DROSOPHILA-SUZUKII CONTAINS A PEPTIDE HOMOLOGOUS TO THE DROSOPHILA-MELANOGASTER SEX-PEPTIDE AND FUNCTIONAL IN BOTH SPECIES

A peptide homologous to the Drosophila melanogaster sex-peptide (SP) w as isolated from Drosophila suzukii accessory glands and its amino aci d sequence determined. The D. suzukii peptide contains 41 amino acids and has a calculated molecular weight of 5100 Da. Comparison of the se quences reveals strong homologies in the N-terminal and C-terminal par ts of the peptides. In the D. suzukii sex-peptide, however, five addit ional amino acids are inserted after amino acid 7. Based on the sequen ce of the peptide, a cDNA coding for the D. suzukii peptide was isolat ed by PCR. Sequence analysis of the cDNA confirmed the SP amino acid s equence determined by peptide sequencing. Furthermore, based on the cD NA sequence, we isolated the D. suzukii sex-peptide gene by inverse PC R. The D. suzukii sex-peptide gene contains an intron and codes for a 60 amino acid precursor. The D. melanogaster and the D. suzuki sex-pep tides elicit rejection behaviour in the presence of males and an incre ased egg laying in virgin females of both species.