Infections patterns and fitness effects ofRickettsiaandSodalissymbionts in the green lacewingChrysoperla carnea

Abstract

AbstractEndosymbionts are wide-spread among insects and can play an essential role in host ecology. The common green lacewing (Chrysoperla carneas. str.) is a neuropteran insect species which is widely used as a biological pest control. We screened for endosymbionts in natural and laboratory populations of the green lacewing using diagnostic PCR amplicons. We found the endosymbiontRickettsiato be very common in all screened populations, whereas a so far uncharacterizedSodalisstrain was solely found in laboratory populations. The newSodalisstrain was characterized using a whole genome shotgun approach. Its draft genome revealed an approximate genome size of 4.3 Mbp and the presence of 5213 coding sequences. Phylogenomic analyses indicated that this bacterium is the sister taxon ofS. praecaptivus. In an experimental approach, we found a negative impact ofSodalison the reproduction success of the green lacewing. Co-infections withRickettsiaandSodaliscaused an even higher decrease of reproductive success than singleSodalisinfections. In contrast, no significant fitness differences were found inRickettsiainfected green lacewings compared to uninfected lacewings. TheRickettsia/Sodalis/Ch. carneasystem presents a promising model to study evolutionary endosymbiont-host interactions in Neuroptera and endosymbiont-endosymbiont interactions in general. The economic and ecological importance of green lacewings in biological pest control warrants a more profound understanding of its biology, which might be strongly influenced by symbionts.