19.05.18 - Charnwood Lodge

The rarest habitat in Leicestershire is undoubtedly the small patch of acid heathland at Charnwood Lodge. On the east side, there is an even smaller patch of Sphagnum bog with a unique flora, so being in the vicinity, this was an obvious place to look for springtails.

I started by sampling from the ancient lichen-covered Charnwood rocks and from vegetation such as Bilberry and Cross-leaved Heath. However, it was a warm and very dry day so this was unproductive. I then moved on to sampling Birch trunks (also unproductive) and then on to beating the Gorse, which produced a large number of springtails, mostly Entomobrya nivalis:


and a few Entomobrya nicoleti:



After this, I moved on to sampling the wet Sphagnum. This contained lots of springtails, including Pogonognathellus longicornis, Orchesella cincta, Tomocerus minor and a few Lepidocyrtus cyaneus - no scales on the legs or the antennae and interocular macrosetae present:




However, the star of the show was Heterosminthurus bilineatus, my first record of this species from VC55:

12.05.18 - Great Merrible

Great Merrible is one of my favourite Wildlife Trust reserves and the site is relatively under-recorded across the board (including springtails, obviously!). We visited on a very pleasant spring day, warm and dry.

I sampled under logs and here I found Tomocerus minor, Isotomurus pseudopalustris and Lepidocyrtus lignorum but the most abundant species was Dicyrtoma fusca, all var. rufescens at this site:




I aslo sampled from mossy Ash trunks and here I found Orchesella cincta, Pogonognathellus longicornis, Entomobrya albocincta and Entomobrya nivalis. However, this sample also produced a surprise. When I opened the pot, the lid was crawling with small, golden globbies. I assumed these would be Sminthurinus aureus but examinations showed that they were in fact Deuterosminthurus pallipes form repandus (the yellow form of this species, the purple form is just "Deuterosminthurus pallipes"):



These gobular springtails are noted for appearing on vegetation (including tree trunks) from spring to autumn. These individuals represent mature adults looking to perform their mating dance on a leaf. Both sexes come in both colour forms and freely interbreed. In the week of this observation we have had several reports of this species from VC55 so I guess this is their time - look out for them.

Heterosminthurus

Genus Heterosminthurus

• Heterosminthurus bilineatus - moderately common (see below).
• Heterosminthurus claviger - rare, a montane species found in pennine grasslands (similar in appearance to H. bilineatus, see below).
• Heterosminthurus insignis - moderately common (a uniform yellow colour).
• Heterosminthurus novemlineatus - very rare (yellow in colour with several (usually nine hence novemlineatus) longitudinal bands of dark pigment).

I am not currently aware of any Heterosminthurus records other than Heterosminthurus bilineatus from VC55.


Heterosminthurus bilineatus:



In H. claviger the lateral stripes are connected posteriorly unlike H. bilineatus (here) which has separate lateral stripes:

H. claviger males (but not females) have peculiar paddle-shaped interocular setae.


The fourth antennal segment (ant4) is subdivided into about six subsegments:



Ocelli:

Deuterosminthurus

Deuterosminthurus species all have a distinctive arrangement of ocelli on the eyespot:

• 3 large ocelli in upper row
• 1 small central ocellus
• 4 lower "normal" ocelli:

• Deuterosminthurus bicinctus (moderately common) - yellow with two large patches of violet pigment on the dorsal side. 
- All setae on the outer side of the tibiotarsus of the third leg (leg3) are about the same length. - In males, long specialised backward-pointing setae are not present at the posterior end of the sixth abdominal segment. - In females, the setae surrounding the anus are all of similar thickness.
• Deuterosminthurus pallipes (common, widespread).
- All setae on the outer side of the tibiotarsus of the third leg (leg3) are about the same length. - In males, long specialised backward-pointing setae are not present at the posterior end of the sixth abdominal segment.  - In females, the setae surrounding the anus are all of similar thickness (c.f. Bourletiella hortensis). 
• Deuterosminthurus sulphureus (moderately common) - uniformly yellow.
- Some of the setae on the outer side of the tibiotarsus of the third leg (leg3) are longer than others. - In males, long specialised backward-pointing setae are present at the posterior end of the sixth abdominal segment. - In females, the setae surrounding the anus are of different thickness. - The mucro is spoon-shaped.

Deuterosminthurus bicinctus:
The nominate form of D. bicinctus is easy to recognize, but there is also a yellow form, Deuterosminthurus bicinctus form flavus (N.B. head is paler than the body).

Possible(?) candidates:




Characteristic arrangement of ocelli:





Deuterosminthurus pallipes:


Bourletiella hortensis is very similar to Deuterosminthurus pallipes but can be distinguished based on the location of the apical filament of the inner claw (unguiculus or empodium) (Bretfeld, 1999):

• Bourletiella hortensis - filament is subapical (also, body shape is quite globular)
• Deuterosminthurus pallipes - filament is apical (body shape tends to be more elongated)

Deuterosminthurus pallipes is a small gobular springtail noted for appearing on vegetation from spring to autumn. These individuals represent mature adults looking to perform their mating dance on a leaf. The distinctive features of this springtail are the long length of the antennae (nearly as long as the body) and the distinctive arrangement of ocelli on the eyespot:




Male antennae distinctly longer (relative to body length) than females:





The other notable thing about this species is that it occurs in two colour forms, purple and a yellow form called Deuterosminthurus pallipes form repandus. This form is easy to confuse with Sminthurinus aureus (which has somewhat shorter antennae, different arrangement of ocelli). Males and females occur in both colour forms, frequently in mixed populations, and freely interbreed:






Frans Janssens says that the angular body shape seen in the specimen above represents an immature individual where the gonads are not fully mature.

All setae on the outer side of the tibiotarsus of the third leg (leg3) are about the same length:

In females, the setae surrounding the anus are all of similar thickness:

12.05.18 - Lyddington Meadow

It would be difficult to call Lyddington Meadow the jewel in the crown of the Leicestershire and Rutland Wildlife Trust, but that doesn't justify the extent to which it has been ignored over the years in terms of biological recording. Lyddington Meadow covers 1.3 hectares (3.2 acres) of semi-improved grassland, subject to occasional flooding. The plant species found, such as Great Burnet and Meadow Foxtail, are typical of grassland in river valleys. The springtails? Well no-one knows, because no-one has ever looked! (Until now.)

The River Welland runs alongside the meadow forming the county border between Rutland and Northampton, and a recently dried up channel runs off this, which I thought was well worth sampling. Unfortunately, this didn't turn up any springtails. Next I tried beating the vegetation (mostly grasses) but that didn't generate any springtails either. Finally I turned to the Hawthorns lining the boundaries of the site. Here, finally, springtails were abundant. However, when I took a close look they turned out to be exclusively Entomobrya nivalis:



So there we have it, Lyddington Meadow. Not the most species-rich patch in VC55 but definitely worth a second look later in the year (adds this to rapidly growing and now improbably long list of sites to revisit).

05.05.18 - Tugby

For various reasons I haven't managed to do any collecting for a few weeks but I was able to put that right on Saturday at a wooded site near Tugby. I sampled from under logs and by brushing tree trunks (mostly moss-covered Ash). Orchesella cincta was by far the most abundant species in both samples with large numbers of adults and juveniles present as well as smaller numbers of Entomobrya nivalis.

Under logs I found Tomocerus minor in good numbers and a few Dicyrtomina minuta, a species I have not encountered previously in VC55:



What was more surprising were good numbers of adult and juvenile Dicyrtoma fusca var. rufescens - a leucistic form of D. fusca with dark ocelli on a pale eyepatch. This is the first time I have seen this variant:

Dicyrtomidae Identification Guide

Members of the Dicyrtomidae are characterised by having a very short fourth antennal segment. Key identification features for each species are described below.

Family Dicyrtomidae
Genus Dicyrtoma
Dicyrtoma fusca

Genus Dicyrtomina: In Europe three distinct species are currently recognized: D. minuta, D. ornata and D. saundersi. In the USA, these are lumped into one species, D. minuta with the variants as subspecies forms:
Dicyrtomina minuta
Dicyrtomina ornata
Dicyrtomina saundersi
Dicyrtomina violacea

Genus Jordanathrix
Jordanathrix nr superba



Dicyrtoma fusca is a small globular springtail (1-2mm) which varies considerably in colour from a dark maroon red to a paler yellow form, the mottled patterning also varies. The head and the body are always the same colour:





The above (commonest) forms are known as Dicyrtoma fusca var.1. There is also a much rarer melanistic dark (almost black) form, Dicyrtoma fusca var.2 (not known from VC55), and a leucistic form with dark ocelli on a pale eyepatch, Dicyrtoma fusca var. rufescens:








Dicyrtomina minuta
A common species found throughout Britain. The name is of this species is confusing - some D. minuta specimens grow bigger than D. ornata. Typically pale gold and less pigmented than D. ornata (dorso-anterior pigmentation lacking in particular). Similar to D. ornata, there is a long, narrow pigment streak on the rear of the abdomen.



Frans Jannsens says that a diagnostic character to distinguish D. minuta from pale D. ornata is the colouration of the interocular+interantennal area:
D. ornata: a distinct midfacial pigmented band.
D. minuta: this band indistinct to absent (often only 2 pigmented dots remaining, 1 interocular + 1 interantennal):




Dicyrtomina ornata
The historical records for a number of groups of springtail are hopelessly confused. These include Entomobrya intermedia/nivalis and also Dicyrtomina ornata/saundersi. This species has been frequently identified by the large rectangular patch of dark pigment on the abdomen, but this species is very variable in pattern and colour. Pale juvenile specimens (<1.5mm) are difficult to separate from D. minuta (see above). Key features:

• Dorsal (in addition to lateral) abdominal pigmentation
• No sharp colour change along the length of the antennae
• Dorsal colour of the 6th abdominal segment (the dorsal anal valve) is dark (c.f. Dicyrtomina saundersi, below):

Dicyrtomina saundersi
Key features:

• Distinct colour change at the joint of sections 2 and 3 of the antennae
• Dorsal colour of the 6th abdominal segment (the dorsal anal valve) is light:

Dicyrtomina violacea
Resembles Dicyrtomina ornata with a solid patch of dark pigment at the posterior end of the abdomen, but unlike D. ornata the abdomen has an entirely purple ground colour with lighter orange reticulations. In D. violacea the head is lighter than the body, whereas in Dicyrtoma fusca the color of the head is similar to the body. Seemingly rare in the UK with very few records.







Jordanathrix nr. superba
This species resembles but is distinct from Dicyrtomina superba from New Zealand. Thought to be a relatively recent introduction to the UK, first recorded about 10 years ago. This species has a patch of dark pigment on the abdomen and is similar in appearance to D. ornata but the colour of the eyepatch is much paler (with dark ocelli) than the all-dark eyepatch of D. ornata:

Orchesella Identification Guide

The genus Orchesella is characterized by:

• Body scales absent.
• 6 antennal segments with ant1+2 both subdivided. However: one or both antennae may be reduced in length due to damage, and the first instars have only 4 antennal segments hence fail to key out.
• Head with 7 + 7 or more eyes, postantennal organ absent.

There are five species on the UK checklist but only two are commonly encountered:

Orchesella cincta "Belted Springtail"
One of the commonest springtails in Britain, reaching ~4mm. Key feature: dorsal surface of abd3 fully pigmented (this can be important in preserved specimens).



Juvenile (<6 antennal segments):



Orchesella villosa "Shaggy Springtail"
Common and widespread, one of the largest springtails reaching ~5mm length. Pigmentation patterns on the body in patches and are variable but ant2-ant4 mostly dark(c.f. O. cincta). Long, backward curved macrosetae on abdomen (although these can be lost):


Bald specimen:


Orange/yellow "knees":

 

 

Orchesella flavescens (rare) looks similar to O. cincta but the broad transverse bar is on abd3 rather than abd4 as in O. cincta. In addition, O. flavescens has two lateral longitudinal stripes (c.f. O. quinquefasciata - 5 longitudinal stripes).