SEMINAR: Bayliss Seminar Series: Host parasite interactions between honey bees (Apis mellifera) and the widespread fungal parasite Nosema apis

European honey bees (Apis mellifera) are a key factor in the production of the food we consume as they pollinate more than 80 agricultural crops of interest, with an estimated value of more than US$ 200 billion each year. However throughout the past decade there has been an increased loss of honey bee stocks globally. Research has indicated a number of possible factors for these declines, including the impact of parasites and pathogens that honey bees can host. For my PhD I am particularly interested in the fungal parasite Nosema apis, which has a worldwide distribution including Western Australia. This spore forming microsporidian is widespread and often present in colonies at low levels. N. apis infections cause task mismatching, energetic stress, dysentery, reduced lifespan and in severe cases the loss of the entire colony. N. apis spores infect adult bees through the ingestion of spore contaminated food and water, however recent research has shown that spores can also be sexually transmitted as they are able to contaminate the males ejaculate. However males maintain an immune system in their ejaculate to combat these parasites, which is highly efficient in killing N. apis spores, as exposure to seminal fluid can kill over 80% of spores. For my PhD I will investigate the spores that survive the seminal fluid exposure. I hypothesise that these surviving spores are resistant to the defences present in the seminal fluid and will therefore not be impacted by additional exposures to seminal fluid of the same male. If this is the case I will investigate how the infectivity of such spore isolates may differ between individuals and colonies by looking at variation in parasite susceptibility. My work aims to unravel the interactions between honeybees and N. apis and I plan to also conduct an experiment to test whether such resistance traits are heritable. My research will add to the knowledge to the interactions between hosts and their parasites and provide novel avenues for the breeding of disease tolerant bees in the future.