Expression profiles of Apiago-1a , Apiago-1b , Apidcr-1a and Apidcr-1b in the four reproductive morphs of A. pisum LSR1. Expression levels of the four genes were estimated by semi-quantitative RT-PCR in the four reproductive morphs: parthenogenetic virginoparae females (Vp), parthenogenetic sexuparae females (Sxp), sexual oviparae females (O) and sexual males (M). Expression was normalized with the gene encoding the ribosomal protein 7 (Apirpl7) as a reference gene . The ratio between the expression of the amplified gene and of the Apirpl7 reference gene was calculated to normalize for variations in experimental conditions, with three replicates. For each gene and morph, gene expression was measured from three batches of 10 adult aphids resulting from three independent biological experiments. The histograms show the averages of normalized expression levels, while letters indicate statistically significant differences among morphs (Duncan grouping in ANOVA).