Friday, 13 September 2019

Recent Unusual UK Collembola Records



An update of the UK list which features two particularly notable additions. The first of these is Entomobrya intermedia, an extremely common species but not one which was not recognised by Steve Hopkin. Since we know know that it stands up under DNA, it has been formally added to the list. The other is the globally invasive Desoria trispinata, a species I have not yet recorded but seems to be spreading rapidly and needs to be on our radar.


Shaw, P., & Trewhella, S. (2019) Recent Unusual UK Collembola Records – Entomobryomorpha and Poduromorpha. British Journal of Entomology and Natural History, 32 (3) 217-230. https://pure.roehampton.ac.uk/portal/files/1192939/BJENH_Shaw19.pdf
Abstract: We report substantial updates to our understanding of the distribution of nine species of UK Collembola (orders Entomobryomorpha and Poduromorpha). We note four species omitted from the main UK key (one very common) and we note the rediscovery of five species in the UK after >50 years. Three of these were previously only collected in the UK by Richard Bagnall in the 1930s.
 


Thursday, 5 September 2019

Progress on the VC55 Springtail Atlas

I have to admit that my springtail work has been on the back burner over the last month for a number of reasons. Summer is a good time to have a break and recharge the batteries, although the difference between the drought summer of 2018 and the wet August of 2019 is dramatic. What I have done recently is to take a look at the VC55 springtail records and do some data visualization using the R platform. Firstly, I mapped all previous VC55 springtail records (n = 560) to the end of 2018 (black squares) (all data copyright Leicestershire and Rutland Environmental Records Centre), then overlaid the records added in 2019 (blue triangles):


click for larger image

This is encouraging because although there are a few other people sporadically recording springtails in VC55, I have specifically targeted most of my efforts this year at extending the geographical coverage into new areas. This is particularly important because so much biological recording defaults to the regular honeypots. It is easy to see this by merging the dataset into a heatmap of observations:


click for larger image

I can make this a little more informative by breaking down the records into families and overlaying this on the heatmap:


click for larger image

The problem with this is that the data set (~600 records) just isn't large enough to say very much about the whole County, or to put it another way, the density of records is too low for good geographical coverage. In addition, there's another problem. I'm not aware of any systematic springtail recording which includes negative results, i.e. the absence of species as well as the presence. We know (anecdotally and from the heatmap) that recording effort is not equally distributed, but the limited dataset means that we simply don't have accurate geographical coverage. Resource limitations mean that there will probably never be widespread systematic recording of springtails, so my approach to this problem has been to adopt a benchmark species to infer recording effort. Orchesella cincta is said to be the most widely distributed species in lowland Britain, so I have adopted this to infer geographical coverage:


click for larger image

Thankfully (for my theory), the O. cincta data fits the heatmap pretty well, so validating this proxy for our atlas. What comes next is clearly getting off my backside and getting back out in the field :-)


Acknowledgements:
  • All data Copyright Leicestershire and Rutland Environmental Records Centre.
  • Data visualization performed using the R platform, v. 3.6.1 (R Core Team (2014) R: A language and environment for statistical computing. R Foundation for Statistical Computing, Vienna, Austria. http://www.R-project.org).
  • J. Cann for assistance with data visualization.


Thursday, 1 August 2019

Springtails in July

Pogonognathellus longicornis

Pogonognathellus longicornis

Although July is pretty much the low point in the springtail calendar, the contrast between this year and last year is stark. While we've had the hottest ever day, we've also had plenty of rain and moderate temperatures. Out and about I've been finding springtails pretty much everywhere, recording the following species at the number of sites shown:

Entomobrya nivalis: 7
Deuterosminthurus pallipes: 4
Entomobrya nicoleti: 4
Orchesella cincta: 2
Entomobrya multifasciata: 1
Isotoma viridis: 1
Pogonognathellus longicornis: 1
Tomocerus minor: 1

Springtails about, but nothing of great interest. However, this has to count as a good July for springtails.


Saturday, 20 July 2019

13.07.19 - Charnwood Lodge

Although Charnwood Lodge is the most heavily recorded site in VC55, I've only made one serious trip for springtails there previously, so it was past time to go back. There was a lot of the routine stuff I'm seeing everywhere at present - Deuterosminthurus pallipes, Pogonognathellus longicornis, Tomocerus minor. Notably, I also found a lot of juvenile Orchesella cincta, and some spanking new adults, a species I've not been seeing for the past few months now making a return:

Orchesella cincta

The highlight of Charnwood Lodge is the acid heath, and grubbing around in the Sphagnum produced a number of Isotoma viridis, which although not unexpected, I think is a new species record for this site:

Isotoma viridis





Saturday, 13 July 2019

30.06.19 - Owston

Owston Springtails


In spite of temperatures over 30C the previous day, springtails were around in the damp bits of Owston. Dicyrtomina ornata reappears in its usual spot but Entomobrya nivalis remains by far the most prevalent species I'm seeing at the present time.




Friday, 5 July 2019

Prepare for lift off!

Pogonognathellus longicornis


It is diagnostic of Pogonognathellus longicornis that this species is able to tightly curl both an4 and ant3 due to their flexible annular structure (c.f. Tomocerus, which is only able to curl ant4 slightly). Frans Jansens made the interesting comment on this photo that this individual is considering jumping and has curled ant4, presumably to avoid damage. This behaviour has not occurred to me before and I need to investigate this further next time I find some curly-wurlys to play with.

Tuesday, 2 July 2019

09.06.19 - Cribb's Meadow

Springtails of Rutland


Many springtails taking their summer break, but Deuterosminthurus pallipes and Entomobrya nivalis particularly abundant.



Tuesday, 25 June 2019

15.06.19 - Saddington Reservoir

Saddington Reservoir Springtails

A short collecting trip filling in a gap on the map. Clockwise from top left: Orchesella cincta, Entomobrya nicoleti, Entomobrya nivalis, Pogonognathellus longicornis.

Wednesday, 19 June 2019

Willowsia

There are two confirmed species of Willowsia in the UK. They resemble shiny, iridescent Entomobrya.

Willowsia platani is an aerial species resistant to desiccation and is found on trees and in buildings. This species has a variable pattern of pigmented bands and spots on the dorsal side (some specimens are much paler than those shown here):





Willowsia platani has characteristic leaf-shaped scales:



The mucro has two teeth and there is a spatulate tenant seta:



The empodium is about two-thirds the length of the claw:




In contrast, Willowsia buski is a plainer-looking species. The scales are a different shape, more triangular then W. platani. Photo by Philippe Garcelon:

Willowsia buski