*3.5. Preparation of Alkenes*

All alkenes apart from 7-pentadecene were prepared from the corresponding C16- and C18-carboxylic acids (oleic acid, linoleic acid, palmitoleic acid) via a modified Barton reductive decarboxylation [43]. 7-Pentadecene was synthesised via 7-pentadecyne, prepared from 1-bromoheptyne and octylmagnesium chloride [44]. The alkyne was partially reduced to the *cis*-alkene in a low yield by the method of Obora et al. [45], although in amounts sufficient to our needs.

**Supplementary Materials:** Supplementary materials (NMR spectra for all semiochemicals) can be found at http://www.mdpi.com/1422-0067/21/2/620/s1.

**Author Contributions:** Conceptualization, B.B. and A.-K.B.-K; methodology, B.B.; R.M. and G.R.F.; investigation, B.B., A.M.W., A.-K.B.-K.; resources, B.B., R.M. and G.R.F.; writing—original draft preparation, B.B.; writing—review and editing, all authors.; funding acquisition, B.B. All authors have read and agreed to the published version of the manuscript.

**Funding:** This research was funded by the Australian Research Council, DE160101313.

**Acknowledgments:** B.B. acknowledges the Australian Research Council for funding (DE160101313). D. Bainbridge is gratefully acknowledged for designing and fabricating the preparative GC collector used in this study. The authors acknowledge the facilities, and the scientific and technical assistance of the Australian Microscopy & Microanalysis Research Facility at the Centre for Microscopy, Characterization & Analysis, The University of Western Australia, a facility funded by the University, State and Commonwealth Governments. The authors thank Kerstin Persson for allowing the use of her land for this study, Bo G. Svenson for assistance with the identification of insects, and Monica Ruibal and Rod Peakall for DNA sequencing of several of our wasp samples, which provided confirmation of our species identification.

**Conflicts of Interest:** The authors declare no conflict of interest. The funders had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript, or in the decision to publish the results.
