Search

Secondary contact between incompletely isolated species can produce a wide variety of outcomes. The vinegar flies Drosophila simulans and D. sechellia diverged on islands in the Indian Ocean and are currently separated by partial pre- and postzygotic barriers. The recent discovery of hybridization between D. simulans and D. sechellia in the wild presents an opportunity to monitor the prevalence of alleles that influence hybridization between these sibling species. We therefore sought to identify those loci in females that affect interspecific mating, and we adapted a two-choice assay to capture female mate choice and female attractiveness simultaneously. We used shotgun sequencing to genotype female progeny of reciprocal F1 backcrosses at high resolution and performed QTL analysis. We found 2 major-effect QTL in both backcrosses, one on either arm of the third chromosome that each account for 32–37% of the difference in phenotype between species. The QTL of both backcrosses overlap and may each be alternate alleles of the same locus. Genotypes at these 2 loci followed an assortative mating pattern with D. simulans males but not D. sechellia males, which mated most frequently with females that were hybrid at both loci. These data reveal how different allele combinations at 2 major loci may promote isolation and hybridization in the same species pair. Identification of these QTLs is an important step toward understanding how the genetic architecture of mate selection may shape the outcome of secondary contact. [ABSTRACT FROM AUTHOR]

This study analyzes the potential of olive pomace fly ash (OPFA) as an alternative alkaline activator for electric arc furnace slag (EAFS) in the manufacture of sustainable cementitious materials. Cements were prepared by replacing 30–50 wt% of EAFS with OPFA and compared with control cements activated with potassium hydroxide (KOH) at concentrations of 4 and 8 M. Cements were characterized by bulk density, water absorption, total porosity, compressive and flexural strength, as well as analytical techniques such as XRD, FTIR and SEM-EDS. The results reveal that the incorporation of 40 wt% OPFA provides optimum properties, reaching maximum compressive and flexural strengths of 20.0 MPa and 5.7 MPa, respectively, after 28 days of curing. These improvements are attributed to the increased formation of C,K-A-S-H gel, which incorporates Fe, the main reaction product that densifies the matrix and reduces porosity. However, 30 wt% OPFA provides insufficient alkali content, which limits the reaction, while excess alkali at 50 wt% OPFA reduces mechanical performance due to unreacted residues and increased interconnected porosity. Compared to KOH-activated cements, which achieve maximum flexural and compressive strengths of 4.4 and 9.5 MPa (EAFS/KOH-8M binders), the results confirm the potential of OPFA as an alternative activator, with significant sustainability advantages. [ABSTRACT FROM AUTHOR]

Drosophila suzukii (Matsumura) (Diptera: Drosophilidae) is a global invasive pest attacking soft-skinned fruit. The specialist larval parasitoid wasp, Ganaspis brasiliensis (Ihering), was recently approved in Europe and the United States for classical biological control releases against D. suzukii. Rearing methods are essential for supporting innundative releases but current methods using fresh fruit are costly and susceptible to variation in host quality. To develop an artificial rearing system, we first compared the performance and development of D. suzukii and G. brasiliensis on fresh raspberries and blueberries and then on various artificial diet shapes and volumes. Drosophila suzukii had 1–2 days shorter development times in raspberry than blueberry, whereas Ganaspis adult development time was similar in both fruit and averaged 25 days. Parasitism rates by G. brasiliensis were significantly higher in blueberry than raspberry in both small and large resource patches. We found that D. suzukii preferred to lay eggs in full sphere diet shapes than in flat diet circles or semisphere diet, and in the first trial with wasps parasitism was only found on D. suzukii larvae in the full sphere shape of raspberry diet. Comparison of parasitism on full sphere raspberry and blueberry diets found higher parasitism in raspberry compared to blueberry diet. Our results indicate potential for further improvement of artificial rearing systems for G. brasiliensis to allow more cost-effective and reliable rearing for biological control programs. [ABSTRACT FROM AUTHOR]

The death and clearance of nurse cells is a consequential milestone in Drosophila melanogaster oogenesis. In preparation for oviposition, the germline-derived nurse cells bequeath to the developing oocyte all their cytoplasmic contents and undergo programmed cell death. The death of the nurse cells is controlled non-autonomously and is precipitated by epithelial follicle cells of somatic origin acquiring a squamous morphology and acidifying the nurse cells externally. Alternatively, stressors such as starvation can induce the death of nurse cells earlier in mid-oogenesis, manifesting apoptosis signatures, followed by their engulfment by epithelial follicle cells. To identify and contrast the molecular pathways underlying these morphologically and genetically distinct cell death paradigms, both mediated by follicle cells, we compared their genome-wide transcriptional, translational, and secretion profiles before and after differentiating to acquire a phagocytic capability, as well as during well-fed and nutrient-deprived conditions. By coupling the GAL4-UAS system to Translating Ribosome Affinity Purification (TRAP-seq) and proximity labeling (HRP-KDEL) followed by Liquid Chromatography tandem mass-spectrometry, we performed high-throughput screens to identify pathways selectively activated or repressed by follicle cells to employ nurse cell-clearance routines. We also integrated two publicly available single-cell RNAseq atlases of the Drosophila ovary to define the transcriptomic profiles of follicle cells. In this report, we describe the genes and major pathways identified in the screens and the striking consequences to Drosophila melanogaster oogenesis caused by RNAi perturbation of prioritized candidates. To our knowledge, our study is the first of its kind to comprehensively characterize two distinct apoptotic and non-apoptotic cell death paradigms in the same multi-cellular system. Beyond molecular differences in cell death, our investigation may also provide insights into how key systemic trade-offs are made between survival and reproduction when faced with physiological stress. Author summary: Cell death occurs throughout development and homeostasis to removed damaged or obsolete cells. Typically dying cells are engulfed by neighboring phagocytic cells. In some cases, the phagocytic cells directly promote the death of neighboring cells, in a process called "phagoptosis." The ovary of the vinegar fly, Drosophila melanogaster, provides a valuable model to investigate the differences between cell death mechanisms. The oocyte is normally supported by nurse cells during its development, and at the end of oocyte development the nurse cells undergo phagoptosis by surrounding follicle cells. Nurse cells can also undergo a form of cell death called apoptosis earlier in development in response to starvation, and apoptotic nurse cells are phagocytosed by follicle cells. To identify and contrast the molecular pathways underlying these morphologically and genetically distinct cell death paradigms, we compared their genome-wide transcriptional, translational, and secretion profiles. In this report, we describe the genes and major pathways identified in the screens and the striking consequences to Drosophila melanogaster oogenesis caused by genetic disruption of these genes. To our knowledge, this study is the first of its kind to comprehensively characterize two distinct apoptotic and non-apoptotic cell death paradigms in the same tissue. [ABSTRACT FROM AUTHOR]

Drosophila melanogaster Meigen (Diptera: Drosophilidae) was used as a model organism and fed on an artificial diet with different clinically important drugs under laboratory conditions. The effects of fluconazole, acyclovir, and piperazine on the survivorship, development, adult longevity, fecundity, and hatching rate of the insect were investigated. The results showed that the highest concentration of fluconazole (1250 mg/L) significantly decreased both the rate of larvae reaching the 3rd instar and the rate of pupation from 93.00 ± 2.95% to 11.00 ± 2.59% (χ² = 134.696; df = 1; p = 0.0001). The highest concentration of acyclovir (200 mg/L) significantly reduced the rate of larvae reaching the 3rd instar and the pupation rate from 91.00 ± 2.17% to 26.00 ± 3.31%. Developmental times were significantly prolonged by high concentrations of all drugs. The high dietary concentrations of drugs also significantly decreased adult longevity to about 7 days. Piperazine was the most negative drug for fecundity (2.45 eggs per female) and hatching (2.87%). Future studies involving combinations of the substances would shed light on the use of more effective drug mixtures to control pest insects that will require smaller quantities and have minimal toxic impact on the environment and nontargets. [ABSTRACT FROM AUTHOR]

The complete mitochondrial genome of Leptopilina myrica Chen, 2023 has been sequenced and analyzed for the first time. The total length we assembled is 15,448 bp, which comprises 13 PCGs, 22 tRNAs, 2 rRNAs, and a CR. The overall nucleotide composition consists of 41.1% A, 37.7% T, 14.7% C, and 6.5% G, respectively. The nucleotide sequences of 13 PCGs and 2 rRNAs from L. myrica and another 10 Drosophila parasitoid species were used for phylogenetic analysis by MrBayes, with one species from Drosophilidae as an outgroup. The result shows that L. myrica is closely related to L. syphax. [ABSTRACT FROM AUTHOR]

Invasive species pose significant ecological and economic threats globally. Zaprionus tuberculatus Malloch, a drosophilid fruit fly native to the Afrotropical region and Indian Ocean islands, is included in the pest list of the Center for Agriculture and Bioscience (CABI) because it uses fruit as breeding sites and can damage cultivated areas. This fly species extended its range across Europe in the late 20th century; in 2020, it was recorded in South America, and currently, it is widely distributed in Brazil. Here, we assess the potential spreading of Zaprionus tuberculatus in Central and North America based on 2 distinct origins of propagules: from South America and from Europe. To this end, we developed species distribution models using bioclimatic variables and elevation data to project potentially suitable habitats and infer invasion routes. In any case, our results indicate suitability for Z. tuberculatus colonization in Central and North America, including major fruit-producing areas in Central American countries and the United States (Florida and California). The rapid dispersal ability of Z. tuberculatus, coupled with its adaptability to diverse environments, underscores the urgency for proactive monitoring and control measures. Therefore, this study provides valuable insights for developing proactive measures to mitigate the spread of Z. tuberculatus and protect agricultural productivity in the Americas., (© The Author(s) 2024. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site—for further information please contact journals.permissions@oup.com.)