DIFFERENT STRIDULATORY VIBRATIONS DURING SEXUAL-BEHAVIOR AND DISTURBANCE IN THE BLOODSUCKING BUG TRIATOMA-INFESTANS (HEMIPTERA, REDUVIIDAE)

Stridulatory vibrations produced by Triatoma infestans females were re corded for the first time as substrate-borne waves and under unrestrai ned conditions, In the context of sexual behaviour, non-receptive fema les stridulated to reject male copulatory attempts, Male-deterring str idulations consisted of long series of repetitive syllables, each comp osed of two chirps: rubbing the tip of the proboscis against the groov e with a postero-anterior movement produced the upward chirp, and, wit h an antero-posterior movement, the downward chirp, Stridulations were also produced under restrained conditions, when bugs were clasped wit h forceps, Both male-deterring and disturbance stridulations were obse rved to differ in their syllable duration, repetition rate as well as in their main carrier frequency, Measurements of the inter-ridge dista nces along the whole stridulatory organ made it unlikely that differen ces in carrier frequency resulted from the use of distinct regions alo ng the organ, More probable, bugs rub their proboscis at different spe eds in order to produce either male-deterring or disturbance stridulat ions. For disturbance stridulations, the possibility that the frequenc y of highest vibration energy lies beyond the maximal sensitivity rang e of the receptors is discussed, and it is speculated that they have b een shaped during evolution to deter predators.