Evaluation of Stomoxys calcitrans (Diptera : Muscidae) behavioral responseto human and related odors in a triple cage olfactometer with insect traps

A triple cage olfactometer provided with insect traps was used for evaluati ng behavioral responses of Stomoxys calcitrans (L.) females to human skin a nd breath, CO2, and L-lactic acid analogs. After demonstrating there were n o significant differences caused by cage location or time of days, sets of 3 olfactometer tests were performed in a day, every 2 h beginnings at 0900 hours. When a human hand was used as attractant. the attraction (expressed as percentage of trapped flies) increased as a function of the time. an inv erted U-shaped relationship between attractancy and air speed was observed, and variation in fly density in the range 25-75 per cage did not affect th e attraction response. When human breath was used as attractant the attract ion increased linearly as a function of time and it was exhalation frequenc y dependent when air flow was absent the highest response was observed: and 24- to 38-h-old flies were more attracted than younger and older. When CO2 was tested. activation and orientation and probing behavior were concentra tion dependent with flows ranging, between 0.0001 and. 0.038 liter s(-1), b ut attraction was not. No attraction was observed with 10,000 or 1,000 mu g of compounds related to L-lactic acid and several synthetic human odors an d related compounds. although orientation was often observed.