June 3, 2016
Fish that are bred to be bolder
or more shy show corresponding changes to their body shape and locomotion,
suggesting that personality changes affect other seemingly unrelated traits.
The findings could be useful in animal breeding, pest management and studies of
complex human behaviors.
In a study performed by North
Carolina State University researchers, zebrafish that were bred to be more
bold—quantified by the shorter amount of time they remained motionless when
placed in new surroundings—displayed a sleeker body shape and
an ability to dart around the water more quickly when startled than those bred
to be more shy.
Brian Langerhans, an assistant
professor of biological sciences at NC State and a senior author on a paper
describing the study, says the research could help scientists learn about the
connectedness of what seem to be disconnected animal traits.
"Complex behaviors, like the
behaviors we call 'personality' or 'temperament,' can be associated—genetically
correlated—with other traits that one might think are independent of such
behaviors, like body shape and swimming abilities," he said. "In
other words, traits that seem unrelated may not be unrelated."
In the study, the researchers
used zebrafish lines that had been selected to be bolder by breeding fish that
stayed still for a maximum of 50 seconds after being introduced into new
surroundings, while shy fish—those that stayed still for more than 3 minutes
when dropped into a new area—were bred to create a shy line.
After just a few generations with
these breeding regimens, the researchers began to see interesting changes to
the different fish lines. Not only did a range of behaviors associated with
stressful situations change, but bold fish lines also displayed a more elongate
body with a larger tail region and generated higher velocity and acceleration
during fast-start startle responses. Shy fish lines had less sleek bodies and
slower startle responses.
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