VOLATILE PHEROMONAL EMISSIONS FROM THE MALE MEDITERRANEAN FRUIT-FLY -EFFECTS OF FLY AGE AND TIME OF DAY

Pheromonal emissions from ''calling'' male Mediterranean fruit flies ( Ceratitis capitata Wied.) were trapped in Tenax-packed traps, using 25 -fly groups of laboratory-reared flies in a 5-L glass/Teflon/stainless steel chamber swept with purified air. Three different fly ages were used (5-6, 11-12, and 20-21 days old), and early-, mid-, and late-morn ing samples were collected from the first two age groups. Thirty-two c omponents were identified; four had not been previously reported [prop an-2-ol, hexanal, phenol, and (Z,E)-alpha-farnesene], and three others had been only partially identified in an earlier study [prop-2-yl (E) -3-octenoate, ethyl (E)-2-octenoate, and propyl (E)-3-octenoate]. Quan titatively, ethyl acetate, 1-pyrroline, ethyl (E)-3-octenoate, geranyl acetate, and (E,E)-alpha-farnesene were the most abundant emission co mponents from 5-6- and 11-12-day-old flies. (E)-2-Hexenoic acid was al so a major component but was not as readily quantified. Total emission s release appeared to peak in early morning with 5-6-day-old flies. Wi th 11-12-day-old flies, the peak tended to move to mid- to late-mornin g, and limited semiquantitative data for 20-21-day-old flies suggest a late-morning maximum.