Dicyrtoma dorsosignata (specimen), Netherlands

Last week, I accidentally documented a springtail species never reported before in the Netherlands:

The species was identified as Dicyrtoma dorsosignata by Frans Janssens (https://www.collembola.org/). Frans passed on the observation to Matty Berg. Matty is a professor at the Vrije Universiteit Van Amsterdam, and the leading expert on soil fauna and specifically springtails in the Netherlands. In a recent interview, when asked who else is structurally finding, identifying and researching springtails: "It's just me".

Whilst Matty agreed with Frans' species ID based on my photo, he still wanted to formalize it as a new addition to dutch fauna by trying to collect a specimen. As I had no idea that it was a special observation during the photography, I had returned the live specimen to the garden.

Last Saturday, Matty came to our home, to try and find a fresh specimen. This post discusses results and is written in honor of his work.

One thing I was eager to learn is how he finds and collects specimens. It turns out to be simple, yet innovative and extremely effective. A large white tray is used to catch them, the white being a useful contrast to see the subjects. Method 1 to fill the tray is to heavily shake plants and bushes whilst keeping the tray under it. Method 2 places piles of dry/rotting leafs from the lawn on a filter, and then shaking the filter heavily, so that the subjects fall in the tray beneath.

As I saw the tray filling up, I cringed at how I didn't think of this earlier. We're in an urban garden, in December, yet there's tons of stuff in the tray. Springtails, but also spiders, crickets, net-winged insects, all kinds of stuff I wasn't expecting. The method is so obvious in hindsight, as it is obvious that I'm not an entomologist. The only thing against this method is that it's disruptive, it displaces almost anything living on the plant. This makes sense for the purpose of research, which needs to be effective, yet for photography subject selection I probably would be a bit more selective.

The next part is innovative. Each time a tray was inspected, we'd typically find many springtails, yet only 3-5 globular springtails, which is what the target was. How do you collect such a tiny creature? Here's how:

https://images3.persgroep.net/rcs/jxLctFq3qZQAa1KomxU5uw9JVwk/diocontent/69958945/_crop/0/0/293/298/_fitwidth/763?appId=93a17a8fd81db0de025c8abd1cca1279&quality=0.8

With this self-made air tube, Matty gently sucks at the end of the tube in his mouth. On the other end of the tube is a small compartment, where they get stuck. Simple as it is, it is a very fast and touch-free way to isolate a springtail without damaging it. When the compartment is full, it's placed in a test tube.

Surprisingly, no magnification tools are used at all, not even a magnifying glass. Just from the creature's profile and the way it mildly shines in daylight, Matty has a pretty good idea of what it is. A sign of experience. The above process was repeated for some 90 minutes. Matty was to do actual detailed inspection of the specimens collected back home, using a microscope. One day after his visit, he sent me this:

Orchesella cincta: 13
Orchesella villosa: 1
Pogonognathellus flavesecens: 1
Entomobrya multifasciata: 145
Heteromurus major: 5
Isotomurus maculatus: 2
Sminthurinus elegans: 2
Sminthurinus alpinus : 1
Parisotoma notabilis: 5
Proisotoma minuta: 1
Entomobrya lanuginosa: 1
Dicyrtomina ornata: 132
Dicyrtomina saundersi: 43
Dicyrtoma fusca: 11
Dicyrtoma dorsosignata: 1

This is next level trolling. So, out of 364 springtails collected, just bloody ONE is Dicyrtoma dorsosignata. And it's at the end of the list. What a cliffhanger.

These microscope photos are by Matty, published with his permission. Note that I increased the contrast. They show different angles of the single Dicyrtoma dorsosignata specimen. Whilst I don't yet understand the key system, apparently the closeup of the furca shows characteristics unique to Dicyrtoma dorsosignata.

And that closes this chapter. It's been fun and educational, gratitude to Frans, Matty and Arp for their help, education and excitement.