This family consists of accessory gland-specific 26Ab peptides or male accessory gland secretory protein 355B from different Drosophila species. Drosophila males, like males of most other insects, transfer a group of specific proteins (Acp26Ab and Acp26Aa in Drosophila) to the females during mating. These proteins are produced primarily in the accessory gland and are likely to influence the female's reproduction [1].

1: Polymorphism and divergence in the Mst26A male accessory gland gene region in Drosophila. Aguade M, Miyashita N, Langley CH; Genetics 1992;132:755-770. PMID:1361475

2: Different forces drive the evolution of the Acp26Aa and Acp26Ab accessory gland genes in the Drosophila melanogaster species complex. Aguade M; Genetics 1998;150:1079-1089. PMID:9799260