Insects

Dendrolimus sibiricus cypovirus-1 (DsCPV-1) is a promising candidate for development as a biological insecticide against Lepidopteran pests. Since in vitro systems have limited potential for large-scale production of entomopathogenic viruses, efficient in vivo production in insect hosts is required. We evaluated DsCPV-1 productivity in an alternative host, Manduca sexta (L.) (Lepidoptera: Sphingidae), after infection at different times during the second instar—on the molting day and 1, 2, and 3 days post-molt—and compared it with productivity in the original host. Viral productivity was quantified by quantitative PCR using a plasmid calibrator, as reduced occlusion body formation in M. sexta limits conventional microscopic quantification of polyhedra. Larvae of the original host, D. sibiricus, were included for comparison. No significant difference in virus yield was observed between the two species, demonstrating that the more economically practical host, M. sexta, possesses an additional advantage: high viral productivity. Viral productivity per larva was unaffected by time after molting. Evaluation of additional parameters, including LT₅₀ and the stability of virus yield, revealed that infecting larvae on days 1 and 2 after molting to the second instar yields optimal virus productivity. Our results demonstrated that DsCPV-1 passaged through M. sexta retained its virulence.

This narrative review examines how eusociality reshapes breeding strategies in Apis mellifera and why honeybee colony phenotypes should be interpreted within a population-based framework. Rather than treating colonies as isolated breeding entities, we examine how genetic variation is generated, redistributed, and maintained through reproductive processes, gene flow, and evolutionary forces acting across interconnected populations. The review synthesises evidence on honeybee reproductive genetics, environmental and nutritional influences, management practices, and temporal variation in colony phenotypes. Together, these dimensions motivate a Genotype × Environment × Time (G × E × T) perspective for interpreting colony performance and improving phenotypic evaluation. Existing breeding programmes demonstrate that selective improvement of colony traits is achievable, while highlighting potential trade-offs between genetic gain, inbreeding, and the maintenance of adaptive diversity. Building on this synthesis, we propose a conceptual framework integrating population-based selection and landscape-scale conservation through a gradient of human selection intensity, from protected conservation populations to managed hybridisation zones. This framework aims to reconcile genetic improvement with the preservation of locally adapted diversity and long-term adaptive potential. Its practical feasibility and comparative effectiveness remain to be evaluated empirically.

Neonicotinoid toxicity to honeybees varies among active ingredients, with the insects being tolerant to thiacloprid but sensitive to imidacloprid. The selective toxicity has been hypothesized to be due to differences in metabolic detoxification by cytochrome P450s. In vitro experiments revealed that CYP9Q3 efficiently metabolises thiacloprid but not imidacloprid, consistent with the toxicity data. Honeybee tolerance to tau-fluvalinate, a pyrethroid acaricide used against Varroa destructor, has also been linked to P450-mediated detoxification. To address the role of CYP9Q3 in vivo in Apis mellifera, we used an RNA interference approach based on double-stranded RNA delivery through the median ocellus of adults to transiently suppress expression of CYP9Q3 in the head. Following confirmation of CYP9Q3 suppression by qPCR, fixed-dose topical bioassays were conducted with the neonicotinoids imidacloprid and thiacloprid and the pyrethroid tau-fluvalinate. Suppression of CYP9Q3 was associated with increased mortality following exposure to thiacloprid and tau-fluvalinate, whereas no increase was observed with imidacloprid. These findings provide in vivo functional evidence supporting the role of CYP9Q3 in honeybee tolerance to thiacloprid and tau-fluvalinate. The RNAi approach offers a valuable tool for investigating the functions of cytochrome P450 enzymes and other genes expressed in the honey bee head that are involved in insecticide susceptibility.