Forstliche Versuchs-und Forschungsanstalt B a d en -W ü rt tem berg, D-7801 Stegen-W ittental Sex Pherom one, (Z ,£ )-5 ,7 -D o d ec ad ie n al, P h ero m o n e In hibitors, Olfactory Receptors, D endrolim us pini, L asiocam pidae The principal com ponent o f the fem ale sex p h e ro m o n e of the E uropean pine m oth Dendrolimus p in i L. (L asiocam pidae) was identified as (Z ,E )-5 ,7 -dodecadienal by capillary gas chrom atography, m ass spectrom etry, single receptor analyses, and field trap p in g tests. T rap s initially baited with 1000 ng o f (Z ,£ )-5 ,7 -d o d e c ad ien a l (> 9 9 % Z E ) effectively m onitored low D. p in i p o p u latio n s over 6 weeks w ithout rebaiting. C aptures d isa p p ea red upon addition o f ^ 1% o f either (£ ,Z )-5 ,7 -d o d e c ad ien a l or (Z ,£)-5,7-dodecadienyl acetate, the key stim u la n ts for additional receptor cell types located in m ale an ten n al h a ir sensilla. The Forest Services o f central E uropean coun tries w ith stands o f Scots pine (Pinus sylvestris L.) en dangered by the feeding o f Panolis flam m ea Schiff. (Noctuidae), Lymantria monacha L. (L ym antriidae), Dendrolimus pini L. (L asiocam pidae) and Bupalus piniarius L. (G eom etridae), are req u ired by law to survey for population densities o f these lepidopterous pests. Bogenschütz [1,2] has em phasized th e p o te n tial o f traps baited w ith sex-attractant chem icals for early detection o f population increases am ong low (non-dam aging) populations o f P. flam m ea and L. monacha. We report here the id en tificatio n o f the prim ary sex pherom one com ponent p ro d u ced by the female European pine m oth, Dendrolimus pin i L. We also describe a synthetic chem ical fo rm u latio n suitable for use in population m onitoring o f this species by survey traps. Fem ale sex pherom one com ponents are c h e m i cally known for four species o f the fam ily L asioReprint requests to E. Priesner or M. D. C hisholm . 0341-0382/84/1100-1192 $ 0 1 .3 0 /0 cam pidae. The tent caterpillars Malacosoma disstria Hbn. and M. californicum Pack, produce sex p heromones whose principal com ponents are (Z ,£ )-5 ,7 -dodecadienal ( Z 5 ,£ 7 -1 2 ;A id) and (£ ,Z )-5 ,7 -d o d e cadienal (£ 5 ,Z 7 -1 2 : Aid) [3, 4], T he sex p h ero m o n e o f the Japanese pine m oth Dendrolimus spectabilis Butl. was reported as (Z ,£ )-5 ,7 -d o d e c a d ie n -l-o l (Z 5 ,£ 7 -1 2 : O H ) [5, 6], and th at o f the M asson pine m oth D. punctatus Wlk., as a co m b in atio n o f this alcohol with the corresponding acetate and p ro p io n ate [7, 8].All four geom etrical isom ers o f the 5,7-dodecadien-l-ols and their acetate and ald ehyde a n a logues were included in o u r study o f the D. pini pherom one. The 5,7-dodecadienes were synthesized and purified by W ittig condensation reactions previously described [9,10]. T he purity o f all final products was b etter th an 98%; the Z 5 ,£ 7 -1 2 :A ld had a purity o f b etter th an 99%.N erve im pulse responses o f single recep to r cells located in h air sensilla (S. trichodea) ...