Pill Woodlouse Armadillidium vulgare?

[JRsbugs]

Hi, when about to post the thread my computer shut me down for automatic updates! So, here we go again,

I didn't measure it but thought it was too big for the normal Woodlouse, but then read they can grow quite large. Mine was at a guess 17 to 19mm stretched out, I think they can get to that size so I just assumed it was a very old one, had a leg or two missing. It did roll up for a start when I tried to lift it off the pot, but when I put it on some paper for further pics it had trouble staying upright. After being on it's back it could only roll to it's side, it took several attempts to get it to stay on it's feet when I helped it.

Janet

[Jason Green]

Hi Janet

*finds it *

I will go for same genus, different species...

Isopoda > Armadillidae > Armadillidium depressum (D. depressum) - Pill woodlouse

Here's Why:

• 1. Better colour match (plain)
• 2. OK for size

RE the rescue: He probably wasn't playing um... ball, as he maybe felt under attack... - Unfortunately they don't always realise we're trying to help them!!!

Just my thoughts... you're probably right though!!

EDIT: Pudsy has put A. vulgare to your Pill...

Take care,

Jason

[JRsbugs]

Hmmm, veeery interesting! It certainly looks a possibilty! I had read there was only ONE Pill Woodlouse in the UK!

From a Gloucestershire Naturalists Society website:

"Armadillidium depressum. This close relative of the common Pill woodlouse, has a southwesterly distribution with Gloucestershire being on the edge of its range. It only rolls into a ball if absolutely necessary, preferring to cling to the surface on which it is found, as it is unable to tuck all its antennae and legs completely away. Found at eleven more sites during the year, it is certainly widespread in the county. The best place to see it is on the roadside wall of the Bisley Road Cemetery, Stroud, where it can be found in good numbers mixing with the next species."

It did seem to want to stay on the side of the pot, and wasn't keen to roll into a ball. So if it is, what is it doing in LINCOLNSHIRE! Lol!

Yes I had wondered if he wasn't playing ball for that reason, but surely they would roll up for defense? But if it is this species, it doesn't roll up unless absolutely necessary!

Hey, I think at nearly 4am I should be in bed!


Janet

[JRsbugs]

Oh I see, LOL!

[tcvarlh]

not an animal I've had much to do with, see 'em in the garden and that's about it, so I looked 'em up:

"Armadillidium vulgare live in family groups. The male and female gather food for the family. Usually, the male protects the family. In spring, the young make their own family group within 10 to 100m of the original family’s burrow.
When they are stimulated, they immediately roll up their body into a globe. This is an excellent defense from their predators such as centipedes, spiders and birds, as it protects sensitive organs.
They also exhibit thigmotaxis, a preference for being in contact with other objects. Their preferred habitat is in confined spaces under stones, litter and vegetation. A group of armadillidium placed in a dish will tend to form into a tight clump and move around together."

cute, rather taken with 'em.
I wonder if they have teenager problems?

[Acutipuerilis]

I'm not sure which it is, but A. depressum was recorded in Cheshire last year, so Lincs is possible.

[Pudding4brains]

Howdy,

Sorry, I had to leave this morning before Janet had her (this here) thread up. To keep things together I'll quote from the Glomeris thread where I had left this message:

Originally Posted by Pudding4brains

Yes - I had already found your images - phat critter that(!) - but ... Ahw ... the disappointment!

No I'm afraid your animal is indeed a positively enormous Armadillidium vulgare and not the A. depressum I was rooting for.

WAB used to "have" a nice set of excellent images in one of the threads but the forces that be in their endless wisdom decided to kick those out as they were hosted off-site, thus achieving precisely what they proclaim to be their reason for banning images from other sites in the forum: A broken and now useless thread. Somehow they missed the point that it's okay to make a new rule to avoid this, but that subsequently enforcing such a rule on old threads is a bit ... well ... "silly".

You'll find some (not quite as nice) images of A. depressum on insecte.org. The animal is much 'wider' and 'flatter' and has a much more conspicuous "nose".

As for the distribution: The images/thread with the A. depressum that WAB used to have (the thread has disappeared too ) were from a garden in Lancaster - I looked it up at the time and it looked like there was a somewhat isolated area around the Lake District or so with a few records, but with a species like this such may very well be due to lack of recognition skills or lack of woodlice recorders altogether.

From France there seem to be tales of the species expanding it's range lately, so it might well be that changing conditions provide more opportunity for it to spread and survive. I'm certainly hoping to record it for the Netherlands one of these days - it's on the "look out for" list anyway

But all that is about A. depressum which Janet's animal is not.

Size is a bit of a gliding-scale issue with Woodlice as the are born as very tiny versions of the adults and keep on shedding/moulting (an hence growing) all their life, so every now and then under very favourable conditions you'll get a specimen that has survived for the longest time, was well fed and healthy and has reached an astonishing size. I think we're looking at one here

Although I tend to be quite sceptical on "big" size estimates I tend to believe this one (give or take a few mm) - the animal just looks it too (while they grow the habitus slightly changes gradually and some morphological recognition features take on more extreme/mature forms.

The A. vulgare I find (not all too common in my neck of the woods, even if by far the commonest Pill Bug) are usually no bigger than 12-14mm - and those I would consider "extremely large" already; most 'biggies' are in the 10-12mm range. Literature for our areas lists them mostly as up to 16mm, but records from Italy etc will have them at up to 21mm.

Age ranges vary greatly between the species with some reaching some 20 years or so, but from the top of my head A. vulgare would usually reach about 2-3 years - assuming that's correct, due to the size it is to be expected that this one might well be 3-4 years. A really respectable granddaddy this one (yes, it's a male).

As for some of the other remarks - even in Britain there's bound to be a decent handful of "Pill Woodlice" species. There should be a number of exotics found mostly in greenhouses etc, such as Armadillo officinalis and some smaller "rolling" species like Buddelundiellidae or Reductoniscus sp., but even of the genuinely native and "big" ones there is probably these (sorry, no hard data at hand):

"True" Pill Woodlice (Armadillidiidae)

• Armadillidium album (small 5-6mm, whitish species found on the beach)
• Armadillidium depressum (huge 20++mm, 'southern', mostly blackish, distinctively protruding and wide frontal triangle (='nose').
• Armadillidium nasutum (large ~13mm (south-Eur=20+mm), 'southern'/synantropic, males blackish, females clearer and more coloured, distinctively protruding and narrow frontal triangle (='nose').
• Armadillidium opacum??? Not sure you have it. (medium-large 12mm, similar to A.vulgare but slightly more colourful, frontal triangle flat but pointed in center of top margin and with two notches behind it)
• Armadillidium pictum (medium 8mm, colourfully patched brownish-yellow, hind corner of epimera on 1st segment not cut off)
• Armadillidium pulchellum (small 6mm, colourfully patched brownish-yellow, hind corner of epimera on 1st segment is cut off)
• Armadillidium vulgare (large 16mm (south-Eur=20+mm), males mostly blackish, females clearer and colourfully patched, frontal triangle flat and wide)
• Eluma purpurascens (large 14-16mm?, somewhat violetish-brown with usually two clear bands, eye of one single ocellus)

I just noticed FE also lists a Armadillidium speyeri which is the first time I even see the species name Will check on that later.

"Fake" Pill Woodlice (these roll up somewhat too)

• Cylisticus convexus (large 14mm (south-Eur=??mm), Porcellio-like headstructure, long uropods sticking out from behind)
• Porcellium sp. Not sure you have these (medium-large, mostly Porcellio/Trachellipus-like but rolling into an incomplete ball

There's bound to be some more ... but hey ...

Some images I had already uploaded to WATW at some point:
Armadillidium pictum (and some A.vulgare)

Hmmm ... it seems I'll have to prepare some more uploads

Later! Arp

[Jason Green]

More marvelous montages!!!!!

I've just looked up my previous posts to find out which species my Pill was, and it too is A. vulgare - ID'd by you, Pudsy!!

[Pudding4brains]

Originally Posted by Jason Green

ID'd by you, Pudsy!!

Well, I'm not going to argue with that ID than

[Jason Green]

Or me. That Pudsy is quite knowledgeable. You should see him if you need something ID'd