Bee health is influenced by multiple factors, including nutrition, immunity, and parasitic pressures. Since the spread of Varroa destructor, overwintering survival has significantly declined, making it one of the most serious threats to honey bee (Apis mellifera L.) populations worldwide. Natural acaricides, such as oxalic acid (OA), are widely employed for managing Varroa mites; however, their pharmacodynamics, particularly their impacts on honey bee physiology and immunity, remain insufficiently understood. We studied effects of oxalic acid on honey bee workers. The study compared three treatments: flumethrin, OA-glycerine strips (OA-G), and OA trickling (OA-T). Twelve colonies were divided into four groups, with samples collected at five time points (0, 24, 48, 72, and 192 h). Physiological changes were assessed through markers of oxidative stress, longevity, and immune parameters. Exposure to oxalic acid via glycerine strips induced a humoral immune response in adult bees. The antimicrobial activity of hemolymph and levels of antimicrobial peptides (abaecin, apidaecin, defensin, and hymenoptaecin) were elevated between 48 and 192 h after OA-G treatment compared to the control group. In contrast, these parameters were not influenced by OA-T or flumethrin treatment. These findings suggest that OA-G strips activate the honey bee's immune system, providing insights into broader implications of OA use in beekeeping. It is crucial to determine whether the activation of humoral immune systems has positive or negative effects, as well as to develop standardized and reliable treatment protocols that ensure both - health of colonies and their effectiveness in controlling Varroa mite infestations.
- Klíčová slova
- Beekeeping, Integrated Pest management, Oxalic acid, Pharmacodynamics, Treatment, Varroa,
- MeSH
- akaricidy * farmakologie MeSH
- antimikrobiální peptidy metabolismus MeSH
- hemolymfa účinky léků metabolismus MeSH
- kyselina oxalová * farmakologie MeSH
- oxidační stres účinky léků MeSH
- pyrethriny farmakologie MeSH
- Varroidae účinky léků MeSH
- včely imunologie účinky léků MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- Názvy látek
- akaricidy * MeSH
- antimikrobiální peptidy MeSH
- flumethrin MeSH Prohlížeč
- kyselina oxalová * MeSH
- pyrethriny MeSH
Varroa destructor is the major cause of honey bee (Apis mellifera) colony losses. Mite control is limited to several miticides. The overuse of tau-fluvalinate has resulted in resistance via a knockdown resistance (kdr) mutation in the sodium channel gene NaVChs (L925V/I/M). In this study, we used the discriminating concentration of tau-fluvalinate (0.25 µg/mL) to detect the resistance of mites in a bioassay. Further, we verified the presence of the kdr mutation in mites from the bioassay via PCR amplification of a fragment of the voltage-gated sodium channel gene (NaVCh), restriction fragment length polymorphisms (RFLPs), and densitometry analyses in pools of surviving or dead mites. Resistance values corresponding to the densitometry of the resistant allele were related to mite survival. In the vial test, the survival of the control group was significantly higher (70.4%) than that of the tau-fluvalinate-treated group (34.3%). Mite survival in the vial test was significantly correlated with the mean proportion of resistance values. Individuals that died after tau-fluvalinate application exhibited an average resistance value of 0.0783, whereas individuals that survived exhibited an average resistance of 0.400. The concentration of tau-fluvalinate in the vials was checked using high performance liquid chromatography under different temperatures and exposure times, and indicates that the stability of tau-fluvalinate stored in the refrigerator (4 ± 1 °C) is at least 14 days. PCR-RFLP of the NaVCh gene fragment verified that the vial test is a suitable, rapid, and cost-effective method for the identification of tau-fluvalinate resistance based on kdr mutation in V. destructor in apiaries.
- Klíčová slova
- Acaricide, Apiary, Honey bee, Restriction, Varroa destructor,
- MeSH
- akaricidy farmakologie MeSH
- biotest metody MeSH
- denzitometrie metody MeSH
- léková rezistence genetika MeSH
- nitrily farmakologie MeSH
- polymerázová řetězová reakce metody MeSH
- polymorfismus délky restrikčních fragmentů MeSH
- pyrethriny farmakologie MeSH
- Varroidae účinky léků genetika MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- srovnávací studie MeSH
- Názvy látek
- akaricidy MeSH
- fluvalinate MeSH Prohlížeč
- nitrily MeSH
- pyrethriny MeSH
BACKGROUND: Sodium channels (SCs) in mites and insects are target sites for pesticides, including pyrethroids. Point mutations in the SC gene have been reported to change the structural conformation of the protein and its sensitivity to pesticides. To find mutations in the SC gene of the mite Varroa destructor (VmNa), the authors analysed the VmNa gene sequences available in GenBank and prepared specific primers for the amplification of two fragments containing the regions coding for (i) the domain II S4-S6 region (bp 2805-3337) and (ii) the domain III S4-3' terminus region (bp 4737-6500), as determined according to the VmNa cDNA sequence AY259834. RESULTS: Sensitive and resistant mite populations did not differ in the amino acid sequences of the III S4-3' terminus VmNa region. However, differences were found in the IIS4-IIS6 fragment. In the resistant population, the mutation C(3004) → G resulted in the substitution L(1002) → V (codon ctg → gtg) at the position equivalent to that of the housefly L925 in the domain II S5 helix. Additionally, the mutation F(1052) → L (codon ttc → ctc) at the position equivalent to that of the housefly F975 in the domain II P-loop connecting segments S5 and S6 was detected in both the resistant and sensitive populations. CONCLUSION: All individuals that survived the tau-fluvalinate treatment in the bioassay harboured the L(1002) → V mutation combined with the F(1052), while dead individuals from both the sensitive and resistant populations harboured mostly the L(1002) residue and either of the two residues at position 1052.
- Klíčová slova
- Varroa destructor, honey bee, kdr resistance, sodium channel, tau-fluvalinate,
- MeSH
- fyziologická adaptace * MeSH
- léková rezistence genetika MeSH
- molekulární sekvence - údaje MeSH
- mutace MeSH
- nitrily toxicita MeSH
- pyrethriny toxicita MeSH
- sekvence aminokyselin MeSH
- sekvence nukleotidů MeSH
- sodíkové kanály genetika MeSH
- Varroidae účinky léků genetika fyziologie MeSH
- včely MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Geografické názvy
- Česká republika MeSH
- Názvy látek
- fluvalinate MeSH Prohlížeč
- nitrily MeSH
- pyrethriny MeSH
- sodíkové kanály MeSH
