....................................................................................................................................10 Introduction.......................................................................................................................11 Materials and methods.....................................................................................................13 Insects...................................................................................................................13 Gut morphology and histology...........................................................................14 Preparation of samples for biochemical tests....................................................14 Zymography.........................................................................................................15 Quantification of cellulase, xylanase and pectinase activities..........................16 Results..............................................................................................................................18 High cellulase activity and gut morphology in Zygentoma..............................18 Qualitative and quantitative location of cellulolytic activity in the digestive system of T. domestica and C. longicaudata.........................................................19 Discussion........................................................................................................................20 List of references..............................................................................................................25 Appendix 2.......................................................................................................................31