Mice mice, baby!

Last month I volunteered, along with some other awesome folk, to help out a fantastic PhD student (with Edinburgh University) with her field study on wood mice (Apodemus sylvaticus) in Callendar Wood near Falkirk. Amy Sweeny was looking at how nutrition affects the relationship between parasite infection risk, the immune response of the mice, and also their reproductive success in the wild. To do this there were 4 experimental grids of traps set out in the forest, two of them were used as controls where no food was added and the other two were supplemented with high protein food pellets - lucky mice!

Toni, Chris and Amy in the field

Apodemus sylvaticus - The Wood Mouse

Humane Sherman traps were set overnight 3 times a week baited with bedding and food, and checked the next morning to see if we had caught any unwilling participants :) Along the way we met many of the varied characters of the wood, including the distinctly smelly but charismatic bank vole, the occasional shrew, frogs and even a wren! When we did catch a wood mouse we took the trap back to the field base where the mice were sexed, roughly aged, weighed, measured, microchipped and had a wee bit of blood taken to check for infection. They were also checked for fleas, mites and ticks which were removed, so many of the mice were released feeling a lot cleaner for their trouble. Some mice were randomly treated with anti-helminthic drugs which got rid of any parasitic nasties such as tapeworms that they might have had living in their gut.

If any of the captured mice were pregnant or showing signs of being so or lactating, they were gently released back into the wood to provide for the next generation :)

Bag of cuteness

Bank vole (smells like cereal and wee!)

Of course science isn't all flowers and rainbows as you may already know, and a sample of the mice in the study that had been recaptured at a later date were sacrificed in order to carry out dissections and find out more about the kind of parasites they carry and the effects of co-infection (infection with multiple different parasites). This study falls under the fairly recent term of 'wild immunology', where scientists try to find out how animal immune systems deal with threats in their natural wild environment. It is somewhat easy to look at the effects of just one disease or parasite under lab conditions with inbred mice that are genetically alike, but much more difficult with many unknowns in the wild because there is tremendous variation to consider which has a bearing on how well the animal fights these infections. Things such as age, life history, infection history (what diseases/infections they may have had in the past), habitat, reproductive history, and genetics are just a few of the variable that add to the complex nature of wild immunology! You can find out more information here.

I had a fantastically fun and educational time helping out with the study so many thanks to Amy and the team for the opportunity :)