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

Abstract

Wolbachia is an obligate endosymbiont whose spread depends mainly on its capacity to alter host reproduction by, for instance, cytoplasmic incompatibility. Several mathematical models have been developed to explain the dynamics of bacterial spread, because of its applied interest. However, some aspects of the host's and bacterium's biology have not been considered in modelling: for instance, changes in Wolbachia proportions during the host's life cycle have been observed in several species, including Drosophila sp., Nasonia sp. and Aedes sp. (Diptera), but also in the grasshopper Chorthippus parallelus (Orthoptera), the species studied in this article. These changes influence the proportion of incompatible crosses and, consequently, infection prevalence in subsequent generations. In this paper, we are interested in ascertaining whether these changes in the infection proportions during the host's life cycle can influence the dynamics of the spread of these bacteria. We have examined its consequences using a mathematical model to predict the evolution of Wolbachia infection frequencies. The simulations were validated by experimental field data from C. parallelus. The main outcome is that those changes above mentioned might affect long-term infection spread, with possible consequences for the current distribution of Wolbachia and the way it affects its host's reproduction.

Modeling the indirect effect of Wolbachia on the infection dynamics of horizontally transmitted viruses

“…We have pointed out that the host life-cycle A previous theoretical study by Martinez-Rodriguez et al ( 2014 ) pointed out that the host life cycle can alter the infection dynamics of CI-inducing Wolbachia , e.g., if some host individuals loose the infection during their life span. An important implication of this study is that hybrid zones involving uni- and bidirectional CI can stably persist, which would not be possible according to standard models (cf.…”

Entomopathogenic microorganisms in locusts and grasshoppers populations and prospects for their use for control of this pest group

“…Potential impact of Wolbachia on processes of hybridization in the overlapping areas of insect host subspecies is noted and horizontal transfer of genes from a genome of a parasite in the host's genome is proved [11,12]. Changes in incidence dynamics of Wolbachia during the life cycle of grasshoppers may be connected with weather conditions [13]. It was discovered that conjoint infection of Chorthippus parallelus Zett.…”

Chorthippus parallelus and Wolbachia: Overlapping Orthopteroid and Bacterial Hybrid Zones

“…Testing the infection frequencies several times in the same populations during the life cycle of these grasshoppers revealed significant differences at certain localities during the summer season. These were associated with a threshold temperature that appears to be lethal to the bacteria, but as a result it clearly influences the proportion of incompatible crosses over time in a given population and, consequently, the prevalence and spread of infection in subsequent generations (Martínez-Rodríguez et al, 2014).…”