Genetic variability in the parasitic fly, Sarcophaga villeneuveana, in south-western Europe and Morocco

Authors: JOURDAN, MIREILLE - Csiro European Laboratory; THOMANN, THIERRY - Csiro European Laboratory; RICHET, RENÉ - Retired Non ARS Employee; FENDANE, YASMINE - Universite Cadi Ayyad; BON, MARIE-CLAUDE - European Biological Control Laboratory (EBCL); SHEPPARD, ANDY - Commonwealth Scientific And Industrial Research Organisation (CSIRO); BAKER, GEOFF - Commonwealth Scientific And Industrial Research Organisation (CSIRO)

Submitted to: BioControl
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/27/2019
Publication Date: 12/9/2019
Citation: Jourdan, M., Thomann, T., Richet, R., Fendane, Y., Bon, M., Sheppard, A., Baker, G. 2019. Genetic variability in the parasitic fly, Sarcophaga villeneuveana, in south-western Europe and Morocco. Biocontrol. 65:59-70. https://doi.org/10.1007/s10526-019-09985-7.
DOI: https://doi.org/10.1007/s10526-019-09985-7

Interpretive Summary: The introduced Mediterranean land snail, Cochlicella acuta, is an invasive pest of grain crops in southern Australia posing a serious threat to the export marketing of Australian cereals. Biological control of this pest in Australia by the parasitoid fly, Sarcophaga villeneuveana, failed, possibly because the parasitoid chosen was imported from France to control snails populations that originated from the Iberian Peninsula or Morocco. The parasitoid fly was extensively collected in France, Spain, Portugal and Australia for DNA analysis. This analysis evidenced that most Australian and French flies separated genetically from those from Spain, Portugal and Morocco, but also that the flies from these three countries were genetically diverse. The combination of these genetic data from the flies and climatic matching analyses point to the need for future searches for best effective biological control agents in southern Spain, southern Portugal and Morocco.

Technical Abstract: The snail, Cochlicella acuta (Müller), is an introduced pest of grain crops in southern Australia, and native to Europe and north-west Africa. Parasitoid flies (Sarcophaga villeneuveana (Enderlein)), have previously been sourced from France to attempt biological control of the pest in Australia, but have failed. Cochlicella acuta has three mitochondrial lineages (CO1 & 16S based) within its native distribution. The snails now found in Australia belong to just one of these lineages; their origins most likely lie in the southern Iberian Peninsula or Morocco, not in France. We collected S. villeneuveana attacking C. acuta in France, Spain, Portugal, Morocco and Australia. Fly lineages (CO1) were not found that aligned with those recorded for the snail host in the same regions. However, geographical patterns were detected amongst haplotypes of S. villeneuveana which encourage further, better targeted searches in Morocco and the southern Iberian Peninsula for a more effective biological control agent(s).