15mm female Meta menardi, found in Wouldham, Kent, beneath a manhole cover for a residential sewer outlet. 16th June 2019.
European Cave Spider (Meta menardi)
Also known as the Large Cave Spider and the Cave Orb-Weaver Spider. There are two very similar species of Cave Spider in the UK which can usually only be accurately distinguished by very close examination, Meta menardi and Meta bourneti. The European Cave Spider, Meta menardi, is one of the UK's largest spiders with a bulky, round, oval body around 10-13mm for males and 12-17mm in length for females, with a leg-span of around 5cm. Sometimes larger specimens can be found. These gentle giants are capable of giving a sharp nip if provoked but are very reluctant to bite and can usually be handled gently without issue. Cave Spiders are members of the Tetragnathidae family of Long-Jawed Orb-Weavers. Both species of Cave Spider are large, long-legged spiders, usually with glossy abdomens.
Although widespread across the UK Cave Spiders are rarely encountered spiders due to their very specific habitat requirements. Meta menardi are considered as widespread, but uncommon. Meta bourneti are considered to be nationally scarce, and most specimens are found in the south and east of England.
Cave Spiders are photophobic, meaning they prefer to live in complete darkness, often in damp locations such as sewers, tunnels and caves. Whilst humans rarely visit caves Cave Spiders are still frequently found living in other suitable habitats, such as railway tunnels, mines, damp cellars, under manhole covers and occasionally in gardens under decking. They have also been recorded living in dense ancient woodland in large hollow oak tree-trunks. Cave Spiders build large orb-webs of up to 30cm in diameter, although they are usually seen waiting beside the web on the walls of their surroundings, rather than in the web itself.
The European Cave Spider usually lives for 2-3 years. After mating in spring adult females deposit their large, teardrop-shaped, white egg-sacs in autumn, usually from September to November, fairly near the entrance to the cave, where the young spiderlings will develop. These large pendant egg-sacs are suspended from the ceiling of the cave and measure 2-3cm in width. Each egg-sac can produce 200-300 spiderlings. The spiderlings will hatch around January or February and will remain in the egg-sac, feeding on the yolk, until after their first moult. In the spring the spiderlings will disperse from the cave exit via ballooning into new areas. Unlike adult Cave Spiders the juveniles are positively phototaxic, meaning they are actually attracted to light. This encourages them to leave the cave and disperse in search of new territories to colonise. In most cases female Cave Spiders will outnumber males on a ratio of 3:1 or even 5:1. Females also usually live longer than the slightly smaller males. Cave Spiders have a fairly low tolerance of cold temperatures and are most frequently encountered in areas that do not see temperatures drop much below 7 degrees Celsius.
Cave Spiders are often confused with False Widow Spiders. One way to separate the two is to look at the legs. Meta species have clearly visible leg-spines that are absent from all Steatoda species.
Adult female Cave Spider, Meta menardi, photographed in a cave in Somerset, 12th August 2022.
The large female Meta menardi, pictured above, was one of 13 specimens found in a cave in Somerset during my search in August 2022. 7 specimens were adult females and 6 specimens were sub-adults. No egg-sacs were found at this time of year on my visit, although egg-sacs were found around this time of year by other spider hunters searching for Cave Spiders at different locations.
The diet of Cave Spiders consists of both flying prey, that is caught in their orb-webs, and crawling prey, that they catch by wandering the walls of their local habitat. These can include sheltering moths, gnats, craneflies, slugs, smaller spiders, and myriapods such as millipedes, centipedes and woodlice. Occasionally Cave Spiders will venture out into the open to hunt for prey at night. During the winter months prey can be very scarce within the depths of caves and tunnels and Cave Spiders may go months without feeding. There is another orb-weaving spider that can often be found sharing the same dark, damp habitat as the Cave Spiders, the Shaded Orb-Weaver, Metallina merianae.
Adult female Cave Spider, Meta menardi, photographed in a cave in Somerset, 12th August 2022.
Within cave habitats there exists a measured degree of association to the subterranean conditions. This degree enables the distinction of three different groups of cave dwelling species.
Troglobites - these are the most specialised of the cave-dwelling organisms and are usually found in the deepest areas of subterranean environments. Troglobites have adapted to these unique habitats and often show such adaptations such as depigmentation, a malformation or complete absence of eyes, elongation of appendages, and a reduced metabolic rate in line with the reduction of prey availability.
Troglophiles - these species can be found both above and below ground, and some stage of their life-cycle is usually above ground. As such they tend to show minimal, or no, adaptations to a subterranean existence.
Trogloxenes - these are species that usually exist outside of caves, but can on occasion be found at the entrance to caves. Trogloxenes are unable to exist entirely in subterranean habitats.
Cave Spiders, both Meta menardi and Meta bourneti, fall into the category of troglophiles. Although adult Cave Spiders will often choose to live deep within cave habitats, the young juveniles will readily disperse outside of the cave environment in search of new territories.
Immature Cave Spider, Meta menardi, photographed in a cave in Somerset, 12th August 2022.
Immature Cave Spider, Meta menardi, photographed in a cave in Somerset, 12th August 2022.
Immature Cave Spider, Meta menardi, photographed in a cave in Somerset, 12th August 2022.
Adult female Cave Spider, Meta menardi, photographed in a cave in Somerset, 12th August 2022.
Adult female Cave Spider, Meta menardi, photographed in a cave in Somerset, 12th August 2022.
Adult female Cave Spider, Meta menardi, photographed in a cave in Somerset, 12th August 2022.
Adult female Cave Spider, Meta menardi, photographed in a cave in Somerset, 12th August 2022.
Adult female Cave Spider, Meta menardi, photographed in a cave in Somerset, 12th August 2022.
Adult female Cave Spider, Meta menardi, photographed in a cave in Somerset, 12th August 2022.
Adult female Cave Spider, Meta menardi, photographed in a cave in Somerset, 12th August 2022.
Adult female Cave Spider, Meta menardi, photographed in a cave in Somerset, 12th August 2022.
Adult female Cave Spider, Meta menardi, photographed in a cave in Somerset, 12th August 2022.
Adult female Cave Spider, Meta menardi, photographed in a cave in Somerset, 12th August 2022.
Adult female Cave Spider, Meta menardi, photographed in a cave in Somerset, 12th August 2022.
12mm adult female Cave Spider, Meta menardi, photographed in Dorset cave, 8th August 2022.
I went in search for Cave Spiders in caves located in Dorset, during August 2022. I managed to find one adult female, one adult male and one sub-adult female Meta menardi during my search. Unfortunately I had accidentally left my headtorch in the car, which was parked about a mile away from the caves. The lights on my diffuser had quickly died and this cave was incredibly dark. On top of this my flash gun batteries were also dying, which meant I had to wait in total darkness for about one minute in between photos whilst I waited for my flash gun to recharge for the next shot.
During each shot I sat on the damp floor patiently waiting for my flash gun to sort itself out. It wasn't long though before a couple of hikers decided to also check out the cave I was waiting in. Naturally they thought they were alone and as they shone their torches around the cave they suddenly pointed their torches at me sitting on the floor of the cave. I swear I've never heard two large grown men scream as loudly as these two guys did when they found me in the cave. They didn't give me chance to explain what I was doing there, they just ran out screaming! lol
12mm adult female Cave Spider, Meta menardi, photographed in a cave in Dorset, 8th August 2022.
12mm adult female Cave Spider, Meta menardi, photographed in a cave in Dorset, 8th August 2022.
12mm adult female Cave Spider, Meta menardi, photographed in a cave in Dorset, 8th August 2022.
12mm adult female Cave Spider, Meta menardi, photographed in a cave in Dorset, 8th August 2022.
10mm female Cave Spider, Meta menardi, photographed in a cave in Dorset, 8th August 2022.
10mm female Cave Spider, Meta menardi, photographed in a cave in Dorset, 8th August 2022.
10mm female Cave Spider, Meta menardi, photographed in a cave in Dorset, 8th August 2022.
13mm adult male Cave Spider, Meta menardi, with Cranefly prey, photographed in a Dorset cave, 8th August 2022.
13mm adult male Cave Spider, Meta menardi, with Cranefly prey, photographed in a Dorset cave, 8th August 2022.
13mm adult male Cave Spider, Meta menardi, with Cranefly prey, photographed in a Dorset cave, 8th August 2022.
13mm adult male Cave Spider, Meta menardi, photographed in a Dorset cave, 8th August 2022.
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15mm female Meta bourneti, 8th December 2022.
Bournet's Cave Spider (Meta bourneti)
Britain's other cave spider, the nationally scarce Meta bourneti, is very similar in appearance to Meta menardi, and can be difficult to distinguish. Adult Meta bourneti can show some possible distinctions from Meta menardi though. Adult Meta bourneti are typically duller and less colourful in appearance, and usually have much fainter markings on their abdomen. Meta bourneti do not usually retain significant dark rings on their legs as they mature. However, the legs of adult Meta menardi usually do retain quite obvious dark rings, and orange rings, throughout their lifespan. Where dark rings are seen on the legs of Meta bourneti they are far more subtle than those found on Meta menardi. Adult Meta bourneti are a similar size to Meta menardi, with males having a body-length of 10-13mm, and females reaching around 13-16mm. A close inspection of the epigyne or pedipalps is needed to be totally sure of species though. This species is also widespread across much of Europe and north Africa.
More views of the 15mm female Meta bourneti, 8th December 2022.
St Denis' Church, East Hatley, Cambridgeshire, 9th September 2022
Bournet's Cave Spiders at St Denis' Church, at East Hatley, Cambridgeshire
In 2006 a small colony of the nationally scarce Meta bourneti were at risk of being left homeless when an old air-raid shelter, where they were discovered in Papworth Everard, Cambridge, was scheduled to be demolished to make way for development. Thankfully a rescue and relocation plan was put into action by Rob Mungovan, who at the time was the Ecology Officer at South Cambs District Council. The Cave Spiders were transferred to an underground room, beneath St Denis' Church, some 11 miles away in East Hatley. The identity of these large orb-weavers was officially confirmed, by microscopic examination, in the summer of 2006 as Meta bourneti by Brian Eversham, entomologist and pervious CEO of the Beds, Cambs and Northants Wildlife Trust. Despite the "nationally scarce" status of Meta bourneti there are actually more records of the rare Meta bourneti in Cambridgeshire than there are for the far more common European Cave Spider, Meta menardi. Since the 2006 discovery of the Cave Spider colony in Papworth Everard there were numerous further sightings of Cave Spiders being discovered in many different dark locations in Cambridgeshire. These included a Gamlingay WWII bunker, drains at Madingley Cemetery and even phone equipment boxes in Arrington. Although proving far more numerous than previously expected none of the other sightings were officially examined and identified to a species level unfortunately.
At the time of the transfer St Denis' Church was a local, disused, medieval church in the small, rural village of East Hatley, Cambridgeshire. Beneath the Grade II* listed building lay a disused furnace chamber that would provide an ideal hideaway, for these dark-loving spiders, where they could continue their existence undisturbed. St Denis' Church was situated in a small local nature reserve and it seemed the ideal location to be used as a receptor site for such a relocation. These rare spiders would share the church with other scarce species, including Brown Long-eared Bats, Plecotus auritus, that roost in the building, and Great Crested Newts, Triturus cristatus, that spend some of their terrestrial life in the church's cellar. The tiny furnace chamber is a dark, damp, underground storage room with limestone walls and a clay covered floor. With no windows in the furnace chamber there is no light entering this underground room, and here the spiders are very rarely ever disturbed by human visitors. Hidden away from the rest of the world the Bournet's Cave Spiders have managed to thrive since their introduction, and successful breeding takes place yearly.
On 9th September 2022 I was given the privilege of surveying and photographing these special spiders. The idyllic old church is situated on the grounds of a small nature reserve. The old wooden door at the entrance to the furnace chamber remains locked to the public, but proudly displays a notice informing visitors of the presence of Cave Spiders beneath the church. I chose autumn for my visit in the hope of finding female Bournet's Cave Spiders guarding their egg-sacs. Thankfully the timing was perfect and I wasn't disappointed. On this visit I was able to record 5 adult male specimens, 11 adult female specimens, and 1 sub-adult specimen. I counted a total of 14 egg-sacs, however, only 5 of these egg-sacs had females guarding them so at least some of the others may have been old egg-sacs. The large, white egg-sacs were suspended from the top of the damp walls and had a diameter of around 20-25mm, each resembling small, hairy table-tennis balls. Two of the adult females were in very close proximity with male specimens, which were likely to be their mating partners or potential suitors.
Due to their largely sedentary nature these spiders typically remained fairly motionless even when exposed to the dimmed light of my studio photography lamp, or even the very bright light from my diffused camera flash unit. Some of the females guarding their egg-sacs began to nervously scuttle around the egg-sac as I approached closely with my camera. One female specimen hid behind her egg-sac when my lens got too close. Using a twig I gently lifted the egg-sac to reveal the hiding spider. To my utter surprise the spider then jumped from the egg-sac and landed on my camera, before slipping off and falling to the ground, about 20 inches below. The spider then walked back to the wall, where its egg-sac was suspended, and slowly began to ascend the wall towards the egg-sac once again. However, the spider never actually returned to the egg-sac whilst I was there watching. It's still not clear whether the spider's jump towards my camera was an attempt to flee or maybe to defend the egg-sac?
I was keen to photograph an adult female specimen on a white background so I chose to capture a lone specimen, that was easily accessible, and wasn't guarding an egg-sac, or partnered with a male. The large female specimen I selected didn't have a particularly swollen abdomen, so either it hadn't mated yet, or it had already produced an egg-sac that it wasn't guarding. As I placed the spider on my white sheet of plastic it was noticeably uncomfortable as its legs failed to grip to the slippery surface. It took a few minutes of escape attempts before the spider finally settled down and remained motionless for a brief moment. This pause allowed me the opportunity to capture my photos. During its escape attempts I used my hand to block its escape routes several times, and at no time did the spider exhibit any defensive behaviour other than to run away. After a few minutes I'd captured the images that I was after, and the spider was placed gently back to the exact same spot on the low ceiling where it was found. Once back in place the spider continued to remain motionless, exactly as it was before its capture.
The tiny furnace chamber of St Denis' Church has probably reached its maximum carrying capacity for this species. Although adult Cave Spiders are photophobic, and choose habitats of total darkness, the newly emerged spiderlings are attracted to light and the majority of these will leave the furnace chamber and head off in search of new territories to colonise. One adult specimen has been found under a manhole cover at a nearby residential property, so these spiders can be found in suitable locations in the area that surrounds the church. The only sub-adult specimen that was found on my visit to the church's furnace chamber had built its web on the archway leading into the chamber, and was the closest specimen to the exiting door.
Within the webs of the Cave Spiders I found the remains of Cellar Spiders, Pholcus phalangioides, as well as a small slug, several woodlice and one Violet Ground Beetle, Carabus violaceus. Their were also mosquitoes on the walls that would provide a light meal for the spiders given the chance. The Cave Spiders are not the only predators living under the church. The furnace chamber is also shared with Cellar Spiders, Pholcus phalangioides, that were slightly more numerous than the Meta bourneti. 19 Pholcus phalangioides specimens were recorded on my visit. Pholcus phalangioides are known spider hunters, and whilst I found evidence that Meta bourneti were feeding on young Pholcus phalangioides, it is highly likely that this is reciprocated with Pholcus phalangioides feeding on the young Meta bourneti too.
* Grateful thanks to Peter Mann for allowing me the opportunity to photograph these Meta Bourneti, and thanks to Rob Mungovan for information on the history of this colony. *
13mm male Meta bourneti, photographed at St Denis Church, Cambridgeshire, 9th September 2022.
In 2017 - 2018 extensive studies were carried out in Italy, on the ecology of Meta bourneti, by Senior Research Scientist, Enrico Lunghi. By studying numerous caves, on small islands in Sardinia, Lunghi made some interesting discoveries. It was shown that Meta bourneti not only require caves with total darkness, but they also require a microclimate with high humidity as well. It was also revealed that Meta bourneti can be found at lower heights on the cave walls during the hotter months of the year, despite the minimal fluctuation in temperature and climatic conditions within the depths of the caves throughout the year. This may be an indicator of just how specific the climate requirements are for this species. The deeper one ventures into a cave the more stable the microclimate is. It comes as no surprise that more mature Meta bourneti are usually found deep within caves, and younger specimens can usually be found nearer the cave exit, where climatic conditions show greater variation in line with external changes to the climate outside of the cave. When compared to Meta menardi it seems that Meta bourneti not only choose environments with a slightly higher temperature but also prefers caves with a higher ceiling. On average Meta menardi also appear to favour European sites at a slightly higher elevation to those of Meta bourneti. This may have just been an adaptation to reduce competition for prey between the two similar species.
Although widespread throughout caves in Italy the population density of Meta bourneti was fairly low, with only one Meta bourneti specimen typically being found in each 3 metre section of caves where this species was present. In England the population density within the old furnace chamber at St Denis' Church is extremely high when compared to long established colonies of Meta bourneti found in the Italian caves. It makes one question whether this is down to the abundance of prey availability within the chamber, or if the spiders remain in such close proximity to each other, in the confines of the chamber, because of the lack of alternative suitable habitat in the local area outside of the church? Despite the "nationally scarce" status of Meta bourneti there are actually more records of Meta bourneti in Cambridgeshire than there are for the far more common European Cave Spider Meta menardi.
13mm male Meta bourneti, photographed at St Denis Church, Cambridgeshire, 9th September 2022.
13mm male Meta bourneti with a leg-span of around 50mm. 9th September 2022.
13mm male Meta bourneti, photographed at St Denis Church, Cambridgeshire, 9th September 2022.
Adult male Meta bourneti, photographed at St Denis Church, Cambridgeshire, 9th September 2022.
Adult male Meta bourneti, photographed at St Denis Church, Cambridgeshire, 9th September 2022.
Adult female Meta bourneti, photographed at St Denis Church, Cambridgeshire, 9th September 2022.
The shrivelled abdomen seen on this adult female Meta bourneti is the result of the female having recently produced an egg-sac.
Adult female Meta bourneti, photographed at St Denis Church, Cambridgeshire, 9th September 2022.
Adult female Meta bourneti, photographed at St Denis Church, Cambridgeshire, 9th September 2022.
Adult female Meta bourneti, photographed at St Denis Church, Cambridgeshire, 9th September 2022.
Adult female Meta bourneti, photographed at St Denis Church, Cambridgeshire, 9th September 2022.
15mm female Meta bourneti guarding her egg-sac, 9th September 2022.
15mm female Meta bourneti guarding her egg-sac, 9th September 2022.
15mm female Meta bourneti guarding her egg-sac, 9th September 2022.
14mm female Meta bourneti guarding her egg-sac, 9th September 2022.
15mm female Meta bourneti guarding her egg-sac, 9th September 2022
15mm female Meta bourneti, photographed at St Denis Church, Cambridgeshire, 9th September 2022.
Adult female Meta bourneti, photographed at St Denis Church, Cambridgeshire, 9th September 2022.
Adult female Meta bourneti, photographed at St Denis Church, Cambridgeshire, 9th September 2022.
Adult female Meta bourneti guarding her egg-sac, 9th September 2022.
7-8mm sub-adult Meta bourneti, photographed at St Denis Church, Cambridgeshire, 9th September 2022.
Cavity Spider / Comb-footed Cellar Spider - (Nesticus cellulanus)
Another species of spider that can also be found in caves, tunnels and other permanently dark habitats is Nesticus cellulanus, also known as the Cavity Spider or Comb-footed Cellar Spider. As a comb-footed spider Nesticus cellulanus builds a small tangle-web or scaffold web. Adult males typically reach 3-5mm and adult females reach 3.5-6mm. Nesticus cellulanus has a pale yellow / orange legs, that sometimes exhibit dark annulations. The carapace is the same colour as the legs, and has a dark, central median band that narrows towards the middle. The carapace is bordered with thin, dark marginal lines. The light coloured abdomen often shows three of four dark rings to both sides of an irregular median band. Darker habitats are usually associated with specimens exhibiting lighter markings.
Adult female specimens can be found all year round but mature males are most commonly seen from March to November. Mating occurs in early summer and between June to August adult females can often be seen carrying a partially translucent pale egg-sac behind them, attached to their spinnerets. Nesticus cellulanus is widespread across the UK but is not often encountered due to its preference for totally dark habitats. Nesticus cellulanus is one of just two identical British species from the Nesticidae family, with Kryptonesticus eremita being the second. Whilst Nesticus cellulanus is common and widespread Kryptonesticus eremita is extremely rare and is confined to just one site in the UK, in Bristol.
The Cave Spider photographs on this page were taken using:
Canon 7D mk I & mk II cameras, Canon 100mm f/2.8L IS Macro lens, Canon 580ex flash, with MK Diffuser.