MULTISENSORY CONTROL OF ESCAPE IN THE COCKROACH PERIPLANETA-AMERICANA.2. PATTERNS OF TOUCH-EVOKED BEHAVIOR

1. Interactions of cockroaches with 4 different predator species were recorded by videography. Some predators, especially spiders, struck fr om relatively short distances and usually contacted a cockroach prior to initiation of escape (Table 1, Fig. 3). This touch frequently occur red on an antenna. Cockroaches turned away from the side on which an a ntenna was touched. 2. We then measured the success of escape from pre dators for cockroaches with either cerci or antennae ablated. Only ant ennal removal caused a significant decrease in the success of escape f rom spiders (Fig. 5). 3. With controlled stimuli, cockroaches responde d reliably to abrupt touch of antennae, legs or body (Fig. 6). Respons es resembled wind-elicited escape: they consisted of a short latency t urn (away from the stimulus) followed by running (Figs. 7, 8). However , lesions show that touch-evoked escape does not depend on the giant i nterneuron system (Table 2). 4. Following section of one cervical conn ective, cockroaches continued to respond to touching either antenna, b ut often turned inappropriately toward, rather than away from, stimuli applied to the antenna contralateral to the severed connective (Table 3, Fig. 10). 5. For certain types of predators touch may be a primary cue by which cockroaches detect predatory attack. Descending somatose nsory pathways for escape are distinct from the GI system.