After the isolation period, inspection trials were conducted in an
apparatus similar to that of Dugatkin & Alfieri (1991) (Fig. 2). The guppies
that occupied the side tanks during the initial preference test were allowed to
inspect in the longitudinal half of a 76 l tank; the rest of the aquarium was
blocked by a clear glass partition to keep the inspectors closer to the observer.
The predator occupied a separate tank adjacent to the inspection apparatus.
Initially, removable opaque partitions blocked both the inspectors and
the observer’s view of the predator as well as the observer’s view of the
inspector(s). Thus, neither the observers nor the inspectors could see the
predator nor could the observer and inspectors see each other prior to
the inspection trial.
Each trial began with a 15 min acclimatization period during which both
opaque partitions were in place. Following acclimatization, the opaque partitions
were lifted and the 2 min inspection trial began. To minimize the observer’s
inspection behavior, it was sequestered in a clear tube within a 9.5 l aquarium
adjacent to the inspection tank. A one-way mirror between the observer’s tank
and the other tanks allowed the observer to view the inspector(s) and the
predator, but not the reverse. The one-way mirror was tinted so that the
inspectors could not see their own mirror images and 60 W incandescent lamps
were hung at a 45 angle above the aquariums to facilitate viewing. The observers responded to both inspectors and predators, indicating that the one-way mirror
did not hinder their view. This design prevented observers and inspectors from
interacting and ensured that the predator would not focus on the observer instead
of the inspector(s).
After the isolation period, inspection trials were conducted in an
apparatus similar to that of Dugatkin & Alfieri (1991) (Fig. 2). The guppies
that occupied the side tanks during the initial preference test were allowed to
inspect in the longitudinal half of a 76 l tank; the rest of the aquarium was
blocked by a clear glass partition to keep the inspectors closer to the observer.
The predator occupied a separate tank adjacent to the inspection apparatus.
Initially, removable opaque partitions blocked both the inspectors and
the observer’s view of the predator as well as the observer’s view of the
inspector(s). Thus, neither the observers nor the inspectors could see the
predator nor could the observer and inspectors see each other prior to
the inspection trial.
Each trial began with a 15 min acclimatization period during which both
opaque partitions were in place. Following acclimatization, the opaque partitions
were lifted and the 2 min inspection trial began. To minimize the observer’s
inspection behavior, it was sequestered in a clear tube within a 9.5 l aquarium
adjacent to the inspection tank. A one-way mirror between the observer’s tank
and the other tanks allowed the observer to view the inspector(s) and the
predator, but not the reverse. The one-way mirror was tinted so that the
inspectors could not see their own mirror images and 60 W incandescent lamps
were hung at a 45 angle above the aquariums to facilitate viewing. The observers responded to both inspectors and predators, indicating that the one-way mirror
did not hinder their view. This design prevented observers and inspectors from
interacting and ensured that the predator would not focus on the observer instead
of the inspector(s).
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