PRELIMINARY EVIDENCE FROM REPRODUCTIVE COMPATIBILITY STUDIES SUGGESTS THAT GONATOCERUS TUBERCULIFEMUR EXISTS AS A CRYPTIC SPECIES COMPLEX, OR A NEW SPECIES IS IDENTIFIED: DEVELOPMENT AND UTILITY OF MOLECULAR DIAGNOSTIC MARKERS

• Author(s): de Le?n, Jesse; Logarzo, Guillermo; Triapitsyn, Serguei; Morgan, David;
• Abstract: Recent work uncovered divergent clades or distinct lineages in populations of Gonatocerus tuberculifemur from South America. G. tuberculifemur is a prospective egg parasitoid candidate agent for a neoclassical biological control program in California against the invasive glassy-winged sharpshooter (GWSS), Homalodisca vitripennis (Germar) [=H. coagulata (Say)]. In the present study, we developed molecular diagnostic markers by two approaches to distinguish field-collected populations of G. tuberculifemur for reproductive compatibility studies. The two diagnostic assays were: polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) of the mitochrondrial cytochrome oxidase subunit I gene (COI) and inter-simple sequence repeat-polymerase chain reaction (ISSR-PCR) DNA fingerprinting. Clade-specific restriction enzymes generated bands of the correct size with high specificity. Analysis of two isofemales lines created from freshly field-collected populations belonging to clade 1 (Tunuyn) and clade 2 (San Rafael) showed that both of our developed molecular diagnostic markers correctly genotyped these isofemale lines, confirming the utility of our diagnostic markers. Based on our molecular work, we predicted that G. tuberculifemur individuals belonging to the two distinct clades would not hybridize. Preliminary mating compatibility studies between these two isofemale lines demonstrated that our prediction was indeed correct. Interspecific crosses produced only male offspring, whereas, the intraspecific control crosses produced both males and females or fertile offspring. Taken together, both our molecular work and the preliminary reproductive compatibility studies strongly suggest that G. tuberulifemur either exists as a cryptic species complex or a new species is identified. Since G. tuberculifemur is under consideration as a biological control agent against the invasive GWSS in California, understanding cryptic variation of this species is critical.
• Publication Date: Nov 2006
• Journal: 2006 Pierce's Disease Research Symposium