Pauesia antennata Mukerji is a specific parasitoid of the brown peach aphid Pterochloroides persicae Cholodkovsky which causes severe damage on almond and peach in Tunisia. To control this pest, P. antennata was collected from Iran, introduced to Tunisia in 2011 and some of their biological parameters were studied in laboratory conditions. Therefore, in orchard, aphid population and sites/zones of Tunisia and aphid behaviour impact on the parasitoid have not been studied. Morphometric measurements, molecular analysis of P. persicae specimens collected from two Tunisian sites [(Akouda-Sousse (Site 1), Sfax (Site 2)] were studied and compared and aphid behaviour versus P. antennata was followed. Results demonstrated a significant difference of four morphological characters (body length, body width, total antennal length, hind femora length). Molecular analysis showed two haplotypes corresponding to the sites. For biological analysis, larval longevities were 14.3 ± 1.52 and 12.6 ± 2.08 days for Site 1 and Site 2, respectively. Fecundities were 20.2 ± 13.57 and 12.3 ± 11.06 larvae/day corresponding to Sites 1 and 2, respectively. A relationship between P. persicae specimens and behaviour versus P. antennata were explained.