Testing the disturbance hiss of the Madagascar hissing Cockroach (Gromphadorhina portentosa) as an anti-predatory response

The display of the disturbance hiss by the Madagascar Hissing Cockroach ( Gromphadorhina portentosa ) is considered to be an anti-predatory response despite there being little direct evidence linking the hiss with survival. Many studies have investi-gated the roles of the aggression and courtship hisses, displayed in this social species, but few have considered the role of the disturbance hiss. This study looked at the stimulus for the disturbance hiss response by placing unfamiliar individuals into different social contexts. A total of 10 male and 10 female G. portentosa were kept separately before being placed into four different social situations for 5 min at a time. The individuals were placed into an established colony of all females , an established colony of all males and an established colony of mixed sex G. portentosa . The subjects were also placed in the presence of a predator, an Emperor Scorpion ( Pandinus imperator Koch). All interactions and hisses were recorded both by video and on a sound-recording device. There was a highly significant difference in the setting in which the disturbance hiss was shown and a highly significant difference in the display rates of the disturbance hiss between the sexes in general, with most displays of the disturbance hiss being when introduced to a mixed sex colony. The findings suggest that the role of the disturbance hiss is not an anti-predatory response when presented with a predator of limited auditory senses. Further study into the behavioural ecology of this species is recommended to understand the range of anti-predatory responses used by this species when presented with different predators. It was also found that there is some social context for the display of the disturbance hiss which warrants further study.