Are Jumping Spiders harmless?
Jumping spiders are usually regarded as harmless to humans. They are small spiders that live on walls and other flat surfaces and catch their prey by jumping, hence their name.
There are countless species around the world and none are listed as dangerous in books, on websites and in information sources apart from in message boards and forums in Tenerife in the Canary Islands.
Residents of the island say that a small black jumping spider can bite you and that if bitten you may end up in hospital. Clearly this is a very important matter but the mystery is why are there no warning in books or on websites about jumping spiders?
Another mystery is what species of jumping spider or spiders is causing a danger to people by biting them? No one seems sure but they all claim that the spiders are black or jet black and some say they are like tiny crabs or have crab-like pincers.
Allergies and allergic reactions to spider bites
It is known that some people are allergic to spider bites and that they can suffer a very bad reaction if bitten but this does not explain why so many people in Tenerife say they have terrible reactions to the bites of these spiders. Surely the island isn’t full of people with spider allergies?
There are plenty of websites that will confirm that allergic reactions can occur to jumping spider bites but none of these sites claim that the spiders are regarded as any real danger. Some sources go as far as saying that it isn’t true that jumping spiders bite and that the creatures are harmless.
This cannot be correct due to the sheer number of reports on Tenerife, and many of these reports say that the victim of the spider bite had to see a doctor or even ended up in hospital.
Jumping Spider bite poll
Symptoms of the jumping spider bite
Those that say they have been bitten by black jumping spiders say that there are two small bite marks and that the area around the bite can really swell up. Some say that a limb may even become paralysed and it can take days or even a week before the swelling goes away..
The area by the bite can become red and inflamed and may itch a lot but it is not recommended that you scratch it because this can make things much worse.
Many say that they are left with scars after being bitten by such a spider.
Macaroeris nidicolens (WALCKENAER, 1802) - ♂ - jumping spider
Treatment for Jumping Spider bites
People in Tenerife say that you need to see a doctor right away if bitten by a jumping spider. Antibiotics are one form of treatment.
It has been said that the spiders cause an infection in the wound and that the flesh may even become necrotic unless treated.
Tenerife Jumping Spiders
There are several species known on the island and the most likely culprit appears to Macaroeris nidicolens judging by descriptions of the appearance of these spiders. It is a blackish spider and may have white markings on its back. Many of the reports say that the black jumping spiders that bite have a white dot or cross on the back.
Macaroeris nidicolens is listed and illustrated in the book Historia Natural de las Islas Canarias by David Bramwell and Zoe L. Bramwell but it doesn’t say anything about these spiders being venomous.
According to Wikipedia the species is found in Europe and Asia but surprisingly if this is the spider that is biting people there is no warning about it and no reports anywhere else.
Perhaps it is some other species then but what species? Nobody seems to know but then most people are not spider or wildlife experts!
Macaroeris nidicolens (WALCKENAER, 1802) - Female - jumping spider
How do people get bitten by spiders?
Now admittedly many people who claim to have been bitten say it happened when they were asleep so didn’t actually see the spider but they point to the evidence of the puncture marks from the bite and how small black jumping spiders live where they are.
It is possible that the spiders have bitten people who have rolled onto them whilst sleeping, and also that victims have sat on spiders or put their hand, leg or arm on one. Spiders will bite if pressure is put on them. It is a natural form of defence.
However, some spider bite victims claim that the spiders jumped on them and attacked them. This is not known of as a form of behaviour from jumping spiders though the spiders are curious and will jump on you but not to bite and attack you. Normally these tiny spiders will run or jump away.
So what is going on here? What species of jumping spider is biting people on Tenerife? It is a real mystery!
© 2013 Steve Andrews
Kurt on February 23, 2018:
The descriptions of the reactions with necrosis seems more in line with the Loxosceles species on the islands, which are endemic.
Fuerteventura and Lanzarote - Loxosceles mahan
Gran Canaria - Loxosceles bentejui
Tenerife - Loxosceles guayota (some consider all of them as this species)
La Gomera and El Hierro - Loxosceles hupalupa
The vast majority of people who report "spider bites" does so without even having seen the spider, let alone having them preserved for identification. Most people can't tell the difference between a beetle and a spider.
Let's not forget that Latrodectus tredecimguttatus, aka the actual black widow, also lives on the islands, which makes the Steatoda "false widow" seems rather irrelevant.
Steve on October 04, 2017:
I live in Tenerife and got bitten already 3-4 times in the last 3 years in Tenerife, always at night. Only since I moved to Las Chafiras, before I never had any bites. However my girlfriend's kids were bitten several times and she lives in Los Abrigos which is the same area. The last time one bit me was only 1 month ago, this time it did bite me unfortunately directly on top of a vene which made it quite bad and a sepsis started. Only antibiotics, other medicaments and cream stopped it. Does anyone have a suggestion on how to keep them outside of the house?
Wayne on June 19, 2017:
I have just returned from holiday and found this topic by experiencing a bite myself. I pointed at a tiny jumping spider and it reared up, I told my wife to look and pointed again. This time it jumped onto the tip of my finger and bit me. It was a total shock but luckily no side effects. .....
Steve Andrews (author) from Tenerife on June 26, 2016:
I am sorry to hear this! It sounds like an allergic reaction. It remains a mystery as to the identification of the spider causing these painful reactions.
Tina chapman. on June 25, 2016:
I woke and disturbed , what I think was the little black darling spider and wow does this hurt, after a nights sleep I have aches and pains all over and the pain to my ankle area is excruciating , no energy and so tired, using antibiotic cream but not doing much, very small puncture but very red and itchy . Tina , tenerife. June 2016
Steve Andrews (author) from Tenerife on March 04, 2014:
I still do not know what this spider that gets reported is!
Bracey on February 13, 2014:
I have told this story countless times!
Was just telling it again and wondered if anyone else had, and winded up here! I had one jump on my hand, it was moving INCREDIBLY fast as i played on an arcade machine in the hotel. It bit me, the pain was sharp, i sucked the bite and i had this awful like red string type stuff hanging out my mouth. I went dizzy for a while but that was it. I even went back to my game, lol.
But exactly as you say with the pincers and it absolutely attacked me for no reason whatsoever! Glad to hear others have had this too and i'm not insane! I'm going back to Tenerife for the first time in about 15 year so i'll report back if it happens again! :D
Steve Andrews (author) from Tenerife on October 09, 2013:
I had a false black widow spider female living here for seven years in a cupboard. They are not regarded as dangerous though they can bite in defence. They are not jumping spiders though but live in webs.
CMHypno from Other Side of the Sun on October 09, 2013:
Invasive species seem to be the main culprit over here and it is thought that the noble false widow spider is the one causing most of the problems. Maybe the Brits are getting bitten more frequently over in Tenerife because they are not used to where the local spiders live and how they behave?
Steve Andrews (author) from Tenerife on October 09, 2013:
I wish it was even more detailed and I could name for certain the species that is causing problems here but so far I have not met anyone who can tell me apart from saying it is a black jumping spider. Until I came to Tenerife nine years ago I had never heard of any danger from these spiders and I have personally held lots of British ones and Tenerife ones too.
Patricia Scott from North Central Florida on October 08, 2013:
This is filled with much detailed information that is useful when jumping spiders share your space. I am not a fan of spiders unless they are outside!! And not moving in my direction.
Steve Andrews (author) from Tenerife on October 08, 2013:
CMHypno it appears to be mainly British people getting bitten here too. I don't understand this because I have been studying natural history since I was a child and never heard of any dangers from jumping spiders and have held loads in my time!
Toby on October 08, 2013:
I'd like to see a video of it jumping!
CMHypno from Other Side of the Sun on October 08, 2013:
Interesting hub and information people need to know. There seem to be more people in the UK having trouble from spider bites as well, with some people having severe reactions and swollen limbs