Do Guppies Play TIT FOR TAT during Predator Inspection Visits?

Cooperative behavior during predator-inspection visits of the guppy (Poecilia reticulata) was examined. Wild caught guppies from Trinidad were tested on two types of mirror. In one treatment individual guppies were tested using a long mirror that ran parallel to the path toward the predator. In the second treatment, guppies were tested with a shorter mirror that was placed at an angle of thirty-two degrees to the path toward the predator. Guppies in both mirror treatments showed consistent behavior throughout a trial, with subjects in the straight-mirror treatment spending more time near the predator. It appears that guppies employ a "conditional-approach" strategy during predator inspections. The conditional-approach strategy instructs a player to swim toward the predator (inspect) on the first move of a game and subsequently only to move forward if the other player swims beside it. "Conditional-approach" is analogous to a TIT FOR TAT strategy, the difference being that the conditional-approach strategy makes no assumptions about the player's payoff matrix.