Bats are not only natural hosts for many common viruses but are also home to a suite of parasites — one being the blood-sucking bat fly. While not much is known about bat flies, these mysterious creatures have co-evolved with bats over millions of years and their survival depends entirely on their hosts. Now, researchers at the Australian Institute of Tropical Health and Medicine (AITHM) are studying this unique relationship to uncover how it might influence disease transmission.
In recent years, bats have become increasingly recognised as carriers of zoonotic diseases due to their role in the spread of viruses like COVID-19 and Hendra virus. James Cook University (JCU) Master’s student and AITHM researcher Mrs Robyn Pearce is investigating the interactions between bat flies, their hosts and the viruses they both carry.
“Bats harbour some really significant viruses that can affect human health,” Mrs Pearce said. “And bat flies, while they don’t directly bite humans, may be responsible for helping viruses spread throughout bat populations. So, understanding bat flies helps us predict and monitor potential disease outbreaks.”
Bat flies are tiny ectoparasites (meaning they are external, living on the outside of a body) that feed on bat blood to survive. Depending on the species of bat fly, they can range in size from about 2 to 6 millimetres. Although technically a fly, Mrs Pearce describes them as a cross between a spider and a tick, with 6 legs and a flattened body.
“Some species of bat flies have wings, while others don’t. There’s a lot of variation between different species, and very little is known about them in Australia,” she said. “Certain species were originally reported decades ago, but there’s been almost no follow-up research. My goal is to catalogue the species we have here and understand which bat flies are associated with which species of bat, and what diseases they may carry.”
Working closely with wildlife carers in North Queensland, Mrs Pearce is gathering bat flies that live on two types of bats: black flying foxes (Pteropus alecto) and little red flying foxes (Pteropus scapulatus).
“When a bat comes into care, generally a carer will remove as many of the bat flies as possible. For my project, I’ve asked them to collect and preserve the insects for me. I’m currently using morphology — which involves examining their physical features under a microscope — and DNA sequencing to identify the different species of bat fly,” she said.
“The next part of my project will focus on examining the viruses found in bat flies and seeing if the types of viruses differ depending on the species of bat they live on. I'm really excited about this stage because it will help us better understand how diseases spread within bat populations. I also expect to discover some new viruses that haven’t been found in bat flies in Australia before."
Ultimately, Mrs Pearce hopes this research will improve understanding on how diseases spread through bat populations in order to better protect people from future outbreaks that cross the species boundary.
“Bat flies are fascinating little creatures,” she said. “By studying them, we’re not just learning about these parasites — we’re uncovering valuable information about bats, ecosystems and the diseases that may eventually help us to predict and prevent future pandemics.”