Living with the enemy: Parasite tolerance in survivor honeybees

Host selection is crucial for parasites, shaping their propagation and vectoring abilities, but also exposing them to varying host immune systems. For the ectoparasite Varroa mite, host selection initiates its reproductive cycle. These mites exploit the period between brood cell capping and bee emergence to produce offspring that disperse with the adult bees. This research investigates factors influencing Varroa mite host choice and honeybee responses. Using diverse bee genotypes at UCR with varying mite tolerance, I conducted a behavioral study to quantify mite host preferences. Results showed that Varroa mites are more attracted to 7-day-old larvae, regardless of genotype. Surprisingly, tolerant bees did not reduce mite attraction compared to susceptible bees. This suggests that tolerant genotypes may mount more effective immune responses against mites, prompting an investigation into these responses and their molecular mechanisms. Understanding the immune responses of mite-tolerant genotypes could inform a molecularly based breeding program for disease-resistant bee stocks.