Characterizing the embryonic development of B. hygida (Diptera: Sciaridae) following enzymatic treatment to permeabilize the serosal cuticle

Enhanced mite control and agricultural safety with etoxazole-loaded chitin nanocrystals: Synthesis, characterization, and ecological impacts

Chitin nanocrystals (ChNCs), known for their high aspect ratio, surface charge, and mobility, are promising bio-based nanomaterials for drug delivery. However, their potential as pesticide carriers in agriculture remains underexplored. Etoxazole, a diphenyl oxalate acaricide, effectively inhibits egg hatching and the normal molting process in mites but suffers from rapid degradation and short persistence in field applications. This study introduces a novel formulation, Eto@ChNC, prepared by complexing TEMPO-oxidized ChNCs with etoxazole via a one-pot method. Eto@ChNC was evaluated for controlling Tetranychus urticae, demonstrating significantly enhanced rapid action and prolonged efficacy compared to traditional formulations. The formulation increased the synergistic effects on mite eggs and deutonymphs by 41.74 % and 67.85 %, respectively, extending effectiveness by two days. The improved performance was attributed to the enhanced wetting ability of Eto@ChNC on leaf surfaces and its superior inhibition of the epidermal chitin content in T. urticae, facilitating greater etoxazole penetration. Transcriptome sequencing revealed numerous differentially expressed genes related to chitin metabolism, elucidating the molecular mechanisms underlying the increased efficacy. Safety assessments confirmed that Eto@ChNC did not elevate toxicity to earthworms or predatory mites and promoted the growth of wheat and cowpea, underscoring its environmental safety. These findings highlight Eto@ChNC as a significant advancement in bio-based acaricide formulations, offering promising applications in mite management.

Pseudolycoriella hygida (Sauaia and Alves)-An Overview of a Model Organism in Genetics, with New Aspects in Morphology and Systematics

Pseudolycoriella hygida (Sauaia & Alves, 1968) is a sciarid that has been continuously cultured in the laboratory for nearly 60 years. Studies on this species have contributed to the understanding of DNA puffs, which are characteristic of Sciaridae, and to the knowledge of more general aspects of insect biology, including cell death, nucleolar organization, and the role of the hormone ecdysone during molting. The genome of Psl. hygida has now been sequenced, and it is the third publicly available sciarid genome. The aim of this work is to expand the current knowledge on Psl. hygida. The morphology of the adults is revisited. The morphology of larvae and pupae is described, together with the behavior of immature stages under laboratory conditions. Cytogenetic maps of the salivary gland polytene chromosomes are presented, together with a comparative analysis of the mitotic chromosomes of six different sciarid species. Pseudolycoriella hygida was originally described as a species of Bradysia and recently moved to Pseudolycoriella. We examine here the systematic position of Psl. hygida in the latter genus. Our results extend the characterization of an unconventional model organism and constitute an important resource for those working on the cytogenetics, ecology, taxonomy, and phylogenetic systematics of sciarids.

Biocatalytic potential of Pseudolycoriella CAZymes (Sciaroidea, Diptera) in degrading plant and fungal cell wall polysaccharides

Soil biota has a crucial impact on soil ecology, global climate changes, and effective crop management and studying the diverse ecological roles of dipteran larvae deepens the understanding of soil food webs. A multi-omics study of Pseudolycoriella hygida comb. nov. (Diptera: Sciaroidea: Sciaridae) aimed to characterize carbohydrate-active enzymes (CAZymes) for litter degradation in this species. Manual curation of 17,881 predicted proteins in the Psl. hygida genome identified 137 secreted CAZymes, of which 33 are present in the saliva proteome, and broadly confirmed by saliva CAZyme catalytic profiling against plant cell wall polysaccharides and pNP-glycosyl substrates. Comparisons with two other sciarid species and the outgroup Lucilia cuprina (Diptera: Calliphoridae) identified 42 CAZyme families defining a sciarid CAZyme profile. The litter-degrading potential of sciarids corroborates their significant role as decomposers, yields insights to the evolution of insect feeding habits, and highlights the importance of insects as a source of biotechnologically relevant enzymes.

Characterization of the mitochondrial genomes of Bradysia hygida, Phytosciara flavipes and Trichosia splendens (Diptera: Sciaridae) and novel insights on the control region of sciarid mitogenomes

Sciarids, also called "fungus gnats" are small, almost entirely dark-coloured insects. Sciarid larvae feed on different substrates and can infest agricultural crops and mushroom nurseries, causing economic losses. Of the 2174 Diptera mitogenome sequences currently available in GenBank, only eight are from the Sciaridae family, none of which are complete circular molecules. Here we describe the mitogenome sequences of three sciarid species: Phytosciara flavipes, Trichosia splendens and Bradysia hygida and provide novel insights on the control region of sciarid mitogenomes. The assembled mitogenomes range from 16,062 bp in P. flavipes to 17,095 bp in B. hygida. All 13 protein coding genes, 22 tRNAs and 2 rRNAs characteristic of insect mitogenomes were identified, but the sequence of the control region could not be determined. Experimental results suggest that the B. hygida control region is about 21 kb long resulting in a 37 kb long mitogenome which constitutes the largest insect mitochondrial genome described so far. Phylogenetic analysis using all Bibionomorpha mitogenome sequences available in GenBank strongly supports the Sciaridae monophyly and led to the identification of species and subfamily specific gene rearrangements. Our study extends the knowledge of this large and diverse insect family that includes agricultural pest species.