14.11.18 - Great Merrible

My first return to Great Merrible since 12.05.18. On that occasion I well remember having to beat a retreat - unstoppable sneezing and eyes streaming so that I couldn't focus on anything, the hayfever forced me to give up. This trip was much more fun - autumn colours and a pleasant temperature. I concentrated on looking for springtails in decaying wood. This turned up a few Pogonognathellus longicornis and a large number of Lepidocyrtus lignorum:




One piece of wet wood literally broke up in my hand and deep inside I found Neanura muscorum. This is regarded as a common species but is my first record for VC55:



This species has no furca - a springless springtail:




Great Merrible:

Katiannidae

Family Katiannidae

Genus Katianna: www.collembola.org - Katianna

To the best of my knowledge there have been four "species" of Katiannidae recorded in the UK. All seem to be associated with the horticultural industry and to have been imported from Australasia:

Katianna (nr) australis (Photo: Mark Horton):




Katianna (nr) schoetti (Photo: Edward Nurcombe):




Katiannidae genus nov.1 sp. nov. (with striped back):




Katiannidae genus nov.1 sp. nov.2 (with orange/red back):




Genus Sminthurinus: www.collembola.org - Sminthurinus
This is a very difficult group with nearly 100 described "species". Badly needs a thorough taxonomic revision.

Sminthurinus aureus is a very common terrestrial springtail, less than 1mm long. It is particularly abundant on the underside of fallen leaves in autumn (as are other globular species). As the names suggests, it has an overall golden colour with no clear banding. Sminthurinus aureus has the 'small abdomen' (the animal's "tail end") wholly fused, while other UK Sminthurinus have a visible division between segments 5 and 6. The fourth antennal segment (ant4) is not subdivided.



Female:




S. aureus comes in a variety of colour forms with varying degrees of dark pigment, e.g. form ochropus:



The entire Sminthurinus aureus group badly needs a taxonomic revision. A good example of this is Sminthurinus reticulatus. Although very similar to S. aureus,S. reticulatus is distinctively patterned with 3-4 transverse bands on the dorsal abdomen plus dark lateral bands which are discontinuous around the posterior end of the abdomen:



However, there is some confusion about the "true" Sminthurinus reticulatus (which DNA evidence supports as a separate species), and Sminthurinus aureus form reticulatus. The differences are said to be:

Sminthurinus reticulatus: transverse abdominal bands are the same dark colour as the lateral bands.
Sminthurinus aureus form reticulatus: transverse abdominal bands are paler than the lateral bands.

There are also reports about differences in the arrangement of the ocelli on the eyespot:

Sminthurinus aureus group (including form reticulatus): Ocelli C and D are distinctly smaller than the others (ABcdEFGH):


Sminthurinus reticulatus: Ocellus C is absent (ABdEFGH):


I have not yet been able to confirm this by observations.

Sminthurinus elegans form ornatus

Small (to 1mm) golden springtail with characteristic patter of four dark longitudinal bands on the abdomen - in this form the typical midstripe of S. elegans is lacking. Found in leaf litter and low vegetation in almost all terrestrial habitats, preferring drier areas than S. aureus.

Sminthurus viridis is a relatively large greenish or yellowish brown springtail reaching 3mm in length. The fourth antennal segment (ant4) is divided into 18 subsegments:


There are two variants of this species. Sminthurus viridis ssp. cinereoviridis has two spots on small abdomen:


In the ecovariant nigromaculatus of S. viridis, three spots are present: https://www.collembola.org/images/stach/1956/Sminthurus-viridis-1956-J-Stach-Poland-PlateXXXII-Fig3.jpg There are supposedly difference in chaetotaxy of the setae on the subcoxa of the third leg, but I have found it impossible to image these. Steve Hopkins was reluctant to accept nigromaculatus as a separate species. As a dyed-in-the-wool taxonomic lumper, I wouldn't disagree. Frans Janssens calls it "Sminthurus viridis ecovariant nigromaculatus", which is said to be associated with sandy areas, heathland, moors, heather, etc.
 

16.11.18 - Leicester Botanical Garden

I went back to Leicester Botanical Garden looking for male Entomobrya nigrocincta (no luck), but while I was there I found some interesting specimens. I started by sampling from a south facing Rosemary hedge (this meant I spent the rest of the day reeking of Rosemary, which was nice except that it makes me think of roast lamb). This turned up huge numbers of Entomobrya multifasciata, but also some other interesting species, Katiannidae genus nov.1 sp. nov.:



and Katiannidae genus nov.1 sp. nov.2:




I then moved on to the clump of Ivy that had yielded the lone female Entomobrya nigrocincta. Once again I found large numbers of Entomobrya intermedia, but this time also a few Entomobrya multifasciata (which was a bit worrying). There were some more Katiannidae genus nov. but the most striking finds here were a number of Jordanathrix nr superba and quite a lot of the biggest Dicyrtomina saundersi I have ever seen - huge beasts!




I will be making future visits to the Garden to keep looking for Entomobrya nigrocincta and to study the Katiannidae genus nov. further.

Fascination and Frustration in Leicester

I was recently sampling at the Leicester Botanical Garden when I found a springtail which has turned out to be equally fascinating and frustrating. I was sweeping Ivy (Hedera helix) and this was producing large numbers of Entomobrya intermedia, but as soon as I saw this banded springtail in the tray I immediately thought Entomobrya multifasciata. However, after getting it home and looking more closely, it didn't look right:





Identification of Entomobrya is based on dorsal pigmentation patterns, and this has been shown to be generally reliable for UK species, although there is some variation from juvenile stages to adult forms, and the occasional worn specimen can be rather pale and difficult to determine. This one seems to be an adult female Entomobrya nigrocincta, and that's where the problem lies. There are currently no UK records for this species. Male E. nigrocincta are unmistakable - ginger with a wide dark transverse band, but females to look similar to E. multifasciata except that the band on abd5 is split into two spots (continuous in multifasciata and th2 is paler than the other segments. I think this is E. nigrocincta but the possibility remains that it could be a variant E. multifasciata. There are two solutions to this problem, DNA barcoding, which is beyond my means - or find a male! I've been back to resample twice so far and have not been able to find any more specimens, male or female. The Ivy bush continues to produce large numbers of Entomobrya intermedia but I have not found and Entomobrya multifasciata there, although they are present elsewhere in the Garden. I'm convinced to that this is Entomobrya nigrocincta but I can't prove it, which is fascinating and frustrating.

So what's going on? Originally from the Canary Isles, Entomobrya nigrocincta has been turning up across Europe over the last decade (GBIF data):



This is a Mediterranean species which is moving north. The Leicester Botanical Garden has a large collection of Mediterranean plants so it's not hard to guess how this species arrived. It's not the only springtail which is headed our way - Entomobrya unostrigata is also coming. As we lose montane species as the mountain tops get too warm for them and they run out of altitude we gain species adapter to warmer climates. It's all change in the springtail world - but then, it always has been, with species moving north and south in response to warmer and cooler climate interludes.


My thanks to Peter Shaw for his help with this specimen.

05.11.18 - Shady Lane Arboretum

With only a short time available we took a quick trip out to Shady Lane Arboretum. I didn't do a lot of sampling but looking under fallen leaves on the wet grass was productive. There were lots of adult Dicyrtomina minuta, but initially I hesitated over these specimens. However on reflection, I think these are juvenile D. minuta:




Lepidocyrtus lignorum was also abundant (predominantly pale with faint traces of blue pigment on the head, thorax and legs; scales present on the legs and ant1+ant2, no scales on ant3+ant4 (c.f. L. curvicollis), eyepatch roundish (less elongate than other species):




The trickiest (for me) specimens to identify were a number of Isotomids. Frans Janssens kindly identified these as Isotomurus but also helpfully pointed out Arne Fjellberg's Pictorial key to Nordic Isotomurus (2007) on the Collembola.org website. Having worked through this I am confident that these specimens are Isotomurus unifasciatus:
i) Dark median line with diffuse lateral patches.
ii) Dark pigment on legs and sides of abdomen extends to the dorsolateral patches (c.f. I. palustris) (above).
iii) Frontoclypeal area bluish (c.f. I. graminis):

27.10.18 - Leicester Botanical Garden

On a fairly inclement day I decided not to venture far afield but just pop down the road to the Leicester Botanical Garden. This site has surprisingly (to me) high biodiversity and not overlooking my local patch turned out to be a very good decision. I started by looking under fallen leaves, something which has been very productive in recent weeks. Surprisingly, all the leaves lying on grass turned out to be springtail-free, but when I started looking at leaves lying on a clay soil border I hit the jackpot. Dicyrtomina saundersi was abundant:



but interestingly, I also found several Jordanathrix nr superba. This is significant as this is only the second locatiion I have found this species at, so now we have two dots on the map!




At that point it rained hard, so we retreated to the tropical greenhouse (where we found some interesting spiders, but that's a whole other story). Beating Ivy yielded abundant Entomobrya intermedia, but also something very interesting (new species alert!), which I plan to write about in future after the record has been confirmed.