Impact of Mixed Infections of Gut Parasites Lotmaria passim and Nosema ceranae on the Lifespan and Immune-related Biomarkers in Apis mellifera

摘要

currently appears to be the predominant trypanosome in honey bees worldwide. Although, the specific effects of by single or mixed with other gut parasites such as on honey bees’ health is still unclear. We consequently measured bees’ survival, parasite loads, the expression of antimicrobial peptides (AMPs) and vitellogenin gene. Thus, (1) bees naturally infected with , (2) healthy bees inoculated with , (3) bees naturally infected with and inoculated with and (4) healthy bees (control) were maintained under controlled conditions. Honey bees infected with or with mixed infections of and had significantly lower survival rates than the control group at 20 days post-inoculation (dpi). A competitive suppression was also detected, provided that the load was significantly affected by the presence of at 15 dpi. Expressions of the AMPs defensin and hymenoptaecin rapidly (two hours post-inoculation) increased in bees infected with and mixed infections. However, this effect was not continuous. In fact, expressions of abaecin, defensin, hymenoptaecin and vitellogenin decreased drastically at 15 dpi in bees with both single and mixed infections. The decrease in the expression of AMPs and vitellogenin throughout this period was consistent with the reduced survivals observed in this study, indicating that mixed infections of and , and even into a scenario of competition between them, may have a synergic effect on the survival and immune-related gene expressions (biomarkers) of worker bees.