Wei Liu

Duck manure, a major pollutant of intensive poultry production, is characterized by high organic load and nutrient content. However, the high water content of duck manure virtually impedes effective manure management. Here, we report the suitability of duck manure as a rearing substrate for larvae of black soldier fly Hermetia illucens L. (Diptera: Stratiomyidae), achieving a corresponding reduction in organic liquid waste. First, duck manure efficiently sustains the development and growth of black soldier fly larvae and is optimized to rear black soldier fly larvae by appropriately adding corn stalk powders. More importantly, the microbiome plays a key role in promoting black soldier fly larvae to bioconvert the duck manure nutrients into insect biomass. Finally, the larval frass exhibited suppressive effects against the plant pathogen Ralstonia solanacearum (Burkholderiales: Burkholderiaceae). Overall, black soldier fly larvae and the microbiome contribute to valorize and bioconvert duck manure in an efficient and environmentally friendly manner, supporting a circular economy.

This study demonstrates the detrimental effects of exogenous uric acid (UA) on the growth of black soldier fly (BSF) larvae, highlighting the role of gut microbiota in UA degradation. We isolated UA-degrading bacterial strains associated with BSF, including Enterococcus faecalis AHAU24. Genomic analysis identified a UA degradation gene cluster in this strain, providing insights into its potential for UA catabolism. Furthermore, mono-association of germ-free larvae with E. faecalis AHAU24 confirmed that this strain alleviates UA-induced growth retardation and enhances bioconversion efficiency by degrading dietary UA.

Natural microbes coexist in a diverse species population with competition for space and nutrient resources. However, the molecular mechanisms underpinning the regulatory networks of microbes among themselves and with their host are still in infancy. Here, it is reported that Drosophila and the commensal Lactiplantibacillus plantarum form an alliance to compete with the pathogenic Serratia marcescens using the integrated three‐species model system. In the dual‐species model, larvae diminish the L. plantarum population, but reversibly increase lactate production through altering its transcriptional reprogramming. In the tripartite‐species model, larvae facilitate the growth of L. plantarum that confers colonization resistance against S. marcescens . On the other hand, S. marcescens launches sophisticated arms race strategies to impair colonization resistance by sensing lactate derived from L. plantarum . More importantly, the S. marcescens population challenged with Drosophila and L. plantarum adaptively diverge into virulent and reduced virulence subclusters with an increase in resistance heterogeneity. To form the alliance with Drosophila , heterogeneity in lactate generation is broadened among L. plantarum subpopulations. Altogether, these findings provide an insight into the host‐commensal‐pathogen symbiosis at both bulk and single‐cell resolutions, advancing fundamental concepts of precise manipulation of bacterial communities.

Host-microbe interactions are virtually bidirectional, but how the host affects their microbiome is poorly understood. Here, we report that the host is a critical modulator to regulate the lifestyle switch and pathogenicity heterogeneity of the opportunistic pathogens Serratia marcescens utilizing the Drosophila and bacterium model system. First, we find that Drosophila larvae efficiently outcompete S. marcescens and typically drive a bacterial switch from pathogenicity to commensalism toward the fly. Furthermore, Drosophila larvae reshape the transcriptomic and metabolic profiles of S. marcescens characterized by a lifestyle switch. More importantly, the host alters pathogenicity and heterogeneity of S. marcescens in the single-cell resolution. Finally, we find that larvae-derived AMPs are required to recapitulate the response of S. marcescens to larvae. Altogether, our findings provide an insight into the pivotal roles of the host in harnessing the life history and heterogeneity of symbiotic bacterial cells, advancing knowledge of the reciprocal relationships between the host and pathogen.

Drosophila suzukii is a notorious pest which causes devastating damage to thin‐skinned fruits, and the larvae feed on the fruit, causing extensive agricultural economic loss. The current application of insecticides to manage this pest results in serious resistance and environmental hazards, so an alternative strategy for D. suzukii biocontrol is urgently needed. Here, we reported that entomopathogenic Bacillus cereus has the potential to biocontrol D. suzukii. We isolated and identified the bacterial strain, B. cereus H1, that was detrimental to the fitness of both D. suzukii progenies and parents. D. suzukii was robustly repelled to depositing eggs on the halves with metabolites of B. cereus H1. Both males and females of D. suzukii were susceptible to B. cereus H1. B. cereus H1 significantly arrested larval development with at least 40% lethal larvae. The median lethal time (LT50) of males and females of D. suzukii challenged with B. cereus H1 was 3 and 2 d, respectively. Moreover, B. cereus H1 disrupted the intestinal integrity and pH value of D. suzukii and resulted in an increase in bacterial load of guts and hemolymph. Mechanistically, infection of B. cereus H1 led to the activation of the dual oxidase (DUOX)‐ROS‐Jun N‐terminal kinase (JNK) pathway. The findings showed that the entomopathogen B. cereus H1 could potentially act as a biological control agent against D. suzukii, advancing fundamental concepts of integrated pest management programs against D. suzukii.

Host-microbe interactions are virtually bidirectional, but how the host affects their microbiome is poorly understood. Here, we report that the host is a critical modulator to regulate the lifestyle switch and pathogenicity heterogeneity of the opportunistic pathogens Serratia marcescens utilizing the Drosophila and bacterium model system. First, we find that Drosophila larvae efficiently outcompete S. marcescens and typically drive a bacterial switch from pathogenicity to commensalism toward the fly. Furthermore, Drosophila larvae reshape the transcriptomic and metabolic profiles of S. marcescens characterized by a lifestyle switch. More important, the host alters pathogenicity and heterogeneity of S. marcescens in the single-cell resolution. Finally, we find that larvae-derived AMPs are required to recapitulate the response of S. marcescens to larvae. Altogether, our findings provide an insight into the pivotal roles of the host in harnessing the life history and heterogeneity of symbiotic bacterial cells, advancing knowledge of the reciprocal relationships between the host and pathogen.

Background: Exposure to extreme cold or heat temperature is one leading cause of weather-associated mortality and morbidity in animals. Emerging studies demonstrate that the microbiota residing in guts act as an integral factor required to modulate host tolerance to cold or heat exposure, but common and unique patterns of animal-temperature associations between cold and heat have not been simultaneously examined. Therefore, we attempted to investigate the roles of gut microbiota in modulating tolerance to cold or heat exposure in mice. Results: The results showed that both cold and heat acutely change the body temperature of mice, but mice efficiently maintain their body temperature at conditions of chronic extreme temperatures. Mice adapt to extreme temperatures by adjusting body weight gain, food intake and energy harvest. Fascinatingly, 16 S rRNA sequencing shows that extreme temperatures result in a differential shift in the gut microbiota. Moreover, transplantation of the extreme-temperature microbiota is sufficient to enhance host tolerance to cold and heat, respectively. Metagenomic sequencing shows that the microbiota assists their hosts in resisting extreme temperatures through regulating the host insulin pathway. Conclusions: Our findings highlight that the microbiota is a key factor orchestrating the overall energy homeostasis under extreme temperatures, providing an insight into the interaction and coevolution of hosts and gut microbiota.

Host-microbe interactions are virtually bidirectional, but how the host affects their microbiome is poorly understood. Here, we report that the host is a critical modulator to regulate the lifestyle switch and pathogenicity heterogeneity of the opportunistic pathogens Serratia marcescens utilizing the Drosophila and bacterium model system. First, we find that Drosophila larvae efficiently outcompete S. marcescens and typically drive a bacterial switch from pathogenicity to commensalism toward the fly. Furthermore, Drosophila larvae reshape the transcriptomic and metabolic profiles of S. marcescens characterized by a lifestyle switch. More important, the host alters pathogenicity and heterogeneity of S. marcescens in the single-cell resolution. Finally, we find that larvae-derived AMPs are required to recapitulate the response of S. marcescens to larvae. Altogether, our findings provide an insight into the pivotal roles of the host in harnessing the life history and heterogeneity of symbiotic bacterial cells, advancing knowledge of the reciprocal relationships between the host and pathogen.

Collective behaviors efficiently impart benefits to a diversity of species ranging from bacteria to humans. Fly larvae tend to cluster and form coordinated digging groups under crowded conditions, yet understanding the rules governing this behavior is in its infancy. We primarily took advantage of the Drosophila model to investigate cooperative foraging behavior. Here, we report that Drosophila‐related species and the black soldier fly have evolved a conserved strategy of cluster digging in food foraging. Subsequently, we investigated relative factors, including larval stage, population density, and food stiffness and quality, that affect the cluster digging behavior. Remarkably, oxygen supply through the posterior breathing spiracles is necessary for the organization of digging clusters. More importantly, we theoretically devise a mathematical model to accurately calculate how the cluster digging behavior expands food resources by diving depth, cross‐section area, and food volume. We found that cluster digging behavior approximately increases 2.2 fold depth, 1.7‐fold cross‐section area, and 1.9 fold volume than control groups, respectively. Amplification of food sources significantly facilitates survival, larval development, and reproductive success of Drosophila challenged with competition for limited food resources, thereby conferring trophic benefits to fitness in insects. Overall, our findings highlight that the cluster digging behavior is a pivotal behavior for their adaptation to food scarcity, advancing a better understanding of how this cooperative behavior confers fitness benefits in the animal kingdom.

Drosophila suzukii (D. suzukii) is a notorious pest that causes devastating damage to thin-skinned fruits because female flies use a serrated ovipositor to pierce the skin of ripening fruits and lay eggs in the flesh with a serrated ovipositor. The current application of insecticides to manage this pest has led to serious resistance and environmental hazards, so there is an urgent need for alternative strategies. In the present work, we reported that identifying a potential entomopathogen Bacillus cereus H1 (B. cereus H1) for D. suzukii from their habitat was lethal to D. suzukii adults following ingestion. First, we isolated and identified an entomopathogen B. cereus H1 from D. suzukii morbid pupae. Next, B. cereus H1 robustly arrested the development of the fly progeny. Moreover, B. cereus H1 exerted an adverse effect on the survival and locomotion of adult flies. Mechanistically, B. cereus H1 disrupted intestinal homeostasis and triggered oxidative innate immunity, resulting in death within 5 days. To the best of our understanding, this study is the first to investigate the role of B. cereus H1 in managing D. suzukii, suggesting that it could be suitable for candidate biopesticides of D. suzukii. Future studies that exploit the mechanism underlying the pathogenicity of B. cereus H1 toward the Spotted Wing Drosophila would improve the knowledge of the ecology of host-entomopathogen interactions in nature.