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Long-read sequencing is driving rapid progress in genome assembly across all major groups of life, including species of the family Drosophilidae, a longtime model system for genetics, genomics, and evolution. We previously developed a cost-effective hybrid Oxford Nanopore (ONT) long-read and Illumina short-read sequencing approach and used it to assemble 101 drosophilid genomes from laboratory cultures, greatly increasing the number of genome assemblies for this taxonomic group. The next major challenge is to address the laboratory culture bias in taxon sampling by sequencing genomes of species that cannot easily be reared in the lab. Here, we build upon our previous methods to perform amplification-free ONT sequencing of single wild flies obtained either directly from the field or from ethanol-preserved specimens in museum collections, greatly improving the representation of lesser studied drosophilid taxa in whole-genome data. Using Illumina Novaseq X Plus and ONT P2 sequencers with R10.4.1 chemistry, we set a new benchmark for inexpensive hybrid genome assembly at US $150 per genome while assembling genomes from as little as 35 ng of genomic DNA from a single fly. We present 183 new genome assemblies for 179 species as a resource for drosophilid systematics, phylogenetics, and comparative genomics. Of these genomes, 62 are from pooled lab strains and 121 from single adult flies. Despite the sample limitations of working with small insects, most single-fly diploid assemblies are comparable in contiguity (>1 Mb contig N50), completeness (>98% complete dipteran BUSCOs), and accuracy (>QV40 genome-wide with ONT R10.4.1) to assemblies from inbred lines. We present a well-resolved multi-locus phylogeny for 360 drosophilid and 4 outgroup species encompassing all publicly available (as of August 2023) genomes for this group. Finally, we present a Progressive Cactus whole-genome, reference-free alignment built from a subset of 298 suitably high-quality drosophilid genomes. The new assemblies and alignment, along with updated laboratory protocols and computational pipelines, are released as an open resource and as a tool for studying evolution at the scale of an entire insect family.

The Drosophilid family comprises over 4000 species, with several species posing potential threats to agriculture, as identified by the European and Mediterranean Plant Protection Organisation (EPPO). Among these species, Drosophila suzukii, Zaprionus tuberculatus and Z. indianus have received attention due to their geographic expansion and potential risks to crops. This research aims to consolidate global data on Z. tuberculatus hosts, with a specific focus on this species' presence in Brazil's Federal District, its first reported location in the Americas. Reviewing existing literature and conducting fieldwork, we identified 61 plant species from 25 botanical families as potential hosts for Z. tuberculatus worldwide, from which 23 species are new hosts. It was noted that Z. tuberculatus had a high density on certain fruits, raising concerns about its potential as a pest. The presence of Z. tuberculatus alongside other pest species, such as Z. indianus and Drosophila suzukii, highlights the complexity of invasive species' interactions and their ecological impacts. These findings emphasize the need for standardized methodologies to evaluate invasive drosophilids' ecological and economic implications, enabling informed management strategies to mitigate their adverse effects on agriculture and ecosystems. [ABSTRACT FROM AUTHOR]

Chemical control of Drosophila suzukii (Diptera: Drosophilidae) based on the use of insecticides is particularly challenging as the insect attacks ripening fruits shortly before harvest. An alternative strategy may rely on the use of yeasts as phagostimulants and baits, applied on canopy as attract-and-kill formulations. The aim of this research was to identify the most attractive among six yeast species for D. suzukii: Saccharomyces cerevisiae, Hanseniaspora uvarum, Clavispora santaluciae, Saccharomycopsis vini, Issatchenkia terricola, and Metschnikowia pulcherrima. The volatile profile of C. santaluciae was described for the first time. Behavioural experiments identified H. uvarum and S. vini as the most attractive yeasts. The characterization of yeast headspace volatiles using direct headspace (DHS) and solid-phase microextraction (SPME) revealed several strain-specific compounds. With DHS injection, 19 volatiles were characterised, while SPME revealed 71 compounds constituting the yeast headspace. Both analyses revealed terpenoids including β-ocimene, citronellol, (Z)-geraniol (nerol), and geranial as distinct constituents of S. vini. H. uvarum and S. vini were further investigated using closed-loop stripping analysis (CSLA) and electroantennography. Out of 14 compounds quantified by CSLA, ethyl acetate, isoamyl acetate, β-myrcene, benzaldehyde and linalool were detected by D. suzukii antennae and might generate the strong attractiveness of S. vini and H. uvarum. Our results highlight a strong attraction of D. suzukii to various yeasts associated with both the flies and their habitat and demonstrate how different sampling methods can impact the results of volatile compound characterization. It remains to be demonstrated whether the distinct attraction is based on special adaptations to certain yeasts and to what extent the metabolites causing attraction are interchangeable. [ABSTRACT FROM AUTHOR]

BACKGROUND: Spinosyns are a group of naturally occurring and semi‐synthetic insecticides with widespread utility in agriculture, including organic production systems. One example is spinetoram (Delegate), which is the only registered insecticide in New York State (for control of Drosophila melanogaster in vineyards) to which vinegar flies have not yet evolved high levels of resistance. However, low levels of resistance have been found in vineyard populations of D. melanogaster, and a highly resistant strain was obtained after only five selections (in the laboratory). We identified the nAChR α6 mutation (G275A) responsible for the resistance and developed a rapid, high‐throughput assay for resistance. RESULTS: Surveys of collections made in 2023 show low levels of the resistance allele in four populations. A correlation was observed between vineyard use of spinetoram and frequency of the resistance allele, but not between county‐wide use of spinosyns and frequency of the resistance allele. CONCLUSIONS: One of the sites we monitored was previously surveyed in 2019 and the frequency of the resistance allele detected in 2023 had increased. Implications of these findings to resistance management of D. melanogaster are discussed. © 2024 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Drosophila glue, a bioadhesive produced by fly larvae to attach themselves to a substrate for several days, has recently gained attention for its peculiar adhesive and mechanical properties. Although Drosophila glue production was described more than 50 years ago, a general survey of the adhesive and mechanical properties of this proteinaceous gel across Drosophila species is lacking. To measure adhesion, we present here a protocol that is robust to variations in protocol parameters, pupal age and calculation methods. We find that the glue, which covers the entire pupal surface, increases the animal rigidity and plasticity when bound to a glass slide. Our survey of pupal adhesion in 25 Drosophilidae species reveals a wide range of phenotypes, from species that produce no or little glue and adhere little, to species that produce high amounts of glue and adhere strongly. One species, D. hydei, stands out from the rest and emerges as a promising model for the development of future bioadhesives, as it has the highest detachment force per glue area and produces relatively large amounts of glue relative to its size. We also observe that species that invest more in glue tend to live in more windy and less rainy climates, suggesting that differences in pupal adhesion properties across species are shaped by ecological factors. Our present survey provides a basis for future biomimetic studies based on Drosophila glue. [ABSTRACT FROM AUTHOR]

The conserved bazooka (baz/par3) gene acts as a key regulator of asymmetrical cell divisions across the animal kingdom. Associated Par3/Baz-Par6-aPKC protein complexes are also well known for their role in the establishment of apical/basal cell polarity in epithelial cells. Here we define a novel, positive function of Baz/Par3 in the Notch pathway. Using Drosophila wing and eye development, we demonstrate that Baz is required for Notch signaling activity and optimal transcriptional activation of Notch target genes. Baz appears to act independently of aPKC in these contexts, as knockdown of aPKC does not cause Notch loss-of-function phenotypes. Using transgenic Notch constructs, our data positions Baz activity downstream of activating Notch cleavage steps and upstream of Su(H)/CSL transcription factor complex activity on Notch target genes. We demonstrate a biochemical interaction between NICD and Baz, suggesting that Baz is required for NICD activity before NICD binds to Su(H). Taken together, our data define a novel role of the polarity protein Baz/Par3, as a positive and direct regulator of Notch signaling through its interaction with NICD. [Display omitted] • PAR3/Bazooka acts generally in Notch-signaling in Drosophila. • PAR3/Bazooka promotes Notch signaling outside the asymmetric division context. • Notch-ICD and PAR3/Bazooka can be associated in the same physical complex. • PAR3/Bazooka acts at the level of the cleaved active Notch-ICD protein fragment. [ABSTRACT FROM AUTHOR]

Background: Spiders evolved different types of eyes, a pair of primary eyes that are usually forward pointing, and three pairs of secondary eyes that are typically situated more posterior and lateral on the spider's head. The best understanding of arthropod eye development comes from the vinegar fly Drosophila melanogaster, the main arthropod model organism, that also evolved different types of eyes, the larval eyes and the ocelli and compound eyes of the imago. The gene regulatory networks that underlie eye development in this species are well investigated revealing a conserved core network, but also show several differences between the different types of eyes. Recent candidate gene approaches identified a number of conserved genes in arthropod eye development, but also revealed crucial differences including the apparent lack of some key factors in some groups of arthropods, including spiders. Results: Here, we re-analysed our published scRNA sequencing data and found potential key regulators of spider eye development that were previously overlooked. Unlike earlier research on this topic, our new data suggest that Hedgehog (Hh)-signalling is involved in eye development in the spider Parasteatoda tepidariorum. By investigating embryonic gene expression in representatives of all main groups of spiders, we demonstrate that this involvement is conserved in spiders. Additionally, we identified genes that are expressed in the developing eyes of spiders, but that have not been studied in this context before. Conclusion: Our data show that single-cell sequencing represents a powerful method to gain deeper insight into gene regulatory networks that underlie the development of lineage-specific organs such as the derived set of eyes in spiders. Overall, we gained deeper insight into spider eye development, as well as the evolution of arthropod visual system formation. [ABSTRACT FROM AUTHOR]

CRISPR base editors can introduce point mutations into DNA precisely, and cytosine base editors (CBEs) catalyze C to T transitions. While CBEs have been thoroughly explored in cell culture and organisms such as mice, little is known about DNA base editing in insects. In this study, we evaluated germline editing rates of three different CBEs expressed under actin (ubiquitous) or nanos (germline) promoters utilizing Drosophila melanogaster. The original Rattus norvegicus-derived cytosine deaminase APOBEC1 (rAPO-1) displayed high base editing rates (~99%) with undetectable indel formation. Additionally, we show that base editors can be used for generating male sterility and female lethality. Overall, this study highlights the importance of promoter choice and sex-specific transmission for efficient base editing in flies while providing new insights for future genetic biocontrol designs in insects. Testing three types of cytosine base editors in fruit flies demonstrates the potential usage of these base editors in genetic biocontrol strategies, with the rAPO-1 achieving high editing efficiency (~99%) with no detectable INDEL mutations. [ABSTRACT FROM AUTHOR]

Insects' host preferences are regulated by multiple factors whose interactions are only partly understood. Here we make use of an in-depth, untargeted metabolomic approach combining molecular networking (MN) and supervised Analysis of variance Multiblock Orthogonal Partial Least Squares (AMOPLS) to untangle egg-laying preferences of Drosophila suzukii, an invasive, highly polyphagous and destructive fruit pest originating from Southeast Asia. Based on behavioural experiments in the laboratory as well as field observation, we selected eight genetically related Vitis vinifera cultivars (e.g., Ancellotta, Galotta, Gamaret, Gamay, Gamay précoce, Garanoir, Mara and Reichensteiner) exhibiting significant differences in their susceptibility toward D. suzukii. The two most and the two least attractive red cultivars were chosen for further metabolomic analyses of their grape skins. The combination of MN and statistical AMOPLS findings with semi-quantitative detection information enabled us to identify flavonoids as interesting markers for differences in the attractiveness of the four studied grape cultivars towards D. suzukii. Overall, dihydroflavonols were accumulated in unattractive grape cultivars, while attractive grape cultivars were richer in flavonols. Crucially, both dihydroflavonols and flavonols were abundant metabolites in the semi-quantitative analysis of the extracted molecules from the grape skin. We discuss how these two flavonoid classes might influence the egglaying behaviour of D. suzukii females and how they could serve as potential markers for D. suzukii infestations in grapes that can be potentially extended to other fruits. We believe that our novel, integrated analytical approach could also be applied to the study of other biological relationships characterised by multiple evolving parameters. [ABSTRACT FROM AUTHOR]

Simple Summary: Long-term exposure to low concentrations of insecticides can cause several adverse effects, both on target insects and on other organisms. Low doses can also generate tolerance in surviving offspring. One simple method to detect the consequences of long-term exposure to residual toxins is to measure deviations from ideal body symmetry. Fluctuating asymmetry (FA) is evidence that insects were stressed during development. This study aimed to verify FA in the wing veins of Drosophila suzukii, a fruit pest controlled by the insecticide acetamiprid. To determine whether low doses of insecticide in the diet induce the asymmetry effect, multigenerational insect breeding was carried out on media supplemented with different concentrations of two insecticides. Nicotine was used as a positive control. Even in the first generation, low doses reduced fertility and caused vein asymmetry. This effect persisted in subsequent generations, indicating a lack of tolerance that led to complete insect death after 10 generations. D. suzukii proved extremely sensitive to acetamiprid, and FA is a good index of this sensitivity. Long-term exposure to low concentrations of toxic substances can cause several adverse consequences ranging from molecular to morphological. Sublethal doses may also lead to increased tolerance in the offspring of surviving individuals. One of the consequences of such stress is deviations from the ideal body symmetry during development, reflected by increased levels of fluctuating asymmetry (FA). This research aimed to verify FA in the wing veins of insects belonging to the Drosophilidae family—Drosophila suzukii, a fruit pest controlled by the insecticide acetamiprid, a neonicotinoid. To determine whether FA varied depending on insecticides present in the diet, multigenerational cultures of D. suzukii were carried out on media supplemented with different concentrations (below the LC50) of two insecticides. Nicotine was used as a positive control. Fecundity decreased, the number of insects decreased, and breeding did not continue beyond the tenth generation. However, the FA level at different concentrations was similar, and high FA values were observed even at lower acetamiprid concentrations. We did not see significant changes in FA levels in subsequent generations. D. suzukii proved extremely sensitive to acetamiprid, and FA is a good index of this sensitivity. [ABSTRACT FROM AUTHOR]

Chemical signals have an important role in the survival of many animals and are essential for the exploration of the resources available in their habitat. All phytophagous insects, including dipterans, use diverse chemical compounds released by plants as olfactory signals to locate their hosts. Spotted wing drosophila, Drosophila suzukii (Matsumura) (Diptera: Drosophilidae), is a generalist fly that uses numerous plants as hosts. In this study, we evaluated the attractiveness of extracts from six plants commonly used as ornamental and medicinal plants in the southern region of Mexico. When the flies were exposed to Piper auritum Kunth (Piperaceae) extract, we observed a stimulating‐attracting effect, especially on females, whereas the other five extracts showed no significant differences from their respective controls. In addition, gas chromatography coupled with mass spectrometry analysis of the P. auritum extract revealed 11 compounds, where safrole and methyl eugenol (ME) showed the highest concentrations of all the compounds found. ME has been shown to attract flies, mainly males of the genus Bactrocera. In this case, we found a stronger effect on female D. suzukii, indicating a potential effect of ME as a kairomone that mainly stimulates the attraction behavior of females. [ABSTRACT FROM AUTHOR]

The African fig fly, Zaprionus indianus Gupta (Diptera: Drosophilidae), is an ecologically diverse pest species that interacts with and feeds on various microbial pathogens including bacteria and yeast found in decomposing fruits. However, the interaction of Z. indianus with its microbial community and microbial pathogens is obscure. To determine the presence of fungal pathogens, we collected wild Z. indianus from the northwestern part of the Indian subcontinent. Based on molecular identification and phylogenetic analysis, Debaryomyces hansenii (Zopf) Lodder & Kreger‐van Rij (isolate ziha1) was the most commonly observed fungus associated with Z. indianus. Furthermore, we identified two more opportunistic fungal pathogens: Aspergillus flavus Link (isolate zias2), and Pichia kudriavzevii Boidin, Pignal & Besson (isolate zibd3). The interaction of isolated fungi with Z. indianus was evaluated in terms of larval mortality, adult emergence, and fecundity. Debaryomyces hansenii ziha1 resulted in 90% emergence rate for adults, and did not cause significant mortality in the larval stage. In contrast, A. flavus zias2 and P. kudriavzevii zibd3 showed a significant reduction in fecundity and caused 99% and 74% larval mortality of Z. indianus, respectively. In the laboratory oviposition preference assay, mated females of Z. indianus preferred D. hansenii ziha1 supplemented food with a positive oviposition index compared to the uninfected control and compared to food infected with P. kudriavzevii zibd3 or A. flavus zias2. These findings underscore Z. indianus' potential to act as a reservoir for both symbiotic and pathogenic fungal species, some of which may be further harnessed for effective fruit fly pest control strategies. [ABSTRACT FROM AUTHOR]

Grape berry moths, particularly Lobesia botrana Denis & Schiffermüller (Lepidoptera: Tortricidae), and vinegar flies, such as Drosophila melanogaster Meigen and Drosophila suzukii Matsumura (Diptera: Drosophilidae), are important vineyard pests, causing severe quality loss of grapes. Several arthropod taxa may be involved in the natural control of these pests. However, the role of arthropod predators in the natural control of vineyard pests remains unclear. We investigated 32 vineyards in the Palatinate region, southwest Germany, under organic and conventional management, which in both cases received either full or reduced fungicide applications (2 × 2 design). Predation of L. botrana eggs and pupae and D. melanogaster pupae on sentinel cards exposed in the vineyards was observed with infrared cameras. In total, nine predator taxa could be identified. The most dominant predator was the European earwig, Forficula auricularia L. (Dermaptera: Forficulidae), with 90% of all predation events. We conclude that F. auricularia is likely a key predator of vineyard pests, and that special attention should be paid to maintain it at high population densities. [ABSTRACT FROM AUTHOR]

The diversity of Drosophilidae was studied from the Grape yard (vineyard) and Tree vegetation from Chikkaballapura district of Karnataka state. The collection was carried out from October 2020 to September 2021 by bottle trapping method. The collected males were identified using body pigmentation, sex comb and genital plate. Diversity indices and similarity indices were estimated. Population stability models were employed to understand the species-environment interaction for stable possession of the niches. Seven species were recorded where five species were common to both the habitats, while Drosophila bipectinata and Amiota sp. were exclusive to tree vegetation. Two invasive species, Zaprionus indianus and Drosophila suzukii were recorded for the first time from both the habitats. Z. indianus was the dominant species in both the vegetations comprising of 82.6% (1547/1874) of the total flies in tree vegetation and 57% (282/494) of the total flies from the grape yard. D. melanogaster has been recorded as accessory species (29.75%) in the grape yard while as accidental species (6.51%) in tree vegetation. The Simpson diversity indicated that the grape yard was more diverse (0.5777) than tree vegetation (0.3107). The Student t-test did not show any significant difference in the distribution of the species in these two habitats (p > 0.05) except for Z. indianus and D. bipectinata (p < 0.001). Francis coefficient of variation, Determination coefficient, and Perkins & Jinks models showed that Z. indianus was the most stable species constituent of the drosophilids recorded. [ABSTRACT FROM AUTHOR]

This study was carried out in peach orchards of Akyamaç, Kemalpaşa and Kömeç villages of Tokat centre in 2023. As a result of the observations made in the orchards of the mentioned villages, damaged peach fruits were cultured in the laboratory. Zaprionus tuberculatus Malloch, 1932 and Zaprionus indianus (Gupta, 1970) (Diptera: Drosophilidae), which are invasive species, were detected as a result of the culture processes. Especially Z. indianus was observed to be intensively reared from the cultures. These species are the first records for the insect fauna of Tokat province. [ABSTRACT FROM AUTHOR]

Transvection is a phenomenon of interallelic communication in which enhancers can activate a specific promoter located on a homologous chromosome. Insulators play a significant role in ensuring functional interactions between enhancers and promoters. In the presented work, we created a model where two or three copies of the insulator are located next to enhancers and promoters localized on homologous chromosomes. Using the Su(Hw) insulator as a model, we showed that the functional interaction between a pair of insulators promotes enhancer–promoter trans-interactions. The interaction between the three insulators, on the contrary, can lead to the formation of chromatin loops that sterically hinder the full enhancer–promoter interaction. The results of the work suggest the participation of insulators in the regulation of homologous chromosome pairing and in communication between distant genomic loci. [ABSTRACT FROM AUTHOR]

The spotted wing drosophila, Drosophila suzukii (Matsumura), is currently distributed in the main soft-skinned fruits production areas in China and 59 other countries, presenting a significant threat to importing nations. Optimal phytosanitary treatments, including fumigation, irradiation, and cold treatment, have been developed to prevent the international movement of this invasive fly. To determine the most cold-tolerant stage and facilitate the development of the technical schedules requested by the Technical Panel on Phytosanitary Treatment (TPPT), cold treatments of D. suzukii immature stages in 'Red Globe' grapes were conducted. Dose–mortality data at 0 °C and 2 °C from repeated trials were subjected to analysis of covariance, linear regression, and probit analysis. Results identified 3 d old pupae as the most cold-tolerant stage, followed by 1 d old pupae, 4 d old larvae, and 6 h old eggs with similar tolerance. The 2 d old larvae were the most sensitive stage. In subsequent confirmatory tests, 3 d old pupae were subjected to cold treatment at 0 °C for 9 and 10 days, and at 2 °C for 10 and 12 days, based on the probit estimation of the probit-9 value. No adult emergence occurred in the confirmatory tests except for one deformed adult from a 2 °C 10 d treatment. Therefore, the recommended treatment schedule requires fruit temperatures below 0.00 °C (or 1.62 °C) for no less than 10 (or 12) continuous days, with treatment efficacy not less than 99.9960% (or 99.9955%) at a 95% confidence level, respectively. These schedules are intended for submission to TPPT for the development of phytosanitary treatment standards. [ABSTRACT FROM AUTHOR]

During locomotion, soft-bodied terrestrial animals solve complex control problems at substrate interfaces, but our understanding of how they achieve this without rigid components remains incomplete. Here, we develop new all-optical methods based on optical interference in a deformable substrate to measure ground reaction forces (GRFs) with micrometre and nanonewton precision in behaving Drosophila larvae. Combining this with a kinematic analysis of substrate-interfacing features, we shed new light onto the biomechanical control of larval locomotion. Crawling in larvae measuring ~1 mm in length involves an intricate pattern of cuticle sequestration and planting, producing GRFs of 1–7 µN. We show that larvae insert and expand denticulated, feet-like structures into substrates as they move, a process not previously observed in soft-bodied animals. These ‘protopodia’ form dynamic anchors to compensate counteracting forces. Our work provides a framework for future biomechanics research in soft-bodied animals and promises to inspire improved soft-robot design. [ABSTRACT FROM AUTHOR]

The study's objective was to evaluate how the capture rate of bottle traps is influenced by their color, number of entry holes, and bait liquids.For this purpose, yellow, blue, green, red, black, white, and transparent (colourless) traps were tested. Apple cider vinegar, grape vinegar, white wine, yeast, and water (control) were used as bait liquids. The number of entry holes was 2, 4, 6, and 8 holes per trap on the side of the bottle traps. The experiments were conducted in a randomised block design with three replicates in a fig orchard (variety Bursa Siyahı) with 437 trees in Aydın province from September 2018 to March 2019. In total, 48 traps were mounted on the experimental trees (1 trap per 1 tree), and counting of the drosophilid individuals in the traps was performed weekly. Red-coloured traps attracted the highest number of drosophilid individuals, followed by yellow-coloured. Regarding different baits, grape vinegar attracted the most drosophilid individuals, followed by white wine. Concerning the number of trap entry holes, the highest number of individuals were caught in traps with the highest number of holes, 8. In all traps, Zaprionus tuberculatus Malloch, 1932 was the species caught in the highest numbers, followed by Drosophila subobscura Collin, 1936 and Drosophila suzukii (Matsumura, 1931). Z. tuberculatus was mostly caught in traps containing grape vinegar, while D. subobscura and D. suzukii were mainly caught in traps containing white wine. In our study, the red-coloured traps containing vinegar with 8 entry holes were the most effective in monitoring drosophilid populations. [ABSTRACT FROM AUTHOR]

The history of biodiversity is closely related to the history of the evolution of species interactions. Diversity can be reduced by competitive exclusion in species with similar ecology that live in the same spatial region. Zaprionus indianus Gupta (Diptera: Drosophilidae) is a pest species that has colonized the American continent in the last 20 years. The expansion of this species in Argentina can generate competition, a major event of the ecology of insect communities exploiting ephemeral and fragmented resources. Zaprionus indianus has shown an overlapping in the breeding and feeding resources and in the distribution with Drosophila melanogaster Meigen and D. simulans Sturtevant (Diptera: Drosophilidae) in north-eastern Argentina. In this study, we analyzed the effect of interspecific competition between larvae of these species reared in cultured media prepared from three natural fruits. Our results revealed that D. simulans has a lower competitive ability with respect to the other species. On the other hand, both the successful colonization of Z. indianus and the differences observed in nature in the relative abundance of these three species between samples of collected and emerged adults cannot be attributed only to effects of interspecific competition. [ABSTRACT FROM AUTHOR]

In the natural world, animals make decisions on an ongoing basis, continuously selecting which action to undertake next. In the lab, however, the neural bases of decision processes have mostly been studied using artificial trial structures. New experimental tools based on the genetic toolkit of model organisms now make it experimentally feasible to monitor and manipulate neural activity in small subsets of neurons during naturalistic behaviors. We thus propose a new approach to investigating decision processes, termed reverse neuroethology. In this approach, experimenters select animal models based on experimental accessibility and then utilize cutting-edge tools such as connectomes and genetically encoded reagents to analyze the flow of information through an animal's nervous system during naturalistic choice behaviors. We describe how the reverse neuroethology strategy has been applied to understand the neural underpinnings of innate, rapid decision making, with a focus on defensive behavioral choices in the vinegar fly Drosophila melanogaster. [ABSTRACT FROM AUTHOR]

Ceratocystis fimbriata, the causal agent of sweetpotato black rot, is a pathogen capable of developing and spreading within postharvest settings. A survey of North Carolina sweetpotato storage facilities was conducted to determine the arthropods present and identify potential vectors of C. fimbriata. Sixteen taxonomic categories were recovered, and the genus Drosophila (Diptera: Drosophilidae) accounted for 79% of individuals sampled, with Drosophila hydei being the most abundant species. Behavioral assays were conducted to determine if D. hydei is attracted to C. fimbriata-inoculated roots and if the pathogen could be recovered from external or intornal surfaces of the insect. Flles were released in insect-trapping pitchers containing either C. fimbriata-inoculated or noninoculated roots or Petri dishes. No significant differences in fly number were detected in sweetpotato-baited pitchers; however, significant differences were found in the pitcher baited with a mature C. fimbriata culture. Flies were subjected to washes to determine if viable C. fimbriata was present (internally or externally); washes were plated onto carrot agar plates and observed for the presence of C. fimbriata colonies. Both external and internal washes had viable C. fimbriata inocula with no significant differences, and inoculated sweetpotatoes had a significantly higher number of flies carrying C. fimbriata. This study suggests that D. hydei can carry C. fimbriata from infected sweetpotatoes and move viable C. fimbriata inocula both externally and internally, making this the first report of any Drosophila sp. serving as a potential vector for the Ceratocystis genus. [ABSTRACT FROM AUTHOR]

Invertebrates lack the immune machinery underlying vertebrate-like acquired immunity. However, in many insects past infection by the same pathogen can 'prime' the immune response, resulting in improved survival upon reinfection. Here, we investigated the mechanistic basis and epidemiological consequences of innate immune priming in the fruit fly Drosophila melanogaster when infected with the gram-negative bacterial pathogen Providencia rettgeri. We find that priming in response to P. rettgeri infection is long-lasting and sexually dimorphic response. We further explore the epidemiological consequences of immune priming and find it has the potential to curtail pathogen transmission by reducing pathogen shedding and spread. The enhanced survival of individuals previously exposed to a non-lethal bacterial inoculum coincided with a transient decrease in bacterial loads, and we provide strong evidence that the effect of priming requires the IMD-responsive antimicrobial-peptide Diptericin-B in the fat body. Further, we show that while Diptericin B is the main effector of bacterial clearance, it is not sufficient for immune priming, which requires regulation of IMD by peptidoglycan recognition proteins. This work underscores the plasticity and complexity of invertebrate responses to infection, providing novel experimental evidence for the effects of innate immune priming on population-level epidemiological outcomes. Author summary: When we are vaccinated, our immune response is able to respond quickly if we are ever exposed to the same pathogen in the future. Unlike humans, the immune systems of invertebrates, such as insects, are not capable of the same type of specific immune memory. However, much work has shown that insects previously exposed to an inactivated pathogen will fare better if they are re-infected–a phenomenon broadly called "immune priming". How insects are able to do this is an exciting focus of current research. We investigated immune priming in the fruit fly, a powerful model system for infection and immunity. We found that exposure to an inactivated form of the bacterial fly pathogen Providencia rettgeri resulted in flies surviving a subsequent live infection. This effect lasted several days, was stronger in male flies, and was seen in different fly genetic backgrounds. We uncovered that priming requires a specific immune response in the fly fat-body (the equivalent to a fly 'liver') that produces an antimicrobial protein called Diptericin. We also found that primed flies were able to keep pathogen growth lower, and that this reduced their ability to spread the infection to other flies. [ABSTRACT FROM AUTHOR]

Native parasitoids are potential tools for the biological control of invasive exotic pests, such as the frugivorous flies spotted‐wing drosophila, Drosophila suzukii Matsumura, and African fig fly, Zaprionus indianus Gupta (both Diptera: Drosophilidae). Following biological invasions, the establishment of exotic species may be restricted, among other things, by their susceptibility to native or established natural enemies. The Neotropical‐native pupal endoparasitoid Trichopria anastrephae Costa Lima (Hymenoptera: Diapriidae), although primarily associated with hosts of the genus Anastrepha (Tephritidae), has also been described to attack Drosophilidae. There are few studies on the interaction between parasitoids native to Argentina and D. suzukii and/or Z. indianus. The present work evaluates the parasitism of T. anastrephae on both species of drosophilids under controlled conditions. Ten larvae (L3) of each host species were exposed separately to a couple of adult T. anastrephae for 72 h (n = 10). For both control and parasitoid treatment, 10 larvae (L3) of D. suzukii and Z. indianus were placed in 10 flasks (repetition) at the L3 stage. Host emergence, the infestation degree index (DI), and the parasitism success rate (SP) were calculated. Drosophila suzukii and Z. indianus emergence differed significantly in controlled conditions being 41% higher for Z. indianus than for D. suzukii. The DI was 100% in D. suzukii and 38% in Z. indianus, and the SP was 48% both in D. suzukii and in Z. indianus. These findings indicate that the native parasitoid T. anastrephae has a high potential as a biocontrol strategy against D. suzukii. In addition, the efficiency of T. anastrephae against Z. indianus, an invasive frugivorous widely spread in the Neotropical region, was evaluated for the first time. [ABSTRACT FROM AUTHOR]

The Asian Drosophila suzukii (Matsumura) (Diptera: Drosophilidae) is a harmful invasive pest widespread throughout Argentinian fruit‐producing regions. It coexists with both pests, the sub‐Saharan African Ceratitis capitata (Wiedemann) and the Neotropical‐native Anastrepha fraterculus (Wiedemann) (both Diptera: Tephritidae), in northwestern Argentina. The Neotropical‐native parasitoid Ganaspis pelleranoi (Brèthes) (Hymenoptera: Figitidae) is frequently found in non‐crop fruit infested by those frugivorous dipterans. The northwestern Argentinian region is known for producing and exporting berries and citrus, which are affected by those pests. Thus, eco‐friendly control strategies are under assessment. This study mainly assessed the potential of the G. pelleranoi population lineage from Tucumán (GpTuc) as a D. suzukii biocontrol agent. First, both the host‐killing effectiveness and the reproductive success of GpTuc on larvae of D. suzukii, C. capitata, A. fraterculus, and Drosophila melanogaster Meigen were compared in no‐choice tests under laboratory conditions. Then, the GpTuc host preference was evaluated in dual‐choice tests (D. suzukii vs. C. capitata or A. fraterculus) under laboratory and field conditions. Naive parasitoid females were allowed to forage for 8 h on screen‐covered Petri dishes filled with host larvae under laboratory conditions and for 48 h on peaches inoculated with host larvae under field conditions. Host puparia dissections were performed to determine the number and condition of parasitoid eggs, first and second instars, such as alive/dead, without/with melanization process, and proportions of parasitized, superparasitized, and dead puparia. Drosophila suzukii was not a suitable host for the successful development of GpTuc immature stages as they did not overcome the host's immune system. However, GpTuc performed efficiently regarding D. suzukii mortality, but parasitoid specificity was restricted to both tephritid species as only thriving offspring were achieved from them. Interestingly, the effectiveness of GpTuc on D. suzukii increased when it co‐occurred with C. capitata instead of A. fraterculus, the preferred host. [ABSTRACT FROM AUTHOR]

Sexual selection has been suggested to influence the expression of male behavioral consistency. However, despite predictions, direct experimental support for this hypothesis has been lacking. Here, we investigated whether sexual selection altered male behavioral consistency in Drosophila melanogaster —a species with both pre- and postcopulatory sexual selection. We took 1,144 measures of locomotor activity (a fitness-related trait in D. melanogaster) from 286 flies derived from replicated populations that have experimentally evolved under either high or low levels of sexual selection for >320 generations. We found that high sexual selection males were more consistent (decreased within-individual variance) in their locomotor activity than male conspecifics from low sexual selection populations. There were no differences in behavioral consistency between females from the high and low sexual selection populations. Furthermore, while females were more behaviorally consistent than males in the low sexual selection populations, there were no sex differences in behavioral consistency in high sexual selection populations. Our results demonstrate that behavioral plasticity is reduced in males from populations exposed to high levels of sexual selection. Disentangling whether these effects represent an evolved response to changes in the intensity of selection or are manifested through nongenetic parental effects represents a challenge for future research. [ABSTRACT FROM AUTHOR]

Drosophila nervous system development progresses through a series of well-characterized steps in which homeodomain transcription factors (HDTFs) play key roles during most, if not all, phases. Strikingly, although some HDTFs have only one role, many others are involved in multiple steps of the developmental process. Most Drosophila HDTFs engaged in nervous system development are conserved in vertebrates and often play similar roles during vertebrate development. In this Spotlight, we focus on the role of HDTFs during embryogenesis, where they were first characterized. [ABSTRACT FROM AUTHOR]

The increased consumption of pesticides can have a negative environmental impact by increasing the essential metals to toxic levels. Bordasul® is a commonly used fungicide in Brazil and it is composed of 20% Cu, 10% sulfur, and 3.0% calcium. The study of fungicides in vivo in non-target model organisms can predict their environmental impact more broadly. The Drosophila melanogaster is a unique model due to its ease of handling and maintenance. Here, the potential toxicity of Bordasul® was investigated by assessing the development, survival, and behavior of exposed flies. Exposure to Bordasul® impaired the development (p < 0.01) and caused a significant reduction in memory retention (p < 0.05) and locomotor ability (p < 0.001). Fungicides are needed to assure the world's food demand; however, Bordasul® was highly toxic to D. melanogaster. Therefore, Bordasul® may be potentially toxic to non-target invertebrates and new environmentally-safe biofertilizers have to be developed to preserve the biota. [ABSTRACT FROM AUTHOR]

The last decade has been highlighted by the increased use of next-generation DNA sequencing technology to identify novel human disease genes. A critical downstream part of this process is assigning function to a candidate gene variant. Functional studies in Drosophila melanogaster, the common fruit fly, have made a prominent contribution in annotating variant impact in an in vivo system. The use of patient-derived knock-in flies or rescue-based, "humanization", approaches are novel and valuable strategies in variant testing but have been recently widely reviewed. An often-overlooked strategy for determining variant impact has been GAL4/upstream activation sequence-mediated tissue-defined overexpression in Drosophila. This mini-review will summarize the recent contribution of ectopic overexpression of human reference and variant cDNA in Drosophila to assess variant function, interpret the consequence of the variant, and in some cases infer biological mechanisms. [ABSTRACT FROM AUTHOR]

Spotted-wing drosophila, Drosophila suzukii (Matsumura) (Diptera: Drosophilidae), is one of the most detrimental pests of small fruit crops worldwide and its control relies heavily on pesticides, so there is a need to develop alternative management practices. Cultural practices that make the microclimate hotter, drier, and brighter than optimal conditions for the pest may be highly effective. In this two-year study, we evaluated how black, white, and metallic plastic mulches influence the raspberry plants' microclimate to reduce D. suzukii larval infestation of fruit in the canopy and increase mortality of fallen larvae and pupae on the ground. All three plastic mulches reduced D. suzukii larval infestation of fruit by 40–72% and killed 80–100% of larvae and pupae placed on the mulch surface. The mechanisms at play are likely the compounded effects of increased ultraviolet (UV) light, hotter and drier conditions in the low canopy, and hot mulch surface temperature. UV light may be especially important since it reduced D. suzukii oviposition in the lab. Overall, plastic mulches can effectively modify the microclimate to make it less favorable for D. suzukii, reducing infestation in fruit and on the ground. [ABSTRACT FROM AUTHOR]

Simple Summary: This study represents the first investigation of the seasonal dynamics and species diversity of Drosophilidae in Moscow, Russia, from 2021 to 2023. Traps were placed on the ground under trees to collect the specimens. Among the collected species, Drosophila obscura Fll., D. phalerata Mg., and D. testacea Roser were the most abundant. Peaks in the abundance of drosophilids varied between years, but the lowest abundance was always observed in May. In 2022, the highest number of flies was collected (9604 specimens), and the highest species diversity (33 species) was recorded. The effects of temperature and precipitation on the species abundance and community diversity indices are evident during the preimaginal developmental stages of drosophila. The insect fauna of natural parks in large cities has not been sufficiently studied in Russia. This study represents the first investigation of the seasonal dynamics and species diversity of Drosophilidae in Moscow city. Traps with fermenting liquid were placed on the ground under trees to collect flies from four natural park sites between early May and late September from 2021 to 2023. A total of 26,420 individuals belonging to 11 genera and 33 drosophilid species were identified, with 21 species from 6 genera being new to the fauna of Moscow. Drosophila obscura Fll., D. phalerata Mg., and D. testacea Roser were the most abundant species in the traps. Peaks in the abundance of drosophilids varied between years, but the lowest abundance was always observed in May. In 2022, the highest number of flies was collected (9604 specimens), with slightly fewer in 2023 (8496 specimens), and even fewer in 2021 (8320 specimens). In 2022, the highest species diversity of drosophilids was also recorded—33 species—while 28 species were found in both 2021 and 2023. The high variability in the abundance of individual drosophila species obscures the differences between the studied years due to the effects of the "Month" and "Site" factors. The diversity metrics exhibit similar patterns among drosophila communities inhabiting comparable biotopes. Specific climatic factors, such as the temperature and precipitation, impact the species abundance and community diversity indices primarily through their effects on the preimaginal stages of drosophila development. For several species, the population dynamics in the spring, post-hibernation, are influenced by the conditions preceding winter. [ABSTRACT FROM AUTHOR]

One of the characteristics of the adult eclosion rhythm in Drosophila melanogaster is that adult emergence time differs greatly between the first and second eclosion days. The emergence time is in the middle of the light period on the first eclosion day, but immediately after light‐on on the second day. We hypothesized that incomplete entrainment of the endogenous pacemaker to the light–dark (LD) cycle is responsible for the daily variation. Due to the very short pupal period of this species, adult emergence may occur before complete synchronization of the pacemaker with the external cycle on the first eclosion day. Therefore, the peak time on the first eclosion day may differ significantly from that on the second day. To verify this hypothesis, using pupae that had pupariated within 24 h, the time difference between the first and second peaks was compared in LD 12:12 or constant darkness at five different temperatures from 30 to 15°C. In both light regimes, the time difference decreased with decreasing temperature and extended pupal duration. The interval between the eclosion peaks approached 24 h, supporting this hypothesis. These results can be interpreted by using a two‐oscillator model. [ABSTRACT FROM AUTHOR]

Spotted‐wing drosophila (SWD), Drosophila suzukii (Matsumura, 1931) (Diptera: Drosophilidae) cause yield losses and important economic impacts in fruits with thin epicarp. In the present study, the combination of powdered sulphur and predators/parasitoids for the control of SWD was analysed. First, the interaction of powered sulphur with Anthocoris nemoralis (Hemiptera: Anthocoridae) on infested strawberry fruits and Trichropia drosophilae (Hymenoptera: Diapriidae) on SWD pupae was evaluated. Second, exposure of predators/parasitoids to strawberry leaves with powdered sulphur was also assessed. Additionally, sublethal effects of powdered sulphur on T. drosophilae parasitism were examined. The results show powdered sulphur did not interfere with the activity of A. nemoralis and caused a significant reduction in fruit infestation. In contrast, sulphur affected the activity of T. drosophilae, reducing parasitism when the two agents were combined. Direct exposure to powdered sulphur did not cause significant mortality of A. nemoralis and T. drosophilae. Finally, previous exposure to sulphur did not affect T. drosophilae in terms of parasitism rates and sex ratio. Based on the results obtained herein, sulphur and T. drosophilae impacts on different stages of SWD when they are applied separately. However, the effects of sulphur on T. drosophilae should be taken into account in combination control strategies of SWD. [ABSTRACT FROM AUTHOR]

The origin, diversification, and secondary loss of sexually dimorphic characters are common in animal evolution. In some cases, structurally and functionally similar traits have evolved independently in multiple lineages. Prominent examples of such traits include the male-specific grasping structures that develop on the front legs of many dipteran insects. In this report, we describe the evolution and development of one of these structures, the male-specific "sex brush." The sex brush is composed of densely packed, irregularly arranged modified bristles and is found in several distantly related lineages in the family Drosophilidae. Phylogenetic analysis using 250 genes from over 200 species provides modest support for a single origin of the sex brush followed by many secondary losses; however, independent origins of the sex brush cannot be ruled out completely. We show that sex brushes develop in very similar ways in all brush-bearing lineages. The dense packing of brush hairs is explained by the specification of bristle precursor cells at a near-maximum density permitted by the lateral inhibition mechanism, as well as by the reduced size of the surrounding epithelial cells. In contrast to the female and the ancestral male condition, where bristles are arranged in stereotypical, precisely spaced rows, cell migration does not contribute appreciably to the formation of the sex brush. The complex phylogenetic history of the sex brush can make it a valuable model for investigating coevolution of sex-specific morphology and mating behavior.

Drosophila remains a pre-eminent insect model system for host–virus interaction, but the host range and fitness consequences of the drosophilid virome are poorly understood. Metagenomic studies have reported approximately 200 viruses associated with Drosophilidae, but few isolates are available to characterize the Drosophila immune response, and most characterization has relied on injection and systemic infection. Here, we use a more natural infection route to characterize the fitness effects of infection and to study a wider range of viruses. We exposed laboratory Drosophila melanogaster to 23 naturally occurring viruses from wild-collected drosophilids. We recorded transmission rates along with two components of female fitness: survival and the lifetime number of adult offspring produced. Nine different viruses transmitted during contact with laboratory D. melanogaster, although for the majority, rates of transmission were less than 20%. Five virus infections led to a significant decrease in lifespan (D. melanogaster Nora virus, D. immigrans Nora virus, Muthill virus, galbut virus and Prestney Burn virus), and three led to a reduction in the total number of offspring. Our findings demonstrate the utility of the Drosophila model for community-level studies of host–virus interactions, and suggest that viral infection could be a substantial fitness burden on wild flies. [ABSTRACT FROM AUTHOR]

Stroke, resulting in hypoxia and glucose deprivation, is a leading cause of death and disability worldwide. Presently, there are no treatments that reduce neuronal damage and preserve function aside from tissue plasminogen activator administration and rehabilitation therapy. Interestingly, Drosophila melanogaster, the common fruit fly, demonstrates robust hypoxic tolerance, characterized by minimal effects on survival and motor function following systemic hypoxia. Due to its organized brain, conserved neurotransmitter systems, and genetic similarity to humans and other mammals, uncovering the mechanisms of Drosophila's tolerance could be a promising approach for the development of new therapeutics. Interestingly, a key facet of hypoxic tolerance in Drosophila is organism-wide metabolic suppression, a response involving multiple genes and pathways. Specifically, studies have demonstrated that pathways associated with oxidative stress, insulin, hypoxia-inducible factors, NFκB, Wnt, Hippo, and Notch, all potentially contribute to Drosophila hypoxic tolerance. While manipulating the oxidative stress response and insulin signaling pathway has similar outcomes in Drosophila hypoxia and the mammalian middle cerebral artery occlusion (MCAO) model of ischemia, effects of Notch pathway manipulation differ between Drosophila and mammals. Additional research is warranted to further explore how other pathways implicated in hypoxic tolerance in Drosophila, such as NFκB, and Hippo, may be utilized to benefit mammalian response to ischemia. Together, these studies demonstrate that exploration of the hypoxic response in Drosophila may lead to new avenues of research for stroke treatment in humans. [ABSTRACT FROM AUTHOR]

Flies in the Drosophila (Sophophora) obscura species group are among the most common native drosophilids in northern temperate and boreal forests; southward, into cool, montane tropical forests they are rare and localized, but diverse. Of the world's 48 species, 18 occur in the New World, including three new neotropical species described here. Here, all New World species are diagnosed, many with images and the use of some new morphological features such as female terminalia (oviscapt and spermathecal structure). A basic phylogenetic scheme of relationships based on 19 morphological characters corresponds well with molecular trees. Type series have been rediscovered of D. algonquin, athabasca, azteca, narragansett, and seminole (all described by Sturtevant and Dobzhansky in 1936), from which a lectotype is designated for each of the first four species and the holotype is recognized for seminole. Drosophila narragansett from the eastern United States, which has been found only once in 60 years, is redescribed in detail from historical material; D. seminole is found to be a synonym of narragansett. The three new species are Drosophila chibcha, n. sp. (from Costa Rica to Venezuela and Peru), D. olmeca, n. sp. (from southern Mexico), both of these in the a nis subgroup; and D. zapoteca, n. sp. (from Guatemala), in the pseudoobscura subgroup. Signifficant new distributional and host records are reported for various species. [ABSTRACT FROM AUTHOR]

Allele frequencies can shift rapidly within natural populations. Under certain conditions, repeated rapid allele frequency shifts can lead to the long‐term maintenance of polymorphism. In recent years, studies of the model insect Drosophila melanogaster have suggested that this phenomenon is more common than previously believed and is often driven by some form of balancing selection, such as temporally fluctuating or sexually antagonistic selection. Here we discuss some of the general insights into rapid evolutionary change revealed by large‐scale population genomic studies, as well as the functional and mechanistic causes of rapid adaptation uncovered by single‐gene studies. As an example of the latter, we consider a regulatory polymorphism of the D. melanogaster fezzik gene. Polymorphism at this site has been maintained at intermediate frequency over an extended period of time. Regular observations from a single population over a period of 7 years revealed significant differences in the frequency of the derived allele and its variance across collections between the sexes. These patterns are highly unlikely to arise from genetic drift alone or from the action of sexually antagonistic or temporally fluctuating selection individually. Instead, the joint action of sexually antagonistic and temporally fluctuating selection can best explain the observed rapid and repeated allele frequency shifts. Temporal studies such as those reviewed here further our understanding of how rapid changes in selection can lead to the long‐term maintenance of polymorphism as well as improve our knowledge of the forces driving and limiting adaptation in nature. [ABSTRACT FROM AUTHOR]

Background: Juvenile hormones (JH) play crucial role in regulating development and reproduction in insects. The most common form of JH is JH III, derived from MF through epoxidation by CYP15 enzymes. However, in the higher dipterans, such as the fruitfly, Drosophila melanogaster, a bis-epoxide form of JHB3, accounted most of the JH detected. Moreover, these higher dipterans have lost the CYP15 gene from their genomes. As a result, the identity of the P450 epoxidase in the JH biosynthesis pathway in higher dipterans remains unknown. Results: In this study, we show that Cyp6g2 serves as the major JH epoxidase responsible for the biosynthesis of JHB3 and JH III in D. melanogaster. The Cyp6g2 is predominantly expressed in the corpus allatum (CA), concurring with the expression pattern of jhamt, another well-studied gene that is crucial in the last steps of JH biosynthesis. Mutation in Cyp6g2 leads to severe disruptions in larval-pupal metamorphosis and exhibits reproductive deficiencies, exceeding those seen in jhamt mutants. Notably, Cyp6g2−/−::jhamt2 double mutants all died at the pupal stage but could be rescued through the topical application of JH analogs. JH titer analyses revealed that both Cyp6g2−/− mutant and jhamt2 mutant lacking JHB3 and JH III, while overexpression of Cyp6g2 or jhamt caused a significant increase in JHB3 and JH III titer. Conclusions: These findings collectively established that Cyp6g2 as the major JH epoxidase in the higher dipterans and laid the groundwork for the further understanding of JH biosynthesis. Moreover, these findings pave the way for developing specific Cyp6g2 inhibitors as insect growth regulators or insecticides. [ABSTRACT FROM AUTHOR]

Adenine phosphoribosyltransferase (APRT) and hypoxanthine-guanine phosphoribosyltransferase (HGPRT) are two structurally related enzymes involved in purine recycling in humans. Inherited mutations that suppress HGPRT activity are associated with Lesch-Nyhan disease (LND), a rare X-linked metabolic and neurological disorder in children, characterized by hyperuricemia, dystonia, and compulsive self-injury. To date, no treatment is available for these neurological defects and no animal model recapitulates all symptoms of LND patients. Here, we studied LND-related mechanisms in the fruit fly. By combining enzymatic assays and phylogenetic analysis, we confirm that no HGPRT activity is expressed in Drosophila melanogaster, making the APRT homolog (Aprt) the only purine-recycling enzyme in this organism. Whereas APRT deficiency does not trigger neurological defects in humans, we observed that Drosophila Aprt mutants show both metabolic and neurobehavioral disturbances, including increased uric acid levels, locomotor impairments, sleep alterations, seizure-like behavior, reduced lifespan, and reduction of adenosine signaling and content. Locomotor defects could be rescued by Aprt re-expression in neurons and reproduced by knocking down Aprt selectively in the protocerebral anterior medial (PAM) dopaminergic neurons, the mushroom bodies, or glia subsets. Ingestion of allopurinol rescued uric acid levels in Aprt-deficient mutants but not neurological defects, as is the case in LND patients, while feeding adenosine or N6-methyladenosine (m6A) during development fully rescued the epileptic behavior. Intriguingly, pan-neuronal expression of an LND-associated mutant form of human HGPRT (I42T), but not the wild-type enzyme, resulted in early locomotor defects and seizure in flies, similar to Aprt deficiency. Overall, our results suggest that Drosophila could be used in different ways to better understand LND and seek a cure for this dramatic disease. [ABSTRACT FROM AUTHOR]

Simple Summary: The life expectancy of Drosophila melanogaster evolves in the laboratory in a downward direction over time. The comparison of two old laboratory-adapted strains, Canton-S and Harwich, suggested that they may be used as a multicellular eukaryote model for studying the effects of individual difference in aging processes on the physiological responses to various environmental factors, including low and high temperature, carbohydrate-heavy food, and caffeinated food in the presence of light-dark cyclicity and constant darkness. We found that the accelerated aging in Harwich was associated with a shorter lifespan, lower fecundity, faster rate of development, smaller body weight, lower concentrations of two main insect sugars, reduced locomotor activity, and larger amount of sleep. Such findings imply that, in the experimental studies of the aging accelerated effects of various adverse factors, the results obtained with only one of the laboratory-adapted strains cannot be generalized to other strains. The documented individual and strain-associated differences in the responses of their daily rhythms to aging and age-accelerated factors allow the recommendation to use at least two distinct strains characterized by a relatively fast and relatively slow aging processes, for the experimental elaboration of relationships between genes, environment, behavior, physiology, and health. Background: Drosophila melanogaster provides a powerful platform to study the physiology and genetics of aging, i.e., the mechanisms underpinnings healthy aging, age-associated disorders, and acceleration of the aging process under adverse environmental conditions. Here, we tested the responses of daily rhythms to age-accelerated factors in two wild-type laboratory-adapted strains, Canton-S and Harwich. Methods: On the example of the 24 h patterns of locomotor activity and sleep, we documented the responses of these two strains to such factors as aging, high temperature, carbohydrate diet, and diet with different doses of caffeine-benzoate sodium. Results: The strains demonstrated differential responses to these factors. Moreover, compared to Canton-S, Harwich showed a reduced locomotor activity, larger amount of sleep, faster rate of development, smaller body weight, lower concentrations of main sugars, lower fecundity, and shorter lifespan. Conclusions: It might be recommended to use at least two strains, one with a relatively fast and another with a relatively slow aging process, for the experimental elaboration of relationships between genes, environment, behavior, physiology, and health. [ABSTRACT FROM AUTHOR]

The cost of reproduction is well studied in females but only recently have the costs of mating been investigated in males. Research suggests that males allocate resources between subsequent mating events, resulting in differential success across mating bouts. Selection should favor allocation strategies that match the likelihood of successive matings. The complexity of the system, however, suggests that one fixed strategy is unlikely to be universally favored and thus I predict that genetic variation for different allocation strategies will be segregating in natural populations. To test this, I measured several components of reproductive performance in eight inbred genotypes of Drosophila melanogaster across three sequential mating events. As predicted, there was genetic variation for how previous experience affected a male's reproductive performance for both the proportion of matings that produced offspring and the proportion of offspring sired (P1). Some genotypes had the highest success in their first matings and declined in successive matings while other genotypes did best in later matings. Mating experience had consistent effects across genotypes on fertility and induced refractoriness to remating. On average, virgin matings produced the highest fertility and third matings most effectively induced refractoriness. Genotype also had a significant effect on fertility. These results have important implications for understanding how selection may be acting on males when there is variation in the likelihood of multiple mating events and could affect the evolution of male allocation strategies in the face of perceived competitors. [ABSTRACT FROM AUTHOR]

Drosophila melanogaster, better known as the fruit fly, has become a widely used model organism that has allowed us to understand many biological behaviors, from sleep to neurological diseases, behavioral patterns, reproduction, and the circadian cycle, which coordinates biological rhythms in a 24-hour daily cycle through its main Zeitgerber, light, especially blue light. Therefore, the aim of this work was to build an optical setup with a hexagonal design that allowed a large number of D. melanogaster cultures to be irradiated homogeneously with blue light simultaneously. This array can cover an illuminance range from 0 to approximately 600 lux by applying a current variation from 0 to approximately 1 A. It also has a real-time timer to turn the lights on and off, programmed in a 12:12 LD cycle for 24 h. The optical setup with its unique design can become a very useful tool for developing experiments and understanding paradigms related to blue light at genetic, behavioral and neuronal levels, among others that are still unanswered. [ABSTRACT FROM AUTHOR]

CO2 anesthesia is the most common method for immobilizing Drosophila for research purposes. But CO2 exposure has consequences—it can impact fertility, behavior, morphogenesis, and cytoskeletal dynamics. In this respect, Drosophila is an outstanding model for studying the impact of CO2 exposure on tissues. In this study we explored the response of intracellular pH (pHi) to a one-minute CO2 pulse using a genetically encoded, ubiquitously expressed pH sensor, tpHusion, to monitor pHi within a live, intact, whole fly. We compared wild-type flies to flies lacking Imaginal disc growth factors (Idgfs), which are chitinase-like proteins that facilitate developmental processes and the innate immune response. Morphogenetic and cytoskeletal defects in Idgf-null flies are enhanced after CO2 exposure. We found that pHi drops sharply within seconds of the beginning of a CO2 pulse and recovers over several minutes. The initial profile was nearly identical in control and Idgf-null flies but diverged as the pHi returned to normal. This study demonstrates the feasibility of monitoring pH in live adult Drosophila. Studies exploring pH homeostasis are important for understanding human pathologies associated with pH dysregulation. [ABSTRACT FROM AUTHOR]

Lifespan is a complex quantitative trait involving genetic and non-genetic factors as well as the peculiarities of ontogenesis. As with all quantitative traits, lifespan shows considerable variation within populations and between individuals. Drosophila, a favourite object of geneticists, has greatly advanced our understanding of how different forms of variability affect lifespan. This review considers the role of heritable genetic variability, phenotypic plasticity and stochastic variability in controlling lifespan in Drosophila melanogaster. We discuss the major historical milestones in the development of the genetic approach to study lifespan, the breeding of long-lived lines, advances in lifespan QTL mapping, the environmental factors that have the greatest influence on lifespan in laboratory maintained flies, and the mechanisms, by which individual development affects longevity. The interplay between approaches to study ageing and lifespan limitation will also be discussed. Particular attention will be paid to the interaction of different types of variability in the control of lifespan. [ABSTRACT FROM AUTHOR]

Neurofibromatosis 1 (NF1) is a multisymptomatic disorder with highly variable presentations, which include short stature, susceptibility to formation of the characteristic benign tumors known as neurofibromas, intense freckling and skin discoloration, and cognitive deficits, which characterize most children with the condition. Attention deficits and Autism Spectrum manifestations augment the compromised learning presented by most patients, leading to behavioral problems and school failure, while fragmented sleep contributes to chronic fatigue and poor quality of life. Neurofibromin (Nf1) is present ubiquitously during human development and postnatally in most neuronal, oligodendrocyte, and Schwann cells. Evidence largely from animal models including Drosophila suggests that the symptomatic variability may reflect distinct cell-type-specific functions of the protein, which emerge upon its loss, or mutations affecting the different functional domains of the protein. This review summarizes the contributions of Drosophila in modeling multiple NF1 manifestations, addressing hypotheses regarding the cell-type-specific functions of the protein and exploring the molecular pathways affected upon loss of the highly conserved fly homolog dNf1. Collectively, work in this model not only has efficiently and expediently modelled multiple aspects of the condition and increased understanding of its behavioral manifestations, but also has led to pharmaceutical strategies towards their amelioration. [ABSTRACT FROM AUTHOR]

Motor and cognitive aging can severely affect life quality of elderly people and burden health care systems. In search for diagnostic behavioral biomarkers, it has been suggested that walking speed can predict forms of cognitive decline, but in humans, it remains challenging to separate the effects of biological aging and lifestyle. We examined a possible association of motor and cognitive decline in Drosophila, a genetic model organism of healthy aging. Long term courtship memory is present in young male flies but absent already during mid life (4–8 weeks). By contrast, courtship learning index and short term memory (STM) are surprisingly robust and remain stable through mid (4–8 weeks) and healthy late life (>8 weeks), until courtship performance collapses suddenly at ~4.5 days prior to death. By contrast, climbing speed declines gradually during late life (>8 weeks). The collapse of courtship performance and short term memory close to the end of life occur later and progress with a different time course than the gradual late life decline in climbing speed. Thus, during healthy aging in male Drosophila, climbing and courtship motor behaviors decline differentially. Moreover, cognitive and motor performances decline at different time courses. Differential behavioral decline during aging may indicate different underlying causes, or alternatively, a common cause but different thresholds for defects in different behaviors. [ABSTRACT FROM AUTHOR]

Introduction: Endosymbiotic Wolbachia bacteria are widespread in nature, present in half of all insect species. The success of Wolbachia is supported by a commensal lifestyle. Unlike bacterial pathogens that overreplicate and harm host cells, Wolbachia infections have a relatively innocuous intracellular lifestyle. This raises important questions about how Wolbachia infection is regulated. Little is known about how Wolbachia abundance is controlled at an organismal scale. Methods: This study demonstrates methodology for rigorous identification of cellular processes that affect whole-body Wolbachia abundance, as indicated by absolute counts of the Wolbachia surface protein (wsp) gene. Results: Candidate pathways, associated with well-described infection scenarios, were identified. Wolbachia-infected fruit flies were exposed to small molecule inhibitors known for targeting those same pathways. Sequential tests in D. melanogaster and D. simulans yielded a subset of chemical inhibitors that significantly affected whole-body Wolbachia abundance, including the Wnt pathway disruptor, IWR-1 and the mTOR pathway inhibitor, Rapamycin. The implicated pathways were genetically retested for effects in D. melanogaster, using inducible RNAi expression driven by constitutive as well as chemically-induced somatic GAL4 expression. Genetic disruptions of armadillo, tor, and ATG6 significantly affected whole-body Wolbachia abundance. Discussion: As such, the data corroborate reagent targeting and pathway relevance to whole-body Wolbachia infection. The results also implicate Wnt and mTOR regulation of autophagy as important for regulation of Wolbachia titer. [ABSTRACT FROM AUTHOR]

As most drosophilid species are not considered as primary pest, studies of their communities in natura, with standardized surveys, are relatively sparse. However, Drosophila suzukii and its rapid expansion through the world led to the implementation of many monitoring programs. As part of a research project on D. suzukii, we set up in 2022 an annual fly monitoring in 16 fruits plantations in France to understand population's dynamics of D. suzukii and to broadly survey drosophilid communities. The captures led to the first observation of Zaprionus tuberculatus in mainland France. Over the whole monitoring, we trapped a total of 111 specimens in a fig orchard located in southern France (Salses‐le‐Château), both in fig trees and nearby hedgerow. The first detection of Zaprionus tuberculatus occurred in July 2022 in the hedgerow, and captures continued until January 2023 with an interruption in November and December. In addition, in this orchard we collected overripe figs in September 2023 from which over 20 Z. tuberculatus have emerged in the following 2 weeks, confirming the establishment of a permanent population. The pest status of Z. tuberculatus and its potential risk for agriculture is not yet clear, but the pest behavior of the close‐relative species Zaprionus indianus, especially on figs, should be a warning point for the entry of Z. tuberculatus into the EU and France, as they may have similar polyphagous habit. The pest status and range expansion of Z. tuberculatus should be assessed to estimate risk to fruit's production. [ABSTRACT FROM AUTHOR]