The number of up- or down-regulated transcripts revealed by paired t-test (SAM) comparisons of the studied groups. Paired t-test comparisons, showing the number of transcripts differing significantly between: i) two vitellogenic female groups (Vit2 and Vit4), ii) between E2-treated males (E) and vitellogenic females (Vit2 and Vit4), iii) between control males (M) and non-vitellogenic females (NV), and iv) between E2-treated males and control males. Vit2 and Vit4 females are 2- and 4-months old females, respectively. The lists of genes for each comparison are shown in detail in Additional file 2, according to the group numbers. The number of up-regulated or down regulated transcripts for each group is shown on the top of the columns.