Immature Stages Research Articles

Exochorionic pattern of ten sand fly species (Diptera: Psychodidae: Phlebotominae) from Mexico

BackgroundPhlebotomine sand flies are of biological importance because of their role as vectors of several pathogens. Morphological identification faces challenges to separate related species; therefore, the study of immature stages, as the egg and its exochorion sculpturing pattern could provide useful characters for taxonomic and phylogenetic studies. In the Americas, morphological information of the egg exochorion obtained through scanning electron microscopy has become a complementary tool for taxonomic classification of sand fly species. The aim of this study was to examine and describe the exochorion pattern of eggs obtained from the abdomen of gravid wild females of 10 sand fly species collected in different areas of Mexico.ResultsWe describe the chorionic pattern of 10 sand fly species collected during the period 1997–2023, which was classified as (1) polygonal, (2) connected and unconnected parallel ridges, (3) verrucose, (4) volcano-like and (5) disperse, being the polygonal pattern the most common among several species of the genera Dampfomyia, Micropygomia and Lutzomyia.ConclusionsThis study describes the exochorion pattern of eggs directly obtained from the abdomen of preserved female specimens, supporting that extraction of eggs directly from an abdomen of a collection specimen might be a viable alternative to gather information of taxonomic value. We describe the eggshell of Bichromomyia olmeca olmeca, Dampfomyia deleoni, Micropygomyia cayennensis, Micropygomyia chiapanensis, Micropygomyia vindicator, Micropygomyia durani, Lutzomyia cruciata, Psathyromyia maya, Psathyromyia texana and Trichopygomyia triramula. We detected differences with respect to previous descriptions of Micropygomyia chiapanensis, Lutzomyia cruciata, and Psathyromyia texana, providing new reference information.

Chemical Composition of Essential Oil from Citrus reticulata Blanco cv. Chachiensis (Chachi) and Its Anti-Mosquito Activity against Pyrethroid-Resistant Aedes albopictus

The overuse of synthetic insecticides has led to various negative consequences, including insecticide resistance, environmental pollution, and harm to public health. This may be ameliorated by using insecticides derived from botanical sources. The primary objective of this study was to evaluate the anti-mosquito activity of the essential oil (EO) of Citrus reticulata Blanco cv. Chachiensis (Chachi) (referred to as CRB) at immature, semi-mature, and mature stages. The chemical compositions of the CRB EO were analyzed using GC-MS. The main components were identified to be D-limonene and γ-terpinene. The contents of D-limonene at the immature, semi-mature, and mature stages were 62.35%, 76.72%, and 73.15%, respectively; the corresponding contents of γ-terpinene were 14.26%, 11.04%, and 11.27%, respectively. In addition, the corresponding contents of a characteristic component, methyl 2-aminobenzoate, were 4.95%, 1.93%, and 2.15%, respectively. CRB EO exhibited significant larvicidal activity against Aedes albopictus (Ae. albopictus, Diptera: Culicidae), with the 50% lethal doses being 65.32, 61.47, and 65.91 mg/L for immature, semi-mature, and mature CRB EO, respectively. CRB EO was able to inhibit acetylcholinesterase and three detoxification enzymes, significantly reduce the diversity of internal microbiota in mosquitoes, and decrease the relative abundance of core species within the microbiota. The present results may provide novel insights into the utilization of plant-derived essential oils in anti-mosquitoes.

Discovery of the Larvae and Pupae of the Black Fly Simulium (Gomphostilbia) khelangense and Breeding Habitats of Potential Pest Species of the S. (G.) chumpornense Subgroup (Simuliidae)

Two species of black flies (Simuliidae) in Thailand, Simulium chumpornense Takaoka and Kuvangkadilok, 2000, and S. khelangense Takaoka, Srisuka & Saeung, 2022, are potent vectors of avian blood protozoa of the genera Leucocytozoon and Trypanosoma and are pests of domestic avian species. Although the adults are abundant throughout Thailand, information on their breeding habitats is limited, and the immature stages of S. khelangense are unknown. We collected the larvae and pupae of S. khelangense from the Mekong River, the first-ever record of Simuliidae from this large continental river. Mitochondrial cytochrome c oxidase I and internal transcribed spacer 2 were used to associate the larvae and pupae with known adults. Both genetic markers strongly supported their identity as S. khelangense. The larvae and pupa of S. khelangense are described. The pupal gill filaments, larval abdominal protuberances, and setae distinguish this species from other members of the S. varicorne species group. The immature stages of S. chumpornense inhabit a wide variety of flowing waters, from small streams (3 m wide) to enormous continental rivers (400 m wide); thus, S. chumpornense is a habitat generalist. In contrast, S. khelangense was found only in the large Mekong River and is, therefore, a habitat specialist. Both species can exploit their principal habitats and produce abundant adult populations.

Virus-vectoring thrips regulate the excessive multiplication of tomato spotted wilt virus using their antiviral immune responses.

The tomato spotted wilt virus (TSWV) is a member of the Tospoviridae family and has an negative/ambisense single-stranded RNA genome. Frankliniella occidentalis and F. intonsa are known to be dominant pests in Capsicum annuum (hot pepper) and can cause damage to the plant either directly by feeding, or indirectly by transmitting TSWV in a persistent and propagative manner, resulting in serious economic damage. This study compared the immune responses of two different thrips species against TSWV infection by transcriptome analysis, which then allowed the assessment of antiviral responses using RNA interference (RNAi). Both adult thrips shared about 90 % of the transcripts in non-viruliferous conditions. Most signal components of the immune pathways were shared by these two thrips species, and their expression levels fluctuated differentially in response to TSWV infection at early immature stages. The functional assays using RNAi treatments indicated that the Toll and JAK/STAT pathways were associated with the antiviral responses, but the IMD pathway was not. The upregulation of dorsal switch protein one supported its physiological role in recognizing TSWV infection and triggering the eicosanoid biosynthetic pathway, which mediates melanization and apoptosis in thrips. In addition, the signal components of the RNAi pathways fluctuated highly after TSWV infection. Individual RNAi treatments specific to the antiviral signalling and response components led to significant increases in the TSWV amount in the thrips, causing virus-induced mortality. These findings suggest that immune signalling pathways leading to antiviral responses are operating in the thrips to regulate TSWV litres to prevent a fatal viral overload. This study also indicates the differential antiviral responses between the TSWV-transmitting F. occidentalis and F. intonsa.

The Effects of Harvesting Period and Inoculant on Second-Crop Maize Silage Fermentative Quality

Southern Europe’s mutating weather conditions and the European environmental agenda have suggested the cropping of maize (Zea mays L.) after winter cereal cultivation, even if shortening the growing period could result in an immature harvesting stage, limiting its silage quality. The experimental design investigated the effects of four harvesting dry matter (DM) classes (DMvl, 23.9%; DMl, 25.3%; DMm, 26.2%; DMh, 30.4%) in two inoculant types (heterofermentative (HE) vs. homofermentative (HOM) on fermentative quality, DM losses, and aerobic stability. The early harvested DMvl and DMl classes had the lowest silage density (<130 kg m−3) and resulted in an organic acids profile lowering the fermentative quality and increasing the DM losses, while no differences were detected following the use of the inoculants. The aerobic stability was more susceptible to further adverse fermentation via opportunistic microorganisms in the DMm and DMh classes, probably due to the lower moisture content, but the use of both HE and HOM lactic acid bacteria seemed to contain this silage surface damage. In summary, a shortening of the maize growing period might limit the achievement of the maturity stage ideal for high-quality silage, hampering the positive effects of both HOM and HE inoculants in the ensiling process of early harvested maize.

Personalized music teaching service recommendation based on sensor and information retrieval technology

In order to fully utilize the existing resources of music information, people have found that music information retrieval technology has important research significance for personalized music teaching. Overall, music information retrieval technology is still in the experimental exploration stage and lacks technical and practical systems. In this context, this article proposes recommendation algorithms that can effectively adjust the content of information services based on user preferences. However, recommendation algorithms are still in an immature and complex stage, and there are still issues with their accuracy. In response to the issue of recommendation accuracy, this article utilizes information retrieval technology to optimize recommendation algorithms. Combine these two algorithms for recommendation. The main steps that affect recommendation results in recommendation algorithms include similarity calculation, nearest neighbor selection method, and score prediction method calculation. The experimental results indicate that the proposed algorithm can effectively solve the existing problems of users, and can also accurately retrieve the content of interest, greatly improving the diversity of the proposed content. We use utilizing algorithmic learning to create a personalized music teaching system that enables students to independently advance towards their self-development goals, ultimately achieving the goal of promoting the harmonious development of students' personalities.

Portray from "him" to "her": Case Study on Media Practices and Practical Significance of Chinese Female-themed Bloggers

The prosperity of new media and self-media has empowered women with more discourse power and influence in self-expression and group advocacy, making female-themed bloggers the emerging agents of gender communication. Through content analysis and text analysis, this paper explores the discourse expression and public influence of female-themed bloggers on social media platforms represented by "Little Red Book." It is found that female-themed bloggers have achieved considerable communication effects by shaping a high sense of social responsibility, ingenious topic planning and issue construction, creative narrative strategies, and text content focusing on women, continuously awakening women's consciousness and promoting gender equality. The article also identifies issues in the immature stage of the female-themed communication ecosystem, uneven content quality, and evident information cocoons, and provides corresponding recommendations.

New developmental data for Dermestes maculatus (Coleoptera: Dermestidae) from the Yangtze River Delta region of China under different constant temperatures

Necrophagous beetles are sometimes used to estimate the minimum postmortem interval (PMImin) in the decay and remains stages of a corpse. Among these, the Dermestidae is one of the most common groups used and therefore has important research and application value. In this study, the developmental events of Dermestes maculatus de Geer, 1774, were recorded at six constant temperatures, and isomorphen diagrams were established. The thermobiological parameters were estimated using linear and non-linear models, and morphological indicators such as larval body length were measured. The results showed that the developmental duration of the whole immature stage decreased from 66.13 ± 8.58 days at 19 °C to 21.9 ± 2.01 days at 34 °C. The survival rate of the immature stages, especially the egg stage, varies greatly with temperature, with the lowest survival observed at 34 °C and the highest at 22 °C. The lower developmental threshold, the intrinsic optimum temperature, and the upper lethal developmental threshold obtained by the curvilinear Optim SSI models were 15.28 °C, 28.36 °C, and 34.03 °C, respectively. The body length, head capsule width, and pronotum width showed obvious growth patterns with larval developmental duration, which were characterized by equations and isomegalen diagrams. This study provides important basic data for the application of D. maculatus to estimate the PMImin in forensic entomology in the Yangtze River Delta region of China.

Assessing the Effect of Thermal Maturation on Shale Organic Matter via PeakForce Quantitative Nanomechanical Mapping

Organic-rich shales have gained significant attention in recent years due to their pivotal role in unconventional hydrocarbon production. These shale rocks undergo thermal maturation processes that alter their mechanical properties, making their study essential for subsurface operations. However, characterizing the mechanical properties of organic-rich shale is often challenging due to its multiscale nature and complex composition. This work aims to bridge that knowledge gap to fully understand the nanomechanical properties of Shale organic matter at various thermal maturation stages. This study employs PeakForce Quantitative Nanomechanical Mapping (PF-QNM) using Atomic Force Microscopy (AFM) to investigate how changes at the immature, early mature, and peak mature stages impact the mechanical properties of the Bakken Shale organic matter. PF-QNM provides reliable mechanical measurements, allowing for the quantification and qualification of shale constituents' elastic modulus (E). We also accounted for the effect of probe type and further analyzed the impact of probe wear on the nanomechanical properties of shale organic matter. In immature shale, the average elastic modulus of organic matter is approximately 6 GPa, whereas in early mature and peak mature shale, it decreases to 5.5 GPa and 3.8 GPa, respectively. Results reveal a mechanical degradation with increasing thermal maturation, as evidenced by a reduction in the Young's modulus (E). Specifically, the immature shale exhibits an 8% reduction in E, while the early mature and peak mature shales experience more substantial reductions of 31% and 37%, respectively. This phenomenon could be attributed to the surface probing of low-modulus materials like bitumen generated during heating. The findings underscore the potential of AFM PF-QNM for assessing the nanomechanical characteristics of complex and heterogeneous rocks like shales. However, it also highlights the need for standardized measurement practices, considering the diverse components in these rocks and their different elastic moduli.

Application of Insect Growth Regulators (IGRs) as Biopesticides for Sustainable Agriculture

The application of conventional pesticides is underlined by many negative externalities including environmental degradation and pest resistance. Consequently, use of biopesticides as alternative agrochemicals is recommended to meet sustainable development goals. Insect growth regulators (IGRs) are biochemical biopesticides. Actually, Biochemical biopesticides are compounds (or exact synthetic analogue) of natural origin possessing active ingredients that control pest in a way that are nontoxic to the target pest, the environment and humans. So, insecticides with growth regulating properties may adversely affect insects by regulating or inhibiting specific biochemical pathways or processes essential for insect growth and development. Ecdysoids and Juvenoids (JH mimics) are among the most promising IGRs. Ecdysoids are synthetic analogues of natural ecdysone and when applied in insects, kill them by formation of defective cuticle. Juvenoids (JH mimics) are synthetic analogues of Juvenile Hormone (JH). Juvenoids have anti-metamorphic effect on immature stages of insect. Along with this, Anti JH or precocenes which act by destroying corpora allata and preventing JH synthesis also act as IGR. In this way, Insect Growth Regulators are potential substitute of insecticides that could be commercially used.

NOXIOUSNESS OF THREE DIFFERENT ESSENTIAL OILS AGAINST RED PALM WEEVIL UNDER CONTROLLED CONDITION

Asian palm weevil, also known as red palm weevil (RPW), Rhynchophorus ferrugineus (Olivier, 1790) (Coleoptera: Curculionidae), has long been regarded as an annoying pest of many palm trees (Arecaceae), particularly date palm. Researchers are very concerned about finding an effective management strategy to control RPW due to its well-known detrimental effects on native date palm, and its economic development. Use of essential oils and botanical extracts is receiving a lot of attention among other control methods. Because they are environmentally safe. However, this study explained the feeding toxicity of three essential oils e.g., clove, black pepper, and eucalyptus seeds against 3rd instar larvae of RPW via feeding bioassay. Results showed that mortality (%) was maximum when treated with a higher dose of clove oil as compared to the other two essential oils. Meanwhile the LC50 value of clove oil was minimal which showed a higher toxicity. Our study concluded that clove oil is useful against the immature stages of R. ferrugineus. So, we suggest that it should be properly placed in IPM strategies against this pest. To enhance the efficacy of such bioactive compounds in laboratory, more work is necessary.

Bionomics, reproductive traits and assessment of forensic relevance of Peckia (Peckia) chrysostoma (Wiedemann, 1830) (Diptera: Sarcophagidae).

Peckia (Peckia) chrysostoma (Wiedemann, 1830) (Diptera: Sarcophagidae) is a colonizer of cadavers in the Neotropical Region. Nevertheless, data on development for the P. (P.) chrysostoma (e.g., instar duration) and behavioral strategies used by the species for locating and colonizing a corpse are scant. We aimed to explore bionomic and reproductive aspects of the flesh fly P. (P.) chrysostoma, and in this article we: (a) provide quantitative data on the life cycle of P. (P.) chrysostoma; (b) present bionomic measurements (length and weight) of larvae and pupae; (c) describe intrauterine egg and larvae development; and (d) analyze the ovo/larviposition behavior by gravid females. Females showed ovaries with discernible eggs and larvae between 8 and 10 days (x̅ = 23.3 eggs/female). This study reports the first observation of egg deposition, an atypical behavior for the species. The average development time for immature stages was 22.24h and 21.36h for 1st and 2nd respectively, and 3rd showed an average development time of 80.47h. Pupa had the longest duration (x̅ = 295.69h). A direct increase was observed in weight (P < 0.05) and length (P < 0.05) throughout time. The average survival time of males and females is approximately 30 days. This study expands the knowledge on P. (P.) chrysostoma, such as facultative ovoviviparity under laboratory conditions and the life cycle, which may benefit future studies for accuracy in entomology-based estimation of minimum post-mortem interval (min PMI).

The Mosquitoes of Morelos, Mexico: DNA Barcodes, Distribution, Ecology and the Resurrection of the Name Culiseta dugesi Dyar and Knab (Diptera: Culicidae)

To update the record of mosquito diversity in the state of Morelos, Mexico, mosquito collections were conducted in both physiographical regions of Morelos: the Neo-volcanic Axis and the South Mountain Range. Immature stages were collected from aquatic habitats, while adult mosquitoes were collected using CDC light traps, Shannon traps and approaching/landing on the collecting personnel. All specimens were identified using taxonomic keys and the mitochondrial cytochrome C oxidase subunit 1 (COI). Following Mexico State, this is the second study of mosquito taxonomy of a complete Mexican state using COI barcoding. In Morelos, a total of 58 species of mosquito occurs, of which we report 12 for first time (Aedes vexans, Ae. euplocamus, Ae. vargasi, Psorophora cilipes, Ps. lineata, Culex restrictor, Cx. interrogator, Cx. nigripalpus, Cx. tarsalis, Cx. sandrae, Cx. lactator and Toxorhynchites moctezuma). Morelos now ranks sixth in mosquito diversity among Mexican states. Phylogenetic trees were constructed for 32 species, including Ae. shannoni, which is a new record for GenBank databases. Additionally, we report COI barcode sequences of Culiseta dugesi Dyar and Knab, which is resurrected from the synonymy of Cs. particeps (Adams). Fourth-instar larvae and adult females of Cs. dugesi were redescribed. This brings the number of mosquito species in Mexico to 248. Ecological and distributional notes for the new records, the medical importance of mosquito species in Morelos, and an identification key for larvae and females of the known Culiseta species occurring in Mexico are also included.

The phylogeny of the tribe Podonomini (Chironomidae: Podonominae) is clarified by new inclusion of Rheochlus Brundin in molecular analysis

Abstract The immature stages of the patagonian podonomine (Diptera: Chironomidae) genus Rheochlus (Diptera: Chironomidae) have been unknown although the adult stage was described over half a century ago. New pupal associations with described adults belonging to two species of Rheochlus allow better understanding of the genus, its diversity and its phylogeny. The pupa of Rheochlus insignis Brundin is the same as an unreared damaged pupal taxon designated Podochlus sp. “Canteras’‘ by Brundin and is described more completely here. Inclusion of R. insignis in a molecular phylogenetic analysis shows it to be sister to two specimens (one a male, the other pharate female) allocated previously to Podochlus but better transferred to Rheochlus. The male morphology is compatible with Rheochlus prolongatus Brundin but we refrain from asserting identity by using ‘cfr.’ prolongatus to indicate the status. Molecular evidence also provides association of the female adult and pupa that are newly described here. We validate Rheochlus as distinguished on pupa and adult, with the type-species Rheochlus insignis from Patagonian Chile and Argentina, Rheochlus prolongatus Brundin from Southern Patagonia Argentina and possibly also from central Patagonia, Rheochlus latisetus Siri &amp; Brodin from Patagonia, and the eastern Australian Rheochlus wirthi Brundin. The latter two species remain known only from their original adult male descriptions. Strengthened support for our concept of Rheochlus as a valid genus, sister group to Podochlus, derives also from an expanded and reanalysed morphological matrix.

Three new species of Puto giant mealybugs (Hemiptera: Coccomorpha: Putoidae) from Mexico and Guatemala, with keys to New World adult females and World adult males

Three new species of Puto Signoret, 1876 are described and illustrated from material intercepted at US plant quarantine inspection, including the adult females, all available immature stages, and for two species, the adult male. Puto philo Powell &amp; Miller, sp. n. and Puto brom Powell &amp; Miller, sp. n. are described from Mexico, and Puto spath Powell &amp; Miller, sp. n. is described from Guatemala. Three keys are included to: the instars of Puto, the New World species of Puto based on adult females, and a world key to the adult males of Puto.

Single-Cell Transcriptome Sequencing Reveals Molecular Expression Differences and Marker Genes in Testes during the Sexual Maturation of Mongolian Horses.

This study aimed to investigate differences in testicular tissue morphology, gene expression, and marker genes between sexually immature (1-year-old) and sexually mature (10-year-old) Mongolian horses. The purposes of our research were to provide insights into the reproductive physiology of male Mongolian horses and to identify potential markers for sexual maturity. The methods we applied included the transcriptomic profiling of testicular cells using single-cell sequencing techniques. Our results revealed significant differences in tissue morphology and gene expression patterns between the two age groups. Specifically, 25 cell clusters and 10 cell types were identified, including spermatogonial and somatic cells. Differential gene expression analysis highlighted distinct patterns related to cellular infrastructure in sexually immature horses and spermatogenesis in sexually mature horses. Marker genes specific to each stage were also identified, including APOA1, AMH, TAC3, INHA, SPARC, and SOX9 for the sexually immature stage, and PRM1, PRM2, LOC100051500, PRSS37, HMGB4, and H1-9 for the sexually mature stage. These findings contribute to a deeper understanding of testicular development and spermatogenesis in Mongolian horses and have potential applications in equine reproductive biology and breeding programs. In conclusion, this study provides valuable insights into the molecular mechanisms underlying sexual maturity in Mongolian horses.

Antibody-blocking of a tick transporter impairs Anaplasma phagocytophilum colonization in Haemaphysalis longicornis ticks

The invasive Asian longhorned tick Haemaphysalis longicornis that vectors and transmits several animal pathogens is significantly expanding in the United States. Recent studies report that these ticks also harbor human pathogens including Borrelia burgdorferi sensu lato, Babesia microti, and Anaplasma phagocytophilum. Therefore, studies that address the interactions of these ticks with human pathogens are important. In this study, we report the characterization of H. longicornis organic anion-transporting polypeptides (OATPs) in interactions of these ticks with A. phagocytophilum. Using OATP-signature sequence, we identified six OATPs in the H. longicornis genome. Bioinformatic analysis revealed that H. longicornis OATPs are closer to other tick orthologs rather than to mammalian counterparts. Quantitative real-time PCR analysis revealed that OATPs are highly expressed in immature stages when compared to mature stages of these ticks. In addition, we noted that the presence of A. phagocytophilum upregulates a specific OATP in these ticks. We also noted that exogenous treatment of H. longicornis with xanthurenic acid, a tryptophan metabolite, influenced OATP expression in these ticks. Immunoblotting analysis revealed that antibody generated against Ixodes scapularis OATP cross-reacted with H. longicornis OATP. Furthermore, treatment of H. longicornis with OATP antibody impaired colonization of A. phagocytophilum in these ticks. These results not only provide evidence that the OATP-tryptophan pathway is important for A. phagocytophilum survival in H. longicornis ticks but also indicate OATP as a promising candidate for the development of a universal anti-tick vaccine to target this bacterium and perhaps other rickettsial pathogens of medical importance.

Comparison of the effect of tea shoots during different seasons in Arma chinensis (Hemiptera: Pentatomidae) reared on Ectropis grisescens (Lepidoptera: Geometridae) pupae.

In this study, we compared the growth, development, and fecundity of Arma chinensis (Fallou) reared on pupae of the geometrid Ectropis grisescens Warren fed on tea shoots during different seasons of the year. The raw data on life history were analyzed using the age-stage, 2-sex life table. When reared on spring or winter geometrid pupae, the duration of the immature stage of A. chinensis was significantly longer than in those produced during the summer or autumn. The survival rate of immature A. chinensis reared on autumn geometrid pupae was significantly lower compared to other treatments. Reproductive diapause was observed in adult A. chinensis reared on winter geometrid pupae. The adult preoviposition period (APOP), total preoviposition period (TPOP), and total longevity were significantly longer in A. chinensis reared on winter pupae than in the other treatments. The fecundity of A. chinensis reared on spring geometrid pupae was significantly lower than in the other treatments. The higher intrinsic rate of increase of the A. chinensis reared on summer pupae (r = 0.0966 day-1) and autumn pupae (r = 0.0983 day-1) resulted in higher fecundity, shorter immature duration, and shorter TPOP compared to the winter and spring populations. These findings can be utilized to enhance and sustain biological control of E. grisescens in tea plantations.

Mosquitoes in crabholes: A hidden realm of culicid diversity in India

This is the first listing of mosquitoes inhabiting crabholes across the diverse landscapes of India. Drawing from an extensive review of existing literature on mosquito diversity in various ecological regions of the country, the adults or immature stages of 68 mosquito species have been found in crabholes. This entomological assessment revealed that 24 species occur in crabholes in mangroves, characterized by brackish water, while an additional 44 species are found in freshwater crabholes in forested areas. The majority of the species appear to have been collected as resting adults, a pattern consistent with earlier observations. The implications of this finding highlight the complex relationship between mosquitoes and their association with crabholes. This new knowledge opens up avenues to future studies that explore the diversity and biology of mosquitoes in these unique habitats.

Expanding the Mesozoic Record of Early Brachyceran Fly Larvae, including New Larval Forms with Chimera-Type Morphologies.

Diptera are one of the four megadiverse groups of holometabolan insects. Flies perform numerous ecological functions, especially in their larval stages. We can assume that this was already the case in the past; however, fly larvae remain rare in most deposits. Here we report new dipteran larvae preserved in Cretaceous (about 99 Ma) Kachin amber from Myanmar and, even older, Jurassic (about 165 Ma) compression fossils from China. Through light microscopy and micro-CT scanning we explore their peculiar morphology and discuss their possible phylogenetic affinities. Several larvae seem to represent the lineage of Stratiomyomorpha. A few others present characters unique to Xylophagidae (awl-flies), as well as to Athericidae (water sniper-flies), resulting in a chimeric morphology. Understanding the exact relationships of most of these specimens with a particular lineage remains challenging, since they differ considerably from any other known dipteran larvae and present some unique traits. Additionally, we report new specimens of Qiyia jurassica Chen et al., 2014, supposedly parasitic larvae, most likely representatives of Athericidae. These new findings offer valuable insights into the evolution of the early diversification of the brachyceran flies and underscore the importance of immature stages in understanding the evolutionary history and ecology of flies.