Dicyrtomina ornata, Heesch, Netherlands
Our garden, little as it may be, has been a valuable source of extreme macro subjects thus far. Yet this being November, the insect world is bracing for winter. Except perhaps for...winter insects.
If it wasn't for our new laser-pen-obsessed cat forcing me outside, I'd had no business there. For no particular reason I figured to do another gaze in the mini pond that I had been ignoring for weeks. These are just buckets of water dug into the ground. I pretty much let nature figure out what to do with this habitat.
Eye ball almost meeting the water line, I normally look into the water. To see if anything moves down below. Being this very close to the water line, I noticed something tiny sitting on the surface itself. Arthropod-like but too small to the naked eye to decipher anything else.
I carefully poured it into a petri dish and took it inside. I had a quick look in the viewfinder and rejoiced: a springtail!
I know they exist. They are likely the most numerous of any insect species in our garden, yet thus far I've never consciously seen one, let alone capture one. Probably because I wasn't trying very hard, yet also because of their small size. They are easy to overlook and even if detected, standard macro photography (1:1) would struggle to capture them in detail, depending on which species it concerns:
Both subjects are springtails. The small blob is a mere 0.25mm, the "giant" 6mm. The particular species on my photo has these dimensions:
- body length (head to butt): 1.7mm
- abdomen at widest point: 0.8mm
- width of head, without antennae: 0.4mm
As seen by the naked eye:
Capturing this tiny subject is challenging in multiple ways:
- As I needed a diagonal angle into the petri dish, I went without the macro rail. Handheld 5:1 macro photography is...interesting.
- Despite the subject being so little, depth of field at 5:1 is still too tiny. It's about 0.25mm. So you can't get the entire subject in focus. Increasing aperture is no solution. This particular lens is useless beyond f/5.6, f/8 tops.
- Resolving power. Whilst I'm generally very happy with this lens, clearly it's unable to resolve fine details at this magnification. The eye, as an example, would be about 0.08mm in size yet still make up hundreds of pixels on the D850's high resolution sensor. This glass, and probably most glass, can't resolve details that fine. It's not a problem for the typical subject (0.5 - 1cm), but this is another league.
Luckily, the subject was strangely compliant. It's alive and unharmed. It didn't respond to my intense focus light and heavy flash. This is the best I was able to produce on day 1. I'll share a few more day 1 shots later. They are far worse, yet I'll use other angles to discuss characteristics of the species.
On day 2, I actually tried to stack this subject. Results of that are also still to come.
As for species ID, likely this is Dicyrtomina ornata. One of 3 winter species looking somewhat similar (the others are Dicyrtomina saundersi and Dicyrtomina minuta), based on this most excellent resource:
The decisive key in this case is the subject having a uniform antennae color, which sets it apart from Dicyrtomina saundersi.
Update: anatomy discussion here:
Stacked image from day 2:
Dicyrtomina ornata is one of the small "globular" Springtails (Collembola) from the family Dicyrtomidae. Within its distribution range it is easily found in leaf litter from late fall to early spring. It can be confused with other species of Dicyrtomina, most notably with D. saundersi.