Nets, Trowels, Traps & Tracks on the Maps
Hanging out with the team collecting invertebrate fauna.
Another drizzly day broke over Fowler’s Bay, and for a while we thought it wasn’t going to be all that productive. Today I was with the “Invert” team – the crew looking for any land based invertebrates, whether they had 6, 8 or a 100 legs. Much like reptiles, these critters actually like it warm, sunny and not that windy… So pretty much the opposite of what today was… The scientists; Ben (Wasps), Jess (Spiders), Erin (Wasps – but an entirely different family to Ben’s) and Ethan (Moths) were all a bit suss on the weather, so they pretty much decided today would be a job-doing and exploratory day.
First we set up a pitfall trap on the edge of a salt lake just out of town. Pitfall traps are pretty cool; imagine a miniature wall that ground-dwelling invertebrates cannot climb over, with both directions leading to a plastic cup buried up to its lip in the ground. Anything running, walking, crawling or hopping along the ground meets the wall, turns to follow it, and sooner or later tumbles straight into the bucket, unable to get out. Once set up they are left for as long as needed, checked a few times a day to see what is in there.
Next, we crossed the highway and cruised into the Yalata Indigenous Protected Area to a mostly pristine native grassland site to set up another kind of bug trap; a ‘Malaise Trap’. This one looks a lot like a tent at first glance, only with three walls not four. It also has a low end and a high end. Flying insects fly into it, hit the back wall, then fly up to the top of the high end, through a small gap, and into a collection jar. Scientists then take them out as needed.
Now, both these traps have a chemical solution put into them which kills and preserves the insects without destroying their DNA. This is extremely useful for scientists to be able to collect, study, transport and store them, but we did have an interesting conversation about ethics. Even if they are just “bugs”, I wanted to know if any of the scientists had any issues with just how many things could get killed by these traps.
We discussed the purpose of specimen collecting (how they are used & what they teach us), alternative non-fatal ways of sampling some researchers are trialling, the fast lifespans & lifecycles of some species (male inverts often only exist to breed once they are adults, so only last a few weeks anyway), how population size or frequency might change people’s thoughts on this, and whether inverts even have any pain receptors, amongst other topics. We’ll do a lesson or two on ethics when I get back I reckon.
After that, it was back in the cars and off into Wahgunyah Conservation Park. In between setting up two more Malaise traps – one in mallee woodland, one in dryland tea tree scrub – we found time to have a go at ‘sweeping’ a few different flowering plants we came across. Instead of using brooms though, this sweeping involves big nets (like grown-up, well built versions of the butterfly nets you might have had as kids). You pass them back and forth over, next to and through the foliage and flowers a few times, then loop them onto themselves so nothing can escape. Then you carefully transfer any target species you’ve got into collector jars.
We got the wasps Erin was looking for, the native bees that Ben’s wasps parasitise (but not the wasps themselves) and a few other odd looking flies, wasps, beetles and bugs that they knew their colleagues would be interested in. Jess and I also caught various spiders of the ground, including a Peacock Spider relative! Then the rain kicked in so we jumped back in the cars and spent an hour and a bit driving around dirt tracks in the middle of nowhere, using GPS to mark promising sites to return to when the weather was better.
Just as we found a spot to turn around, the sun briefly popped out and team leader Ben called a snack break. While we were admiring the cliff top scenery, Jess looked at the ground and found the exact type of spider (a poorly known family called the Segestriidae or ‘Tube Webs’) that she’s currently studying. We joined in and soon found a few other specimens nearby. As we were doing that, Ethan found a Case Moth caterpillar – by chance also exactly what he is studying at the moment as well. Suddenly what had been a day with little expectations had turned into a success. Together we found him over a two dozen ‘cases’ – most old, but a fair few with living caterpillars in them. Then to top it off I chanced upon a trapdoor spider door!
As you might expect, the drive home this afternoon, chatting to Jess & Erin about how their childhood interest in 'bugs' lead to careers in STEM, was a happy one.