Christine Johanna Picard

Background: The black soldier fly ( Hermetia illucens ) is an emerging model for bioconversion and industrial rearing. Its genome is highly repetitive, yet the contribution of transposable elements (TEs) to population divergence and demographic processes. The sampled populations represent a gradient of demographic histories, including wild and near-wild North American populations, and domesticated European strains with shared industrial origins. Difference in TE composition may influence genome structure, regulatory variation, and evolutionary responses to captive environments. Results: A comparative analysis of the repetitive landscape was done for four H. illucens genomes, one of which is a wild-caught specimen. Total repeat content was high across all assemblies (67.6% to 70.8%) and dominated by LINE elements. Class-level TE diversity was nearly identical among genomes, but multiple DNA transposon families showed distinct lineage-specific differences. Large families including Maverick and Academ were generally depleted relative to the wild sample. Divergence profiles revealed patterns consistent with recent turnover in several families. Family level turnover, rather than class level change, accounted for the most difference among the genomes. TE-associated structural variants (TESVs) were also not uniformly distributed. Most chromosomes showed mid-chromosome enrichment, and a pronounced TESV peak on chromosome 5 overlapped a histone rich region containing many unclassified repeats. Use of a repeat library derived from multiple genomes increased the number of detected TESVs and improved classification within complex regions, demonstrating that multi-genome libraries enhance annotation accuracy compared to single reference-based models. Conclusions: Multiple DNA transposon families show evidence of recent or lineage-specific amplification in H. illucens , suggesting that TE amplification contributes to genome variation during demography-associated TE turnover. The multi-genome-based library improved TE detection and classification, providing a proof of concept that even a small lineage-inclusive repeat library enhances annotation accuracy and capture TE diversity missed by single-reference approaches. Together, these findings demonstrate that TE family turnover plays a significant role in shaping genome architecture and adaptation in this species.

The use of arthropods in a medicolegal framework is well-known and widely adopted in forensic death investigations. Typically, the life cycle and community composition of carrion arthropods can be used to establish a timeframe of events occurring after the death of an individual. However, because of their unique life strategies (eg the precise detection, location, and exploitation of ephemeral resources) and high dispersal abilities as adults, carrion arthropods can reveal much more information than meets the eye. In recent years, carrion arthropods have revealed important biological and chemical information regarding the substrates that they routinely visit in a natural environment: animal carcasses, feces, microbes, parasites, and even hazardous chemicals. These insects can act as environmental drones, passively acquiring vast amounts of biological and chemical information that can easily be extracted by investigators, given they know what to look for and what methodologies are available for such analyses. This forum piece presents the different ways that carrion arthropods, particularly blow flies, have been used as proxies to assess the health of the local environment and how these methodologies can be leveraged in a forensic context. Further, we propose environmental forensic entomology as an emerging framework and extension of forensic entomology, which currently includes stored products entomology, urban entomology, and medicolegal entomology. Finally, we outline recommendations for future research in this area and propose guidelines for the use of such data in a legal setting.

Understanding the tripartite interaction between diet, the microbiome, and host physiology is essential for optimizing the bioconversion efficiency of black soldier fly larvae (Hermetia illucens). These interactions were investigated by analyzing life-history traits and metatranscriptomes of larvae fed carbohydrate-rich (1P:5C), protein-rich (5P:1C), and balanced ratio macronutrient (1P:1C) diets. The results showed that dietary macronutrients correlated with shifts in the microbial community and gene expression. In particular, optimal larval performance, characterized by the highest weight and survivorship, was achieved on the balanced ratio diet. While the carbohydrate-rich diet increased microbial alpha diversity and enriched microbial transcripts for carbohydrate metabolism and transport, it significantly delayed pupation, reduced larval weight, and induced host immune genes related to pathogen recognition. Larval guts were predominantly composed of the fungal genus Magnusiomyces, no matter the diet, whereas the frass microbiome was primarily bacterial. In the frass, Klebsiella dominated the carbohydrate-rich diet, while Streptococcus, Lactobacillus, and Klebsiella were the most prevalent taxa in the balanced and protein-rich treatments. Significant correlations were identified between host gene expression and microbial alpha diversity and transcript expression, suggesting host-microbe crosstalk in response to nutritional stress. Ultimately, these findings demonstrate that balanced macronutrient ratios are required to synchronize host-microbiota metabolic synergy and mitigate physiological stress, providing a definitive mechanistic framework for optimizing industrial black soldier fly rearing outcomes.

Understanding the complex interplay between a host, its diet, and its microbiome is crucial for comprehending an organism's health and adaptability. Diet impacts both the host and microbiome, which then influence each other. We used black soldier fly larvae (Hermetia illucens) as a model to investigate this tripartite interaction due to its resilience and bioconversion capabilities. We analyzed life-history traits and metatranscriptomics in larvae fed three diets: carbohydrate-rich, protein-rich, and balanced. Our results showed that dietary macronutrients correlated with shifts in the microbial community and gene expression. The carbohydrate-rich diet, in particular, led to increased microbial diversity and carbohydrate metabolism transcripts. However, this diet also negatively affected larval weight and development, suggesting potential host control over the microbiome. Overall, black soldier fly performance was highest on the balanced diet. This study highlights the black soldier fly's resilience and its value as a model for exploring host-diet-microbe interactions.

The black soldier fly (Hermetia illucens) is a globally important species, yet little is known about the behavior of adults in nature. Here, we investigated (a) whether wild populations exhibit lekking behaviors, (b) whether wild adults feed, and (c) the microbial diversity of the adult gut. Fieldwork was conducted in Alajuela Province, San Ramon, Costa Rica at three sites (a field station, a local farm, and an ecolodge compost facility). At all three sites, a highly female-skewed sex ratio (F:M=0.98) was observed. Despite many sampling attempts within 30-m of the oviposition site, no mating behaviors were directly observed within this radius, mostly due to the lack of males. Modeling confirmed female abundance declined sharply with increasing distance, and indeed no individuals were observed beyond a 7.5-m radius from the oviposition site, supporting the hypothesis that males and females may occupy distinct habitats in the wild, consistent with lekking. Modeling also revealed BSF were mostly observed between 9:00-14:30, with a peak at 12:00-noon. BSF sightings peaked at 34.7 ° C, 78.5% RH, and 8000 µW/cm² of UV-AB light, while none were observed past 40 ° C. The presence of vertebrate DNA in the guts of adults revealed that 100% of individuals previously fed as adults, possibly to supplement nutritional reserves during long-distance flights. Lastly, microbial community analysis revealed a core community of microbes present within the gut of wild-caught BSF. By considering spatial molecular ecology at three field sites, this study highlights the strong association of the black soldier fly with human-modified environments, suggesting environmental structure and resource availability may play a large role in shaping wild fly behavior. This work presents the first detailed field report of H. illucens in the Neotropics and offers some critical insights for future fieldwork as well as baseline traits for industrial applications.

Over the past decade, insect agriculture has evolved from a focus on protein production to a broader vision of insects as sustainable biomanufacturing platforms. Once hindered by regulatory, cultural, and economic barriers, the field has emerged stronger through innovation and diversification. Insects now represent powerful tools for biotechnology, bioremediation, and soil enhancement, offering solutions to global challenges such as pollution, food security, and climate change. As living bioreactors, they enable medical and agricultural innovation, though ethical and ecological safeguards remain essential for sustainable advancement.

As the demand for sustainable protein grows, insect farming has emerged as a promising solution. The yellow mealworm ( Tenebrio molitor ), among other commercially farmed species, presents a variety of environmental and nutritional advantages to conventional livestock. However, mealworm colonies are vulnerable to pathogens, necessitating novel strategies for enhancing their immune resilience. This study used a transcriptomic approach to investigate the potential immunostimulatory effects of low-intensity ultraviolet B (UVB) irradiation on mealworm larvae. Mealworm larvae were exposed to UVB light for 14 days, followed by a fungal challenge ( Beauveria bassiana ). UVB irradiation did not significantly affect survival 14 days post-challenge but negatively impacted larval weight. Analysis of differential gene expression showed a notable increase in the activity of Toll pathway transcripts and the transcripts encoding three antimicrobial peptides (AMPs) immediately following UVB exposure. This research indicates that while UVB irradiation triggers AMP production in mealworms, this does not enhance resistance to the fungal pathogen Beauveria bassiana . These observations lay the groundwork for additional studies exploring UVB radiation’s effects on insect immune systems and its potential use in commercial insect rearing.

Just like traditional livestock, farmed insects harbour genetic variation and can be selectively bred to optimise traits of interest. This BugBook article presents a comprehensive overview of how genetics can contribute to improving insect production for food and feed. Molecular genetics and genomics approaches for generating the data essential for understanding species biology are presented, as well as their implementation in dedicated selective breeding programmes, and options for health and quality control of mass rearing operations. To harness the breeding potential of farmed insects, methods to investigate population genetic diversity and structure through population and evolutionary genetic principles are provided as well as tools for monitoring genetic variation and assessing genetic consequences of captive breeding to adequately manage populations. An overview is given on quantitative genetics of farmed insects, how to record phenotypes and pedigrees, estimate genetic parameters, and design optimal breeding programmes. Lastly, the role of functional genetics in insect production is discussed, the biological link between DNA and phenotypic variation, and key to effectively apply genetic improvement strategies through selective breeding. This article identifies knowledge gaps in insect breeding and provides recommendations for application and future research. Major challenges in the field of genetics of farmed insects include how to phenotype large numbers of individual insects over generations; how environmental factors affect trait expression, including interaction with genetics; and how to translate results from laboratory settings to mass rearing environments. This article will contribute to further develop the area of genetics of insects for food and feed.

In 2013, the United Nations Food and Agriculture Organization identified insects as a promising solution for sustainably feeding the world’s growing population. However, despite a decade of development and innovation, the insect industry has yet to fully realize its environmental and economic potential. This review takes an evidence-based approach to addressing key challenges in the sector, including integrating circular production systems within existing regulatory frameworks in the Global North, ensuring product safety in circular systems, assessing allergen risks associated with insect-based products, mitigating biosecurity risks linked to non-native insect species, evaluating the environmental safety of insect by-products, and promoting animal welfare in insect production. While significant challenges remain, the evidence presented highlights how further research can help unlock opportunities for the industry to achieve its full potential globally. Ultimately, we argue that overcoming challenges – ‘working out the bugs’ – is a fundamental step in the evolution of any emerging industry. Furthermore, greater support for the transition to circular economies will accelerate the sector’s ability to generate meaningful environmental, ethical, and economic benefits.

This editorial explores how harnessing the biological potential of BSF can help valorize organic waste streams. It examines the current progress in insect genetics (i.e. artificial selection and biomanufacturing) and the critical research and regulatory challenges that must be addressed to fully realize the potential of these insect-based solutions.