What did you eat today?

For most people its a difficult and uncomfortable subject but what if I told you that I could figure out where you’ve been and what you’ve eaten based only on your poop. That’s right I said it, poop. So, yeah there may be a nicer way to say it, such as faeces, but lets be honest, it doesn’t make the subject any less uncomfortable or any nicer, so why beat around the bush? Anyway, back to my original statement, like most people I like my privacy, so when I first heard about this concept, I was a little uneasy until I continued reading.

Example of a pitfall trap, August 2008. Photo: Ross Winton, Flickr, Creative commons

I mean, I have thought about the fact that poop can tell people what I’ve eaten, but where I’ve been? That’s just creepy but that’s what scientists are doing. Particularly Stephane Boyer, Robert Cruickshank and Stephen Wratten, however their reasons are much less creepy. You see, they want to collect the poop from animals that usually feed on things like insects to find out what that animal has eaten and where its been. This may not sound cool or interesting to most people but from a conservation point of view, it is.

Many people only see insects, spiders and worms as creepy crawlies, a group to be afraid of. They are very rarely seen as things that need to be protected because they lack that cute and cuddly factor. New Zealand has many native insects that the native birds feed on and native worms that the native snails feed on. The natives may survive without their normal food but chances are that some will need to adapt, and some may die if they are not able to eat other things.

Giant native New Zealand snail, August 24 2014. Photo: Shellie, Flickr, Creative commons

Collecting insects and spiders can be quite difficult and can lead to the death of them due to the trapping methods used. One of the common methods of collecting crawling insects and spiders is what is known as a pitfall trap. The insects walk along the ground and fall into the trap that has previously been dug into the ground. The trap is filled with liquid and the insects will drown. The is an effective method of collecting insects but destructive so not suitable for collecting rare insects. Some insects and worms can be difficult to collect as well such as the native earthworms in New Zealand. Some of these worms can burrow deep into the soil so aren’t found when the soil is sampled.

Stephane, Robert and Steve have figured out a way to look at insects and gather information about them without killing any insects or spiders. This is where the poop comes in. Now as you know, what goes in also goes out, so when an animal such as a kiwi eats a spider, parts of that spider will be in the kiwi’s poop. If that kiwi also eats a weta, a cockroach and a worm before the spider comes out, then parts of these will also be in the poop of the kiwi.

Based on other research involving seals, Stephane, Robert and Stephen have figured out that the poop of animals like the kiwi, can be looked at and from this they can figure out what the kiwi has eaten. Just by looking at this poop, scientists can find new species, figure out if rare species are present in a particular area and also figure out how many of one species there are in a particular area.

Brown kiwi looking for food, December 8 2007. Photo: Eric Carlson, Flickr, Creative commons

Every living thing contains DNA, and it is this that scientists use to identify the insects in poop. Being able to identify insects is beneficial for conservation, particularly for things such as the native New Zealand land snail. Different strategies have been created so that identification is easier. These strategies involve looking at all of the DNA in the poop using special chemicals called primers and a special method called PCR. The primers and PCR increases the amount of DNA. Stephane, Robert and Steve came up with three ways in which primers can be used to figure out what the insects are.

A tracking device can also be used so that if a possible new species is found in the poop then the area can be set with traps and the new species found. The tracking device would be planted on an animal that has eaten the targeted species, such as a kiwi, and the movements can be tracked to find out where the new species may be found.

Using a tracking device is also helpful as it means that certain animals can be used over others, for example if you wanted to collect soil dwelling insects then you would attach a tacking device to a kiwi rather than a bat.

So next time you go for a walk in the bush, or step in poo think about all that information that lies beneath your feet and what can be done with this information.


The author Stephanie Hillis is a postgraduate student in the Master of Science taught at Lincoln University. She wrote this article as part of her assessment for ECOL 608 Research Methods in Ecology.

Boyer, S., Cruickshank, R. H., & Wratten, S. D. (2015). Faeces of generalist predators as ‘biodiversity capsules’: A new tool for biodiversity assessment in remote and inaccessible habitats. Food Webs, 3, 1-6.

Leave a Reply