Shade response in the escape behavior of the cockroach, Periplaneta americana

Abstract

The termination of the escape behavior in the cockroach Periplaneta americana was investigated. Escape behavior was effectively terminated when cockroaches were allowed to select a dark shelter and hide beneath it. This shade-induced pause in escape running (a shade response) was observed even in very low-light levels (less than 0.01 lux). Contributions of the ocelli and the compound eyes to the shade response were examined. Removal of both compound eyes resulted in complete disappearance of the shade response. Animals with just the ocelli removed were less likely to shelter in the shadowed area, especially under a low-light condition. Input from compound eyes seems to be essential to the shade response. The ocellus may enhance the function of compound eye, and its modulatory function is effective in low-light conditions.