With virus vectoring Varroa destructor mites in about 90% of US beekeepers colonies, especially those in the commercial industry rely on some form chemical compound or miticide like amitraz to eradicate them. A promising new strain of honey bees is being developed at Purdue University that is helping reduce annual colony losses due to the ectoparasitic mites feeding on them. This recent publication demonstrates that Indiana mite-biting bees have decreased winter mortality compared to some commercially available stocks many commercial and hobbyist beekeepers rely on. The mite-biter colonies survived three times higher than the Italians in this recent study conducted at Purdue University. Beekeepers can help reduce the population of varroa with the mite-biter bee that researchers are breeding to resist them. But even more significant was Nerexin-1 gene expression corelated with the proportion of mutilated mites from the mite-biting bees’ mandibles. Some say breeding for resistance to varroa is like breeding sheep to resist wolves, but sheep cannot kill wolves — bees can certainly kill mites.
“The aim of this study was to assess the efficacy of selecting for increased mutilation of V. destructor mites as a tool to breed V. destructor resistant bees and the possible involvement of AmNrx-1 in mite biting behavior. We expanded the evaluation of the Indiana mite-biter stock by comparing it with an Italian commercial genotype for V. destructor mutilations, mite population growth, and winter survival. We also correlated mite population growth and the proportion of mutilated mites with the expression of AmNrx-1 in bees, to assess the value of this gene as a potential marker of V. destructor resistance.”
Link to the Apidologie publication:
Image: Dr. Greg Hunt and Krispn Given evaluating one of their Mite-biter/grooming colonies