Large cells suppress the reproduction of Varroa destructor.

BACKGROUND: The parasitic mite, Varroa destructor has posed a threat to the health and survival of European honey bees, Apis mellifera worldwide. There is a prevailing belief that small comb cells could provide a management tool against Varroa mites. However, the hypothesis that smaller cells can impede Varroa reproduction has not been fully tested. Here, we tested this hypothesis under laboratory conditions by using two distinct Varroa in vitro rearing systems: one involved gelatin capsules of different sizes, specifically size 00 (0.95 mL) versus size 1 (0.48 mL), and the second consisted of brood comb cells drawn on 3D printed foundations with varying cell sizes, ranging from 5.0 mm to 7.0 mm at 0.5 mm intervals. RESULTS: The results showed that mother mites in size 00 cells had significantly lower fecundity and fertility compared to those in size 1 cells. Interestingly, the reproductive suppression in larger cells could be reversed by adding an extra worker larva. Similarly, gonopore size of mother mites was smaller in size 00 cells, but restored with another host larva. Furthermore, both the fecundity and fertility of mother mites decreased linearly with the size of brood comb cells. CONCLUSIONS: Our results suggest that the reproduction of V. destructor is hindered by larger cells, possibly because larger brood cells disperse or weaken host volatile chemical cues that are crucial for Varroa reproduction. The insights derived from this study are expected to hold significant implications for the implementation of Varroa management programs. © 2024 Society of Chemical Industry.

The Effect of Comb Cell Size on the Development of Apis mellifera Drones.

The growth and development of honeybees are influenced by many factors, one of which is the cell size of the brood comb. Larger worker bees can be obtained by being raised in bigger cells. However, whether cell size has the same effect on drone development is still unknown. Here, using 3D-printed foundations, we observed the development of drones kept in comb cells of different sizes from the late larval stage through eclosion. The results showed that drones in larger cell-size combs had heavier body weights, longer body lengths, and larger head widths, thorax widths, and abdomen widths compared to those in smaller cell-size combs. Furthermore, regardless of developmental stages, the drones' body weights increased linearly with the comb's cell size. However, the other morphological changes of drones in different developmental stages were out of proportion to the cell-size changes, resulting in smaller cells with a higher fill factor (thorax width/cell width). Our findings confirm that comb cell size affects the development of honeybees; drones become bigger when raised in large cells.

Enhancing Coccinella Beetle Biological Pest Control via a Floral Approach in Cucumber Greenhouse.

Flower-rich habitats are crucial for promoting biodiversity and ecosystem services within agricultural ecosystems, such as pollination and pest control. The present study investigates the efficacy of employing floral structures as a criterion for the selection of plant species in order to enhance the attraction of natural enemies within cucumber greenhouses, consequently augmenting floral resources. The results of our study provide evidence that flower strips have a beneficial effect on the fitness of critical natural predators, while not facilitating the proliferation of detrimental insect species. These findings exhibit potential for enhancing pest-management services in the agricultural sector. The findings of our study demonstrate that pest levels within greenhouse environments closely resemble those observed in real-world commercial cropping systems. As a result, the introduction of Coccinella septempunctata and Menochilus sexmaculatus biocontrol agents is confirmed to be a reliable and efficient method for pest management. The phenomenon of predator-prey density dependency is recognized as a crucial element in the implementation of biological control strategies. Furthermore, we investigate the impact of floral resources on the reproductive capacity of indigenous predators. The impact of Coriandrum sativum on fertility is substantial, indicating that the presence of a varied plant assortment with overlapping flowering periods can prolong the availability of floral resources. This study highlights the significance of flower-rich habitats and deliberate plant selection in augmenting biodiversity, ecosystem services, and pest management within agricultural settings. The implementation of conservation biological control technologies presents supplementary ecological advantages, thus offering practical implications for the promotion of sustainable agricultural practices.

Population genomics of honey bees reveals a selection signature indispensable for royal jelly production.

In order to interpret the molecular mechanisms that modulating the organism variations and selection signatures to drive adaptive evolutionary changes are indispensable goals in the new evolutionary ecological genetics. Here, we identified the gene locus associated to royal jelly production through whole-genome sequencing of the DNA from eight populations of honeybees. The analysis of the samples was composed of 120 individuals and each pointed extremely opposite trait values for a given phenotype. We identified functional single nucleotide polymorphisms (SNPs) candidate that might be essential in regulating the phenotypic traits of honeybee populations. Moreover, selection signatures were investigated using pooling sequencing of eight distinct honeybee populations, and the results provided the evidence of signatures of recent selection among populations under different selection objectives. Furthermore, gene ontology (GO) annotation and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses indicated that selected genes were potentially involved in several biological processes and molecular functioning, which could directly or indirectly influence the production of royal jelly. Our findings can be used to understand the genomic signatures, as well as implicate a profound glance on genomic regions that control the production trait of royal jelly in honey bees.

CRISPR/Cas9 to generate plant immunity against pathogen.

Different types of molecular approaches have been used for improving resistance against pathogens to secure food. Efficient and advanced genome editing tool as paralleled to earlier techniques like Zinc Finger Nuclease (ZFN), transcription activator-like effector nucleases (TALENs), and Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR). The approach of CRISPR/Cas9 has updated our abilities of genetic manipulation in many crops. The assembly of purposes that can be achieved through CRISPR/Cas9 and its related products make it a powerful system that will expose novel prospects in the complex domain of plant-pathogen interactions and will help to develop crop resistance against pathogens. CRISPR/Cas9 engineering permits DNA endonuclease guided by an RNA for a range of genome engineering applications across various eukaryotic species and provides an effective platform to create resistance against bacteria, viruses, insects, and fungi. In this review, we discuss CRISPR-Cas9 engineered crop plants resistant to specific pathogens.

Q-SNARE protein FgSyn8 plays important role in growth, DON production and pathogenicity of Fusarium graminearum.

SNAREs (Soluble N-ethylmaleimide-sensitive factor attachment protein receptors) help intracellular vesicle trafficking and membrane fusion among eukaryotes. They are vital for growth and development of phyto-pathogenic fungi such as Fusarium graminearum which causes Fusarium Head Blight (FHB) of wheat and barley. The SNARE protein Syn8 and its homologues play many roles among different organisms. Here, we have characterized FgSyn8 in F. graminearum as a homologue of Syn8. We have integrated biochemical, microbiological and molecular genetic approaches to investigate the roles of this protein. Our results reveal that FgSyn8 is indispensable for normal vegetative growth, conidiation, conidial morphology and pathogenicity of F. graminearum. Deoxynivalenol (DON) biochemical assay reveals active participation of this protein in DON production of F. graminearum. This has further been confirmed by the production of bulbous structures among the intercalary hyphae. FgSyn8 mutant strain produced defects in perithecia formation which portrays its role in sexual reproduction. In summary, our results support that the SNARE protein FgSyn8 is required for vegetative growth, sexual reproduction, DON production and pathogenicity of F. graminearum.

Prevalence of bee viruses in Apis cerana cerana populations from different locations in the Fujian Province of China.

Prevalence of honeybee viral diseases has recently been causing major problems in the beekeeping industry, causing economic losses worldwide. Honeybees are susceptible to a variety of diseases and various pathogens. Among these pathogens, prevalence viruses, along with other factors, are seriously threatening the health of bee species. In the present study, samples were collected from 80 Apis cerana cerana (A. c. cerana) colonies from three different locations, Cangshan, Fuan, and Yongtai, in the Fujian Province of China. All samples were screened using the reverse transcription polymerase chain reaction (RT-PCR) method for detection of seven honeybee viruses, namely, Chinese sacbrood virus (CSBV), deformed wing virus (DWV), Israeli acute paralysis virus (IAPV), black queen cell virus (BQCV), chronic bee paralysis virus (CBPV), acute bee paralysis virus (ABPV), and Kashmir bee virus (KBV). Our results showed that CSBV was the most prevalent as it was detected in (90%), of the samples, DWV was detected in (81.25%), and IAPV was detected in (26.25%). In contrast, insignificant prevalence results were obtained from all apiaries for BQCV, CBPV, APBV, and KBV, which were not detected in any sample. Here, we are providing the first report on the molecular detection of honeybee viruses, especially the prevalence of IAPV, from different regions in the Fujian Province of China with a high prevalence of bee viruses, on A. c. cerana, and there is great concern for the presence of honeybee viruses in the population of the native honeybee (A. c. cerana) in China.