Wolbachiaeffects in natural populations ofChorthippus parallelusfrom the Pyrenean hybrid zone

Abstract

We evaluate for the first time the effect of Wolbachia infection, involving two different supergroups, on the structure and dynamics of the hybrid zone between two subspecies of Chorthippus parallelus (Orthoptera) in the Pyrenees. Wolbachia infection showed no effects on female fecundity or a slight increment in females infected by F supergroup, although in the last case it has to be well established. Cytoplasmic incompatibility (CI) is confirmed in crosses carried out in the field between individuals from a natural hybrid population. This CI, registered as the relative reduction in embryo production (s h ), was of s h = 0.355 and s h = 0.286 in unidirectional crosses involving B and F supergroups, respectively. CI also occurred in bidirectional crosses (s h = 0.147) but with a weaker intensity. The transmission rates of the two Wolbachia strains (B and F) were estimated by the optimization of a theoretical model to reach the infection frequencies observed in certain population. To fit this scenario, both supergroups should present transmission rates close to 1. Further, we have simulated the infection dynamics, and hence, the capacity of Wolbachia to structure the population of the host insects and to affect to reproduction and genetic introgression in the hybrid zone. This represents a first example of the influence of Wolbachia in an insect natural hybrid zone.

Aquatic Hemiptera in Southwest Cameroon: Biodiversity of Potential Reservoirs of Mycobacterium ulcerans and Multiple Wolbachia Sequence Types Revealed by Metagenomics

“…An important consideration in species infected with symbionts that can cause cytoplasmic incompatibility, such as Wolbachia, is introgression of mitochondrial haplotypes following symbiont-driven selective sweeps [124]. In some cases, this introgression can penetrate across hybrid zones during breakdown of reproductive barriers [125][126][127]. In this respect, it is noteworthy that a phylogenetic analysis of Limnogonus spp.…”

Chromosomal localization of Wolbachia inserts in the genomes of two subspecies of Chorthippus parallelus forming a Pyrenean hybrid zone

“…Previous phylogenetic studies revealed that current Cp populations are infected by Wolbachia from B and F supergroups and that the F strains co-diverged with their grasshopper hosts in allopatry, as opposed to the more recent horizontal transmission of B strains (Zabal-Aguirre et al 2010, 2014; Martinez-Rodriguez et al 2016). This indicates that Wolbachia insertions present in the pure grasshopper genomes at the origin of the hybrid zone have further evolved, and perhaps have recombined, as part of the hybrid genome.…”

“…CI results in embryonic lethality of offspring from an infected male mated to either an uninfected female or an infected female with a different Wolbachia strain and is the most common host modification produced by Wolbachia (reviewed in Werren et al 2008; Serbus et al 2008; LePage and Bordenstein 2013). CI-inducing Wolbachia present in both subspecies of Cp may contribute to the evolutionary dynamics of the hybrid zone by preventing hybridization of grasshoppers with incompatible Wolbachia strains (Zabal-Aguirre et al 2010, Zabal-Aguirre et al 2014). Furthermore, a previous study found that Wolbachia negatively affects chiasmata formation and induces spermatid malformation in hybrid males of this species; these cytogenetical effects may result in modifications of paternal chromatin that contribute to the pathology of CI (Sarasa et al 2013).…”

New Insight into Wolbachia Epidemiology: Its Varying Incidence During the Host Life Cycle Can Alter Bacteria Spread

“…Experimental data from C. parallelus suggest that partial rescue happens between strains of Wolbachia, since the value of H BI (0.83) is greater than that of H UNI (0.67) Zabal-Aguirre et al 2014). This partial rescue can result in, for instance, more viable eggs from a cross between a coinfected male and an F-infected female than from one between a coinfected male and an uninfected female.…”