Abstract
This article explores learned changes in the disturbance hiss of the hissing cockroach, Gromphadorhina portentosa. Compared to extensive research on learning in other cockroaches, studies with this species are rare. Of the natural behaviors of G. portentosa, the disturbance hiss is also seldom investigated. Two experiments were conducted to address these deficits. The first experiment investigated habituation to repeated tactical stimulus delivered near the cerci. The effect of sex and heat were also assessed in a group design. This experiment found typical habituation trends, with males showing higher rates of hissing, and heated cockroaches showing marginally higher rates of hissing. Similar, but less pronounced results were seen with probability of movement. The second experiment explored classical conditioning by presenting an olfactory stimulus prior to, and along with, tactile stimulation. After conditioning, the olfactory stimulus and a second novel olfactory stimulus were presented on opposite ends of the apparatus to determine if there was conditioned preference. No evidence of conditioned response was observed in this experiment. Hissing and movement were observed during and after tactile stimulation, but responses were not observed before trials or during olfactory stimulus presentations. No preference between novel and conditioned odor was observed in the preference test. These findings confirm habituation in G. portentosa but highlight challenges in eliciting conditioned responses, emphasizing the need for further research to enhance understanding of insect learning and behavior.