A fly\’s most valuable butt.

Ok, here we go – fresh post that has little to do with Alaskan adventures from two years ago and a lot to do with Greek bears, their poop, and traces of their poop in fly bottoms!

After Alaska and six months of working as a GIS and environmental technician at the University of the West of England (a position which, by the way, is a big step-up from nanny, but equally enjoyable), I finally got a PhD studentship! Having done my BSc at UWE as well, I now am starting to feel I have entered deep into the belly of the beast and I am never getting out. However, I happen to like beasts, so that\’s absolutely fine by me.

What might also be true is that my amazing supervisor and other great people at the university got so fed up with me talking about how much I wanted to do a PhD on my bears in Greece (yes, my bears. I have claimed them now as their supreme leader and full time poop collector) that they just went \’ah, for the love of god, someone give this woman a studentship or she will never shut up\’. Not sure that\’s a 100% correct representation of how universities choose their PhD candidates, but there has not been a day where I haven\’t felt incredibly lucky to have been given the chance. So, before I get into the juicy technical bit, let\’s get one thing straight: Not a genious, just a very persistent bear enthusiast.

Ok. My project focuses on brown bear (Ursus arctos) ecological networks in both a habitat modelling and a field monitoring level. My supervisors and I are looking into novel, and more importantly, low-budget methods of modelling and monitoring large carnivore ecological networks.

So for a very large part of my research, I stare (and swear) at a computer and create habitat models. I assess the suitability of habitats for brown bears in Greece, and soon wolves and lynx too, and then I swear some more and create corridor models to predict how good habitats might be linked together. However, the harsh truth is, maps are just pretty pictures without any field data to back them up! So, the most exciting side of my project is field season, where I get to frolic in the wild mountains of northern Greece and collect a lot of data to validate my maps. *very high-pitched noises of excitement, especially useful if you are trying to communicate with bats*

 

\”Why bears?\”, you may ask. First of all, why would you even ask that? One shouldn\’t need an excuse, but I will do it, just this once:

In ecology sometimes we need to look at the big things to see if everything else is doing alright too. Bears are classed as what we call an apex predator – they proudly chill on the top of the intricate food systems of their ecological communities, worried about very few other creatures other than, well, other bears and the occasional unwise human who decides to challenge them to unfair duals. Apex predators, I\’ll have you know, are extremely important – they are what we call keystone species – they have the very unique role of maintaining the structure and balance of  an ecological community, even in really small numbers. The best example for their incredible power to influence ecosystems is the dramatic changes that occured in Yellowstone National Park after the reintroduction of wolves. I can endlessly speak about this but my hero, George Monbiot, absolutely nails it in his TedTalk (this talk, by the way, has been one of the greatest influences and top inspiration for why I do what I do).

On top of that, bears are also excellent gardeners – who doesn\’t love a good gardener!? They turn over stones, fertilise the land, dig great big holes and break off branches – perhaps a little destructive as gardening goes, but ecosystems need an equal amount of chaotic events to their fine order. A bit like a child\’s bedroom, ecosystems struggle to stay tidy, but mess in healthy amounts just means that someone had a good time!

Bears are also pretty excellent fund magnets and offer themselves as the perfect flagship species – an ambassador for the entire ecosystems they inhabit. You don\’t easily get people excited about European red slugs, this is not a fair world…

So, back to my initial point, bears are pretty great.

Equally, in ecology sometimes we look at tiny things to find out about the big and fierce. And here is where they fly butts jump in to save the day! Invertebrate-derived DNA (iDNA) is a monitoring method where invertebrates are used a a medium for monitoring another organism. Say, if a tick feeds on a ferret, you should be able to find ferret DNA in the tick too – good luck de-ticking ferrets by the way… Makes sense?

Disclaimer: If you are some sort of invert enthusiast, a fly nerd, or anything else cool like that, and you are interested in learning more about it, first of all, read this post (duh!), but also message me and I can get you a list of the coolest bedtime reads.

So, why am I so excited about invertebrate gut content? Why not just find the bloody animals instead – they are big enough, right? Nope. Bears, wolves and lynxes, the three large carnivores in southern Europe, are very elusive creatures and tracking them can be very challenging and very costly. On top of that, most monitoring methods are suitable for only one of the species. Bears are usually tracked using radio collars, lengthy hair trap networks and scat surveys. Scat surveys, which are somehow becoming my favourite thing in the world. I love me a fresh bear dropping. I am classy like that.

 

Guess what? Bears shit in the woods. They also shit on forestry roads, in cherry fields, big open valleys and paved roads – not as selective as you\’d think when it comes to bowel movement. This makes this great heap of goodness pretty hard to spot. Most scat surveys in Greece are done following the forestry road network, which is extensive, but not representative necessarily of the entire bear society! Shy bears and non-dominant individuals might be missed out completely, seasonal diet changes might drive them away from these roads, and quite often spotting skills vary between surveyors. Not everyone is a prime shit-spotting queen.

So, wouldn’t it be wonderful if we could magically perform unbiased scat surveys that scan larger areas, just by catching flies?

I decided to go on a 3-year PhD journey to find out (amongst other things hopefully)! Here is how it works:

1. It all starts with a fresh and steamy heap of bear shit. Here is one they prepared earlier:
2. Flies are gross and eat shit.
3. We catch those scat-eating flying bastards. Previous studies have shown that flies disperse over a radius of 2km per day and can carry amplifiable host DNA in their guts for about 24-96 hours. We created a 2×2 grid network and sampled in the middle of randomly selected grids using the following highly sophisticated equipment (clearly illustrated in with the drawing skills of a 5 year-old below): a mosquito net, a plastic Tupperware, some stones and rope to keep it all together, and the stinkiest fly bait I could possibly hope for. Seriously, that thing smells like the contents of a box containing cheese, dirty socks, vinegar, eggs and a hint of sick, all sealed and left to brew for five years. I am pretty popular back home.

 

4. Then I kill (all murdering at this point has been approved by an ethics committee, so fly sympathisers out there, back right off) and preserve the flies and carry them in the UK… in a suitcase (I also, by the way, had to acquire a permit for that)! Other women carry hairdryers, I carry dried-up flies.

5. We then dissect the fly to isolate the abdomens (by the very intricate method of chopping their butts off), use primers to target specific hosts, in this case bears and soon lynx and perhaps one day also wolves, extract the DNA and run PCRs.

So, at the moment, I am spending an awful lot of time in the lab learning how to do all the things I previously thought only super clever people are allowed to touch. I am so out of my comfort zone, I sometimes feel like I live in a parallel universe.

 

So every now and then I have to remind myself to see the bigger picture:

This is the first time this is being done to track mammals in a temperate climate. I am hoping to collect enough presence/absence data from the flies, to eventually be able to verify the habitat suitability and corridor models. I am very excited to be working on this project, not just because I love tracking bears (if you hadn’t picked that up already), but because of the potential of this monitoring method. The diversity of applications is immense! We are currently looking at targeted individuals, but iDNA can be adapted to suit a very large amount of studies. People have demonstrated its use in creating mammalian biodiversity libraries by extracting all the genetic material and then identifying species with the use of metagenomics (writing as if I know what I\’m talking about..). There has even been a small success in looking for microsatellites, allowing for individual differences between animals of the same species. It is pretty fascinating how far a fly bottom can take you…