Medfly-Wolbachia symbiosis: genotype x genotype interactions determine host’s life history traits under mass rearing conditions

BackgroundWolbachia pipientisis a widespread, obligatory intracellular and maternally inherited bacterium, that induces a wide range of reproductive alterations to its hosts. Cytoplasmic Incompatibility (CI) is causing embryonic lethality, the most common of them. Despite thatWolbachia-borne sterility has been proposed as an environmental friendly pest control method (Incompatible Insect Technique, IIT) since 1970s, the fact thatWolbachiamodifies important fitness components of its hosts sets severe barriers to IIT implementation. Mass rearing of Mediterranean fruit fly,Ceratitis capitata(medfly), is highly optimized given that this pest is a model species regarding the implementation of another sterility based pest control method, the Sterile Insect Technique (SIT). We used the medfly-Wolbachiasymbiotic association, as a model system, to study the effect of two differentWolbachiastrains, on the life history traits of 2C. capitatalines with different genomic background.ResultsWolbachiaeffects are regulated by bothC. capitatagenetic background and theWolbachiastrain.Wolbachiainfection reduces fertility rates in bothC. capitatagenetic backgrounds and shortens the pre-pupa developmental duration in the GSS strain. On the other hand, regardless of the strain ofWolbachia(wCer2,wCer4) infection does not affect either the sex ratio or the longevity of adults.wCer4 infection imposed a reduction in females’ fecundity butwCer2 did not. Male mating competitiveness, adults flight ability and longevity under water and food deprivation were affected by both the genetic background of medfly and the strain ofWolbachia(genotype by genotype interaction).ConclusionWolbachiainfection could alter important life history traits of mass-rearedC. capitatalines and therefore the response of each genotype on theWolbachiainfection should be considered toward ensuring the productivity of theWolbachia-infected insects under mass-rearing conditions.