Wolbachia in European Populations of the Invasive Pest Drosophila suzukii: Regional Variation in Infection Frequencies

Abstract

The invasive pest Drosophila suzukii is characterized by a specific fresh-fruit targeting behavior and has quickly become a menace for the fruit economy of newly infested North American and European regions. D. suzukii carries a strain of the endosymbiotic bacterium Wolbachia, named wSuz, which has a low infection frequency and no reproductive manipulation capabilities in American populations of D. suzukii. To further understand the nature of wSuz biology and assess its utility as a tool for controlling this pest’s populations, we investigated the prevalence of Wolbachia in 23 European D. suzukii populations, and compared our results with those available in American populations. Our data showed a highly variable infection frequency with a mean prevalence of 46%, which is significantly higher than the 17% found in American populations. Based on Multilocus Sequence Typing analysis, a single wSuz strain was diagnosed in all European populations of D. suzukii. In agreement with American data, we found no evidence of cytoplasmic incompatibility induced by wSuz. These findings raise two questions: a) why Wolbachia is maintained in field populations of D. suzukii and b) what are the selective forces responsible for the variation in prevalence within populations, particularly between European and American continents? Our results provide new insights into the D. suzukii-Wolbachia association and highlight regional variations that await further investigation and that should be taken into account for using Wolbachia-based pest management programs.

Wolbachia‐mediated protection against viruses in the invasive pest Drosophila suzukii

“…In a recent study another direct fitness benefit of Wolbachia was observed in an Italian population of D. suzukii : infected females had higher fecundity than uninfected ones (Mazzetto et al ., ). These phenotypes can potentially explain the maintenance of Wolbachia strains in natural populations without reproductive manipulation (Fenton et al ., ), as has been found in North American and European populations of D. suzukii (Hamm et al ., ; Cattel et al ., ).…”

“…Until now little was known about the symbiotic community of D. suzukii, despite maternally inherited symbionts being common and important components of arthropod biology and ecology (Zchori-Fein & Bourtzis, 2011). Some studies revealed that D. suzukii naturally harbours Wolbachia (Cordaux et al, 2008;Siozios et al, 2013;Hamm et al, 2014;Cattel et al, 2016), which is the most common endosymbiont in arthropods with an estimation of 52% of arthropod species infected (Weinert et al, 2015). Only one strain of Wolbachia has been identified in field populations of D. suzukii based on Multilocus Sequence Typing (MLST) markers, at least in North America and in Europe, which is closely related to wRi (Siozios et al, 2013;Hamm et al, 2014;Cattel et al, 2016).…”

Genome comparisons indicate recent transfer ofwRi‐likeWolbachiabetween sister speciesDrosophila suzukiiandD. subpulchrella

“…The published crossing studies in D. suzukii and D. subpulchrella , which found no statistically significant CI caused by w Suz or w Spc, are relatively small (Cattel et al., 2016; Hamm et al., 2014). They are comparable to the experiments that inferred no CI associated with the native Wolbachia infections in D. yakuba , D. teissieri , and D. santomea (Charlat, Ballard, & Mercot, 2004; Zabalou et al., 2004).…”

Back and forth Wolbachia transfers reveal efficient strains to control spotted wing drosophila populations

“…Data indicated that w Suz is the only natural infection in D . suzukii , where it does not induce strong CI (Cattel, Kaur, et al., ; Hamm et al., ). These results indicate that the implementation of IIT in D .…”