@article{beza-beza_wiegmann_ware_petersen_gunter_cole_schwarz_bertone_young_mikaelyan_2024, title={Chewing through challenges: Exploring the evolutionary pathways to wood-feeding in insects}, volume={3}, ISSN={["1521-1878"]}, url={https://doi.org/10.1002/bies.202300241}, DOI={10.1002/bies.202300241}, abstractNote={Decaying wood, while an abundant and stable resource, presents considerable nutritional challenges due to its structural rigidity, chemical recalcitrance, and low nitrogen content. Despite these challenges, certain insect lineages have successfully evolved saproxylophagy (consuming and deriving sustenance from decaying wood), impacting nutrient recycling in ecosystems and carbon sequestration dynamics. This study explores the uneven phylogenetic distribution of saproxylophagy across insects and delves into the evolutionary origins of this trait in disparate insect orders. Employing a comprehensive analysis of gut microbiome data, from both saproxylophagous insects and their non-saproxylophagous relatives, including new data from unexplored wood-feeding insects, this Hypothesis paper discusses the broader phylogenetic context and potential adaptations necessary for this dietary specialization. The study proposes the "Detritivore-First Hypothesis," suggesting an evolutionary pathway to saproxylophagy through detritivory, and highlights the critical role of symbiotic gut microbiomes in the digestion of decaying wood.}, journal={BIOESSAYS}, author={Beza-Beza, Cristian F. and Wiegmann, Brian M. and Ware, Jessica A. and Petersen, Matt and Gunter, Nicole and Cole, Marissa E. and Schwarz, Melbert and Bertone, Matthew A. and Young, Daniel and Mikaelyan, Aram}, year={2024}, month={Mar} }
 @article{ashbrook_schwarz_schal_mikaelyan_2024, title={Lethal disruption of the bacterial gut community in Eastern subterranean termite caused by boric acid}, volume={10}, ISSN={["1938-291X"]}, url={https://doi.org/10.1093/jee/toae221}, DOI={10.1093/jee/toae221}, abstractNote={Abstract The Eastern subterranean termite, Reticulitermes flavipes (Kollar) (Blattodea: Rhinotermitidae), is a significant pest, causing extensive damage to structures that amount to substantial economic losses. Boric acid is widely used for wood preservation due to its stability and broad-spectrum insecticidal properties, yet its impact on termite gut microbiomes and the implications of such effects remain understudied. Our study evaluates the dose-dependent mortality of R. flavipes upon being provided boric acid treated filter papers and investigates the resulting dysbiosis within the termite gut microbiome. Consistent with reports from other insects, mortality increased in a dose-dependent manner, with the highest boric acid concentration (203.7 µg/cm2 of filter paper) significantly reducing termite survival. 16S rRNA gene sequencing of the gut bacterial microbiome revealed notable shifts in composition, indicating boric acid-induced dysbiosis. Aside from an overall decrease in bacterial diversity, the relative abundance of some symbionts essential for termite nutrition decreased in response to higher boric acid concentrations, while several opportunistic pathogens increased. Our findings extend the understanding of boric acid’s mode of action in termites, emphasizing its ability to significantly modulate the bacterial symbiont community, which can have dire effects on termite biology. Considering its ability to protect wood from further termite consumption, our study supports the continued use of boric acid and related compounds for termite-resistant treatments for wood.}, journal={JOURNAL OF ECONOMIC ENTOMOLOGY}, author={Ashbrook, Aaron R. and Schwarz, Melbert and Schal, Coby and Mikaelyan, Aram}, editor={Husseneder, ClaudiaEditor}, year={2024}, month={Oct} }
 @article{schwarz_tokuda_osaki_mikaelyan_2023, title={Reevaluating Symbiotic Digestion in Cockroaches: Unveiling the Hindgut's Contribution to Digestion in Wood-Feeding Panesthiinae (Blaberidae)}, volume={14}, ISSN={["2075-4450"]}, url={https://doi.org/10.3390/insects14090768}, DOI={10.3390/insects14090768}, abstractNote={Cockroaches of the subfamily Panesthiinae (family Blaberidae) are among the few major groups of insects feeding on decayed wood. Despite having independently evolved the ability to thrive on this recalcitrant and nitrogen-limited resource, they are among the least studied of all wood-feeding insect groups. In the pursuit of unraveling their unique digestive strategies, we explored cellulase and xylanase activity in the crop, midgut, and hindgut lumens of Panesthia angustipennis and Salganea taiwanensis. Employing Percoll density gradient centrifugation, we further fractionated luminal fluid to elucidate how the activities in the gut lumen are further partitioned. Our findings challenge conventional wisdom, underscoring the significant contribution of the hindgut, which accounts for approximately one-fifth of cellulase and xylanase activity. Particle-associated enzymes, potentially of bacterial origin, dominate hindgut digestion, akin to symbiotic strategies observed in select termites and passalid beetles. Our study sheds new light on the digestive prowess of panesthiine cockroaches, providing invaluable insights into the evolution of wood-feeding insects and their remarkable adaptability to challenging, nutrient-poor substrates.}, number={9}, journal={INSECTS}, author={Schwarz, Melbert and Tokuda, Gaku and Osaki, Haruka and Mikaelyan, Aram}, year={2023}, month={Sep} }
 @article{schwarz_beza-beza_mikaelyan_2023, title={Wood fibers are a crucial microhabitat for cellulose- and xylan- degrading bacteria in the hindgut of the wood-feeding beetle Odontotaenius disjunctus}, volume={14}, ISSN={["1664-302X"]}, url={http://dx.doi.org/10.3389/fmicb.2023.1173696}, DOI={10.3389/fmicb.2023.1173696}, abstractNote={Wood digestion in insects relies on the maintenance of a mosaic of numerous microhabitats, each colonized by distinct microbiomes. Understanding the division of digestive labor between these microhabitats- is central to understanding the physiology and evolution of symbiotic wood digestion. A microhabitat that has emerged to be of direct relevance to the process of lignocellulose digestion is the surface of ingested plant material. Wood particles in the guts of some termites are colonized by a specialized bacterial fiber-digesting microbiome, but whether this represents a widespread strategy among insect lineages that have independently evolved wood-feeding remains an open question.In this study, we investigated the bacterial communities specifically associated with wood fibers in the gut of the passalid beetle Odontotaenius disjunctus. We developed a Percoll-based centrifugation method to isolate and enrich the wood particles from the anterior hindgut, allowing us to access the wood fibers and their associated microbiome. We then performed assays of enzyme activity and used short-read and long-read amplicon sequencing of the 16S rRNA gene to identify the composition of the fiber-associated microbiome.Our assays demonstrated that the anterior hindgut, which houses a majority of the bacterial load, is an important site for lignocellulose digestion. Wood particles enriched from the anterior hindgut contribute to a large proportion of the total enzyme activity. The sequencing revealed that O. disjunctus, like termites, harbors a distinct fiber-associated microbiome, but notably, its community is enriched in insect-specific groups of Lactococcus and Turicibacter.Our study underscores the importance of microhabitats in fostering the complex symbiotic relationships between wood-feeding insects and their microbiomes. The discovery of distinct fiber-digesting symbionts in O. disjunctus, compared to termites, highlights the diverse evolutionary paths insects have taken to adapt to a challenging diet.}, journal={FRONTIERS IN MICROBIOLOGY}, publisher={Frontiers Media SA}, author={Schwarz, Melbert and Beza-Beza, Cristian. F. F. and Mikaelyan, Aram}, year={2023}, month={Jun} }