Balancing life history investment decisions in founding ant queens

Reproduction is a very critical step in the life of an organism. Females must balance their investment in different life-history traits while reproducing. During the process of colony founding in social organisms, such as ants or bees, a trade-off between reproduction and immunity might be very stringent, because queens might be constrained to invest into immune protection of themselves and their developing offspring until the first workers emerge. Here we investigate how different levels of microbial pressure affect colony founding success of Lasius niger ant queens and whether investment into immune defense traits comes at a substantial cost to the queens. In a first experiment mated queens were exposed to four different environments: sterile housing, autoclaved soil, untreated soil and soil containing two opportunistic pathogens. In this experiment, we investigated an immediate cost, i.e., the success of producing the first brood, and a potential delayed cost, i.e., queen survival and colony founding success after hibernation. For the latter, we removed the first brood after hibernation to reveal hidden costs via the application of an additional stressor. We found that irrespective of the microbial environment all queens successfully managed to start a colony, with queens in the soil treatments showing a higher worker production than the queens in the sterile environment. This suggests that either soil components or soil microbes benefit colony growth. After hibernation queens in microbe soil showed significantly lower survival and could not replace a lost brood. In a second experiment, we investigated whether external immune defense in the form of formic acid use can explain part of the costs imposed on queens. We found that queens used formic acid to sanitize their new nest suggesting that queens founding a colony under high microbial pressure are forced to pay a substantial cost by investing in both reproduction and immunity simultaneously. Our results suggest that early, simultaneous investment in reproduction and immunity can allow colony growth under microbial pressure but may be costly in terms of resistance to later challenges. Ant queens may thus be trading off insurance against future challenges for increased pathogen immunity

Complex interactions in a host-symbiont-microbiome triangle: The wasp Asobara japonica, the endosymbiont Wolbachia and the remainder microbiome

Recent research on microbial communities suggests that symbiont-induced phenotypes are not caused by the symbiont alone but in interaction with the remainder host microbiome. Despite this, most current investigations limit themselves to binary host-symbiont interactions ignoring potential microbe-microbe and host-microbe interactions. The inclusion of microbe-microbe and host-microbe interactions into host-symbiont studies is needed, as they will not only help to understand symbiotic interactions better but will also to draw general predictions on the possible future of symbioses in our changing world. In this thesis, I investigate the tripartite interaction between the endosymbiont Wolbachia, its host, the parasitic wasp Asobara japonica, and the remainder microbiome. Wolbachia infection in these wasps causes asexual reproduction, which can occasionally fail, potentially due to microbe-microbe or host-microbe interactions. By investigating the complex interactions between host genotype, bacterial community composition and symbiont status in the field and experimentally, I show that the symbiont-induced reproductive phenotype is executed in close interaction with the host genotype and the remainder microbiome. This study, therefore, provides an important first step to deepening our understanding of this tripartite interaction

Microbial community composition of nest-carton and adjoining soil of the ant Lasius fuliginosus and the role of host secretions in structuring microbial communities

The ant Lasius fuliginosus stabilizes its carton-nest structures through the growth of fungi. Here we investigated the fungal and bacterial community composition in nest-carton and adjoining soil of L. fuliginosus. We found that fungal communities in the nest were stable and distinct from surrounding soil over 2 y, while bacterial communities were not stable with the differentiation between nest and surrounding soil changing over the years. This suggests that in contrast to bacterial communities, fungal communities in the nest are actively managed by the ant L. fuliginosus, a result that was corroborated by additional growth assays. In these assays we found that an antagonistic fungus was inhibited when incubated with extracts of ant body parts, while fungal associates were not only not affected but even partly favoured in their growth. Overall our results support a role of host secretions in shaping the association between L. fuliginosus and fungal partners

Host, Symbionts, and the Microbiome: The Missing Tripartite Interaction

International audienceSymbiosis between microbial associates and a host is a ubiquitous feature of life on earth, modulating host phenotypes. In addition to endosymbionts, organisms harbour a collection of host-associated microbes, the microbiome that can impact important host traits. In this opinion article we argue that the mutual influences of the microbiome and endosymbionts, as well as their combined influence on the host, are still understudied. Focusing on the endosymbiont Wolbachia, we present growing evidence indicating that host phenotypic effects are exerted in interaction with the remainder microbiome and the host. We thus advocate that only through an integrated approach that considers multiple interacting partners and environmental influences will we be able to gain a better understanding of host–microbe associations

Data and scripts from: Microbiome composition is shaped by geography and population structure in the parasitic wasp Asobara japonica, but not in the presence of the endosymbiont Wolbachia

A detailed description of how samples were collected, processed, and analysed can be found in the publication: Brinker et al. 2022, Microbiome composition is shaped by geography and population structure in the parasitic wasp Asobara japonica, but not in the presence of the endosymbiont Wolbachia.,The microbial community composition is crucial for diverse life-history traits in many organisms. However, we still lack a sufficient understanding of how the host microbiome is acquired and maintained, a pressing issue in times of global environmental change. Here we investigated to what extent host genotype, environmental conditions, and the endosymbiont Wolbachia influence the bacterial communities in the parasitic wasp Asobara japonica. We sampled multiple wasp populations across ten locations in their natural distribution range in Japan and sequenced the host genome (whole genome sequencing) and microbiome (16S rRNA gene). We compared the host population structure and bacterial community composition of wasps that reproduce sexually and are uninfected with Wolbachia with wasps that reproduce asexually and carry Wolbachia. The bacterial communities in asexual wasps were highly similar due to a strong effect of Wolbachia rather than host genomic structure. In contrast, in sexual wasps, bacterial communities appear primarily shaped by a combination of population structure and environmental conditions. Our research highlights that multiple factors shape the bacterial communities of an organism and that the presence of a single endosymbiont can strongly alter their compositions. This information is crucial to understanding how organisms and their associated microbiome will react in the face of environmental change

Microbiome composition is shaped by geography and population structure in the parasitic wasp Asobara japonica , but not in the presence of the endosymbiont Wolbachia

International audienceThe microbial community composition is crucial for diverse life-history traits in many organisms. However, we still lack a sufficient understanding of how the host microbiome is acquired and maintained, a pressing issue in times of global environmental change. Here we investigated to what extent host genotype, environmental conditions, and the endosymbiont Wolbachia influence the bacterial communities in the parasitic wasp Asobara japonica. We sampled multiple wasp populations across ten locations in their natural distribution range in Japan and sequenced the host genome (whole genome sequencing) and microbiome (16S rRNA gene). We compared the host population structure and bacterial community composition of wasps that reproduce sexually and are uninfected with Wolbachia with wasps that reproduce asexually and carry Wolbachia. The bacterial communities in asexual wasps were highly similar due to a strong effect of Wolbachia rather than host genomic structure. In contrast, in sexual wasps, bacterial communities appear primarily shaped by a combination of population structure and environmental conditions. Our research highlights that multiple factors shape the bacterial communities of an organism and that the presence of a single endosymbiont can strongly alter their compositions. This information is crucial to understanding how organisms and their associated microbiome will react in the face of environmental change

Microporous silica based membranes for desalination

This review provides a global overview of microporous silica based membranes for desalination via pervaporation with a focus on membrane synthesis and processing, transport mechanisms and current state of the art membrane performance. Most importantly, the recent development and novel concepts for improving the hydro-stability and separating performance of silica membranes for desalination are critically examined. Research into silica based membranes for desalination has focussed on three primary methods for improving the hydro-stability. These include incorporating carbon templates into the microporous silica both as surfactants and hybrid organic-inorganic structures and incorporation of metal oxide nanoparticles into the silica matrix. The literature examined identified that only metal oxide silica membranes have demonstrated high salt rejections under a variety of feed concentrations, reasonable fluxes and unaltered performance over long-term operation. As this is an embryonic field of research several target areas for researchers were discussed including further improvement of the membrane materials, but also regarding the necessity of integrating waste or solar heat sources into the final process design to ensure cost competitiveness with conventional reverse osmosis processes