The metabolic interactions between ticks and symbiotic bacteria
Ticks (Acari: Ixodida) feed exclusively on blood, and are persistently missing B vitamins and co-factors from their meal. Many species, including those of the genus Rhipicephalus (Ixodidae) harbor Coxiella-like endosymbionts (CLE), which provide their hosts with vital nutrients. We have demonstrated that removal of CLE has negative effects on tick development and reproductive fitness. Additionally, computational evidences suggest that CLE produce excess of l-proline which is transported to the tick cells. Nevertheless, the actual foundation underlying symbiosis maintenance in ticks has not been demonstrated to date.
We now study the effect of nutrient supplementation on aposymbiotic ticks, and characterized the role of l-proline in CLE-Rhipicephalus symbiosis.
Speciation and cytoplasmic incompatibility of parasitic wasps
Speciation, the divergence of one species into two or more species, is driven by the reduction of gene flow between diverging populations through the emergence of reproductive barriers. Endosymbiont induced Cytoplasmic Incompatibility (CI), an incompatibility between sperm and egg, which leads to inviable offspring, is effective in promoting speciation processes. together with Prof. Dr. Johannes Steidle, and Marie Pollmann from Hohenheim University in Germany, we study the involvement of CI and its effect on speciation in the parasitoid Lariophagus distinguendus (Hymenoptera: Pteromalidae). We were able to connect the occurrence of CI to infections with Spiroplasma (Mollicutes) of the ixodetis group and confirmed it as CI-inducer by excluding other candidates, by locating Spiroplasma in the ovaries as required for maternal transmission, and by artificially inducing CI through the transfer of Spiroplasma-infected hemolymph to uninfected individuals.
Vector competence and microbiomes of Culicoides biting midges
Culicoides biting midges are vectors of numerus viral disease agents of Ruminants, mainly Bluetongue virus (BTV). Vector competence of Culcioides species depends on specific interactions between the vector and the virus. One of the factors that affect the internal environment of the vector is its microbial communities. We study the competence of Culicoides imicola and Culicoides oxystoma, the main vector species in Israel, to disseminate various BTV serotypes in relation to their microbiome characteristics.
Ecology of endosymbiotic community in spiders
Many arthropods are infected with maternally transmitted endosymbionts that can manipulate the reproduction of their hosts to promote symbiont spread within the host population. It is becoming clear that co-infection of hosts by multiple strains of such endosymbionts is much more common than previously appreciated, yet we know very little about how such endosymbionts interact within a host, whether they influence host phenotype in non-additive ways, and how their interactions feedback to influence symbiont spread and persistence in host populations. Together with Dr. Jen White and Dr. Jeremy Van Cleve form the University of Kentucky, USA, we propose to address this knowledge gap using the bacterial endosymbionts in a Linyphiid spider, Mermessus fradeorum, which is naturally co-infected with up to five strains of endosymbiotic bacteria.