Biology of Asphondylia prosopidis complex (Diptera: Cecidomyiidae) and its fungal associates: potential biological control candidates for South African mesquite

The Asphondylia prosopidis complex produces four distinct bud galls on Mesquite with fungal associates in the Southwestern U.S. These gall midges are being considered as potential biological candidates to reduce Mesquite seed production in South Africa. Previous publications suggest that this complex may consist of more than one species; furthermore, there has been no detailed description about the fungal associates in Mesquite. Therefore, before exporting this insect to South Africa, it is important to understand the relationships among the gall midges in the complex and between the gall midge and fungal associates. In this study, 1) COI was used to evaluate the molecular relationships of the gall midge complex. Samples were collected in AZ, NM, and TX from 2007 to 2009. The phylogeny of each group from the Maximum Parsimony, Maximum Likelihood and Bayesian Inference suggest four cryptic species in the complex. 2) In 2009, the fungal associates were cultured in PA media. ITS and EF1A loci were used to identify the fungal associates in the complex. Once fungal DNA sequences are completed, we will compare them with fungal strains from South Africa. 3) In 2009, after dissecting 1,000 individual galls in the field, one promising gall midge species showed single-sexed galls (90%) and mixed galls (10%) from each raceme. This observation also has a significant aspect in that at least two sexually different racemes are required for importation into South Africa to successfully produce galls on the Mesquite.