Species of the week- 18

It’s been a truly hectic couple of weeks at uni, and it’s not looking like its going to ease off until the Easter break. I’ve taken some time off this weekend to get out, do some birding, find some new insects, and write this blog! It’s about a species that I’d been wanting to see for ages, and last week, saw my first. I’ve yet to find one for myself though…

The species I’ve chosen this week is a striking, and truly fascinating little spider, the Spitting Spider: Scytodes thoracica! Thanks very much to Will Hawkes (website: https://www.willhawkesphotography.com/) for finding this spider, showing it to me, and letting me use his amazing photos!

Wills pic

The Spitting Spider is a completely unmistakeable species! It is unique in many ways: firstly, it has only 6 eyes (the vast majority of spider species have 8), secondly, it’s the only spider in Britain with this colouration, and finally, its method of prey capture is amazing!

The Spitting Spider doesn’t move very fast, so can’t outrun its prey. It also doesn’t make a web. What it does do is creep up to its prey and squirt it with a venomous, sticky, silk-like substance, fired from its chelicerae at a range of around 10mm (pretty impressive when you consider the spider has a body length of 3-5mm!). It even waves its chelicerae from side to side as it squirts out the substance, in order to completely cover its prey, ensuring that it is gummed down. Prey consists of a variety of very small invertebrates, such as small flies. The Spitting Spider also uses its long-range weapon to ward off attacks from larger spiders.

Wills pic 2

Due to its small size and slow movements, Scytodes thoracica is no doubt under-recorded. That said, this species appears to be genuinely quite uncommon. Wills record looks to be the first one in West Cornwall! It is only found in and around houses, and has a distinct southerly distribution bias. Here is a link to the Spider Recording Scheme website for extra information, and a distribution map: http://srs.britishspiders.org.uk/portal/p/Summary/s/Scytodes+thoracica

I hope you’ve enjoyed reading about what must be one of Britain’s coolest Arachnids. Keep your eyes peeled, they could be living right under your nose!

 

February pan-species additions

This year, I’m trying to see 1000 species new to myself in the UK. I’m finding it a huge undertaking, but managed to stay ahead of schedule in January at least, with 98 additions. February was a worse month for pan-species lifers, but I still managed 67 new species. This means that for January and February together, I’m almost exactly on target! Here’s a summary of the new things I managed to find from across all the groups.

Algae: 6 new species found in February, all seaweeds (marine algae if you’re trying to sound scientifically respectable). That brings my total for the group to 30.

Lichens: 5 new species this month, bringing my group total to 17. I’m still not really making much headway with the group.

Fungi: 4 new species, taking my total to 108. Struggling on slowly.

Bryophytes: Now here’s a group I’m making some headway with! 30 new species this month, taking my total to 178. This month included some really nice species, some of which are shown below.

 

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Bartramia pomiformis
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Cephaloziella turneri
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Phaeoceros laevis

 

Vascular Plants: 3 new species this month, including Fumaria bastardii. Well, it was quite hard to identify… That took my total to 871.

Molluscs: 3 new species this month, taking my total to 101. These included the shelled Slug Testacella maugei, and the introduced Snail on sand dunes Theba pisana.

 

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A cute baby Testacella maugei

 

Bryozoans: 2 new species, taking my total to 3. Membranipora membranacea (Kelp Bryozoan) and Alcyonidium diaphanum.

Annelid Worms: 1 new species. That took my total to 13.

Arachnids: 1 new species, the Linyphiid Drapestica socialis. 76 my new total.

Myriapods: 1 new species, taking my total to 50! Cylindroiulus nitidus.

Crustaceans: 3 new species, including the Codworm Lernaeocera branchialis from a fish dissection.

Hymenoptera: 1 new species, bringing my total to 67.

Coleoptera: 3 new species, bringing my total to 220. These included the Carabid Asaphidion curtum.

 

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Asaphidion curtum

 

Diptera: 2 new species, including the Cranefly Tipula rufina seemingly ‘in off’ at the beach in Falmouth to take my total to 89.

Moths: 1 new species added, Dotted Border. Total now 483.

Birds: 1 new species, the Hume’s Leaf Warbler on Portland. 254 birds now seen.

So there we go, I’m just about managing to keep on track! With 83 new species needed in March however, I may leave myself some catching up to do when the insects appear in the summer.

 

 

 

 

Species of the week- 17

The species I’ve chosen this week is something completely different to anything I’ve written about before, it’s Velella velella, otherwise known as the By-the-wind-sailor. It is in the phylum Cnidaria, (along with jellyfish and anemones), but is itself a colonial hydrozoan. This means that each By-the-wind-sailor is actually composed of many small organisms, some of which are specialised to feed and reproduce, others of which are specialised for protection. Though there are other colonial hydrozoans, the By-the-wind-sailor is unique enough to be the only member of its genus globally. Here is one of many By-the-wind-sailors which were washed up in the Penzance area following recent high winds.

 

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Velella velella

 

Velella velella is unusual in that the colony has no control over where they are travelling, their direction of travel changes with the wind, which blows their sail-like structure. Some By-the-wind-sailors have their sail running diagonally across the ‘float’ from NE to SW, whereas others have their sail NW to SE. This means that under the same wind conditions, different individuals may drift in completely opposite directions! At first this might seem counterintuitive, but I believe (I haven’t done my research into this) that it’s a very clever adaptation. Relying purely on the wind as a form of locomotion is risky, and can cause mass strandings of V.velella. By having two forms which travel in opposite directions in the same wind conditions, it is ensured that whilst some individuals are blown towards land, others will be blown away. That’s my idea anyway…

V.velella can be found in all of the worlds oceans, but is rarely seen close to land. It feeds on whatever small organisms get caught by its dangling tentacles, which can include shrimps and young fish. In the UK, this unmistakeable species is rarely recorded away from the far Western coasts, nearest to the Atlantic Ocean. Here is its distribution:

https://species.nbnatlas.org/species/NBNSYS0000178601#overview

The recent strong Westerlies have caused many NE to SW sailed By-the-wind-sailors to wash up on the Cornish coasts. These individuals will have been blown North-west from the central Atlantic Ocean. The strong westerlies haven’t just been bringing Velella velella to our shores, but rare birds too! Today, a cracking 1st winter Bonaparte’s Gull (from North America) turned up at Helston boating lake, and an American Herring Gull was reported further West! I suspect flocks a Ring-billed Gulls to be reported over the coming days. It could be a good week of birding… Here are a couple of phonescopes of the Bonaparte’s Gull from earlier (off-topic but it’s a beauty).

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