Host Traits Research Articles

Wood microbiome variation and interactions with fungal symbionts of invasive ambrosia beetles

The microbiomes of plants can modulate the impacts of pests, including through interactions with microbiomes of pathogen vectors such as ambrosia beetles. While physical and chemical traits of plant hosts are known to affect beetle-carried microbes, how beetle and host microbiomes interact is seldom explored. We aimed to determine whether wood-inhabiting endophytes mediate host susceptibility to Fusarium dieback, an emergent tree disease complex that includes ambrosia beetle vectors. We studied three competent host tree species (Persea americana, Salix spp., Platanus racemosa) common in disease hot spots in agricultural and wildland habitats. Using culturing methods, we compared wood microbiomes of 319 attacked and 133 non-attacked trees across a network of 47 beetle-infested and 41 non-infested plots in southern California, USA. We conducted 1,148 in vitro assays to evaluate antagonism by wood-inhabiting endophytic fungi (60 species) and bacteria (40 species) to the Fusarium pathogens, finding 15 fungal and 11 bacterial species with clear antagonism to the pathogen. Such wood endophytes may potentially protect tree hosts as biological control agents. Antagonistic microbes were more common in attacked trees than in non-attacked trees, suggesting the abundance of antagonistic fungi and bacteria in the wood is insufficient to determine host susceptibility to attack or they are enriched in attacked trees. Wood-inhabiting microbial communities were consistently different between cultivated P. americana and wildland tree species, as there were some differences based on host attack status. Differences between attacked and non-attacked trees were reflected in different microbial consortia rather than the abundance of individual, antagonistic microbial species.

From host individual traits to community structure and composition: Bartonella infection insights

BackgroundPhylogeny, combined with trait-based measures, offers insights into parasite sharing among hosts. However, the specific traits that mediate transmission and the aspects of host community diversity that most effectively explain parasite infection rates remain unclear, even for the Bartonella genus, a vector-borne bacteria that causes persistent blood infections in vertebrates.MethodsThis study investigated the association between rodent host traits and Bartonella infection, as well as how rodent community diversity affects the odds of infection in the Atlantic Forest, using generalized linear models. Additionally, we assessed how host traits and phylogenetic similarities influence Bartonella infection among mammal species in Brazil. To this end, rodents were sampled from ten municipalities in Rio de Janeiro, southeastern Brazil. Then, we calculated several diversity indices for each community, including Rényi’s diversity profiles, Fisher’s alpha, Rao’s quadratic entropy (RaoQ), Functional Diversity (FDis), Functional Richness (FRic), and Functional Evenness (FEve). Finally, we compiled a network encompassing all known interactions between mammal species and Bartonella lineages recorded in Brazil.ResultsWe found no significant relationship between diversity indices and the odds of Bartonella infection in rodent communities. Furthermore, there was no statistical support for the influence of individual-level traits (e.g., body length, sex, and age) or species-level ecological traits (e.g., locomotor habitat, dietary guild, and activity period) on Bartonella infection in rodents. A country-scale analysis, considering all mammal species, revealed no effect of host traits or phylogeny on Bartonella infection.ConclusionsThis study highlighted wild mammals that share Bartonella lineages with livestock, synanthropic, and domestic animals, underscoring the complexity of their maintenance cycle within the One Health framework. A key question arising from our findings is whether molecular host–cell interactions outweigh host body mass and ecological traits in influencing Bartonella infection, potentially opening new avenues for understanding host–parasite relationships and infection ecology.Graphical

Influence of bark chemistry on distribution of epiphytic mosses on basal trunk of <i>Cryptomeria japonica</i>

Epiphytic mosses are integral parts of forest community structure in the Darjeeling Hills of the Eastern Himalayan region with remarkable contributions to the ecosystem functionality. The study was framed to assess the richness and spatial distribution of epiphytic mosses growing on the basal trunk of Cryptomeria japonica (Thunb. ex. L.) D.Don, and also to evaluate the explanatory host traits for shaping the moss assemblage. Field measurements and sampling were performed near Lamahatta village within Darjeeling district on 270 microplots placed on tree trunks. A total of twelve mosses represented by the members of Dicranales and Hypnales were recorded. Low species diversity was observed with dominance and maximum cover of Syrrhopodon confertus. Canonical correspondence analysis predicted a distinct combination of chemical requirements for local colonization of each moss. The results also demonstrated influence of bark acidic inputs on abundance and co-existence of bryophytes. The outcome can be potentially helpful in depicting the community structure of non-vascular epiphytes, which may further be considered while developing forest management strategies.

Temporal changes in streamflow can predict parasitism levels in freshwater prawns better than host traits

Abstract Understanding how changes in the hydrological regime drive parasite loads and dynamics remains a challenging issue in ecological parasitology. Temporal changes in streamflow and rainfall are key hydrological factors that could alter interactions between the parasite and host and affect parasitism levels. However, to investigate the effect of streamflow, rainfall and its mechanisms, it is important to control host traits that can also influence parasitism levels in freshwater systems. Here, we used a cymothoid‐palaemonid prawn model to test the combined effects of streamflow and rainfall accounting for host traits to predict variations in parasite loads in stream ecosystems. We collected the palaemonid prawns monthly for 2 years and measured the variation of rainfall and streamflow (i.e. stream discharge) at the time of prawn sampling. Our best model showed that streamflow can predict parasitism levels in prawns better than host traits. We found a higher prevalence and abundance of parasites in reduced streamflow compared to increased ones. We also found higher ectoparasite loads in females rather than males and occurring in autumn and winter rather than in spring and summer. Our results also showed that ectoparasite loads also suffer an effect of host body size, sex and moult stage, but not host age. Our findings show that reduced streamflow can facilitate host finding that favours parasite transmission in dry seasons and increase parasitism levels in stream systems. Temporal variability in streamflow can have a strong influence on parasite loads and dynamics compared to host traits in stream ecosystems. Identifying how interactions between aquatic invertebrates and parasites respond to variability in the hydrological regime can help to better understand and predict disease outbreaks as habitat reduction and disturbance continue in stream ecosystems.

How host ecology influences the parasite communities of three Australian flathead fishes, Platycephalus spp. (Scorpaeniformes: Platycephalidae)

This study investigated the role of host traits, habitat, and sampling season on the prevalence and intensity of parasites in three species of platycephalid fishes. Three host species sampled were dusky flathead (Platycephalus fuscus, n = 3), blue-spotted flathead (Platycephalus caeruleopunctatus, n = 38), and tiger flathead (Platycephalus richardsoni, n = 59). A total of 14 metazoan parasite species were collected over 15 months, between July 2020 and September 2021. The parasites found included a chondracanthid copepod, adult hemiuroidean trematodes, cestode plerocercoids, larval and adult acanthocephalans, larval and adult nematodes, and an unknown species of helminth. General linear models were used to assess the relationship between host traits and sampling season with parasite infection intensity. The infection intensity of an unidentified plerocercoid species in P. caeruleopunctatus was found to be significantly associated with both sampling season and the interaction of host mass with sex. In P. richardsoni the infection intensity of the acanthocephalan, Corynosoma sp. was found to correlate with sampling season. The highest richness of parasite taxa was recorded from P. richardsoni, which may be due to the wide depth range of P. richardsoni, coupled with its generalist diet.

Influence of genetic and environmental factors on the success of endosymbiont transfers in pest aphids.

There is increasing interest in exploring how endosymbionts could be useful in pest control, including in aphids, which can carry a diversity of endosymbionts. Endosymbionts often have a large impact on host traits, and their presence can be self-sustaining. Identifying useful host-endosymbiont combinations for pest control is facilitated by the transfer of specific endosymbionts into target species, particularly if the species lacks the endosymbiont. Here, we complete a comprehensive literature review, which included 56 relevant papers on endosymbiont transfer experiments in aphids, to uncover factors that might influence transfer success. We then report on our own microinjection attempts of diverse facultative endosymbionts from a range of donor species into three agriculturally important aphid species as recipients: the green peach aphid (Myzus persicae), bird cherry-oat aphid (Rhopalosiphum padi), and Russian wheat aphid (Diuraphis noxia). Combining this information, we consider reasons that impact the successful establishment of lines carrying transferred endosymbionts. These include a lack of stability in donors, deleterious effects on host fitness, the absence of plant-based (versus vertical) transmission, high genetic variation in the endosymbiont, and susceptibility of an infection to environmental factors. Taking these factors into account should help in increasing success rates in future introductions.

Comparative Analyses of Lycodon rufozonatus and Lycodon rosozonatus Gut Microbiota in Different Regions.

The interactions between hosts and the gut microbiota are intricate and can significantly affect the ecology and evolution of both parties. Various host traits, including taxonomy, diet, social behaviour, and external factors such as prey availability and the local environment, all play an important role in shaping composition and diversity of the gut microbiogta. In this study, we explored the impact of intestinal microorganisms on the host in adapting to their respective ecological niches in two species of snakes. We collected feces from Lycodon rufozonatus and Lycodon rosozonatus from different geographical locations and used 16S rRNA gene sequencing technology to sequence the v3-v4 region. The results revealed that there was no significant difference in the alpha diversity of intestinal microorganisms between L. rufozonatus and L. rosozonatus. The gut microbiota of all individuals comprised four main phyla: Pseudomonadota, Bacteroidota, Bacillota, and Actinomycetota. At the genus level, the genus Salmonella dominated the enterobacterial microbiota in the samples from Hainan, while there was no obvious dominant genus in the enterobacterial microbiota of the samples from the other four localities. Comparative analysis of enzyme families annotated to the gut microbiota between L. rufozonatus and L. rosozonatus from the four sampling regions by CAZy carbohydrate annotation revealed that nine enzyme families differed significantly in terms of glycoside hydrolases (GHs). In addition, we compared the composition of gut microbial communities between L. rufozonatus and L. rosozonatus and investigated the impact of the differences on their functions. Our results will provide insights into the coevolution of host and gut microbes.

Universal versus taxon-specific drivers of helminth prevalence and intensity of infection.

Two key epidemiological parameters, prevalence and mean intensity of infection, together capture the abundance of macroparasite populations, the strength of density-dependent effects they experience, their potential impact on host population dynamics and the selective pressures they exert on their hosts. Yet, the drivers of the extensive variation observed in prevalence and mean intensity of infection, even among related parasite taxa infecting related hosts, remain mostly unknown. We performed phylogenetically grounded Bayesian modelling across hundreds of amphibian populations to test the effects of various predictors of prevalence and intensity of infection by six families of helminth parasites. We focused on the potential effects of key host traits and environmental factors pertinent to focal host populations, i.e. the local diversity of the amphibian community and local climatic variables. Our analyses revealed several important determinants of prevalence or intensity of infection in various parasite families, but none applying to all families. Our study uncovered no universal driver of parasite infection levels, even among parasite taxa from the same phylum, or with similar life cycles and transmission modes. Although local variables not considered here may have effects extending across taxa, our findings suggest the need for a taxon-specific approach in any attempt to predict disease dynamics and impacts in the face of environmental and climatic changes.

Shedding light on the diversity of epiphytic mosses in some Mexican forests

Background: Epiphytic mosses are one of the most common groups in forest environments but among the most neglected by researchers in Mexico. Questions: What is the epiphytic mosses diversity, measured in richness, turnover, and community composition in Mexican forests? Species of study: Epiphytic mosses. Study site and years: Humid mountain forest, pine-oak and tropical evergreen forests. Study period: 2015 to 2021. Methods: Through a literature review and field work we compiled data on epiphytic mosses in three forest types in Mexico. We assessed the data using alpha and beta diversity analysis, indicator species, and community composition. Additionally, we explored the influence of elevation and forest type on the observed diversity patterns. Results: We report a richness of 147 species of epiphytic mosses across three types of Mexican forests. The humid mountain forest was the best sampled forest with the highest moss species richness. Although species richness is different for the forests studied, species turnover is similar among them. We demonstrated that elevation and forest type are highly correlated with species richness of epiphytic mosses. Conclusions: The epiphytic mosses studied here collectively represent over 15 % of the moss richness of Mexico. Forest type and elevation seem to be the drivers of this widely distributed richness. Finally, we call for more in-depth studies of the forests presented here, as well as those in other latitudes including variables such as humidity and host traits, to provide a more complete picture of an overlooked Mexican flora.

Patterns of microbiome composition in tsetse fly Glossina palpalis palpalis during vector control using Tiny Targets in Campo, South Cameroon.

Novel vector control tools against African trypanosomiases require a deep understanding of the factors driving tsetse vector fitness or population resilience in their ecosystems. Following evidence of microbiota-mediated host fitness or traits shaping, including insecticide resistance in arthropod populations, we undertook a comparative study of the microbiota in wild-caught tsetse flies during vector control with deltamethrin-impregnated traps called Tiny Targets. The bacterial microbiome composition of tsetse flies collected before and after 6, 12, and 18 months of vector control were characterized using high-throughput sequencing of the V3-V4 hypervariable region of the bacterial 16S rRNA gene and compared. Overall, 48 bacterial genera and five phyla were identified. The primary symbiont Wigglesworthia dominated almost all the samples with an overall relative abundance of 71.76%. A significant increase was observed in microbiome diversities over the vector control with new taxa identified. Interestingly, few genera, like Curvibacter for instance, displayed a regularly increasing abundance, from 0.57% to 0.65%, 4.73%, and 8.57% after 6, 12, and 18 months of tsetse control, respectively. This study provided preliminary for further investigation into the role and mechanism of action of microbiota in tsetse fly fitness under selective pressure like insecticides.IMPORTANCEThe interest in vector control in the fight against African trypanosomiases has been reinforced in recent years, with the development of small insecticide-impregnated screens, known as "Tiny Targets". As some tsetse biotopes are difficult to access for their installation, other tools are under consideration that involve using bacteria harbored by the tsetse vector to block the development of trypanosomes or impair the tsetse's fitness in its natural environment. Several bacterial symbionts were previously described as important for tsetse fly development, and some like Burkholderia and Citrobacter also found in tsetse flies were found associated with insecticide tolerance in other arthropods. In this research, we found the bacterial genera, Curvibacter and Acinetobacter, increased in abundance in tsetse flies during vector control. These bacteria deserve further attention to determine if they can interfere with insecticides used to control tsetse fly populations.

From Skin to Gut: Understanding Microbial Diversity in Rana amurensis and R. dybowskii.

Amphibians face the threat of decline and extinction, and their health is crucially affected by the microbiota. Their health and ecological adaptability essentially depend on the diverse microbial communities that are shaped by unique host traits and environmental factors. However, there is still limited research on this topic. In this study, cutaneous (C) and gut (G) microbiota in Rana amurensis (A) and R. dybowskii (D) was analyzed through 16S amplicon sequencing. Groups AC and DC significantly differed in alpha diversity, while the gut groups (AG and DG) showed no such differences. Analyses of Bray-Curtis dissimilarity matrix and unweighted UniFrac distances showed significant differences in cutaneous microbiota between groups AC and DC, but not between groups AG and DG. Stochastic processes significantly influenced the assembly of cutaneous and gut microbiota in amphibians, with a notably higher species dispersal rate in the gut. The predominant phyla in the skin of R. amurensis and R. dybowskii were Bacteroidetes and Proteobacteria, respectively, with significant variations in Bacteroidota. Contrarily, the gut microbiota of both species was dominated by Firmicutes, Proteobacteria, and Bacteroidetes, without significant phylum-level differences. Linear discriminant analysis effect size (LEfSe) analysis identified distinct microbial enrichment in each group. Predictive analysis using phylogenetic investigation of communities by reconstruction of unobserved states 2 (PICRUSt2) revealed the significant functional pathways associated with the microbiota, which indicates their potential roles in immune system function, development, regeneration, and response to infectious diseases. This research underscores the critical impact of both host and environmental factors in shaping amphibian microbial ecosystems and emphasizes the need for further studies to explore these complex interactions for conservation efforts.

The Dominance of Coinfecting Parasites' Indirect Genetic Effects on Host Traits.

AbstractIndirect genetic effects (IGEs) exist when there is heritable variation in one organism's ability to alter a second organism's traits. For example, parasites have antigens that can induce a host immune response, as well as disparate strategies to evade or suppress host immunity; among-parasite genetic variation in these antigens generates among-host variation in immune traits. Here, we experimentally show that the cestode parasite Schistocephalus solidus exerts an IGE on an immune trait (peritoneal fibrosis) in its threespine stickleback host: stickleback developed strong fibrosis after exposure to some parasite genotypes but not others. A complication arises during coinfection, when two or more parasite genotypes may impose conflicting IGEs on the same host trait. What parasite-controlled trait will the host express? Will the host trait reflect the more immune-stimulatory parasite genotype or the more immune-evasive genotype? These alternatives can be quantified by estimating the dominance coefficient, as if a coinfected host were a heterozygote. We experimentally estimated the dominance of S. solidus IGEs by coinjecting antigens from different parasite genotypes. Contrary to our a priori hypotheses, coinjected antigens induced an overdominant effect, stronger than either parasite's antigens alone. We present a mathematical model showing that the value of this IGE dominance is biologically important, affecting the evolutionary dynamics of parasites in a density- and frequency-dependent manner. The model indicates that overdominance would be detrimental to immigrants when resident prevalence is high. This combination of experimental data and modeling provides an example of a parasite IGE on host traits and the evolutionary significance of IGE dominance.

Host traits rather than migration and molting strategies explain feather bacterial load in Palearctic passerines

Host traits rather than migration and molting strategies explain feather bacterial load in Palearctic passerines

The fecal microbiota of Holstein cows is heritable and genetically correlated to dairy performances.

The fecal microbiota of ruminants constitutes a diversified community that has been phenotypically associated with a variety of host phenotypes, such as production and health. To gain a better understanding of the complex and interconnected factors that drive the fecal bacterial community, we have aimed to estimate the genetic parameters of the diversity and composition of the fecal microbiota, including heritabilities, genetic correlations among taxa, and genetic correlations between fecal microbiota features and host phenotypes. To achieve this, we analyzed a large population of 1,875 Holstein cows originating from 144 French commercial herds and routinely recorded for production, somatic cell score, and fertility traits. Fecal samples were collected from the animals and subjected to 16S rRNA gene sequencing, with reads classified into Amplicon Sequence Variants (ASVs). The estimated α- and β-diversity indices (i.e., Observed Richness, Shannon index, Bray-Curtis and Jaccard dissimilarity matrices) and the abundances of ASVs, genera, families and phyla, normalized by centered-log ratio (CLR), were considered as phenotypes. Genetic parameters were calculated using either univariate or bivariate animal models. Heritabilities estimates, ranging from 0.08 to 0.31 for taxa abundances and β-diversity indices, highlight the influence of the host genetics on the composition of the fecal microbiota. Furthermore, genetic correlations estimated within the microbial community and between microbiota features and host traits reveal the complex networks linking all components of the fecal microbiota together and to their host, thus strengthening the holobiont concept. By estimating the heritabilities of microbiota-associated phenotypes, our study quantifies the impact of the host genetics on the fecal microbiota composition. In addition, genetic correlations between taxonomic groups and between taxa abundances and host performance suggest potential applications for selective breeding to improve host traits or promote a healthier microbiota.

Niche partitioning and host specialisation in fish-parasitising isopods: Trait-dependent patterns from three ecosystems on the east coast of India.

Due to their large size and obligate nature, Cymothoid isopods inflict a high degree of tissue damage to fish. Still, they are understudied at an ecosystem level despite their global presence and ecological role. In this work, we collected fish host-isopod parasite data, along with their life history and ecological traits, from the northern part of the east coast of India and investigated patterns in host specialisation and preference of isopod parasites using a trait-based network perspective. We observed that the region of attachment of the parasite (buccal cavity, branchial cavity, and skin) and host fish ecology (schooling behaviour and habitat characteristics) influenced host specialisation and preference. We found that branchial cavity-attaching parasites preferred schooling, pelagic fishes, whereas buccal cavity-attaching parasites preferred mostly non-schooling, demersal fishes. Skin-attaching parasites were found to be generalists and had no preference based on our examined host traits.

Selection for stress tolerance and longevity in Drosophila melanogaster have strong impacts on microbiome profiles

There is experimental evidence that microbiomes have a strong influence on a range of host traits. Understanding the basis and importance of symbiosis between host and associated microorganisms is a rapidly developing research field, and we still lack a mechanistic understanding of ecological and genetic pressures affecting host-microbiome associations. Here Drosophila melanogaster lines from a large-scale artificial selection experiment were used to investigate whether the microbiota differ in lines selected for different stress resistance traits and longevity. Following multiple generations of artificial selection all selection regimes and corresponding controls had their microbiomes assessed. The microbiome was interrogated based on 16S rRNA sequencing. We found that the microbiome of flies from the different selection regimes differed markedly from that of the unselected control regime, and microbial diversity was consistently higher in selected relative to control regimes. Several common Drosophila bacterial species showed differentially abundance in the different selection regimes despite flies being exposed to similar environmental conditions for two generations prior to assessment. Our findings provide strong evidence for symbiosis between host and microbiomes but we cannot reveal whether the interactions are adaptive, nor whether they are caused by genetic or ecological factors.

Deciphering functional groups of rumen microbiome and their underlying potentially causal relationships in shaping host traits.

Over the years, microbiome research has achieved tremendous advancements driven by culture-independent meta-omics approaches. Despite extensive research, our understanding of the functional roles and causal effects of the microbiome on phenotypes remains limited. In this study, we focused on the rumen metaproteome, combining it with metatranscriptome and metabolome data to accurately identify the active functional distributions of rumen microorganisms and specific functional groups that influence feed efficiency. By integrating host genetics data, we established the potentially causal relationships between microbes-proteins/metabolites-phenotype, and identified specific patterns in which functional groups of rumen microorganisms influence host feed efficiency. We found a causal link between Selenomonas bovis and rumen carbohydrate metabolism, potentially mediated by bacterial chemotaxis and a two-component regulatory system, impacting feed utilization efficiency of dairy cows. Our study on the nutrient utilization functional groups in the rumen of high-feed-efficiency dairy cows, along with the identification of key microbiota functional proteins and their potentially causal relationships, will help move from correlation to causation in rumen microbiome research. This will ultimately enable precise regulation of the rumen microbiota for optimized ruminant production.

METAZOAN PARASITE COMMUNITY OF THE YELLOW SNAPPER LUTJANUS ARGENTIVENTRIS: FACTORS THAT INFLUENCING SPECIES COMPOSITION AND RICHNESS.

A total of 366 individuals of Lutjanus argentiventris (Peters, 1869) were collected over a 5-yr period (October 2018 to June 2022) from Acapulco Bay, Mexico. Parasite communities in Lutjanus argentiventris were quantified and analyzed to determine the main factors that generate changes in species richness and/or species composition over time. The digeneans and copepods were the best-represented parasite groups. The parasite communities were characterized by a high numerical dominance of ectoparasites, mainly isopod larvae. Species richness at the component community level (9-23 species) was similar to the reported richness in other Lutjanus spp. The parasite communities of Lutjanus argentiventris exhibited high variability in species composition, suggesting that each parasite species may respond differently to environmental changes. However, the species richness and diversity were fairly stable over time; therefore, a clear pattern of interannual variation was not observed. Variations in the community structure probably were due to factors such as host traits (e.g., feeding behavior and body size), and possible interannual differences in environmental factors amplified by the occurrence of the anomalous event of La Niña.

Temporal dynamics of parasite populations and communities of blue sea catfish Ariopsis guatemalensis (Günther, 1864), in a eutrophic coastal lagoon from Mexican Pacific

ABSTRACT The temporal dynamics of parasite populations and communities of blue sea catfish Ariopsis guatemalensis from a tropical eutrophic coastal lagoon was studied during an annual cycle. A total of 620 adult fishes were collected between January and December 2019. Eleven taxa of parasites were identified, three of monoxenous (single-host life cycle), and eight of heteroxenous (multi-host life cycle) parasites. The infection levels of two monoxenous (Neotetraonchus vegrandis and Ergasilus sp.) and five heteroxenous (Austrodiplostomum sp. Pseudoacanthostomum panamense, Pseudoleptorhynchoides lamothei, Contracaecum sp. and Hysterothylacium perezi) parasite species varied between sampling months and/or climatic seasons. The infection dynamics of these group of parasites were influenced by environmental changes generated by the dry/rainy cycle, which can affect the availability of intermediate host populations, and the feeding and reproductive behaviour of the host. Although the species composition of the parasite communities remains quite stable over time, its structure registers important changes mainly during the rainy season. Some host traits such as the feeding and reproductive behaviour, body size, physical condition, and sex of the host, as well as the temporal replacement of numerically dominant parasite species, were the main factors responsible for variations in the parasite community structure.

Wolbachia impacts microbiome diversity and fitness-associated traits for Drosophila melanogaster in a seasonally fluctuating environment.

The microbiome contributes to many different host traits, but its role in host adaptation remains enigmatic. The fitness benefits of the microbiome often depend on ecological conditions, but theory suggests that fluctuations in both the microbiome and environment modulate these fitness benefits. Moreover, vertically transmitted bacteria might constrain the ability of both the microbiome and host to respond to changing environments. Drosophila melanogaster provides an excellent system to investigate the impacts of interactions between the microbiome and the environment. To address this question, we created field mesocosms of D. melanogaster undergoing seasonal environmental change with and without the vertically transmitted bacteria, Wolbachia pipientis. Sampling temporal patterns in the microbiome revealed that Wolbachia constrained microbial diversity. Furthermore, Wolbachia and a dominant member of the microbiome, Commensalibacter, were associated with differences in two higher-order fitness traits, starvation resistance and lifespan. Our work here suggests that the interplay between the abiotic context and microbe-microbe interactions may shape key host phenotypes that underlie adaptation to changing environments. We conclude by exploring the consequences of complex interactions between Wolbachia and the microbiome for our understanding of eco-evolutionary processes that shape host-microbiome interactions.