The black soldier fly, Hermetia illucens, is increasingly studied for its ability to convert organic waste into protein, offering solutions for waste valorisation and livestock feeding. Adult performance is critical for egg production, yet the behavioural and molecular bases of sugar feeding in adult black soldier flies remain poorly understood. To fill this gap, we combined behavioural assays, morphological analyses, electrophysiological recordings and gustatory receptor (GR) repertoires and expression. All the experimental tests conducted in this study converge to show that adult flies can detect and consume sucrose, with females responding more strongly than males. Genome analysis identified 28 GRs, a surprisingly small number for a generalist fly, including only three putative sugar-specific GRs homologous to those of the eight known sugar GRs in Drosophila. Moreover, one of these GRs showed a general high level of expression including in the head and in the antennae whereas the other two displayed tissue-specific patterns of expression. We also identified a high number of GR pseudogenes, including four putative sugar receptor pseudogenes, indicating multiple gene loss events of GRs compared with other dipterans sharing a similar ecological niche. Despite this reduced GR repertoire, adult black soldier flies retained strong behavioural and physiological sensitivity to sugars in their environment. The set of behavioural, morphological and electrophysiological tools developed here provides a foundation for deeper investigations into feeding behaviour in this species of growing agroecological importance.

Chemosensory systems play a central role in host detection, feeding behavior, and habitat selection in hematophagous insects. Here, we performed a comparative evolutionary analysis of chemosensory gene repertoires across 13 species of the Chagas disease vector genus Rhodnius. While gustatory receptors (GRs), ionotropic receptors (IRs), odorant-binding proteins (OBPs), and chemosensory proteins (CSPs) remained globally conserved, odorant receptors (ORs) displayed extensive lineage-specific expansions, tandem duplications, dynamic transcriptomic regulation, and recurrent signatures of positive selection. Major OR expansions were observed in Rhodnius robustus and Rhodnius colombiensis, suggesting increased sensory diversification in ecologically heterogeneous lineages. In contrast, conserved GR1 expression supports the maintenance of ancestral sugar-detection pathways despite hematophagy lifestyle. We further found no evidence of the canonical insect CO₂-associated GRs, suggesting alternative molecular mechanisms for CO₂ perception in Triatominae. Several receptors, including Orco, also displayed shifts in selective constraints between sylvatic and domiciliary species, consistent with sensory remodeling associated with adaptation to domestic habitats. Together, our results identify ORs as the most evolutionarily dynamic component of the Rhodnius chemosensory repertoire and highlight contrasting evolutionary trajectories among chemosensory gene families during ecological diversification and vector adaptation.

Abstract The black soldier fly, Hermetia illucens , is increasingly valued in applied entomology due to its remarkable capacity to upcycle organic waste and for high nutritional value of its larvae. As a result of global expansion and domestication, the species now displays substantial genetic diversity, yet performance differences between strains remain poorly documented. This study aimed to better understand the relationship between genotype and phenotype, as well as their interaction, to support the improvement of its domestication. Five distinct strains collected from the wild by artisanal farmers or obtained from industrial farms were genetically characterized using whole genome sequencing. These analyses revealed high genetic divergence based on mitochondrial genome and SNP nuclear genome phylogeny. To assess phenotypic performance, the strains were reared on three diets differing in nutritional value: poor (alfalfa meal), intermediate (wheat bran) and rich (chicken feed) and their growth rate was assessed. At harvest, we evaluated different life history traits including survival rate, average larval mass, feed conversion ratio, substrate reduction and bioconversion rate. Statistical analyses revealed strong effects of both diet and strain (p < 0.001), but the key result was the pronounced strain × diet interaction. Performance varied drastically depending on substrate quality: some strains showed high versatility across all diets, while others performed mainly on nutrient-rich substrates or excelled in substrate degradation. In contrast, other strains displayed more specialized profiles, with marked sensitivity to fibrous diets. These contrasted reaction norms highlight that diet performance cannot be interpreted independently of the strain genetics. Overall, these findings underscore the value of preserving diverse local genetic resources and the need for improved molecular tools to guide strain selection. Implication This study shows that performance of the black soldier fly depends strongly on interactions between genetic background and diet, confirming the importance of genotype–environment relationships. While results are based on a limited number of strains and substrates, the consistent strain × diet interaction suggests broader relevance for rearing systems. These findings highlight the need to integrate genomic data into phenotypic assessments. Practically, they indicate that strain selection should be tailored to substrate type to optimize productivity and efficiency. This has direct economic benefits for insect farming and waste management industries because improved strain–diet matching can enhance organic waste bioconversion and support circular economy strategies. Overall, preserving genetic diversity and developing molecular tools for strain selection are key steps toward more sustainable and efficient insect production systems of this study have implications for the development and sustainable BSF systems production.

The evolution of endosymbiont genomes is likely influenced by the ecological interactions with their hosts. Here, we studied the evolution of Spiroplasma genomes detected within Morpho butterflies sampled in the wild. Spiroplasma was detected in 4 out of the 11 Morpho species studied and displayed a 3 times larger genome size as compared to Spiroplasma genomes documented in other hosts. This inflation in genome size is caused by massive and recent expansion of various mobile genetic elements and by the acquisition of new genes stemming from prophages. In particular, we documented the peculiar evolution of the toxin genes in plasmids that may enhance host resistance to parasites. Phylogenetic comparisons with Spiroplasma extracted from other host point at a unique origin of Spiroplasma in Morpho , and strong divergence from Spiroplasma found in other Lepidoptera. Resequencing data obtained for multiple populations of the two sister-species M. helenor and M. achilles living in sympatry over the majority of their distribution revealed a opposite prevalence (97% in M. achilles and 3% in M. helenor ), suggesting contrasted ecological interactions with these two host-species. Reconciliation analysis of the phylogenetic relationships of Morpho mitochondrial genomes and Spiroplasma genomes was then consistent with a predominant vertical transfer of the endosymbiont. Altogether, our results suggest a key role of ecological interactions with the host in the evolution of endosymbiont genomes and point at a putative interaction of Spiroplasma with reproductive isolation between sympatric species of butterflies. ### Competing Interest Statement The authors have declared no competing interest.

Social insects' nests harbor intruders known as inquilines,1 which are usually related to their hosts.2,3 However, distant non-social inquilines may also show convergences with their hosts,4,5 although the underlying genomic changes remain unclear. We analyzed the genome of the wingless and blind bee louse fly Braula coeca, an inquiline kleptoparasite of the western honey bee, Apis mellifera.6,7 Using large phylogenomic data, we confirmed recent accounts that the bee louse fly is a drosophilid8,9 and showed that it had likely evolved from a sap-breeder ancestor associated with honeydew and scale insects' wax. Unlike many parasites, the bee louse fly genome did not show significant erosion or strict reliance on an endosymbiont, likely due to a relatively recent age of inquilinism. However, we observed a horizontal transfer of a transposon and a striking parallel evolution in a set of gene families between the honey bee and the bee louse fly. Convergences included genes potentially involved in metabolism and immunity and the loss of nearly all bitter-tasting gustatory receptors, in agreement with life in a protective nest and a diet of honey, pollen, and beeswax. Vision and odorant receptor genes also exhibited rapid losses. Only genes whose orthologs in the closely related Drosophila melanogaster respond to honey bee pheromone components or floral aroma were retained, whereas the losses included orthologous receptors responsive to the anti-ovarian honey bee queen pheromones. Hence, deep genomic convergences can underlie major phenotypic transitions during the evolution of inquilinism between non-social parasites and their social hosts.

Blood feeding is a secondary adaptation in hematophagous bugs. Many proteins are secreted in the saliva that are devoted to coping with the host's defense and to process the blood meal. Digestive enzymes that are no longer required for a blood meal would be expected to be eventually lost. Yet, in many strictly hematophagous arthropods, α-amylase genes, which encode the enzymes that digest starch from plants, are still present and transcribed, including in the kissing bug Rhodnius prolixus (Hemiptera, Reduviidae) and its related species, which transmit the Chagas disease. We hypothesized that retaining α-amylase could be advantageous if the bugs occasionally consume plant tissues. We first checked that the α-amylase protein of Rhodnius robustus retains normal amylolytic activity. Then we surveyed hundreds of gut DNA extracts from the sylvatic R. robustus to detect traces of plants. We found plant DNA in 8% of the samples, mainly identified as Attalea palm trees, where R. robustus are usually found. We suggest that although of secondary importance in the blood-sucking bugs, α-amylase may be needed during occasional plant feeding and thus has been retained.

Resistance of mosquitoes to insecticides is one example of rapid adaptation to anthropogenic selection pressures having a strong impact on human health and activities. Target-site modification and increased insecticide detoxification are the two main mechanisms underlying insecticide resistance in mosquitoes. While target-sites mutations are well characterised and often used to track resistance in the field, the genomic events associated with insecticide detoxification remain partially characterised. Recent studies evidenced the key role of gene duplications in the over-expression of detoxification enzymes and their potential use to track metabolic resistance alleles in the field. However, such genomic events remain difficult to characterise due to their complex genomic architecture and their co-occurrence with other resistance alleles. In this concern, the present work investigated the role of a large genomic duplication affecting a cluster of detoxification enzymes in conferring resistance to the pyrethroid insecticide deltamethrin in the mosquito Aedes aegypti. Two isofemale lines originating from French Guiana and being deprived from major target-site mutations showed distinct insecticide resistance levels. Combining RNA-seq and whole genome pool-seq identified a 220 Kb genomic duplication enhancing the expression of multiple contiguous cytochrome P450s in the resistant line. The genomic architecture of the duplicated loci was elucidated through long read sequencing, evidencing its transposon-mediated evolutionary origin. The involvement of this P450 duplication in deltamethrin survival was supported by a significant phenotypic response to the P450 inhibitor piperonyl butoxide together with genotype-phenotype association and RNA interference. Experimental evolution suggested that this P450 duplication is associated with a significant fitness cost, potentially affecting its adaptive value in presence of other resistance alleles. Overall, this study supports the importance of genomic duplications affecting detoxification enzymes in the rapid surveillance and management of resistance in the field.

Blood feeding is a secondary adaptation in hematophagous bugs. A lot of secreted proteins are devoted to cope with the host’s defences an to process the blood meal. In contrast, one can expect that digestive enzymes that became useless were lost during or after this peculiar adaptation. And yet in many strictly hematophagous arthropods, alpha-amylases genes, coding the enzymes that digest starch from plants, are still present and transcribed, including the kissing bug Rhodnius prolixus (Hemiptera, Reduviidae) and its related species, which transmit the Chagas disease. We hypothesized that retaining alpha-amylase could be advantageous if the bugs happen to consume occasionally plant tissues. To this end, we first checked that the alpha-amylase protein of Rhodnius robustus retained normal amylolytic activity. Then we surveyed hundreds of gut DNA extracts from the sylvatic R. robustus to detect traces of plants. We found plant DNA in 8% of the samples, mainly identified as Attalea palm trees, the usual dwelling of R. robustus. We suggest that although maybe rarely of use in a bug lifetime, alpha-amylase may be crucial at some nutritionally critical moments and thus has been preserved.

BACKGROUND Blood feeding is a secondary adaptation in hematophagous bugs that ancestrally feed on plants. Many vector proteins are devoted to cope with the host’s defenses and to process the blood meal. In contrast, one can expect that some digestive enzymes devoted to phytophagous diet were lost during or after this peculiar adaptation. And yet, in many strictly hematophagous arthropods, alpha-amylases genes, coding the enzymes that digest starch from plants, are still present and transcribed, including in the blood-sucking bug Rhodnius prolixus and its related species R. robustus (Hemiptera, Reduviidae, Triatominae). Triatominae bugs are vectors of Trypanosoma cruzi , the causal agent of Chagas’disease. Besides the parasitic human infection by the vector-borne route via an exposition to infected feces, an oral route is documented by the ingestion of contaminated food or juices made from palm fruit trees. METHODOLOGY/PRINCIPAL FINDINGS We hypothesized that retaining alpha-amylase could be advantageous if the bugs happen to consume occasionally plant tissues. To this end, we surveyed hundreds of gut DNA extracts from the sylvatic species R. robustus caught on palm trees to detect traces of plant meals. We found plant DNA in over 8 % of the R. robustus samples, mostly the palm tree Attalea speciosa . Moreover, we showed that the R. robustus alpha-amylase retained normal amylolytic activity. CONCLUSIONS Preserving alpha-amylase function could be an important way of optimally harness plant substrates, and plant feeding could be a way for bridging the gap between two blood meals. Our data indicate that plants are a common and yet underestimated food source in the wild for Triatomine. Author Summary Adaptation to a specific diet is often accompanied by metabolic, behavioral, physiological changes and hence by genetic changes like gene family expansion, gene losses or gains. In blood-sucking insects some adaptive features such as salivary components acting against blood clotting are known. However, it is intriguing that a digestive enzyme, alpha-amylase, which digests starch, is conserved in those animals, because blood does not contain starch nor related glucose polymers. This is the case in the blood-sucking bugs of the Rhodnius genus (Hemiptera, Reduviidae), which are vectors of the Chagas’disease, an important health issue in Latin America. In this study, we evidence for the first time that sylvatic bugs R. robustus also consume plant tissues in the wild. We detected by PCR performed on DNA from digestive tract that a significant number of wild-caught individuals harbored plant DNA, especially from Attalea palm trees, on which they used to nest. We showed that the amylase enzyme is normally active on starch. We suggest plant feeding could be a way for bridging the gap between two blood meals but might not be linked to nutritional distress.

Asgard archaea include the closest known archaeal relatives of eukaryotes. Here, we investigate the evolution and function of Asgard thymidylate synthases and other folate-dependent enzymes required for the biosynthesis of DNA, RNA, amino acids and vitamins, as well as syntrophic amino acid utilization. Phylogenies of Asgard folate-dependent enzymes are consistent with their horizontal transmission from various bacterial groups. We experimentally validate the functionality of thymidylate synthase ThyX of the cultured ‘ Candidatus Prometheoarchaeum syntrophicum’. The enzyme efficiently uses bacterial-like folates and is inhibited by mycobacterial ThyX inhibitors, even though the majority of experimentally tested archaea are known to use carbon carriers distinct from bacterial folates. Our phylogenetic analyses suggest that the eukaryotic thymidylate synthase, required for de novo DNA synthesis, is not closely related to archaeal enzymes and might have been transferred from bacteria to protoeukaryotes during eukaryogenesis. Altogether, our study suggests that the capacity of eukaryotic cells to duplicate their genetic material is a sum of archaeal (replisome) and bacterial (thymidylate synthase) characteristics. We also propose that recent prevalent lateral gene transfer from bacteria has markedly shaped the metabolism of Asgard archaea.

Background The Black Soldier Fly (BSF) Hermetia illucens is a cosmopolitan fly massively used by industrial companies to reduce biowaste and produce protein and fat for poultry and aquaculture feed. However, the natural history and the genetic diversity of the BSF are poorly known. Here, we present a comprehensive phylogeny and time tree based on a large dataset of complete mitochondrial genomes better to understand the evolution and timing of the BSF. Results In this study, we analyzed 677 CO1 sequences derived from samples found all over the five continents, leading us to discover 52 haplotypes, including ten major haplotypes. This worldwide cryptic genetic and genomic diversity is mirrored at a local scale in France, in which we found five major haplotypes sometimes in sympatry. Phylogenetic analyses of 60 complete mitochondrial genomes robustly resolved the phylogeny of the major BSF haplotypes. We estimate the separation events of the different haplotypes at more than 2 million years for the oldest branches characterizing the ancestral split between present North American lineages and the other highly diverse south-central American clades, possibly the following radiation beyond the isthmus of Panama northwards. Our data confirm that this North American lineage ultimately gave birth to almost all commercial BSF stocks that participated in the worldwide BSF dissemination through farm escapements. Conclusions Our data resolve the phylogenetic relationships between the major lineages and give insights into the BSF’s short and long-term evolution. Our results indicate that commercial BSF stock’s genetic and genomic diversity is very low. These results call for a better understanding of the genomic diversity of the BSF to unravel possible specific adaptations of the different lineages for industrial needs and to initiate the selection process.

SummaryThe nutritional symbiosis promoted by bacteria is a key determinant for adaptation and evolution of many insect lineages. A complex form of nutritional mutualism that arose in blood-sucking insects critically depends on diverse bacterial symbionts that supplement the diet of their nutrient-poor hosts with B vitamins. For instance, the triatomine bugRhodnius prolixus, one of the main vectors of the Chagas disease in humans, is known to maintain a nutritional symbiosis with the gut symbiontsRhodococcus rhodnii.In this study, we show thatWolbachiasymbionts are also widely distributed in theRhodniusgenus. We have screened a large set ofRhodniusblood-sucking bugs samples belonging to 17 different species and to the three phylogenetic groups,prolixus, pallescensandpictipes. We assembled 13 genomes ofWolbachiainfecting eightRhodniusspecies fromprolixusandpictipesgroups. We demonstrate that theseWolbachiabelong to supergroup F and are closely related toWolbachiainfecting the bedbugCimex lectularius(wCle). Although bedbugs and triatomines are very distantly related hemipteran bugs, the genomes of their respectiveWolbachiawere highly similar, suggesting recent horizontal host switches. We also show thatRhodnius Wolbachiagenomes infecting theprolixusgroup encode intact biotin operon, the hallmark of nutritional symbiosis in bedbugs. This operon is lacking from all the otherWolbachiainfectingR. pictipes. Finally, host genome analyses provide evidence of massiveWolbachia-to-Rhodniusgene transfers in almost samples, providing footprints of past infections that support a widespread and probably ancient symbiotic association betweenWolbachiaand triatomine bugs.Our results suggest that bothWolbachiaandR. rhodniigut symbionts and theirRhodniushost maintain a highly prevalent symbiotic relationship, in which the vertically-inheritedWolbachiahas the metabolic potantial to ensure or complement, the nutritional mutualism provided by the gut symbionts. Specific loss of the biotin operon in some symbiont genomes suggests that the boundaries between obligatory mutualism, facultative mutualism and parasitism inWolbachiaare transient and fluid, supporting a dynamic process of transition and reversion from one state to another.

We provide in this study a very large DNA dataset on Rhodnius species including 36 samples representing 16 valid species of the three Rhodnius groups, pictipes, prolixus and pallescens. Samples were sequenced at low-depth with whole-genome shotgun sequencing (Illumina technology). Using phylogenomics including 15 mitochondrial genes (13.3 kb), partial nuclear rDNA (5.2 kb) and 51 nuclear protein-coding genes (36.3 kb), we resolve sticking points in the Rhodnius phylogeny. At the species level, we confirmed the species-specific status of R. montenegrensis and R. marabaensis and we agree with the synonymy of R. taquarussuensis with R. neglectus. We also invite to revisit the species-specific status of R. milesi that is more likely R. nasutus . We proposed to define a robustus species complex that comprises the four close relative species: R. marabaensis, R. montenegrensis, R. prolixus and R. robustus. As Psammolestes tertius was included in the Rhodnius clade, we strongly recommend reclassifying this species as R. tertius . At the Rhodnius group level, molecular data consistently supports the clustering of the pictipes and pallescens groups, more related to each other than they are to the prolixus group. Moreover, comparing mitochondrial and nuclear tree topologies, our results demonstrated that various introgression events occurred in all the three Rhodnius groups, in laboratory strains but also in wild specimens. We demonstrated that introgressions occurred frequently in the prolixus group, involving the related species of the robustus complex but also the pairwise R. nasutus and R. neglectus . A genome wide analysis highlighted an introgression event in the pictipes group between R. stali and R. brethesi and suggested a complex gene flow between the three species of the pallescens group, R. colombiensis, R. pallescens and R. ecuadoriensis . The molecular data supports also a sylvatic distribution of R. prolixus in Brazil (Pará state) and the monophyly of R. robustus . As we detected extensive introgression events and selective pressure on mitochondrial genes, we strongly recommend performing separate mitochondrial and nuclear phylogenies and to take advantages of mito-nuclear conflicts in order to have a comprehensive evolutionary vision of this genus.

The genome size of five Rhodnius species (R. milesi, R. nasutus, R. neivai, R. prolixus, and R. robustus) and two Psammolestes species (P. coroedes and P. tertius) were estimated using flow cytometry and/or k-mer distributions in genome sequences. Phylogenetic generalized linear mixed models highlighted significant genome size variations among species and between sexes, with R. prolixus showing the largest genome. In this study we provide the first data on female genome size in Triatominae. For five species, female genome size did not differ from males, except for R. robustus, where females had smaller genomes. Genome size estimations based on the k-mer distribution method were less than those estimated from flow cytometry, but both methods exhibited the same pattern of sexual differences. Further genomic studies are needed to infer whether genome size variation could be an adaptive trait in Rhodnius.

Little is known about the evolution and biosynthetic function of DNA precursor and the folate metabolism in the Asgard group of archaea. As Asgard occupy a key position in the archaeal and eukaryotic phylogenetic trees, we have exploited very recently emerged genome and metagenome sequence information to investigate these central metabolic pathways. Our genome-wide analyses revealed that the recently cultured Asgard archaeon Candidatus Prometheoarchaeum syntrophicum strain MK-D1 ( Psyn ) contains a complete folate-dependent network for the biosynthesis of DNA/RNA precursors, amino acids and syntrophic amino acid utilization. Altogether our experimental and computational data suggest that phylogenetic incongruences of functional folate-dependent enzymes from Asgard archaea reflect their persistent horizontal transmission from various bacterial groups, which has rewired the key metabolic reactions in an important and recently identified archaeal phylogenetic group. We also experimentally validated the functionality of the lateral gene transfer of Psyn thymidylate synthase ThyX. This enzyme uses bacterial-like folates efficiently and is inhibited by mycobacterial ThyX inhibitors. Our data raise the possibility that the thymidylate metabolism, required for de novo DNA synthesis, originated in bacteria and has been independently transferred to archaea and eukaryotes. In conclusion, our study has revealed that recent prevalent lateral gene transfer has markedly shaped the evolution of Asgard archaea by allowing them to adapt to specific ecological niches.

Background The Black Soldier Fly (BSF) Hermetia illucens is a cosmopolitan fly heavily used by industrial companies to reduce biowaste and produce protein and fat for poultry and aquaculture feed. However, the natural history and the genetic diversity of the BSF are poorly known. Results In this study, we analyzed 677 CO1 sequences derived from samples found all over the five continents, leading us to discover 52 haplotypes, including ten major haplotypes. We refined the definition of these haplotypes by sequencing 59 mitochondrial genomes. We could derive an estimate of the separation events of the different haplotypes at more than two million years for the oldest branches. This worldwide cryptic genetic and genomic diversity is mirrored at a local scale in France, in which we found five major haplotypes sometimes in sympatry. Conclusions Our data resolve the phylogenetic relationships between the major lineages and give insights into the dispersal and the numbers of BSF neo-introduction at global and local scales. Our results indicate that commercial BSF stock's genetic and genomic diversity is very low. In addition, this broodstock participates in disseminating the BSF in the wild. Taken together, these results call for a better understanding of the genomic diversity of the BSF to unravel possible specific adaptations of the different lineages for industrial needs and to initiate the selection process.

BACKGROUND:With the expansion of high throughput sequencing, we now have access to a larger number of genome-wide studies analyzing the Transposable elements (TEs) composition in a wide variety of organisms. However, genomic analyses often remain too limited in number and diversity of species investigated to study in depth the dynamics and evolutionary success of the different types of TEs among metazoans. Therefore, we chose to investigate the use of transcriptomes to describe the diversity of TEs in phylogenetically related species by conducting the first comparative analysis of TEs in two groups of polychaetes and evaluate the diversity of TEs that might impact genomic evolution as a result of their mobility.RESULTS:We present a detailed analysis of TEs distribution in transcriptomes extracted from 15 polychaetes depending on the number of reads used during assembly, and also compare these results with additional TE scans on associated low-coverage genomes. We then characterized the clades defined by 1021 LTR-retrotransposon families identified in 26 species. Clade richness was highly dependent on the considered superfamily. Copia elements appear rare and are equally distributed in only three clades, GalEa, Hydra and CoMol. Among the eight BEL/Pao clades identified in annelids, two small clades within the Sailor lineage are new for science. We characterized 17 Gypsy clades of which only 4 are new; the C-clade largely dominates with a quarter of the families. Finally, all species also expressed for the majority two distinct transcripts encoding PIWI proteins, known to be involved in control of TEs mobilities.CONCLUSIONS:This study shows that the use of transcriptomes assembled from 40 million reads was sufficient to access to the diversity and proportion of the transposable elements compared to those obtained by low coverage sequencing. Among LTR-retrotransposons Gypsy elements were unequivocally dominant but results suggest that the number of Gypsy clades, although high, may be more limited than previously thought in metazoans. For BEL/Pao elements, the organization of clades within the Sailor lineage appears more difficult to establish clearly. The Copia elements remain rare and result from the evolutionary consistent success of the same three clades.

Abstract The germlines of metazoans contain transposable elements (TEs) causing genetic instability and affecting fitness. To protect the germline from TE activity, gonads of metazoans produce TE-derived PIWI-interacting RNAs (piRNAs) that silence TE expression. In Drosophila, our understanding of piRNA biogenesis is mainly based on studies of the Drosophila melanogaster female germline. However, it is not known whether piRNA functions are also important in the male germline or whether and how piRNAs are affected by the global genomic context. To address these questions, we compared genome sequences, transcriptomes, and small RNA libraries extracted from entire testes and ovaries of two sister species: D. melanogaster and Drosophila simulans. We found that most TE-derived piRNAs were produced in ovaries and that piRNA pathway genes were strongly overexpressed in ovaries compared with testes, indicating that the silencing of TEs by the piRNA pathway mainly took place in the female germline. To study the relationship between host piRNAs and TE landscape, we analyzed TE genomic features and how they correlate with piRNA production in the two species. In D. melanogaster, we found that TE-derived piRNAs target recently active TEs. In contrast, although Drosophila simulans TEs do not display any features of recent activity, the host still intensively produced silencing piRNAs targeting old TE relics. Together, our results show that the piRNA silencing response mainly takes place in Drosophila ovaries and indicate that the host piRNA response is implemented following a burst of TE activity and could persist long after the extinction of active TE families.

The maize stalk borer, Busseola fusca, is an important Lepidopteran pest of cereal crops in Central, East, and Southern Africa. Crop losses due to B. fusca feeding activity vary by region, but can result in total crop loss in areaswith high levels of infestation. Genomic resources provide critical insight into the biology of pest species and can allow for the development of effective management tools and strategies to mitigate their impact on agriculture. To this end, we sequenced, assembled, and annotated the genome of B. fusca. The total assembled genome size was 492.9Mb with 19,417 annotated protein-coding genes. Using a comparative approach, we identified a putative expansion in the Chorion gene family, which is involved in the formation of the egg shell structure. Our analysis revealed high repeat content within the B. fusca genome, with LTR sequences comprising the majority of the repetitive sequence. We hope genomic resources will provide a foundation for future work aimed at developing an integrated pest management strategy to reduce B. fusca's impact on food security.

Triatoma petrocchiae is the newly member of the Triatoma brasiliensis species complex. This species overlaps with T. brasiliensis in geographic and ecotypic occupation in the sylvatic habitat because both inhabit rocky outcrops in the semi-arid portion of Brazilian northeast. In this region T. brasiliensis is the most important Chagas disease vector because it constantly colonizes domiciles. In contrast, T. petrocchiae is rarely found in peri or intradomiciliary habitats - reason why little is known about this species. Therefore, Here, we present information for the first time on. the T. petrocchiae ecotopes, genetic diversity, Trypanosoma cruzi prevalence/genotyping in comparison to T. brasiliensis. We found T. brasilensis (N=223) and T. petrocchiae (N=69) in co-habitation in rocky outcrops in three Districts of Paraiba and Rio Grande do Norte states. Forty-tree T. petrocchiae insects of eleven sampling spots (composing three geographic populations) were genotyped for the mitochondrial Cyt B gene and little geographic structure was observed. Tajima's D test suggested that species is evolving toward a mutation-drift equilibrium in our collection range. Sylvatic T. petrocchiae had 4% (3/68) of infected insects by T. cruzi, whereas T. brasiliensis had 26% (59/223). Fluorescent Fragment Length Barcoding demonstrated that all three T. petrocchiae harbored TcI whereas T. brasiliensis had TcI, but also TcIII, TcII/TcVI and T. rangeli genotype A, sometimes under mixed infections. None of infected T. petrocchiae were carrying mixed infections. However, this result should be confirmed using a larger pool of infected bugs. We here presented the first documentation of T. rangeli infecting T. brasiliensis. The finding of infected T. petrocchiae calls for constant vector monitoring because the epidemiologic scenario is dynamic and sylvatic vectors are progressively found in adaptation to anthropic environments.