Effect of age and sex on the sensitivity of antennal and palpal olfactory cells of houseflies

The olfactory system of newly emerged houseflies (Musca domestica L.; Diptera, Muscidae) is already functional; very few differences compared to sexually mature houseflies exist for the responses to 1-octen-3-ol, amylacetate, 2-pentanone, 3-methylphenol, R-limonene, muscalure, and 6-methyl-5-hepten-3-one. Sex differences are also almost absent, except for a higher sensitivity of females to acetic acid. Large differences exist between the sensitivity of antennae and palps to different odours. Antennae are sensitive to all odours tested. Palps are mainly sensitive to 3-methylphenol and 2-pentanone, both in percentage of responding cells and in response level. The sensitivity to amyl acetate was similar in palps and antennae. The responses to other odours were low in the palps. We conclude that traps baited with attractive odours may lure houseflies of all ages and both sexes.