Mediterranean False Widow - Steatoda paykulliana

13mm adult female Steatoda paykulliana

Mediterranean False Widow Spider  /  Eastern  False Widow  (Steatoda paykulliana)

Steatoda paykulliana is a Mediterranean species of False Widow that's not established in the UK, but does turn up here fairly regularly, as an accidentally imported species. 

Steatoda paykulliana typically grow to a body-length of around 8-13mm for females, and with a leg-span of up to 35mm. Males are usually smaller at 5-9mm in body-length.

Steatoda paykulliana is established throughout the Mediterranean. This spider find its way to the UK fairly regularly, hidden amidst imported produce, particularly grapes. This species has historically only been found living in the wild in England on a couple of very rare occasions, and this has always been a case of isolated specimens spotted during the warmer months of the year. These isolated cases are due to Steatoda paykulliana specimens arriving here as accidental stowaways, usually amidst imported fruit, and then escaping, or being released into the wild by the finder. There is no evidence available to substantiate any claimed reports of Steatoda Paykulliana ever being found established anywhere in the UK. 

Steatoda paykulliana is named in honour of the Swedish naturalist Gustaf von Paykull. With its dark black body, and often red markings, this is the species most likely to be mistaken for the far more venomous Black Widow Spiders of the Latrodectus genus, which are also not present in the UK, but do also very occasionally turn up in imported goods. The red markings on the Mediterranean False Widow can also be yellow, orange or white instead of red. However Steatoda paykulliana never possess the red hour-glass marking usually present on the underside of most Black Widow Spiders.

The bite of Steatoda paykulliana, as with other Steatoda species, can be moderately painful, but it is generally regarded to be of little or no medical significance to humans in most cases. Steatoda paykulliana, like other False Widows in the Steatoda genus, are not aggressive and bites to humans are very rare in the Mediterranean countries where Steatoda paykulliana are native. In laboratory conditions, during the 1960's & 70's when such tests were more socially acceptable, Steatoda Paykulliana have been proven to possess a venomous bite powerful enough to kill small mammals, including mice and even large guinea pigs!  (see page 26) LINK. The French INPN (The National Inventory of Natural Heritage) reports that in laboratory conditions Steatoda Paykulliana has also been proven to kill adult rats and cause temporary paralysis in rabbits. LINK

Nearly all Steatoda paykulliana specimens that arrive in the UK amidst imported fruit are juveniles. Due to their size it would be much harder for adult specimens to hide undetected. As juveniles the female specimens that arrive in the UK have no chance of turning up here in a gravid state, and therefore cannot reproduce and spread, unless by chance there happened to be juveniles of both sexes accidentally brought into the UK in the same shipment. Juvenile and sub-adult Steatoda paykulliana look quite different to the adult females and have annulated legs, tend to be brown in colour and often have cream coloured markings, making them easier to mistake for other Steatoda species that are established in the UK. 

The abdominal markings of Steatoda paykulliana are often referred to as resembling the shape of fish bones. As the female spider matures the abdominal markings change and take on the brighter colours. The pale crescent at the front of the abdomen typically changes from cream or white to yellow, then orange, and finally red as the female reaches maturity. At this stage the rest of the spider turns to a very dark black colour. Some female specimens may retain the yellow or orange band even through to maturity. Other specimens can occasionally skip the stages where the crescent is yellow and orange, and go straight from white / cream to red.

Often pictures of Steatoda paykulliana found in books only show the spider as a fully developed adult female, which obviously looks quite different from the sub-adult specimens that turn up in the UK as accidental stowaways amidst imported fruit. Adult male Steatoda paykulliana can look somewhat similar to sub-adult specimens. Adult males usually have orangey-brown legs, which are notably darkened at the joints, and a dark brown abdomen, which usually still displays the white / cream coloured fishbone markings. The tips of the male's pedipalps are slightly swollen and pointed in shape.

It's often reported that any accidentally introduced colonies of Steatoda Paykulliana would not be able to survive our winters in most parts of the UK, and that this would only change if our winters were to become milder in the future. However this is not true. Steatoda Paykulliana is winter-resistant and has been found at altitudes of 700m in West Bulgaria, where the winters are quite severe and the snow stays on the ground for some time due to the adjacent low mountains. Unless Steatoda Paykulliana evolves this species is currently not as adaptable to new and varying habitats though as Steatoda nobilis, which has thrived since being introduced to the UK from the Mediterranean. Steatoda Paykulliana requires more specific conditions to successfully breed. Steatoda paykulliana is a xerophile, thermophile species, so it requires warm, dry conditions, and it's not the cold of our winters that would kill it off in the UK, but our country is simply too damp for this species to successfully breed here in the wild.

Where I have found Steatoda Paykulliana, in Cyprus and southern Spain, the conditions were very hot and very dry, and the spiders were found hidden away in darkness beneath rocks on sandy soil at coastal sites. This xerophilic species seems to require hot, dry conditions with low humidity, where it builds its web low to the ground. The most obvious places that would appear to meet its needs would be within human habitations, and yet within its natural range Steatoda Paykulliana is usually found outside of homes. The eggs of Steatoda paykulliana are pale pink in colour and are wrapped up in a white egg-sac. The average number of eggs in an egg-sac is around 65. In their native range the young spiderlings hatch towards the end of summer. The newly emerged spiderlings are orange in colour and often display the pale fishbone markings on their abdomen. They may hibernate during the colder months before maturing at the start of the following summer. 

Could Steatoda paykulliana be established anywhere in the UK?

Currently no, Steatoda paykulliana is not established anywhere in the UK and has never been proven to ever successfully breed here either. The only Steatoda paykulliana that have ever been found in the UK have been isolated specimens. Due to the unsuitability of our climate I believe it's fairly unlikely that Steatoda Paykulliana will become established anywhere in the UK in the near future either. However, with Steatoda paykulliana regularly arriving in the UK as accidental imports it's quite possible that at some point in the future Steatoda Paykulliana could well adapt to the wetter climate of the UK, just as Steatoda nobilis has done. If Steatoda paykulliana was able to adapt then and it may eventually find parts of the UK that are suitable to its requirements, allowing it to become established here at some point. 

There have been occasional reports of isolated specimens of Steatoda Paykulliana being found living in the wild in the UK in the past. In 2008 the BBC featured an article about exotic spiders in the UK, and when discussing Steatoda paykulliana they had a quote from Stuart Hine, who ran the Insect Identification Service at the Natural History Museum. In the BBC article it was claimed that Stuart Hine reported Steatoda paykulliana were already established here in the UK back in 2008. He reportedly went on to say: "Now we have found it in Plymouth, and it looks as if it is here to stay".  LINK,  LINK 2. Stuart Hine has since been in touch with me (October 7th 2021) to clarify this situation, and it seems the press misquoted him and got their facts completely wrong. So although the occasional specimens may have been found in the wild here in the UK there is no proof Steatoda Paykulliana have ever become established anywhere in this country. Stuart did have one female Steatoda paykulliana specimen sent to him, that was found in a log pile in a porch from Bedfordshire. It went on to produce a viable egg sack.  LINK

There were also some speculative records from Kent, near a fruit import warehouse in 2008. Other sources claim sightings from Dorset, Milton Keynes, Plymouth and Tilbury Docks in Essex. Uksafari.com is one source incorrectly claiming that Steatoda paykulliana is established at Plymouth and Essex. According to Stuart Hine, who investigated the reported colony in Plymouth, sightings there have already been confirmed as a mistaken identification of Steatoda nobilis. The claimed colony at Tilbury Docks was reported to be around the site of a major fruit importer so this case may have been feasible at one time, and a small, short-lived Steatoda paykulliana colony might have existed there at some point in the past. However if any short-lived colonies did become temporarily established in the UK they clearly died off quite quickly. There was a claim of Steatoda Paykulliana having previously become established in a conservatory and outbuildings in Dorset back in 2017. Unfortunately, as with all these reported cases, there was no photographic evidence to substantiate this doubtful report and it could not be confirmed. -  LINK  In 2017 Stuart Hine did once write "Given the frequency that these come in on grapes from Southern Europe I have no doubt that it's just a matter of time before it becomes established".

It's not surprising that members of the public often confuse the common, widespread, and well established Steatoda nobilis with the imported Steatoda paykulliana, when the media regularly print images of the wrong species to accompany their news stories. In 2013 The Independent used a photo of a juvenile Steatoda paykulliana with a scare-mongering story they ran on Steatoda nobilis "invading a school" in Gloucestershire. - LINK

I'd love to hear from anyone who believes they might have any photos of these spiders found at any site in the UK. Please get in touch with a photo.  email