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Fig. 9. Responses evoked by tactile stimulation of the lateral edge of the abdomen
in 61-week-old tethered cockroaches under intact and decapitated conditions
and young intact animals. Young intact animals readily show escape behavior
when stimulated (data from Schaefer and
Ritzmann, 2001). By contrast, intact 61-week-old cockroaches did
not escape when stimulated. Following decapitation, however, forward
directional escape responses (Schaefer et
al., 1994) were easily elicited in aged individuals.