COLLEMBOLA > ENTOMOBRYOMORPHA > ENTOMOBRYOIDEA > Entomobryidae > Entomobryinae

As previously noted, Entomobrya intermedia is often confused with Entomobrya nivalis as they are so similar, with the only visual difference being the pattern of the markings at the end of the abdomen. Distinguishing the species relies on determining whether the 'U' shape is complete. In Entomobrya intermedia, there are usually clear gaps between the bottom horizontal bar and the longitudinal lines, which is often described as having the corners missing. In Entomobrya nivalis the 'U' shape is effectively continuous, although often with a much thinner and/or partially broken bottom bar.

The problem is, that whilst the pattern is relatively easy to explain, in life it can be quite variable from one individual springtail to another, with some specimens having nice clear markings whereas in others they may be feint or worn.

As far as I'm aware, Entomobrya intermedia wasn't formally recognised as a separate species when the 'key' was compiled by Steven Hopkin back in 2007 even though some records go all the way back to the late 1800's. I could be wrong, but it looks like the two species may have been treated as variants as records only started creeping up in 2010 according to the NBN Atlas, steadily rising over the next four years with a comparatively enormous peak in 2015, then dropping down a bit before stabilising and then slowly reducing over the past couple of years. The total number of records nationwide at the time of writing is only just over 500 during the whole of that period.

Entomobrya nivalis has only a hundred or so more records than Entomobrya intermedia but, interestingly, follows virtually the same recording trend - clearly another example of under-recording given that the species is described as being extremely common and widespread across the country, "surely being present in every hectare on the map, except perhaps for the summits of the highest mountains".

Updated, Jan.25 (v.2)