Pheromone-dependent species recognition mechanisms betweenNeodiprion pinetum andDiprion similis on white pine.

The sex pheromones ofNeodiprion pinetum (Norton) andDiprion similis (Hartig) consist of two isomers, 2S,3S,7S and 2S,3R,7R, in either the acetate orpropionate forms of 3,7-dimethylpentadecan-2-ol, respectively. The 2S,3S,7S acetate isomer is utilized byN. pinetum as the major pheromone component and the 2S,3R,7R acetate as a Synergist. ConverselyD. similis utilizes 2S,3R,7R as propionate the major pheromone component and 2S,3S,7S propionate as a Synergist. This was confirmed in the field in both Michigan and Wisconsin. Capillary gas-liquid chromatographie analyses revealed that these two isomers are present in the natural pheromones of both species at the ratios close to those predicted by artificial blending of the two optical isomers.