Hi, I’m Zoe! I’m a third-year Geography BSc student at the University of Lincoln and am currently on a placement with My Square Metre, helping Ed with some biodiversity-related projects. I recently wrote a post about terrestrial invertebrates and how I am using pitfall trapping to investigate their population on some of My Square Metre’s sites. This week, we headed back to the sites to collect these traps and have an initial look at what we had caught.
Collecting the traps
On Monday, we headed back to the site to collect all the traps which had been set and left out for four days, to catch any ground-dwelling terrestrial invertebrates that were passing by the area. I was nervously hoping that the traps had been successful, and expecting to see a mix of spiders, beetles and true bugs, alongside some slugs.
We first collected the few traps which I set out in My Square Metre’s existing wildflower meadow, just to have a brief look into the types of invertebrates that are benefitting from the planting which has already been done. All three traps in the meadow were successful, which was a good start! From initial examination, these have caught small bugs, beetles and spiders.
We did initially have some hiccups to iron out as the test tubes we had planned to transfer the samples into were smaller than the volume of liquid that we had in the traps, and many of the invertebrates we had caught were too small to accurately sort them on-site. After a quick trip to the local shop, we solved this by using small water bottles to store the samples temporarily until we were back at the office.
On My Square Metre’s other site, which has not yet been planted with wildflowers, we had seven traps to find. The grass and other vegetation were much shorter in this field, making the traps easier to find – great for us, but not so much for the local wildlife. Six of the traps were successful – the final trap was compromised by a mole digging a molehill into the side of the cup. These traps had also caught plenty – beetles, spiders, millipedes and lots of tiny insects, as well as a lot of small slugs. After making sure we had labelled all the samples correctly and collected all our equipment to leave no trace, we headed back to the office to process the samples.
Preserving the invertebrates
As I’m going to be identifying the invertebrates that we caught, it was important to make sure that they were preserved properly. Back at the office, I carefully sorted through each sample with some tweezers, ensuring all the invertebrates were moved into a labelled test tube of clean preservative and any debris was discarded. This took a while, as small bugs can look surprisingly similar to pieces of dirt or vegetation, but it was an important step to make identification easier for my future self. I also moved the slugs into their own test tubes, so that their slimy mucus didn’t stick to any of the other invertebrates.
Over the coming weeks, I will be working through all our test tubes, using a stereo microscope to identify the invertebrates. Some species are easier to identify than others – there are over 650 species of spider alone in the UK, for example! However, even just identifying the family or genus of an invertebrate can provide enough data to compare changes in trends over time. I am now looking forward to getting stuck into analysing these samples and sharing plenty of microscope photographs of different beetles and spiders with the My Square Metre team.
