Independent cytoplasmic incompatibility induced byCardiniumandWolbachiamaintains endosymbiont coinfections in haplodiploid thrips populations

Abstract

Cardinium and Wolbachia are common maternally inherited reproductive parasites that can coinfect arthropods, yet interactions between both bacterial endosymbionts are rarely studied. For the first time, we report their independent expression of complete cytoplasmic incompatibility (CI) in a coinfected host, and CI in a species of the haplodiploid insect order Thysanoptera. In Pezothrips kellyanus, Cardinium-induced CI resulted in a combination of male development (MD) and embryonic female mortality (FM) of fertilized eggs. In contrast, Wolbachia-induced CI resulted in FM together with postembryonic mortality not previously reported as a CI outcome. Both endosymbionts appeared to not influence fecundity but virgins produced more offspring than mated females. In coinfected individuals, Wolbachia density was higher than Cardinium. Wolbachia removal did not impact Cardinium density, suggesting a lack of competition within hosts. Maternal transmission was complete for Wolbachia and high for Cardinium. Our data support theoretical predictions and empirical detection of high endosymbiont prevalence in field populations of the native range of this pest thrips. However, previous findings of more frequent loss of Wolbachia than Cardinium, particularly in field populations of the host's invasive range, suggest that genetic diversity or varying environmental factors between field populations also play a role in shaping host-endosymbiont dynamics.

Transcriptome of Tetranychus urticae embryos reveals insights into Wolbachia‐induced cytoplasmic incompatibility

“…Each cross combination contained at least 24 biological repeats. Following previous studies (Mouton et al, 2005;Nguyen et al, 2017), samples that produced fewer than 10 eggs were excluded.…”

Wolbachia dominate Spiroplasma in the co‐infected spider mite Tetranychus truncatus

“…Haplo‐diploid thrips populations co‐infected by Wolbachia and Cardinium induce complete CI. Whereas Wolbachia density in these thrips co‐infections is higher than Cardinium density, Wolbachia removal does not impact Cardinium density, suggesting a lack of competition within hosts (Nguyen et al ., ).…”

“…Symbiont co-infections are common in arthropods, such as spider mites, aphids and grasshoppers (Machtelinckx et al, 2012;Lukasik et al, 2013;Wamwiri et al, 2013;Funkhouser-Jones et al, 2015;Moutailler et al, 2016;Zhang et al, 2016;Zytynska and Weisser, 2016;Nguyen et al, 2017). The presence of co-infections in mites and other arthropods raises questions about how such infections are generally maintained.…”

Sex ratios in the haplodiploid herbivores, Aleyrodidae and Thysanoptera: A review and tools for study

“…Recently, Nguyen et al (2017) found the first-recorded CI in Thysanoptera, caused by Wolbachia and Cardinium coinfections in Pezothrips kellyanus. In haplodiploid organisms, CI can cause female mortality (FM) or a male development (MD) phenotype (Vavre et al 2001, Nguyen et al 2017.…”

“…Recently, Nguyen et al (2017) found the first-recorded CI in Thysanoptera, caused by Wolbachia and Cardinium coinfections in Pezothrips kellyanus. In haplodiploid organisms, CI can cause female mortality (FM) or a male development (MD) phenotype (Vavre et al 2001, Nguyen et al 2017. In FM, all fertilized eggs in a CI cross fail to develop, while in MD, fertilized eggs survive but as haploid males (Vavre et al 2001, Nguyen et al 2017.…”