Use of Mixture Designs to Investigate Contribution of Minor Sex Pheromone Components to Trap Catch of the Carpenterworm Moth, Chilecomadia valdiviana Stephen L. Lapointe 1 & Wilson Barros-Parada 2,3 & Eduardo Fuentes-Contreras 2 & Heidy Herrera 4 & Takeshi Kinsho 5 & Yuki Miyake 5 & Randall P. Niedz 1 & Jan Bergmann 4 Received: 30 June 2017 /Revised: 20 September 2017 /Accepted: 9 November 2017 /Published online: 22 November 2017 # This is a U.S. government work and its text is not subject to copyright protection in the United States; however, its text may be subject to foreign copyright protection 2017 Abstract Field experiments were carried out to study re- sponses of male moths of the carpenterworm, Chilecomadia valdiviana (Lepidoptera: Cossidae), a pest of tree and fruit crops in Chile, to five compounds previously identified from the pheromone glands of females. Previously, attraction of males to the major component, (7 Z ,10 Z )-7,10- hexadecadienal, was clearly demonstrated while the role of the minor components was uncertain due to the use of an experimental design that left large portions of the design space unexplored. We used mixture designs to study the potential contributions to trap catch of the four minor pheromone com- ponents produced by C. valdiviana. After systematically ex- ploring the design space described by the five pheromone components, we concluded that the major pheromone compo- nent alone is responsible for attraction of male moths in this species. The need for appropriate experimental designs to ad- dress the problem of assessing responses to mixtures of se- miochemicals in chemical ecology is described. We present an analysis of mixture designs and response surface modeling and an explanation of why this approach is superior to com- monly used, but statistically inappropriate, designs. Keywords Geometric mixture designs . Response surface modeling . (7Z,10Z)-7,10-hexadecadienal . Lepidoptera . Cossidae Introduction Mixture and mixture-amount experimental designs combined with response surface modeling have many applications in entomology in general and specifically in the discipline of chemical ecology. Many insects use multi-component blends as sex or aggregation pheromones. Design of experiments (DOE) for optimization of blends is a special problem in the field of statistics and DOE. The fundamental characteristic of blends, or mixtures, is that the proportions of all components of a blend will vary simultaneously as the proportion of any one component in the blend is varied. Thus, it is impossible to vary the proportion of a single ingredient without changing the proportion of one or more of the remaining ingredients. The approach of holding one or more blend components con- stant while adding a variable amount of another component has the undesirable effect of confounding proportionality with amount. If the sum of the proportions does not equal one, then proportion and amount are confounded. Electronic supplementary material The online version of this article (https://doi.org/10.1007/s10886-017-0906-0) contains supplementary material, which is available to authorized users. * Stephen L. Lapointe stephen.lapointe@ars.usda.gov * Jan Bergmann jan.bergmann@pucv.cl 1 United States Horticultural Research Laboratory, U.S. Department of Agriculture, Agricultural Research Service, 2001 South Rock Road, Ft. Pierce, FL 34945, USA 2 Millenium Nucleus Center in Molecular Ecology and Evolutionary Applications in the Agroecosystems (CEM), Facultad de Ciencias Agrarias, Universidad de Talca, Talca, Chile 3 Present address: Escuela de Agronomía, Pontificia Universidad Católica de Valparaíso, Quillota, Chile 4 Instituto de Química, Pontificia Universidad Católica de Valparaíso, Valparaíso, Chile 5 Shin-Etsu Chemical Co. Ltd, 6-1, Ohtemachi 2-chome, Chiyoda-ku, Tokyo 100-0004, Japan J Chem Ecol (2017) 43:1046–1055 https://doi.org/10.1007/s10886-017-0906-0