Effect of antibiotic, temperature curing of Wolbachia and seasonal variation on the reproductive fitness of the uzifly Exorista sorbillans (Diptera: Tachinidae)

Wolbachia is a cytoplasmically inherited endocellular bacterium known to cause number of reproductive alterations in its insect hosts and various fitness effects which allow its spread in host populations. In the Uzifly Exorista sorbillans, endoparasite of silkworms, the prevalence of Wolbachia is high in the field. In the present study, we investigated Wolbachia’s effects on the Uzifly fitness traits by measuring fecundity and hatching rate in crosses involving infected and cured individuals. We tested two types of treatments for removing Wolbachia, antibiotic therapy and high temperature treatments. We didn’t detect any cytoplasmic incompatibility in crosses between infected males and uninfected females but we found evidence for positive fitness effects associated with Wolbachia infection in females which could help promote the spread of Wolbachia in Exorista sorbillans populations. We also found an influence of the type of treatment used to remove Wolbachia: females treated by antibiotics have a lower fecundity than females cured by high temperature which could indicate a negative effect of the antibiotherapy on females’ fitness or a higher fecundity under an elevated temperature. Furthermore, the monitoring of the uzifly populations during two years revealed seasonal variations of reproductive fitness traits which may be linked to temperature.