Certain Environmental Factors Influencing the Acoustic Communication in the Sexual Behaviour of the Leafhopper Amrasca devastans (DISTANT) : Homoptera : Cicadellidae

Abstract

The role of certain environmental factors in influencing the substrate-borne acoustic communication associated with the sexual behaviour of the leafhopper, Amrasca devastans (DISTANT) was studied under the laboratory conditions. The sound emission as well as the sexual behaviour was high at 28±1°C and was inhibited by a low (18±1°C) or a high temperature (38±1°C). A high humidity (⪀80% r.h.) was found to inhibit the sexual communication and behaviour of this leafhopper whereas a low humidity (30-40% r.h.) had no effect on these responses. Singing by the sexes in complete darkness was as high as in the presence of light. However, the copulatory responses were reduced in the dark. The leafhoppers kept under a short day-length (8L-16D) for 5 days after emergence sang and copulated as high percentages as those kept under a long day-length (13L-11D) for 5 days after emergence. The sexual communication leading to mating was not done by the two sexes being present on different leaves which had been in out of contact with each other; but was done by those being present on the same leaf. This fact imposes a severe limitation in the reproduction of these insects since no air-borne distance stimulus is involved in their communication.