The Sex Pheromones of Two Pine Sawfly Species, Gilpinia frutetorum and Gilpinia socia: Chemical Identification, Synthesis and Biological Activity

3,7-Dimethylpentadecan-2-ol and 3-methylpentadecan-2-ol were identified in female whole body extracts from the two pine sawfly species Gilpinia frutetorum and Gilpinia socia. This is the first observation of 3-methylpentadecan-2-ol in extracts of a female pine sawfly species. Synthetic and highly pure stereoisomers of 3,7-dimethylpentadecan-2-ol and 3-methylpentadecan-2-ol were used to verify that the (2S,3R,7R)-isomer of 3,7-dimethylpentadecan- 2-ol and (2S,3R)-3-methylpentadecan-2-ol were present in the extracts. The four stereoisomers of 3-methylpentadecan-2-ol and their biologically active esters were produced via chemoenzymatic methods and the synthesis is described in detail. Male G. socia antennae responded strongly in EAG recordings to the (2S,3R)-isomer of the acetate and propionate of 3-methylpentadecan-2-ol. Male antennae of both G. frutetorum and G. socia also responded to the (2S,3R,7R)- and (2S,3R,7S)-acetates of 3,7-dimethylpentadecan-2-ol

Influence of temperature on larval defecation and its use in estimating canopy population size of pine sawflies (Hymenoptera: Diprionidae)

The frequency of defecation in relation to constant0/simulated outdoor temperatures and larval age (instar) was examined under laboratory conditions in four species of pine sawflies (Diprionidae): Gilpinia frutetorum (Fabricius), Diprion pini (Linnaeus), D. similis (Hartig) and Macrodiprion nemoralis (Enslin). Defecation interval and total faecal production was regular under higher constant temperatures (higher production in younger instars, second and third) and production significantly decreased under varying air temperatures during the same period (24 hours) when larvae of younger instars were influenced more by lower temperatures. The influence of larval age (instar) on faecal production was insignificant if larvae were exposed to varying temperatures during 24 hours. Faecal production and temperature were positively correlated in each of the four species and instars tested, as well as in total (all the test species and instars combined). Implications of the results for estimating canopy larval density by frass-drop measurements in the field are briefly discussed.

PICROMERUS BIDENS IN CANADA (HETEROPTERA: PENTATOMIDAE)

A European bug Picromerus bidens (L.) is reported from Quebec feeding on larvae of the introduced sawfly Gilpinia frutetorum (F.) (Hymenoptera: Diprionidae). A colour photograph of the bug and an illustration of the anterior femur and tibia are included.