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James McCulloch

@jamesimcc.bsky.social

540 followers 190 following 67 posts

PhD student in genomics at the Wellcome Sanger Institute/University of Cambridge. National recorder for springtails. Evolutionary biology, entomology, taxonomy, natural history... https://www.sanger.ac.uk/person/mcculloch-james/

www.sanger.ac.uk

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James McCulloch @jamesimcc.bsky.social · Jan 21

Send me records: I am excited to be taking on the role of national springtail recorder. I have huge shoes to fill, but I hope to continue the progress Peter Shaw made in understanding the taxonomy and biology of the UK's #springtails.

www.brc.ac.uk/scheme/colle...

Orchesella flavescens, one of the UK's largest springtails. It's an elongate springtail, with long antennae, often with a differing number of segments on each antenna (but with a maximum of six). It can be identified by the pattern consisting of parallel longitudinal dark lines running the length of the abdomen, contrasting against a paler ground colour. This is a relatively scarce woodland species.

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James McCulloch @jamesimcc.bsky.social · 6d

366 days ago I started my PhD at the @sangerinstitute.bsky.social. No better time to publish my profile on the Sanger website ⬇️

www.sanger.ac.uk/person/mccul...

I tend to have my taxonomic hat on when posting here, but there is a bigger picture!

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James McCulloch @jamesimcc.bsky.social · Aug 24

(S. trinotatus has these setae, while bimaculatus does not)

James McCulloch @jamesimcc.bsky.social · Aug 24

Finding hyper-specific details like this to back up an identification never fails to make me smile!

James McCulloch @jamesimcc.bsky.social · Aug 24

I will finish by sharing this beautiful and romantic video of Sminthurides courtship. One of my favourite things!

www.youtube.com/watch?v=p7IV...

🧵7/7

Weiße Wasserkugelspringer (Sminthurides aquaticus) beim Paarungsritual 💕

YouTube video by Dominik Grimm

www.youtube.com

James McCulloch @jamesimcc.bsky.social · Aug 24

Finally, this is the tiny Sminthurides bifidus. These are synanthropic aquatic springtails found on the edge of glasshouse water features and fish tanks. The dorsal black marking is quite variable.

The males are smaller and have antennal clasping organs to grasp the females in courtship! 🧵6/7

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James McCulloch @jamesimcc.bsky.social · Aug 24

This is Seira domestica, a slender springtail almost never found outdoors (in the UK, at least). Lepidocyrtus have similar iridescent scales but have 2 teeth on the mucro (furca apex), not 1.

When assembled, this will be the first reference-quality genome from the subfamily Seirinae! 🧵5/7

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James McCulloch @jamesimcc.bsky.social · Aug 24

This is Sminthurinus igniceps, a relative but less distinctive. It can be told from dark S. aureus by having a head paler than the body, and from S. domesticus by having mostly orangey antennae.

This species is also synanthropic, but seemingly moving out more into the wider countryside. 🧵4/7

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James McCulloch @jamesimcc.bsky.social · Aug 24

Despite its spots which seem to glow among the woodchips, S. bimaculatus is very similar to S. trinotatus. You need to look for a pair of hairs called subapical ventral setae on the dens, part of the springing organ (furca) that gives springtails their name. This arrow shows where they'd be! 🧵3/7

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James McCulloch @jamesimcc.bsky.social · Aug 24

This beautiful species, Sminthurinus bimaculatus, has been the British springtail I've most wanted to see. As with the other 3 spp., it's primarily synanthropic, meaning it's associated with human habitats like this flowerpot. 🧵2/7

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James McCulloch @jamesimcc.bsky.social · Aug 24

I've reached 100 British springtail species! This was helped by a recent glasshouse sampling trip, where I added these 4 species.

3 are now in the pipeline to have reference-quality genomes sequenced for the first time, by the @sangerinstitute.bsky.social. More info in the thread below! 🧵1/7

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Reposted by James McCulloch

KamilSJaron.bsky.social @kamilsjaron.bsky.social · Aug 16

We are excited to attending #ESB2025 find …
@arf-mln.bsky.social to chat about beetle genomics
@jamesimcc.bsky.social about sedges or springtails evolution
Sam Ebdon about distr. of dominance
Myself about diptera comparative genomics

And all of us to chat about any whacky reproduction #obscuromics

A slightly outdated group photo of the obacuromics group, at the tree of life programme, Wellcome Sanger Institute - so you know spot us at ESEB

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James McCulloch @jamesimcc.bsky.social · Aug 15

Yes, sorry for the delay!

Reposted by James McCulloch

Joss Carr @josscarr.bsky.social · Aug 5

I'm doing an online talk on 16/09 about my MSc thesis, which was all about iNaturalist data for invertebrates in the UK, and the alarmingly high proportion of it which 'falls through the cracks' due to data quality concerns. Please join if interested!

Link: www.eventbrite.co.uk/e/falling-th...

Falling through the Cracks: iNaturalist Invertebrate Records in the UK

Joss Carr discusses his MSc Research Project investigating the data quality of UK invertebrate records on iNaturalist.

www.eventbrite.co.uk

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James McCulloch @jamesimcc.bsky.social · Jul 23

While the data are thin for signata and flavosignata, it’s the case that minuta, saundersi & ornata can be found under the same log. Despite apparent morphological identicalness, there could be other reasons they don’t outcompete each other, e.g. physiological/metabolic adaptations to different food

James McCulloch @jamesimcc.bsky.social · Jul 17

That's exciting! I'm on the look out for springtail samples from across the world for a future project - I'll direct message you!

James McCulloch @jamesimcc.bsky.social · Jul 16

Now that we have a name for this springtail, it is much easier for us to monitor its spread, analyse its interaction with the ecosystem, identify its origins, and study its populations & evolution through the lens of genomics.

Read the full description here: soil-organisms.org/index.php/SO...

View of Entomobrya petri sp. nov.: A new species of springtail found in the British Isles

soil-organisms.org

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James McCulloch @jamesimcc.bsky.social · Jul 16

A huge thank you to @persmiseth.bsky.social for showing me a population of these springtails when I was visiting Edinburgh earlier this year; some of them then became the type specimens. Also, Alex McDermott-Roberts and @jaiiiiiii1.bsky.social for providing specimens/photos from elsewhere.

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James McCulloch @jamesimcc.bsky.social · Jul 16

While it appears similar to true E. imitabilis, described from a single Chinese specimen, the pattern of E. petri is unique. The chaetotaxy - the arrangement of hairs (setae) on different parts of the body - is also unique.

Click the Alt text on these images for explanations of what they depict!

A composite of illustrations of different body parts. Elements A and B show the dorsal and ventral pattern respectively; to the right of the dorsal pattern illustration is the chaetotaxy formula for the relevant body segments. Each of the five most taxonomically useful segments in terms of their chaetotaxy - the head, the 2nd thoracic segment, and the 2nd, 3rd, and 4th abdominal segments - has between 2 and 5 somewhat arbitrarily-chosen "compartments" with the formula detailing the number of macrosetae (the thickest type of "hair") in each compartment.

Element C shows the configuration of a small part of the manubrium - the basal part of the furca (springing organ). This is a combination of pseudopores (two in this case - the open circles) surrounded by a number of setae (four here).

Element D shows the shape of the "apical bulb" at the very tip of the fourth antennal segment. E. petri has a bilobate apical bulb.

Element E shows the foot and the dentation of the claw - one of the ways in which E. petri differs from true E. imitabilis beyond colour pattern.

Finally, element F shows the apex of the dens and the mucro (the other two parts of the furca other than the manubrium). The mucro of E. petri has two teeth and a basal spine which reaches the tip of the basal tooth.

This rather complicated looking figure provides the chaetotaxy (arrangement of setae (hairs)) for the taxonomically important body segments. These are the head, 2nd and 3rd thoracic segments, and 2nd, 3rd, and 4th abdominal segments (in order from A-F). The diagram of the head also includes the relative size and position of each ocellus which makes up the eye.

The dotted boxes delimit the "compartments" of each segment, which is how you get the standard chaetotaxy formula as given in the other figure.

This chaetotaxy scheme was first introduced by Jordana in his 2012 volume of the Synopses on Palaearctic Collembola, which covers the subfamily Capbryinae and tribe Entomobryini of the family Entomobryidae. The chaetotaxy of any of the members of these groups should, in theory, be able to be represented using this scheme.

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James McCulloch @jamesimcc.bsky.social · Jul 16

Formerly known as Entomobrya nr imitabilis, this morphospecies was first spotted in 2015. Since then it has appeared across the whole length of the British Isles - the type specimens were found on an Edinburgh gravestone. Where it has come from and how it has spread so quickly is a mystery...

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James McCulloch @jamesimcc.bsky.social · Jul 16

I'm so excited to share that this springtail, one that seems to have rapidly appeared in graveyards and gardens across the UK, now has a proper name: Entomobrya petri!

I hope this will be the first of many new species descriptions, allowing us to track our rapidly changing springtail fauna. 🧵⬇️

Soil Organisms Journal @soilorganismsj.bsky.social · Jul 16

📢✨ONLINE FIRST✨ New #collembola species found in the UK!

James McCulloch @jamesimcc.bsky.social National Recorder of Sprintails, tells the world about Entomobrya petri! 💚

Please REPOST 📢🪱🌱

soil-organisms.org/index.php/SO...

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Reposted by James McCulloch

Biological Recording Company @biologicalrecording.co.uk · Jul 16

James McCulloch (National Springtail Recorder) discusses the constantly increasing species list for UK Collembola.

British Springtails: How Many Species Really Are There?

James McCulloch (National Springtail Recorder) discusses the constantly increasing species list for UK Collembola.

biologicalrecording.co.uk

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James McCulloch @jamesimcc.bsky.social · Jul 15

That would be very useful - it'd be ideal to make sure I'm not missing any records! Thanks!

James McCulloch @jamesimcc.bsky.social · Jul 11

This coming Tuesday lunchtime!
I’m looking forward to talking springtails, speciation, and cryptic diversity.
Sign up! ⬇️

Biological Recording Company @biologicalrecording.co.uk · Jul 4

🔬 Coming soon: British Springtails – How Many Species Are There?
Join @jamesimcc.bsky.social to explore how genomes & citizen science are reshaping UK biodiversity.

www.eventbrite.co.uk/e/1359900281...

@royentsoc.bsky.social @fieldstudiesc.bsky.social @nbntrust.bsky.social @britentsoc.bsky.social

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Reposted by James McCulloch

Frank Ashwood @frankashwood.bsky.social · Jul 10

Yesterday we had earthworm cocoons, today I bring you springtail spermatophores!

Springtails, like many soil invertebrates, reproduce by a male leaving these structures (sperm-rich fluid on a stalk), which the female will sniff out and collect to fertilise her eggs. Romantic!

#SoilBiodiversity 🧪

A photograph of a springtail spermatophore: a thin transparent stalk with a glob of clear fluid on the top.

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James McCulloch @jamesimcc.bsky.social · May 24

Wow, that's a blast from the past!