INTRODUCTION

Lepidopteran silk has a long tradition of commercial exploitation (Anquetil and Walter, 1996). The traditional standing of spider silk, on the other hand, has until now been mainly that of a mystical material made by a rather dubious creature (Hilliard, 1994). Recently, however, spider silks have attracted considerable attention as potential blueprints for designing modern ‘techno-fibres’ (Vollrath and Knight, 2001). Web silks have unusual characteristics for structural proteins. Instead of growing inside the body, they are extruded and body contact is not important for their function. Moreover, most silks function best in the dry and not in the aqueous state. A single fibre typically is of considerable purity and is many hundreds of meters long. Indeed, a single fibre is also thick enough to be handled, allowing its mechanical properties to be measured and analysed with traditional methods (Madsen et al., 1999). Finally, partly because of their proven commercial track record, silks have attracted considerable attention and funding. Hence, novel insights are rapidly accumulating (Kaplan et al., 1994); especially in the areas of silk genomics (e.g., Prince et al., 1995; Guerette et al., 1996; Lewis, 1999; Hayashi and Lewis, 2000), silk chemistry (Lewis, 1992; Winkler and Kaplan, 2000), silk structure (Grubb and Jelinski, 1997; Beek et al., 1999; Sirichaisit et al., 1999; Riekel and Vollrath, 2001), silk spinning (Knight and Vollrath, 1999b, 2001a, 2001b), silk mechanics (Thiel and Kunkel, 1994a; Vollrath et al., 2001), silk modelling (Fossey and Kaplan, 1994; Gosline et al., 1994; Termonia, 1994; Thiel and Viney, 1995), and silk copying (O'Brien et al., 1994, 1998; Lazaris et al., 2002).