High Reproductive Capacity Research Articles

Transcriptome analysis identifies key genes in juvenile hormone and ecdysteroid signaling pathways and their roles in regulating reproductive system development of adult Monochamus saltuarius.

Monochamus saltuarius is an important vector of pinewood nematode in Eurasia with a high reproductive capacity. Endocrine hormones play a key role in insect reproduction. Understanding the mechanism of internal regulation can provide targets for pest control. However, this type of research on M. saltuarius remain limited. Our study constructed transcriptome of the internal reproductive systems in male and female M. saltuarius across three development stages. Interference experiments targeting the MSALMet1 and exploring its critical role in reproduction. Transcriptome results revealed that 42 genes related to the juvenile hormone and ecdysteroid pathways were identified. Among them, 12 genes were significantly enriched in reproduction-related pathways, and the expression patterns of 14 genes aligned with the developmental trend of the internal reproductive system, suggesting that they may play a regulatory role in reproductive processes. Furthermore, protein-protein interaction networks elucidated the complex interactions among these genes, shedding light on their diverse functions. Notably, bioinformatics analysis and interference experiments revealed that MSALMet1 having the profound effect on reproductive system development in both sexes. These findings highlight the critical role of endocrine-related genes in regulating reproductive development and provide a theoretical foundation for regulating reproduction at molecular level, potentially contributing to M. saltuarius population control.

Investigating the Phylogenetic Relationships of the Iranian Honey Bee with Other Bee Breeds Worldwide Using the Cytochrome Oxidase I Region

Background: Honey bees, classified within the insect class and widely distributed globally, consist of 26 identified subspecies across five evolutionary lines. Among these, the Iranian honey bee (Apis mellifera meda) is notable for its presence in Iran and neighboring regions. This subspecies exhibits unique biological traits, including a high reproductive capacity and effective propolis collection, distinguishing it from other local bee populations. Understanding genetic diversity within these populations is crucial for conservation and breeding efforts. Objectives: The aim of this study is to determine the phylogenetic relationships and natural variations of the Iranian honey bee in comparison to other bee breeds worldwide using the cytochrome oxidase I (COI) region. Methods: The study focuses on the identification of COI gene sequences in honeybees. The mitochondrial COI gene sequences related to the Iranian honey bee and eight populations of other honey bee breeds from around the world (24 ecotypes) were extracted and aligned from the genome database (NCBI). BLAST was used for sequence retrieval, and Clustal W was employed for alignment among species. Phylogenetic analysis was performed using MEGA software, applying the Neighbor Joining method to construct a phylogenetic tree based on the edited sequences. The percentage of nucleotide substitutions and replacements was calculated using the maximum likelihood method. Additionally, molecular diversity indices were computed using DnaSP software to assess genetic variation and conservation parameters among populations. Results: The bioinformatics analysis of biological data revealed that transfer substitution occurred more frequently than crossover substitution. Additionally, the percentage of substitution in pyrimidine bases was higher than in purine bases. The dN/dS substitution ratio in the gene locus sequence across the examined ecotypes was estimated at 0.08, indicating purifying selection during the evolution of this gene locus. Furthermore, examination of the COI region of the mitochondrial genome identified a total of 4 haplotypes, 20 mutations, and 195 polymorphic loci within the entire studied population. The neutrality values, based on Tajima's test, indicated effects related to genetic drift, genetic bottlenecks, or balancing selection during the evolutionary history of the studied population. Phylogenetic analysis revealed nine distinct categories of evolutionary paths for the COI gene in the studied ecotypes. In the phylogenetic tree, the Iranian honey bee was placed in a separate cluster, exhibiting the highest and lowest phylogenetic distances relative to Apis koschevnikovi and Apis mellifera, respectively. Conclusions: This research indicates that the conserved region of the mitochondrial cytochrome oxidase gene among various bee species is minimal, highlighting significant polymorphism and susceptibility to mutations. A total of 20 mutations and 195 polymorphic sites were identified, suggesting purifying selection processes that contribute to the gene's biological functions. The study also demonstrates that the COI region can effectively differentiate Iranian honey bee populations from others globally. Overall, these findings enhance our understanding of genetic diversity and evolutionary relationships within bee species, underscoring the importance of continued research for conservation efforts.

Multi-Omics Approaches Uncovered Critical mRNA-miRNA-lncRNA Networks Regulating Multiple Birth Traits in Goat Ovaries.

The goat breeding industry on the Tibetan Plateau faces strong selection pressure to enhance fertility. Consequently, there is an urgent need to develop goat lines with higher fertility and adaptability. The ovary, as a key organ determining reproductive performance, is regulated by a complex transcriptional network involving numerous protein-coding and non-coding genes. However, the molecular mechanisms of the key mRNA-miRNA-lncRNA regulatory network in goat ovaries remain largely unknown. This study focused on the histology and differential mRNA/miRNA/lncRNA between Chuanzhong black goat (CBG, high productivity, multiple births) and Tibetan goat (TG, strong adaptability, single birth) ovaries. Histomorphological analysis showed that the medulla proportion in CBG ovaries was significantly reduced compared to TG. RNA-Seq and small RNA-Seq analysis identified 1218 differentially expressed (DE) mRNAs, 100 DE miRNAs, and 326 DE lncRNAs, which were mainly enriched in ovarian steroidogenesis, oocyte meiosis, biosynthesis of amino acids and protein digestion, and absorption signaling pathways. Additionally, five key mRNA-miRNA-lncRNA interaction networks regulating goat reproductive performance were identified, including TCL1B-novel68_mature-ENSCHIT00000010023, AKAP6-novel475_mature-ENSCHIT00000003176, GLI2-novel68_mature-XR_001919123.1, ITGB5-novel65_star-TCONS_00013850, and VWA2-novel71_mature-XR_001919911.1. Further analyses showed that these networks mainly affected ovarian function and reproductive performance by regulating biological processes such as germ cell development and oocyte development, which also affected the plateau adaptive capacity of the ovary by participating in the individual immune and metabolic capacities. In conclusion, we identified numerous mRNA-miRNA-lncRNA interaction networks involved in regulating ovarian function and reproductive performance in goats. This discovery offers new insights into the molecular breeding of Tibetan Plateau goats and provides a theoretical foundation for developing new goat lines with high reproductive capacity and strong adaptability to the plateau environment.

The genome landscape of the Xinglong buffalo

BackgroundXinglong buffalo, as an indigenous breed in Hainan province of China, possesses characteristics such as high humidity tolerance, disease resistance and high reproductive capacity. Combined with whole genome sequencing technology, comprehensive investigation can be undertaken to elucidate the genomic characteristics, functions and genetic variation of Xinglong buffalo population.ResultsXinglong buffalo has the highest genetic diversity, lowest runs of homozygosity average length, and fasted decay of linkage disequilibrium in our study population. Phylogenetic tree results revealed that Xinglong buffalo was gathered together with Fuzhong buffalo firstly. The population genetic structure analysis indicates that at K = 3, the Xinglong buffalo for the first time showed a distinct ancestral origin from other water buffalo. Furthermore, compared to different populations, candidate genes displaying significantly distinct patterns of single nucleotide polymorphisms (SNPs) (e.g., RYR2, COX15, PCDH9, DTWD2, FCRL5) distribution have been identified in the Xinglong buffalo.ConclusionsBased on the whole genome sequencing data, this study identified a substantial number of SNPs and assessed the genetic diversity and selection signatures within the Xinglong buffalo population. These results contribute to understanding the genomic characteristics of Xinglong buffalo and their genetic evolutionary status. However, the practical significance of these signatures for genetic enhancement still requires confirmation through additional samples and further experimental validation.

Research on Resistance Monitoring, Risk Assessment, and Mechanisms of <i>Megalurothrips usitatus</i>

<i>Megalurothrips usitatus</i>, also known as common thrips or cowpea thrips, is a widely distributed and highly destructive pest, primarily infesting legume crops. Due to its short generation cycle, high reproductive capacity, and concealed lifestyle, the effectiveness of chemical pesticide control has been continuously diminishing with the modernization of agricultural production and the extensive use of pesticides. <i>Megalurothrips usitatus</i> has gradually developed resistance to various commonly used pesticides, with resistance levels increasing year by year, thus exacerbating the difficulty of pest management and causing significant economic losses to agricultural production. Scholars, both domestically and internationally, have conducted in-depth research using methods from morphology, molecular biology, and ecology, showing that there are three main causes of pest resistance: enhanced detoxification enzymes, reduced sensitivity at target sites, and decreased cuticle penetration. These findings provide a wealth of theoretical support for resistance monitoring and management. The resistance of <i>Megalurothrips usitatus</i> to multiple pesticides is not only a local issue but also affects global agricultural sustainability. Research on the monitoring, risk assessment, and mechanisms of resistance in <i>Megalurothrips usitatus</i> contributes to prolonging the effective use of pesticides, improving control outcomes, and enhancing both the yield and quality of cowpea crops. These studies also provide a scientific basis for developing more effective control strategies and ensuring sustainable agricultural development.

Enhancing cotton whitefly (Bemisia tabaci) detection and counting with a cost-effective deep learning approach on the Raspberry Pi.

The cotton whitefly (Bemisia tabaci) is a major global pest, causing significant crop damage through viral infestation and feeding. Traditional B. tabaci recognition relies on human eyes, which requires a large amount of work and high labor costs. The pests overlapping generations, high reproductive capacity, small size, and migratory behavior present challenges for the real-time monitoring and early warning systems. This study aims to develop an efficient, high-throughput automated system for detection of the cotton whiteflies. In this work, a novel tool for cotton whitefly fast identification and quantification was developed based on deep learning-based model. This approach enhances the effectiveness of B. tabaci control by facilitating earlier detection of its establishment in cotton, thereby allowing for a quicker implementation of management strategies. We compiled a dataset of 1200 annotated images of whiteflies on cotton leaves, augmented using techniques like flipping and rotation. We modified the YOLO v8s model by replacing the C2f module with the Swin-Transformer and introducing a P2 structure in the Head, achieving a precision of 0.87, mAP50 of 0.92, and F1 score of 0.88 through ablation studies. Additionally, we employed SAHI for image preprocessing and integrated the whitefly detection algorithm on a Raspberry Pi, and developed a GUI-based visual interface. Our preliminary analysis revealed a higher density of whiteflies on cotton leaves in the afternoon and the middle-top, middle, and middle-down plant sections. Utilizing the enhanced YOLO v8s deep learning model, we have achieved precise detection and counting of whiteflies, enabling its application on hardware devices like the Raspberry Pi. This approach is highly suitable for research requiring accurate quantification of cotton whiteflies, including phenotypic analyses. Future work will focus on deploying such equipment in large fields to manage whitefly infestations.

Selection and Regulatory Network Analysis of Differential CircRNAs in the Hypothalamus of Goats with High and Low Reproductive Capacity

The objectives of this investigation were to identify differentially expressed circular RNAs (circRNAs) in the hypothalamus of goats with high and low prolificacy and construct a circRNA-mRNA regulatory network to uncover key potential circRNAs that influence goat prolificacy. Transcriptome analysis was performed on hypothalamus samples from low-prolificacy (n = 5) and high-prolificacy (n = 6) Chuanzhong black goats to identify circRNAs that influence prolificacy in these goats. Differential expression analysis identified a total of 205 differentially expressed circRNAs, comprising 100 upregulated and 105 downregulated circRNAs in the high-prolificacy group compared with the low-prolificacy group. Enrichment analysis of these differentially expressed circRNAs indicated significant enrichment in Gene Ontology terms associated with mammalian oogenesis, negative regulation of neurotransmitter secretion, reproductive developmental processes, hormone-mediated signaling pathways, and negative regulation of hormone secretion. Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis highlighted significant enrichment in the oxytocin signaling pathway, GnRH signaling pathway, and hormone-mediated oocyte maturation. The hypothalamus of low- and high-prolificacy goats contains circular RNAs (circRNAs), including chicirc_063269, chicirc_097731, chicirc_017440, chicirc_049641, chicirc_008429, chicirc_145057, chicirc_030156, chicirc_109497, chicirc_030156, chicirc_176754, and chicirc_193363. Chuanzhong black goats have the potential to influence prolificacy by modulating the release of serum hormones from the hypothalamus. A circRNA-miRNA regulatory network was constructed, which determined that miR-135a, miR-188-3p, miR-101-3p, and miR-128-3p may interact with differentially expressed circRNAs, thereby regulating reproductive capacity through the hypothalamic-pituitary-gonadal axis. The results of this study enhance our knowledge of the molecular mechanisms that regulate prolificacy in Chuanzhong black goats at the hypothalamic level.

Physiological reactions of some entomopathogenic nematodes to long-term storage

Entomopathogenic nematodes (EPNs) are commonly used for pest control. Determining the optimal storage duration for EPNs is crucial for their effective utilization. The aim of this study is to determine the efficacy and reproductive capacities of some EPNs stored for different durations. Heterorhabditis bacteriophora Poinar, 1976 (Rhabditida: Heterorhabditidae) HBH Hybrid Strain, HBNL, and HB4 isolates, as well as Steinernema feltiae Weiser, 1955 (Rhabditida: Steinernematidae) SADIÇ and ST5 isolates, were used in the study. The Infective Juveniles (IJs) stored at 4ºC for 6, 12, 18, and 24 months were assessed for their efficacy and reproductive capacities on last instar larvae of Galleria mellonella L., 1758 (Lepidoptera: Pyralidae) at the end of the periods. This study was conducted at Bursa Uludağ University, Plant Protection Department, Nematology Laboratory. The highest mortality rate observed on G. mellonella larvae was 86.67% on the H. bacteriophora HBH Hybrid Strain stored for 6 months. Similarly, the highest reproductive capacity was determined to be 153 000 IJs/G. mellonella larva, also on the H. bacteriophora HBH Hybrid Strain stored for 6 months. This study showed significant results in determining the effects of storage durations on the efficacy and reproductive capacity of the EPNs.

Acaricidal potential of Bidens pilosa in the control of the red palm mite

Raoiella indica Hirst, 1924 (Prostigmata: Tenuipalpidae), is one of the leading pest mites on plants of the Arecaceae family, especially palm and banana trees. This species has a high reproductive capacity and rapid dissemination, but the control methods available for this species are still limited. Therefore, this work aimed to evaluate the acaricidal effect of blackjack (Bidens pilosa) on adult individuals of R. indica. The experiment was conducted in a completely randomized design, using the plant structures of blackjack to prepare the extracts. The experimental units consisted of coconut leaf discs (4 cm), with moistened cotton at the bottom of the Petri dish (10.0 × 1.2 cm), and around the disc to maintain turgidity and prevent mites from escaping. Spraying was carried out on 12 adult females of R. indica per sample unit, with seven repetitions for each concentration, using an airbrush with a constant pressure of 1.3 psi and 1 mL of solution per repetition plate. The acaricidal effect was evaluated 12, 24, 36, 48, 60, and 72 hours after spraying. The mortality of R. indica was proportional to the increase in the concentration of the blackjack plant extract, and the lethal concentrations obtained, CL50 and CL 90, were estimated between 1.49% and 4.19%, indicating the acaricidal potential of B. pilosa. Phenolic compounds were the majority of compounds found in this study.

Melanaphis sacchari/sorghi complex: current status, challenges and integrated strategies for managing the invasive sap-feeding insect pest of sorghum.

Melanaphis sacchari (Zehntner;Hemiptera: Aphididae), sugarcane aphid (SCA), is an invasive phloem-feeder found worldwide with a wide host range of economically important plants including sorghum and sugarcane. Given its high reproductive capacity and ability to rapidly spread over long distances, SCA presents challenges for effective control, leading to substantial economic losses. Recent studies have identified two multiloci SCA genotypes specialized in feeding on sugarcane (MLL-D) and sorghum (MLL-F) in the USA, which raises concerns as the USA is the second largest sorghum-producing country. This has encouraged research towards identifying these two biotypes where some research has stated them as two species; MLL-D clade to be M. sacchari and MLL-F clade to be M. sorghi Theobald (Hemiptera: Aphididae), sorghum aphid (SA). This review aims at compiling research progress that has been made on understanding the SCA/SA species complex. Furthermore, this review also highlights a wide range of management strategies against SCA/SA that includes both biological and chemical methods. In addition, the review emphasizes studies examining host plant resistance to understand and evaluate the role of R-genes and phytohormones such as jasmonic acid, salicylic acid and ethylene against SCA. Beside this, plant volatiles and other secondary metabolites such as flavonoids, terpenes and phytanes are also explored as potential control agents. Being an invasive pest, a single management tactic is inadequate to control SCA population and hence, integrated pest management practices incorporating physical, cultural and biological control methods should be implemented with exclusive chemical control as a last resort, which this review examines in detail. © 2024 The Author(s). Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Role of nuclear protein Akirin in the modulation of female reproduction in Nilaparvata lugens (Hemiptera: Delphacidae).

Introduction: Akirin as a highly conserved transcription factor, exerts a profound influence on the growth, development, immune response, and reproductive processes in animals. The brown planthopper (BPH), Nilaparvata lugens, a major pest in rice production in Asia, possesses high reproductive capacity, a critical factor contributing to reduced rice yields. The aims of this study were to demonstrate the regulatory role of Akirin in the reproduction of BPH. Methods: In this study, quantitative PCR (qPCR) was used to detect the mRNA expression of genes. RNA interference (RNAi) was used to downregulate the expression of Akirin gene, and RNA sequencing (RNA-seq) was used to screen for differentially expressed genes caused by Akirin downregulation. Hormone contents were measured with the enzyme linked immunosorbent assay (ELISA), and protein content was evaluated with the bicinchoninic acid (BCA) method. Results: Using BPH genome data, we screened for an Akirin gene (NlAkirin). An analysis of tissue-specific expressions showed that NlAkirin was expressed in all tissues tested in female BPH, but its expression level was highest in the ovary. After inhibiting the mRNA expression of NlAkirin in BPH females, the number of eggs laid, hatching rate, and number of ovarioles decreased. Transcriptome sequencing was performed, following a NlAkirin double-stranded RNA treatment. Compared with the genes of the control, which was injected with GFP double-stranded RNA, there were 438 upregulated genes and 1012 downregulated genes; the expression of vitellogenin (Vg) and vitellogenin receptor (VgR) genes as well as the mRNA expression of genes related to the target of rapamycin (TOR), juvenile hormone (JH), and insulin pathways involved in Vg synthesis was significantly downregulated. As a result of NlAkirin knockdown, the titers of JH III and Ecdysone (Ecd) were downregulated in unmated females but returned to normal levels in mated females. The ovarian protein contents in both unmated and mated females were downregulated. Discussion and conclusion: Our results suggest that NlAkirin affects female BPH reproduction by regulating the mRNA expression of genes related to the Vg, VgR, TOR, JH, and insulin signaling pathways, in addition to the titers of JH III and Ecd. The findings of this research provide novel insights into the regulatory role of Akirin in insect reproductive capacity.

Comparing Energetics and Physiological Trait Patterns of North American Birds to Support Ecological Risk Assessment

The environmental risk assessment (ERA) of plant protection products (PPPs) is commonly conducted for a number of standard laboratory species, though its scope includes all species, especially those that are vulnerable or endangered. This begs the question of how the eco-physiological and life history traits of those data-rich species compare to those of less documented species. This paper investigates the utility of a database of such traits, the Add-my-Pet collection of Dynamic Energy Budget theory, for the ERA of North American birds. We identified 72 bird species in the collection that have a federal listing status or are otherwise of interest for the ERA of PPPs and compared their eco-physiological and life history traits in relation to body size, feeding guild, and taxonomic identity to those of 446 terrestrial Holarctic birds, as well as those of standard lab species, notably the northern bobwhite, mallard, and zebra finch. The properties of standard lab species generally align with those of a similar taxonomy and size, with the notable exception of the relatively high reproductive capacity of the northern bobwhite and mallard due to the unique properties of laboratory study data. In addition, taxonomy appears to be a better predictor of eco-physiological traits than feeding guild. We conclude that, to identify representative species for the ERA of PPPs, more traits need to be included, such as those directly linked to the likelihood of exposure and those related to reproductive behavior.

Lindernia dubia (L.) Pennel as an Alien Weed in Central Spain: A Case Study.

Lindernia dubia (L.) Pennell is a species with invasive behavior outside of its native range of distribution (America), linked mainly to aquatic habitats. This annual species has been acknowledged as a weed in rice paddies in Europe and Asia. Due to the impacts of this invasive plant, some authors have even listed this species as a global invader. The present work focused on spontaneous plant species occurring in seedlings of Typha domingensis Pers. grown in central Spain for the establishment of constructed wetlands. Weed inventory revealed the presence of L. dubia as a dominant spontaneous species in this crop environment. A suite of mesocosm experiments were designed to study the population density of L. dubia versus that of the other dominant plant species, and to determine traits associated with its weedy potential. The results showed that L. dubia presents competitive attributes such as morphological variability, early flowering, long seeding time, short growth cycle, small and light seeds and a high seed production and germination rate (25 °C), meaning a high reproductive capacity in a cycle of about three months for plant growth in non-limiting conditions. The data obtained from this work provide a basis for understanding the weedy potential of L. dubia, and for management decisions of a potentially invasive species, which has been little investigated in Europe.

An Orphan Gene Enhances Male Reproductive Success in Plutella xylostella.

Plutella xylostella exhibits exceptional reproduction ability, yet the genetic basis underlying the high reproductive capacity remains unknown. Here, we demonstrate that an orphan gene, lushu, which encodes a sperm protein, plays a crucial role in male reproductive success. Lushu is located on the Z chromosome and is prevalent across different P. xylostella populations worldwide. We subsequently generated lushu mutants using transgenic CRISPR/Cas9 system. Knockout of Lushu results in reduced male mating efficiency and accelerated death in adult males. Furthermore, our findings highlight that the deficiency of lushu reduced the transfer of sperms from males to females, potentially resulting in hindered sperm competition. Additionally, the knockout of Lushu results in disrupted gene expression in energy-related pathways and elevated insulin levels in adult males. Our findings reveal that male reproductive performance has evolved through the birth of a newly evolved, lineage-specific gene with enormous potentiality in fecundity success. These insights hold valuable implications for identifying the target for genetic control, particularly in relation to species-specific traits that are pivotal in determining high levels of fecundity.

Comparative analysis of testicular fusion in Spodoptera litura (cutworm) and Bombyx mori (silkworm): Histological and transcriptomic insights

Spodoptera litura commonly known as the cutworm, is among the most destructive lepidopteran pests affecting over 120 plants species. The powerful destructive nature of this lepidopteran is attributable to its high reproductive capacity. The testicular fusion that occurs during metamorphosis from larvae to pupa in S.litura positively influences the reproductive success of the offspring. In contrast, Bombyx mori, the silkworm, retains separate testes throughout its life and does not undergo this fusion process. Microscopic examination reveals that during testicular fusion in S.litura, the peritoneal sheath becomes thinner and more translucent, whereas in B.mori, the analogous region thickens. The outer basement membrane in S.litura exhibits fractures, discontinuity, and uneven thickness accompanied by a significant presence of cellular secretions, large cell size, increased vesicles, liquid droplets, and a proliferation of rough endoplasmic reticulum and mitochondria. In contrast, the testicular peritoneal sheath of B.mori at comparable developmental stage exhibits minimal change. Comparative transcriptomic analysis of the testicular peritoneal sheath reveals a substantial difference in gene expression between the two species. The disparity in differential expressed genes (DEGs) is linked to an enrichment of numerous transcription factors, intracellular signaling pathways involving Ca2+ and GTPase, as well as intracellular protein transport and signaling pathways. Meanwhile, structural proteins including actin, chitin-binding proteins, membrane protein fractions, cell adhesion, extracellular matrix proteins are predominantly identified. Moreover, the study highlights the enrichment of endopeptidases, serine proteases, proteolytic enzymes and matrix metalloproteins, which may play a role in the degradation of the outer membrane. Five transcription factors-Slforkhead, Slproline, Slcyclic, Slsilk, and SlD-ETS were identified, and their expression pattern were confirmed by qRT-PCR. they are candidates for participating in the regulation of testicular fusion. Our findings underscore significant morphological and trancriptomic variation in the testicular peritoneal sheath of S.litura compared to the silkworm, with substantial changes at the transcriptomic level coinciding with testicular fusion. The research provides valuable clues for understanding the complex mechanisms underlying this unique phenomenon in insects.

Unlocking the potential of local rabbit population: morphological insights for sustainable rabbit farming in Burkina Faso’s challenging environments

This study explores the potential of rabbits as a sustainable solution for poverty alleviation and food security in Burkina Faso, a country facing socio-economic and environmental challenges. In the context of limited resources and employment opportunities, rabbits offer advantages such as small size, short generation interval and high reproductive capacity. The research focuses on characterising the morphology of Burkina Faso’s local rabbit population, comparing it with two Italian breeds: a local medium-growing breed called Leprino di Viterbo (LV) and a fast-growing hybrid (a crossbred New Zealand × California, NZC). Utilising path analysis and principal component analysis, the study identifies key morphometric traits crucial for breeding programs and examines the influence of specific traits on body weight (BW) gain and heat stress resilience through ‘Transpiration Indexes.’ Findings highlight the importance of variables like chest girth (CG), abdominal girth (AG), rump width (RW) and nose to shoulders length (NSL) in influencing body weight (BW) and reveal significant size and shape differences among the breeds. The study suggests potential climate adaptation in Burkina Faso’s rabbit population, providing practical insights for breeding programs in resource-constrained regions. This research not only advances scientific understanding but also provides practical insights for breeding programs in resource-constrained regions, emphasising the importance of certain morphological traits for heat dissipation.

Recent and future distribution of the alien Chinese pond mussel Sinanodonta woodiana (Lea, 1834) on the European continent

The alien freshwater mussel Sinanodonta woodiana (Lea, 1834) has rapidly spread throughout Europe over the past decades. This species can cope with a broad range of environmental conditions and has a high reproductive capacity making S. woodiana a successful invader. Due to its negative effects on native freshwater mollusk communities and parasitized fish it is critical to identify suitable habitats where S. woodiana may persist and how these habitats may be altered under future climate projections. We applied multivariate ordination methods to analyze the space-time relationship and a maximum entropy approach (MaxEnt) to predict the recent (1970–2000) and future (2041–2060 and 2081–2100) distribution of S. woodiana using environmental and climate variables for the European continent. After first sightings in 1979 there were only a few new locations and findings which increased unevenly and exponentially to a maximum of about 100 new locations per year followed by decline during the last few years. Under recent climate condition, 2.3% of European watersheds are predicted as highly suitable habitat for S. woodiana and located in the temperate climate zone between 40°N and 60°N. Suitable habitat was associated with lowland watersheds characterized by fluviatile deposits and agriculture. Elevation, the distance between water bodies, land cover and mean temperature of the coldest quarter were the main factors influencing the modeling results. For future climate scenarios, highly suitable habitat increased to 2.4% by the middle of this century and decreased to 2.2% by the end of the century under the ‘least radiative forcing’ scenario. For the intermediate and high radiative forcing in 2050 and 2100, highly suitable habitat decreased to 2.2% and 1.7% and to 2.2% and 2.2%, respectively. Results from our study can be used as a baseline to better understand potential invasion pathways, identify high risk areas, and to initiate early detection and rapid response strategies.

Optimized properties of live vaccine influenza reassortant strains obtained by reverse genetics

Classical reassortment in developing chicken eggs is a well-established technique for obtaining LAIV strains. Naturally generated reassortant vaccine strains are characterized by high reproductive capacity, genetically stable characteristics of temperature sensitivity and cold resistance, which correspond to the characteristics of the MDV involved in crossing with the epidemic virus. Along with antigenic relevance, natural reassortment ensures attenuation of vaccine strains, good reproduction capacity in upper respiratory tract cells and inability to reproduction in the lower respiratory tract. With classical reassortment, the speed and efficiency of obtaining vaccine reassortants largely depend on the properties of epidemic virus, and therefore cannot be stable. The potential of reverse genetics is attractive because it allows to obtain vaccine reassortants quickly and efficiently, reduce the likelihood of spontaneous mutations; however, the vaccine strain is deprived of the advantages of natural selection, in which the most viable clones are selected. This study presents the results of comparatively assessed A(H3N2) LAIVs obtained in parallel by classical reassortment and reverse genetics according to criteria confirming that vaccine strains inherit the necessary properties that guarantee their harmlessness and high reproduction in chicken embryos. Strains for LAIV obtained by both methods retained all attenuating mutations inherited from the MDV, were highly reproductive at the optimal temperature, with temperature sensitivity corresponded to the MDV. However, strains obtained by reverse genetics, was observed to have partial loss of cold resistance in comparison with that of the MDV and classical reassortants. Reduced cold adaptation may negatively affect vaccine effectiveness. It is important that after several additional passages in chicken embryos at low temperature, the cold resistance of the vaccine strain, assembled by reverse genetics, was increased. Credibly that cold resistance is a phenotypic trait, the degree of manifestation of which depends on the temperature conditions of virus multiplication. The selective factor of reduced incubation temperature is missing in reverse genetics. In order for the cold-adapted phenotype to be fully realized, additional passages at low temperature of RG-reassortants are necessary. Thus, the reverse genetics method using plasmid technology allows to effectively prepare reassortant strains for LAIV. An important stage in obtaining vaccine strains using genetic engineering techniques should be the control of their cold-adapted phenotype and its optimization by additional passages at low temperature.

PRODUCTIVITY INDICATORS OF BUKOVINIAN TYPE EWES OF ASCANIAN MEAT-WOOL BREED WITH CROSS-BRED WOOL IN CONDITION OF BUKOVINA

Objective. Presentation of indicators Bukovinian type ewes of Ascanian meat-wool breed with cross-bred wool are given. As a result of research, it was established, that the animals are of a strong constitution, well adapted to conditions of Bukovinian humid climate. Ewes with high reproductive capacity: fertilization made 93.5%, multiple fertility – 131.5, yield of lambs per 100 ewes – 124 heads, with their high viability. The lambs are born of strong constitution, large enough, with high live weight. Live weight at birth is influenced by the sex of the animal. It is established, that the rams live weight is higher than that of ewe-lambs by 7.8%. Ewes have high milk productivity. From a single ewe for the milking period (137 days) 116.6 kg of milk was obtained, with average daily milk yield 0.883 kg, from which 25 kg of solid cottage cheese (brynza) was produced. In gross income, a part of sheep milk products makes about 60%, meat in live mass – 45%, when that of wool – only 3.0%. Conclusions. As the research result, we established, that the Bukovinian type sheep of Ascanian meat-wool breed with cross-bred wool have high indicators of a reproductive capacity and of a combined productivity. However, further Bukovinian type improvement and the increase of milk, meat, and wool productivity indicators requires effective selection methods. The research methods: zootechnical, economic, and biometric.

Efficiency of temperature and storage duration on some morphological measurements and reproductive capacity of the entomopathogenic nematode Heterorhabditis bacteriophora Poinar, 1976 (Rhabditida: Heterorhabditidae)’s Turkish HBH hybrid strain

Entomopathogenic nematodes (EPNs) are successfully used in the biological control of agricultural insect pests. This study aims to determine the body length of hermaphrodite individuals, egg diameter and reproductive capacity obtained from Infective Juveniles (IJs) stored at different temperatures and durations. Heterorhabditis bacteriophora Poinar, 1976 (Rhabditida: Heterorhabditidae)’s Hybrid Strain HBH was used in the study. IJs stored at 15, 25 and 35°C for 7, 14 and 21 days were inoculated onto Galleria mellonella L., 1758 (Lepidoptera: Pyralidae) last instar larvae at a dose of 100 IJs. On the 2nd day of infection, hermaphrodite individuals and eggs were obtained by dissecting the larvae. The reproductive capacity was determined 10-12 days after infection. The study was conducted in Bursa Uludağ University, Faculty of Agriculture, Plant Protection Department, Nematology Laboratory in 2023. In conclusion, the longest hermaphrodite individuals and egg diameter were obtained as 6207.22 µm and 55.65 µm, respectively from the IJs stored for 7 days at 15°C. The highest reproductive capacity was also observed as 167.500 IJs per G. mellonella larva in IJs stored under the same conditions with respect to temperature and time. This study is important for assessing the morphological effects of different temperature values and storage durations on EPNs.