Tuesday, 19 April 2016

Researching the impacts of cats on bats

Hi- my name is Abbie Case, I have just finished studying for an MSc in Conservation Biology at Manchester Metropolitan University. I have always been fascinated by bats so I was thrilled when the opportunity arose to be able to research them for my Master’s thesis.

The title of my project was, “Investigating domestic cat (Felis catus) predation on British bats through the use of molecular techniques” and when telling this to people it was interesting to see the amount of people who were surprised that cats were actually predators of bats! Being honest, myself included! However, domestic cat predation on British wildlife is a serious is sue as it is estimated annually cats kill up to 100 million animals, with small mammals making up 70% of that total.

It is estimated that 250,000 bats are killed by cats every year; however since research into this subject area is scarce, this figure is believed to be a massive underestimation. However, bat carers can agree with the serious impact caused by cats, since 30% of all casualties they receive are believed to have been as a direct result of cat attack; the typical evidence usually in the form of punctures/tears to the wing membrane.

The primary aim of my research was to develop a method, which was fully optimised, to ensure maximum results, to test swab samples from injured and perished bats in order to detect if domestic cat DNA was present. This in turn could then potentially lead to the better quantification of cat predation on British bat species. Also, the research could help with establishing methods for management and control of the predation, for example as a guide for cat owners regarding what time of day to avoid letting their pet outside.

To ensure I gained maximum possible sample yield, across locations throughout the UK, I took to social media to enlist the help of bat groups and carers to ask for their assistance in swabbing the wings of any casualties they received. I created a webpage (http://thebatcatproject.weebly.com/ ) with details about the project and a form to fill in where people could register their interest and get involved. With thanks to Bat Conservation Trust and bat groups nationwide I received an overwhelming number of people who wished to participate!

To all registered volunteers, I dispatched a swabbing kit which contained: instructions on how to optimally swab bat wings, gloves to minimise contamination risk, swabs, and a prepaid envelope addressed to the University for sending back samples. These kits were posted out during March/April so they were with bat carers for the bat season.

Once the basic procedures of the method had been established, I optimised stages to ensure the process was efficient as possible.  For example: testing two different swabbing techniques to see which had a higher DNA recovery, and also testing different annealing temperatures during Polymerase Chain Reaction (PCR) to see which gave a greater yield of target DNA.

When it came to analysing the received samples from bat carers, all samples underwent successful DNA extraction and amplification- so this showed that the method worked and was reliable!

Next, through a process called melt curve analysis it is possible to look at results and distinguish between present species- since different species have different melting temperatures of DNA fragments. The average melting temperature of domestic cat DNA was calculated, and it was therefore assumed that samples which had a temperature of equal to or greater than contained cat DNA.

The final results of my study showed samples, which could be assumed to contain cat DNA, and therefore my developed method worked! Hopefully as research into this area continues, more samples can be analysed and the impact of cat predation on British bat species can be more comprehensively understood.

Research into cats as predators of bats is still being carried out at Manchester Metropolitan University, and it is still possible to get involved! Their website http://bat-research-mmu.weebly.com/ gives information on the project and details of other bat research going on at the institution.