Comparison of content and composition of TE related piRNAs in piRNA clusters detected with different methods. Each bar itemizes the fraction of TE related and clustered sequence reads according to the different repeat classes. Bars labelled with 1 refer to putative piRNA clusters detected with the Girard et al.  method, bars labelled with 2 refer to putative piRNA clusters detected with proTRAC. Mapping piRNA like sequences to TE sequences was performed allowing only perfect matches (left side) and allowing up to two mismatches (right side).