Identification of chemicals that affect the naturally occurring interactions be- tween organisms requires sophisticated chemical techniques, such as those docu- mented in volume 1, in combination with effective bioassays. Without an effective bioassay, the identification becomes akin to looking for a needle in a haystack, but without any idea of what a needle looks like. To a large extent serniochemical identifications must be driven by bioassays. The design of bioassays for use in chemical ecology is governed by the sometimes conflicting objectives of ecological relevance and the need for...