a backup system for navigation as well as using landmarks to get back to the
hive – they are using a cognitive map to integrate their position,” he says. “They worked out where they were and within
a few hundred metres had corrected their direction and got back to the hive, just as fast as the control group.”
One aspect of the study was to look at how anaesthetic may shift or disrupt the circadian clock and how that may cause
post-operative sleep disruption in patients.
“This study funded by the Royal Society’s Marsden Fund is part of a broader programme of work, to learn how anesthetics
clock-shifts the human biological clock and induces jet-lag like symptoms,” says Dr Cheeseman. “Our research also uses
mammal models and clinical trials to see to what extent anesthetics disrupts the circadian clock.”
“We are looking at the effect of anesthesia on the circadian clock and how it impacts on navigation by honey bees, and
relating that to anesthesia in clinical situations for humans.”
These findings have implications for surgery and the impact anesthesia has on causing post-operative sleep problems in
people.
“If we can stop that happening, we might decrease hospital and recovery time for patients suffering from post-operative
fatigue and circadian disruption,” he says.
The study findings were published this week in the journal, Proceedings of the National Sciences of America (PNAS) and were reported internationally online this week.
ENDS