Isotomurus maculatus

The text at NatureSpot implies that the inverted crown-shaped mark on the rear abdomen is distinctive - I could just about make this out on some of mine but it was a bit of a stretch on one or two (though it was easier looking at the photos than the specimens). The AIDGAP Collembola key doesn't specifically refer to this mark, but does refer to and illustrate the "distinct pattern" and the crown-shape highlighted at NatureSpot isn't really discernible in that illustration. These seemed to key satisfactorily to Isotomurus maculatus, although I stumbled at the final couplet as I would say that some of the pigment is concentrated in a vague dorsal stripe. However the two alternatives (palsutris and plumosus) both have much more distinct mid-dorsal stripes than my individuals.

These four appeared to be attracted to light (LEDs on a sheet) as they were concentrated around the lights in the middle of the sheet rather than randomly around the edge of the sheet as if they'd merely accidentally landed on the sheet, as sometimes seems to be the case with springtails. The sheet was on a chalk stone hardstanding (fairly recently laid) on an arable margin.

4x Isotomurus maculatus, Wendling Beck Environment Project (Norfolk, UK), 12th October 2022

These one also appeared on a sheet where I had LED lights to attract moths and other nocturnal insects. This one was in the middle of an arable field, the only close structure being a telegraph pole, so not exactly the synanthropic site associated with human activity that this species is often supposed to be associated with.

Isotomurus maculatus, Wendling Beck Environment Project (Norfolk, UK), 30th October 2022

This one was found in a pitfall trap.

Isotomurus maculatus, Wendling Beck Environment Project (Norfolk, UK), betweeen 29th January and 3rd February 2023

Another one that appeared while light trapping for insects, though it's not clear if it was attracted to the light or landed on the sheet by accident.

Isotomurus maculatus, Wendling Beck Environment Project (Norfolk, UK), betweeen 8th October 2023