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Hello! I added many new sections with information that I have researched from a variety of sources, primarily scholarly ones. I kept some of the previous information, but I also removed information that was not properly sourced. I also moved around a few of the older sentences to give the reader an easier time navigating the page. Hope you enjoy!
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'''''Pholcus phalangioides''''', commonly known as '''daddy long-legs spider''' or '''long-bodied cellar spider''', is a spider of the family [[Pholcidae]]. It is also known as the '''skull spider''' due its [[cephalothorax]] resembling a [[human skull]]. This is the only spider species described by the Swiss [[Entomology|entomologist]] [[Johann Kaspar Füssli]], who first recorded it for science in 1775.<ref>{{cite web|title=The Nearctic Spider Database: Pholcus phalangioides (Fuesslin, 1775) Description|url=http://www.canadianarachnology.org/data/spiders/3744|url-status=dead|archiveurl=https://web.archive.org/web/20091106140807/http://www.canadianarachnology.org/data/spiders/3744|archivedate=2009-11-06|accessdate=2016-08-28|website=canadianarachnology.org}}</ref>
[[File:Long Bodied Cellar Spider (Pholcus phalangioides).jpg|thumb|Feeding on an ant]]


Females have a body length of about 8&nbsp;mm while males tend to be slightly smaller. The length of the spider's legs are on average 5 or 6 times the length of its body.<ref name=":0">{{Cite web|last=Mazza|first=Giuseppe|date=2016-06-23|title=Pholcus phalangioides|url=https://www.monaconatureencyclopedia.com/pholcus-phalangioides/?lang=en|access-date=2020-10-21|website=Monaco Nature Encyclopedia|language=en-US}}</ref>
'''''Pholcus phalangioides''''', commonly known as '''daddy long-legs spider''' or '''longbodied cellar spider''', is a spider of the family [[Pholcidae]]. It is also known as the '''skull spider''' due its [[cephalothorax]] resembling a [[human skull]].

Females have a body length of about 8&nbsp;mm and males are slightly smaller. The length of its legs are about 5 or 6 times the length of its body (reaching a legspan up to 7&nbsp;cm in females).


''Pholcus phalangioides'' has a habit of living on the ceilings of rooms, caves, garages or cellars. This spider species is considered beneficial in parts of the world because it kills and eats other spiders, including species considered dangerous such as [[redback spider|redback]] spiders.<ref name="Queensland">[http://www.qm.qld.gov.au/Find+out+about/Animals+of+Queensland/Spiders/Modern+Spiders+Infraorder+Araneomorphae/Daddy-long-legs+spiders/Daddy-long-legs Daddy Long Legs&nbsp;– Queensland Museum]</ref><ref>[http://www.brisbaneinsects.com/brisbane_weavers/Pholcidae.htm FAMILY PHOLCIDAE&nbsp;– Daddy long-leg Spiders]</ref>
''Pholcus phalangioides'' has a habit of living on the ceilings of rooms, caves, garages or cellars. This spider species is considered beneficial in parts of the world because it kills and eats other spiders, including species considered dangerous such as [[redback spider|redback]] spiders.<ref name="Queensland">[http://www.qm.qld.gov.au/Find+out+about/Animals+of+Queensland/Spiders/Modern+Spiders+Infraorder+Araneomorphae/Daddy-long-legs+spiders/Daddy-long-legs Daddy Long Legs&nbsp;– Queensland Museum]</ref><ref>[http://www.brisbaneinsects.com/brisbane_weavers/Pholcidae.htm FAMILY PHOLCIDAE&nbsp;– Daddy long-leg Spiders]</ref>


Pholcus phalangioides is known to be harmless to mankind and actually provides many benefits to humans, including the potential for the medicinal use of their webs.<ref name=":1">{{Cite web|title=Longbodied Cellar Spider|url=https://extension.psu.edu/longbodied-cellar-spider|access-date=2020-10-21|website=Penn State Extension|language=en}}</ref><ref name=":3">{{Citation|last=Shahbuddin|first=M.|title=Natural Silk of Pholcus Phalangioides, a Common Home Spider Species for Wound Healing Applications|date=2016|url=http://link.springer.com/10.1007/978-981-10-0266-3_45|work=International Conference for Innovation in Biomedical Engineering and Life Sciences|volume=56|pages=216–221|editor-last=Ibrahim|editor-first=Fatimah|place=Singapore|publisher=Springer Singapore|doi=10.1007/978-981-10-0266-3_45|isbn=978-981-10-0265-6|access-date=2020-10-21|last2=Puat|first2=N. A.|last3=Mirghani|first3=M. E. S.|last4=Raus|first4=R.A.|editor2-last=Usman|editor2-first=Juliana|editor3-last=Mohktar|editor3-first=Mas Sahidayana|editor4-last=Ahmad|editor4-first=Mohd Yazed}}</ref><ref name=":4">{{Cite journal|last=Roozbahani|first=Hassan|last2=Asmar|first2=Mahdi|last3=Ghaemi|first3=Naser|last4=Issazadeh|first4=Khosro|date=2014-07-01|title=Evaluation of Antimicrobial Activity of Spider Silk Pholcus Phalangioides Against Two Bacterial Pathogens in Food Borne|url=http://www.ijabbr.com/article_7988.html|journal=International Journal of Advanced Biological and Biomedical Research|volume=2|issue=7|pages=2197–2199|issn=2383-2762}}</ref>
This is the only spider species described by the Swiss [[Entomology|entomologist]] [[Johann Kaspar Füssli]], who first recorded it for science in 1775.<ref>{{cite web |title=The Nearctic Spider Database: Pholcus phalangioides (Fuesslin, 1775) Description |url=http://www.canadianarachnology.org/data/spiders/3744 |url-status=dead |archiveurl=https://web.archive.org/web/20091106140807/http://www.canadianarachnology.org/data/spiders/3744 |archivedate=2009-11-06 |accessdate=2016-08-28 |website=canadianarachnology.org}}</ref>

==Habitat==
== Description ==
Originally a species restricted to warmer parts of the west [[Palearctic]],<ref>{{cite book |last1=Adams |first1=Richard J. |title=Field Guide to the Spiders of California and the Pacific Coast States |url=https://books.google.com/?id=6a3HAQAAQBAJ&pg=PA73&lpg=PA73&dq=phalangioides+originally+OR+originated+europe#v=onepage&q=phalangioides%20originally%20OR%20originated%20europe&f=false |page=73 |date=2014-01-28 |accessdate=2016-09-08|isbn=9780520957046 }}</ref>{{better source |reason=Not an exact citation for the claim; book says 'originally from central Europe'. |date=September 2016}} through the help of humans this [[synanthrope]] now occurs throughout a large part of the world.<ref name=Queensland />{{better source |reason=This page only establishes that the Pholcus phalangioides was introduced to Australia from Europe. |date=August 2016}} It is unable to survive in cold weather, and consequently it is restricted to (heated) houses in some parts of its range.

=== Sexual Dimorphism ===
[[Sexual dimorphism]] is apparent in Pholcus phalangioides in the form of the females being slightly larger than the males of the species. The body length of this species varies anywhere from 6 to 10 mm with the average male being around 6 mm in length and the average female ranging from 7 to 8mm in length.<ref name=":0" /><ref name=":1" /> As indicated by their nickname “daddy long-legs spider,” these spiders boast eight very long and thin legs which are covered in thin, grey bristles. On average, these legs are roughly 5 to 6 times as long as the spider’s body.<ref name=":0" /> The average length of an adult female’s legs, for instance, are roughly 50 mm.<ref name=":1" /> The two smaller legs up front are known as palps and are important in the predation and mating of this species. These palps are also notably longer in females of the species.<ref name=":2">{{Cite web|title=BioKIDS - Kids' Inquiry of Diverse Species, Pholcidae: INFORMATION|url=http://www.biokids.umich.edu/critters/Pholcidae/|access-date=2020-10-21|website=www.biokids.umich.edu}}</ref>

=== Morphology ===
The bodies of daddy long-legs spiders can be divided into two parts: the prosoma, commonly known as the cephalothorax, and [[opisthosoma]], or posterior part of the body which hosts most of the spider's internal organs.<ref>{{Cite web|title=Opisthosoma - an overview {{!}} ScienceDirect Topics|url=https://www.sciencedirect.com/topics/veterinary-science-and-veterinary-medicine/opisthosoma|access-date=2020-10-21|website=www.sciencedirect.com}}</ref>The round, peanut-like shape of the spider’s [[cephalothorax]] has earned the Pholcus phalangioides species the nickname “skull spider.” The translucent body of the daddy long-legs spider tends to be a grey-pale brown color with a dark spot on the back of the prosoma and some dark, blurred spots on the dorsal side of the opisthosoma.<ref name=":0" />                  

Although some other members of the family [[Pholcidae]] have six eyes, Pholcus phalangioides is an eight-eyed spider.<ref name=":2" /> The eyes are arranged such that there is a pair of smaller, dark eyes at the front of the prosoma followed by three parallel rows of pairs of larger eyes.<ref name=":0" />

A hard [[exoskeleton]] coats the bodies of daddy long-legs spiders. Depending on the age of the spider, this exoskeleton must be shed at different times. Younger spiders tend to [[Moulting|moult]] much more often. During moulting, or shedding, the spider will produce certain enzymes that release the rest of its body from the underlying tissue of its exoskeleton thus allowing it to escape the exoskeleton. The remnant outer skin or exoskeleton is known as the exuvia.<ref name=":0" />

=== Life Span ===
It takes about one year for these spiders to mature after they are born, and their life span is generally two years post maturity.<ref name=":1" />

== Phylogeny ==

=== Close Relatives ===
[[File:Harvestman (Opiliones) - Mississauga, Ontario 01.jpg|thumb|233x233px|Harvestman Spider ([[Opiliones]])]]
A member of the genus ''[[Pholcus]]'' in the family [[Pholcidae]], the daddy long-legs spider shares ancestry with roughly 1,340 similar cellar-spiders such as the granddaddy long-legs spider, carpenter spider, and vibrating spider. All of these spiders are known for their characteristic long legs which can range from 5 to 6 times the size of their bodies. This is not to be confused with physically similar organisms such as [[crane fly]] insects and harvestmen spiders of the order [[Opiliones]].<ref>{{Cite web|title=Pholcidae Definition and Examples - Biology Online Dictionary|url=https://www.biologyonline.com/dictionary/pholcidae|access-date=2020-10-21|website=Biology Articles, Tutorials & Dictionary Online|language=en-US}}</ref>

=== Genetic Population Structure ===
The population sizes of Pholcus phalangioides are influenced greatly by the presence of human buildings since these spiders prefer colder habitats indoors. Given the vast amount of human buildings, most daddy long-legs spider populations tend to be relatively small, dispersed widely, and greatly isolated from one another. This small size combined with low mobility for populations results in an increased importance placed on the role of [[genetic drift]], and more specifically the [[founder effect]], on population structure. Although some [[gene flow]] does exist between populations, in studies its importance has been insignificant when compared to that of geographical isolation-driven genetic drift. As a result, most daddy long-legs spiders of the same population living in the same geographical region with have a very low degree of genetic variation. On the other hand, this genetic drift results in significant interpopulation differentiation.<ref>{{Cite journal|last=Schäfer|first=Martin A.|last2=Hille|first2=Axel|last3=Uhl|first3=Gabriele B.|date=2001-01|title=Geographical patterns of genetic subdivision in the cellar spider Pholcus phalangioides (Araneae)|url=https://www.nature.com/articles/6888150|journal=Heredity|language=en|volume=86|issue=1|pages=94–102|doi=10.1046/j.1365-2540.2001.00815.x|issn=1365-2540}}</ref>

== Habitat and Distribution ==

=== Habitat ===
The daddy long-legs spider is not suited for survival in cold environments, and thus it prefers the warmth of the indoors. Members of this species have a particular affinity for dimly lit, dark areas that are quiet and calm. For this reason, these spiders are commonly found in the corners of buildings and people’s homes as well as in attics. Populations of Pholcus phalangioides living outdoors can be found in caves and in between rock crevices.<ref name=":2" /><ref name=":0" />

=== Geographic Distribution ===
It is hypothesized that this species is native to the subtropical regions of Africa, Europe, and Asia due to its preference for warmer, more humid climates. A [[Synanthrope|synanthropic]] species, the Pholcus phalangioides has largely had its modern geographic distribution determined by the evolution and spread of humans around the world. Today, these spiders can be found on every continent in the world but are especially concentrated in South America and Europe.<ref name=":0" />

== Diet ==
In a similar fashion to other members of the family Pholcidae, the daddy long-legs spider is carnivorous predator that feeds on insects, other spiders, and small invertebrates. Unlike many other spiders, who simply feed on prey that have gotten stuck in their webs, these spiders will frequently venture out from their own webs to hunt other spiders resting in their respective webs and feed on them or their eggs. In times of low prey availability, both the males and females of the species will turn to [[cannibalism]] in order to meet their nutritional needs and survive.<ref name=":2" /><ref name=":0" /><ref>{{Cite journal|last=Jackson|first=Robert R.|last2=Rowe|first2=R. J.|date=1987-01-01|title=Web-invasion and araneophagy by New Zealand and Australian pholcid spiders|journal=New Zealand Journal of Zoology|volume=14|issue=1|pages=139–140|doi=10.1080/03014223.1987.10422692|issn=0301-4223|doi-access=free}}</ref>

== General Ethology ==
[[File:Pholcus phalangioides - Palestine.webm|thumb|283x283px|Pholcus phalangiodes rare conflict between population]]

=== Web Patterns ===
In general, the webs of daddy long-legs spiders are loose and horizontal in nature with many irregularities. These loose, three-dimensional webs are often intertwined with the webs of other skull spiders of the same population. This does not present either spider with any problems, and they live peacefully unless of course resources are low at which point the spiders will turn to cannibalism.<ref name=":0" />

=== Communication ===
Pholcus phalangioides is not known as a social species of spider. The extent of this spider’s communication is seen in times of mating. The primary form of communication for these spiders is through the use of touch and chemicals, specifically [[Pheromone|pheromones]].<ref name=":2" /><ref name=":0" />

== Predation Behaviors ==

=== Predators ===
[[File:Pholcus-phalangioides-20190725c.jpg|thumb|234x234px|Pholcus phalangioides feeding on species of [[wasp]] in its web]]
Much like most other species of spider, skull spiders too must be on the lookout for other spiders that could be looking to feed on them. One such family of spiders that is a commonly known predator of Pholcus phalangioides is the [[Jumping spider|Salticidae]], better known as the jumping spiders. Some of these spiders simply leap into the webs of their prey and attack them. Others, employ a certain strategy known as [[mimicry]] in order to trick the daddy long-leg spiders and capture them.<ref name=":5">{{Cite journal|last=Jackson|first=Robert R.|date=1990|title=Predator-prey interactions between jumping spiders (Araneae, Salticidae) and Phokus phalangioides (Araneae, Pholcidae)|url=https://zslpublications.onlinelibrary.wiley.com/doi/abs/10.1111/j.1469-7998.1990.tb04734.x|journal=Journal of Zoology|language=en|volume=220|issue=4|pages=553–559|doi=10.1111/j.1469-7998.1990.tb04734.x|issn=1469-7998}}</ref>

A jumping spider species whose aggressive mimicry behavior towards skull spiders has been well studied is the [[Portia fimbriata]] species of the genus ''[[Portia (spider)|Portia]]''. This mimicry takes the form of the jumping spider producing certain specialized vibrations near the edge of the skull spider’s web. These vibrations cause the skull spider’s web to oscillate in such a way that it mimics the oscillations that would be produced when a form of prey gets stuck in their web. The jumping spider will then continue on with these vibrations for very long durations of time, up to three days in some instances.<ref name=":0" /> Naturally, the skull spider assumes that this is an indication that they have caught some sort of prey and will move toward the host of the vibrations. At this point, the jumping spider is in an optimal position to leap onto and attack the skull spiders, thus subduing them in many instances. In addition to employing mimicry, these jumping spiders are also particularly good at preventing the skull spiders from inducing their whirling defense mechanism which tends to be an effective way for daddy long-legs spiders to defend themselves from predators.<ref name=":5" />

=== Defensive Behaviors ===
The primary defense strategy employed by daddy long-legs spiders in moments of predation is the action of whirling. Whirling, or a gyration of the body, consists of the skull spider swinging its body around in a circle repeatedly while its legs remain fixed on the web.<ref name=":5" /> This whirling strategy is induced as soon as the skull spider, who is sensitive to touch, recognizes any sort of movement occurring in its web. According to recent research, the duration of this whirling seems to be related to the specific kind of predator that the skull spider encounters. Short-duration whirling can be induced simply by a human touching the skull spider’s web or occasionally by spider of a different species. Long-duration whirling which can last several hours or even days is elicited by members of the P. phalangioides species specifically in response to the presence of the more threatening Salticid, or jumping, spiders much more often than for spiders of other families. The rapid gyrating associated with the whirling disturbs the vision of the Salticid spiders such that they can no longer rely on their acute eyesight to pinpoint the location of the skull spiders. This disruption results in the safety of the skull spiders from an otherwise deadly predator.<ref>{{Cite journal|last=Heuts|first=B. A|last2=Witteveldt|first2=M|last3=Dionisio Pires|first3=L. M|last4=van Wageningen|first4=F|date=2001-06-13|title=Long-duration whirling of Pholcus phalangioides (Araneae, Pholcidae) is specifically elicited by Salticid spiders|url=http://www.sciencedirect.com/science/article/pii/S0376635701001577|journal=Behavioural Processes|language=en|volume=55|issue=1|pages=27–34|doi=10.1016/S0376-6357(01)00157-7|issn=0376-6357}}</ref>

=== Mimicry ===
Much like the [[Jumping spider|Salticidae]] family of spiders, the daddy long-legs spider also uses mimicry as a predatory tactic to subdue its prey; however, unlike jumping spiders, recent research hints that they do not rely on vision as a forefront for predation like the Salticids. This mimicry also consists of creating specialized vibrations to trick the prey into thinking that it has caught an insect or another spider. The prey then slowly approaches its supposed catch at which point the skull spider raises up on its long leg. The skull spider patiently waits until the exact moment in which the prey touches one of its legs. At that moment, the daddy long-legs spider quickly immobilizes the spider by using its legs to wrap up the prey in layers of silk. Its long legs give it plenty of distance from the prey to avoid being bitten in retaliation. After immobilizing it, the skull spider can administer its venomous bite to the prey and consume it.<ref name=":6">{{Cite journal|last=Jackson|first=R. R.|last2=Brassington|first2=Roxanne J.|date=1987|title=The biology of Pholcus phalangioides (Araneae, Pholcidae): predatory versatility, araneophagy and aggressive mimicry|url=https://zslpublications.onlinelibrary.wiley.com/doi/abs/10.1111/j.1469-7998.1987.tb01531.x|journal=Journal of Zoology|language=en|volume=211|issue=2|pages=227–238|doi=10.1111/j.1469-7998.1987.tb01531.x|issn=1469-7998}}</ref><ref name=":0" />

Even forms of prey that do not fully make it onto the skull spider’s web aren’t safe. Often, the prey will trip over the edges of the skull spider’s web, thus providing the skull spider with an optimal time to attack. Pholcus phalangioides is capable of clinging onto its web with two of its legs while the rest of its body leans out of the web and shoots silk in the direction of its prey to subdue it.<ref name=":6" />

== Common Myths ==


==Behaviour==
=== Bite ===
It is a common misconception that the daddy long-legs spider is incapable of biting humans due to an inability of their fangs to penetrate our epidermis. This is untrue based upon the fact that the fangs of the spider are roughly 0.25 mm long while the thickness of our skin’s [[epidermis]] is less than that at around 0.1 mm long.<ref name=":0" /><ref>{{Cite web|title=Anatomy of the Skin|url=https://www.utmb.edu/pedi_ed/CoreV2/Dermatology/page_03.htm|access-date=2020-10-21|website=www.utmb.edu}}</ref>
[[File:Pholcus phalangioides - Palestine.webm|thumb|left|Fighting Pholcus phalangioides]]


=== Venom ===
''P. phalangioides'' is not considered aggressive, its first line of defense being to shake its [[Spider web|web]] violently when disturbed, resulting in rapid bobbing or circular motion that makes it difficult for a predator to precisely strike its body. It can easily catch and eat other spiders (even those much larger than itself, such as ''[[Eratigena atrica]]''{{citation needed|date=July 2016}}), mosquitoes and other insects, and [[woodlice]]. When food is scarce, it will prey on its own kind.
Another commonly held belief is that the daddy long-legs spider is the most venomous spider in the world. Although these spiders are capable of hunting and killing some of the most venomous spiders in the world such as the [[Redback spider|redback]] spider, they themselves are not even close to being as dangerous to humans. In fact, according to researchers [[Greta Binford]] and Pamela Zobel-Thropp, the effects of daddy long-legs venom on humans and other mammals is negligible. It has been shown that in humans, the skull spider bite simply results in a mild stinging sensation that has no long-term health consequences.<ref>{{Cite journal|last=Zobel-Thropp|first=Pamela A.|last2=Mullins|first2=Jennifer|last3=Kristensen|first3=Charles|last4=Kronmiller|first4=Brent A.|last5=David|first5=Cynthia L.|last6=Breci|first6=Linda A.|last7=Binford|first7=Greta J.|date=2019|title=Not so Dangerous After All? Venom Composition and Potency of the Pholcid (Daddy Long-Leg) Spider Physocyclus mexicanus|url=https://www.frontiersin.org/articles/10.3389/fevo.2019.00256/full|journal=Frontiers in Ecology and Evolution|language=English|volume=7|doi=10.3389/fevo.2019.00256|issn=2296-701X}}</ref> A recent study has even shown that [[Pholcidae]] venom has a relatively weak effect, even on insects.<ref>{{cite web|date=|title=Have you heard this one?|url=https://spiders.ucr.edu/daddy-long-legs|access-date=2019-12-16|website=Department of Entomology|publisher=UC Riverside|quote=}}</ref>


== Potential Medicinal Benefits ==
Peak breeding in this species occurs between June and September.<ref name=animaldiversity>{{cite web
The use of spider silk in the medical field has gained much recognition over the last twenty years. Silk has been praised for its wound healing purposes due to the fact that it contains important very important compounds such as [[vitamin K]]. Spider silk is primarily composed of proteins made up of [[non-polar]] amino acids such as [[glycine]] and [[alanine]]. However, it also contains the organic compound [[pyrrolidine]] which functions to hold the silk’s moisture and potassium nitrate which prevents any fungal or bacterial growth from occurring on the silk.<ref>{{Cite journal|last=Blamires|first=Sean J.|last2=Tseng|first2=Yi-Hsuan|last3=Wu|first3=Chung-Lin|last4=Toft|first4=Søren|last5=Raubenheimer|first5=David|last6=Tso|first6=I.-Min|date=2016-05-24|title=Spider web and silk performance landscapes across nutrient space|url=https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4877650/|journal=Scientific Reports|volume=6|doi=10.1038/srep26383|issn=2045-2322|pmc=4877650|pmid=27216252}}</ref><ref name=":4" />
| last = Ferrick
| first = A.
| title = ADW: Pholcus phalangioides: INFORMATION
| publisher=[[Animal Diversity Web]]
| year = 2002
| url = http://animaldiversity.ummz.umich.edu/site/accounts/information/Pholcus_phalangioides.html
| accessdate = 2016-08-28}}</ref> The female holds the {{citation needed span|20 to 30|date=August 2016}} eggs in her [[pedipalp]]s.<ref name=animaldiversity /> Spiderlings are transparent with short legs, and change their skin about 5 or 6 times as they mature.


In a study from 2015 in Malaysia, researchers determined that spider silk from Pholcus phalangioides was able to stimulate cellular metabolic activity in teeth pulp stem cells and human keratinocyte cell line (HaCaT). This study showed that spider silk may be able to stimulate a wide range of cellular activity, and thus provides promise in potentially using spider silk as an ingredient in active wound dressings to treat patients.<ref name=":3" />
''P. phalangioides'' has been recorded invading foreign webs and eating the host spiders.<ref>{{Cite journal|last=Jackson|first=Robert R.|last2=Rowe|first2=R. J.|date=1987-01-01|title=Web-invasion and araneophagy by New Zealand and Australian pholcid spiders|journal=New Zealand Journal of Zoology|volume=14|issue=1|pages=139–140|doi=10.1080/03014223.1987.10422692|issn=0301-4223|doi-access=free}}</ref>


Similarly, a study from 2014 out of Iran illustrated that certain antimicrobial biomolecules that are found in the spider silk of daddy long-legs spiders were able to elicit an inhibitory effect on [[Gram-positive bacteria|gram-positive]] bacteria [[Listeria monocytogenes|L. monocytogenes]] and [[Gram-negative bacteria|gram-negative]] [[Escherichia coli|E. coli]], both drug-resistant human [[Pathogen|pathogens]]. Given the fact that there are many infectious bacterial diseases that are resistant to antibiotics, researchers are hoping that the anti-microbial biomolecules of spider silk may hold the answers they are looking for.<ref name=":4" />
==Venom==
There is a common misconception that [[Pholcidae]] are the most [[venomous]] spiders in the world, but are harmless to humans because their fangs cannot penetrate human skin. Both of these claims have been proved untrue. Recent research has shown that pholcid venom has a relatively weak effect, even on insects.<ref>{{cite web |url= https://spiders.ucr.edu/daddy-long-legs|title= Have you heard this one?|date= |website= Department of Entomology|publisher= UC Riverside|access-date= 2019-12-16|quote=}}</ref> In the ''[[MythBusters]]'' episode "[[MythBusters (2004 season)#Daddy Long-Legs|Daddy Long-Legs]]" it was shown that the spider's fangs (0.25&nbsp;mm) could penetrate human skin (0.1&nbsp;mm), but that only a very mild burning feeling was felt for a few seconds.<ref>
{{cite episode
|title = Buried in Concrete, Daddy Long-legs, Jet Taxi
|episodelink = MythBusters (2004 season)#Episode_13_.E2.80.93_.22Buried_in_Concrete.2C_Daddy_Long-legs.2C_Jet_Taxi.22
|url = http://dsc.discovery.com/fansites/mythbusters/episode/episode-tab-07.html
|accessdate = 11 February 2011
|series = MythBusters
|serieslink = MythBusters
|season = 2004
|number = 13
|network = [[Discovery Channel]]
|airdate = 25 February 2004
|url-status = dead
|archiveurl = https://www.webcitation.org/5x6WICDFF?url=http://dsc.discovery.com/fansites/mythbusters/episode/episode-tab-07.html
|archivedate = 11 March 2011
|df = dmy-all
}}{{clr}}
</ref>


==Gallery==
==Gallery==

Revision as of 13:35, 21 October 2020

Pholcus phalangioides
With cranefly prey (spiderlings visible at right)
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Arthropoda
Subphylum: Chelicerata
Class: Arachnida
Order: Araneae
Infraorder: Araneomorphae
Family: Pholcidae
Genus: Pholcus
Species:
P. phalangioides
Binomial name
Pholcus phalangioides
Füssli, 1775

Pholcus phalangioides, commonly known as daddy long-legs spider or long-bodied cellar spider, is a spider of the family Pholcidae. It is also known as the skull spider due its cephalothorax resembling a human skull. This is the only spider species described by the Swiss entomologist Johann Kaspar Füssli, who first recorded it for science in 1775.[1]

Females have a body length of about 8 mm while males tend to be slightly smaller. The length of the spider's legs are on average 5 or 6 times the length of its body.[2]

Pholcus phalangioides has a habit of living on the ceilings of rooms, caves, garages or cellars. This spider species is considered beneficial in parts of the world because it kills and eats other spiders, including species considered dangerous such as redback spiders.[3][4]

Pholcus phalangioides is known to be harmless to mankind and actually provides many benefits to humans, including the potential for the medicinal use of their webs.[5][6][7]

Description

Sexual Dimorphism

Sexual dimorphism is apparent in Pholcus phalangioides in the form of the females being slightly larger than the males of the species. The body length of this species varies anywhere from 6 to 10 mm with the average male being around 6 mm in length and the average female ranging from 7 to 8mm in length.[2][5] As indicated by their nickname “daddy long-legs spider,” these spiders boast eight very long and thin legs which are covered in thin, grey bristles. On average, these legs are roughly 5 to 6 times as long as the spider’s body.[2] The average length of an adult female’s legs, for instance, are roughly 50 mm.[5] The two smaller legs up front are known as palps and are important in the predation and mating of this species. These palps are also notably longer in females of the species.[8]

Morphology

The bodies of daddy long-legs spiders can be divided into two parts: the prosoma, commonly known as the cephalothorax, and opisthosoma, or posterior part of the body which hosts most of the spider's internal organs.[9]The round, peanut-like shape of the spider’s cephalothorax has earned the Pholcus phalangioides species the nickname “skull spider.” The translucent body of the daddy long-legs spider tends to be a grey-pale brown color with a dark spot on the back of the prosoma and some dark, blurred spots on the dorsal side of the opisthosoma.[2]                  

Although some other members of the family Pholcidae have six eyes, Pholcus phalangioides is an eight-eyed spider.[8] The eyes are arranged such that there is a pair of smaller, dark eyes at the front of the prosoma followed by three parallel rows of pairs of larger eyes.[2]

A hard exoskeleton coats the bodies of daddy long-legs spiders. Depending on the age of the spider, this exoskeleton must be shed at different times. Younger spiders tend to moult much more often. During moulting, or shedding, the spider will produce certain enzymes that release the rest of its body from the underlying tissue of its exoskeleton thus allowing it to escape the exoskeleton. The remnant outer skin or exoskeleton is known as the exuvia.[2]

Life Span

It takes about one year for these spiders to mature after they are born, and their life span is generally two years post maturity.[5]

Phylogeny

Close Relatives

Harvestman Spider (Opiliones)

A member of the genus Pholcus in the family Pholcidae, the daddy long-legs spider shares ancestry with roughly 1,340 similar cellar-spiders such as the granddaddy long-legs spider, carpenter spider, and vibrating spider. All of these spiders are known for their characteristic long legs which can range from 5 to 6 times the size of their bodies. This is not to be confused with physically similar organisms such as crane fly insects and harvestmen spiders of the order Opiliones.[10]

Genetic Population Structure

The population sizes of Pholcus phalangioides are influenced greatly by the presence of human buildings since these spiders prefer colder habitats indoors. Given the vast amount of human buildings, most daddy long-legs spider populations tend to be relatively small, dispersed widely, and greatly isolated from one another. This small size combined with low mobility for populations results in an increased importance placed on the role of genetic drift, and more specifically the founder effect, on population structure. Although some gene flow does exist between populations, in studies its importance has been insignificant when compared to that of geographical isolation-driven genetic drift. As a result, most daddy long-legs spiders of the same population living in the same geographical region with have a very low degree of genetic variation. On the other hand, this genetic drift results in significant interpopulation differentiation.[11]

Habitat and Distribution

Habitat

The daddy long-legs spider is not suited for survival in cold environments, and thus it prefers the warmth of the indoors. Members of this species have a particular affinity for dimly lit, dark areas that are quiet and calm. For this reason, these spiders are commonly found in the corners of buildings and people’s homes as well as in attics. Populations of Pholcus phalangioides living outdoors can be found in caves and in between rock crevices.[8][2]

Geographic Distribution

It is hypothesized that this species is native to the subtropical regions of Africa, Europe, and Asia due to its preference for warmer, more humid climates. A synanthropic species, the Pholcus phalangioides has largely had its modern geographic distribution determined by the evolution and spread of humans around the world. Today, these spiders can be found on every continent in the world but are especially concentrated in South America and Europe.[2]

Diet

In a similar fashion to other members of the family Pholcidae, the daddy long-legs spider is carnivorous predator that feeds on insects, other spiders, and small invertebrates. Unlike many other spiders, who simply feed on prey that have gotten stuck in their webs, these spiders will frequently venture out from their own webs to hunt other spiders resting in their respective webs and feed on them or their eggs. In times of low prey availability, both the males and females of the species will turn to cannibalism in order to meet their nutritional needs and survive.[8][2][12]

General Ethology

Pholcus phalangiodes rare conflict between population

Web Patterns

In general, the webs of daddy long-legs spiders are loose and horizontal in nature with many irregularities. These loose, three-dimensional webs are often intertwined with the webs of other skull spiders of the same population. This does not present either spider with any problems, and they live peacefully unless of course resources are low at which point the spiders will turn to cannibalism.[2]

Communication

Pholcus phalangioides is not known as a social species of spider. The extent of this spider’s communication is seen in times of mating. The primary form of communication for these spiders is through the use of touch and chemicals, specifically pheromones.[8][2]

Predation Behaviors

Predators

Pholcus phalangioides feeding on species of wasp in its web

Much like most other species of spider, skull spiders too must be on the lookout for other spiders that could be looking to feed on them. One such family of spiders that is a commonly known predator of Pholcus phalangioides is the Salticidae, better known as the jumping spiders. Some of these spiders simply leap into the webs of their prey and attack them. Others, employ a certain strategy known as mimicry in order to trick the daddy long-leg spiders and capture them.[13]

A jumping spider species whose aggressive mimicry behavior towards skull spiders has been well studied is the Portia fimbriata species of the genus Portia. This mimicry takes the form of the jumping spider producing certain specialized vibrations near the edge of the skull spider’s web. These vibrations cause the skull spider’s web to oscillate in such a way that it mimics the oscillations that would be produced when a form of prey gets stuck in their web. The jumping spider will then continue on with these vibrations for very long durations of time, up to three days in some instances.[2] Naturally, the skull spider assumes that this is an indication that they have caught some sort of prey and will move toward the host of the vibrations. At this point, the jumping spider is in an optimal position to leap onto and attack the skull spiders, thus subduing them in many instances. In addition to employing mimicry, these jumping spiders are also particularly good at preventing the skull spiders from inducing their whirling defense mechanism which tends to be an effective way for daddy long-legs spiders to defend themselves from predators.[13]

Defensive Behaviors

The primary defense strategy employed by daddy long-legs spiders in moments of predation is the action of whirling. Whirling, or a gyration of the body, consists of the skull spider swinging its body around in a circle repeatedly while its legs remain fixed on the web.[13] This whirling strategy is induced as soon as the skull spider, who is sensitive to touch, recognizes any sort of movement occurring in its web. According to recent research, the duration of this whirling seems to be related to the specific kind of predator that the skull spider encounters. Short-duration whirling can be induced simply by a human touching the skull spider’s web or occasionally by spider of a different species. Long-duration whirling which can last several hours or even days is elicited by members of the P. phalangioides species specifically in response to the presence of the more threatening Salticid, or jumping, spiders much more often than for spiders of other families. The rapid gyrating associated with the whirling disturbs the vision of the Salticid spiders such that they can no longer rely on their acute eyesight to pinpoint the location of the skull spiders. This disruption results in the safety of the skull spiders from an otherwise deadly predator.[14]

Mimicry

Much like the Salticidae family of spiders, the daddy long-legs spider also uses mimicry as a predatory tactic to subdue its prey; however, unlike jumping spiders, recent research hints that they do not rely on vision as a forefront for predation like the Salticids. This mimicry also consists of creating specialized vibrations to trick the prey into thinking that it has caught an insect or another spider. The prey then slowly approaches its supposed catch at which point the skull spider raises up on its long leg. The skull spider patiently waits until the exact moment in which the prey touches one of its legs. At that moment, the daddy long-legs spider quickly immobilizes the spider by using its legs to wrap up the prey in layers of silk. Its long legs give it plenty of distance from the prey to avoid being bitten in retaliation. After immobilizing it, the skull spider can administer its venomous bite to the prey and consume it.[15][2]

Even forms of prey that do not fully make it onto the skull spider’s web aren’t safe. Often, the prey will trip over the edges of the skull spider’s web, thus providing the skull spider with an optimal time to attack. Pholcus phalangioides is capable of clinging onto its web with two of its legs while the rest of its body leans out of the web and shoots silk in the direction of its prey to subdue it.[15]

Common Myths

Bite

It is a common misconception that the daddy long-legs spider is incapable of biting humans due to an inability of their fangs to penetrate our epidermis. This is untrue based upon the fact that the fangs of the spider are roughly 0.25 mm long while the thickness of our skin’s epidermis is less than that at around 0.1 mm long.[2][16]

Venom

Another commonly held belief is that the daddy long-legs spider is the most venomous spider in the world. Although these spiders are capable of hunting and killing some of the most venomous spiders in the world such as the redback spider, they themselves are not even close to being as dangerous to humans. In fact, according to researchers Greta Binford and Pamela Zobel-Thropp, the effects of daddy long-legs venom on humans and other mammals is negligible. It has been shown that in humans, the skull spider bite simply results in a mild stinging sensation that has no long-term health consequences.[17] A recent study has even shown that Pholcidae venom has a relatively weak effect, even on insects.[18]

Potential Medicinal Benefits

The use of spider silk in the medical field has gained much recognition over the last twenty years. Silk has been praised for its wound healing purposes due to the fact that it contains important very important compounds such as vitamin K. Spider silk is primarily composed of proteins made up of non-polar amino acids such as glycine and alanine. However, it also contains the organic compound pyrrolidine which functions to hold the silk’s moisture and potassium nitrate which prevents any fungal or bacterial growth from occurring on the silk.[19][7]

In a study from 2015 in Malaysia, researchers determined that spider silk from Pholcus phalangioides was able to stimulate cellular metabolic activity in teeth pulp stem cells and human keratinocyte cell line (HaCaT). This study showed that spider silk may be able to stimulate a wide range of cellular activity, and thus provides promise in potentially using spider silk as an ingredient in active wound dressings to treat patients.[6]

Similarly, a study from 2014 out of Iran illustrated that certain antimicrobial biomolecules that are found in the spider silk of daddy long-legs spiders were able to elicit an inhibitory effect on gram-positive bacteria L. monocytogenes and gram-negative E. coli, both drug-resistant human pathogens. Given the fact that there are many infectious bacterial diseases that are resistant to antibiotics, researchers are hoping that the anti-microbial biomolecules of spider silk may hold the answers they are looking for.[7]

  • Male with prey
    Male with prey
  • Cellar spider carrying its spiderlings
    Cellar spider carrying its spiderlings
  • Female with egg sac
    Female with egg sac
  • Female with offspring
    Female with offspring
  • Cellar spider in Oxfordshire
    Cellar spider in Oxfordshire
  • Cellar Spider with Green Lacewing
    Cellar Spider with Green Lacewing
  • Web
    Web

References

  1. ^ "The Nearctic Spider Database: Pholcus phalangioides (Fuesslin, 1775) Description". canadianarachnology.org. Archived from the original on 6 November 2009. Retrieved 28 August 2016.
  2. ^ a b c d e f g h i j k l m n Mazza, Giuseppe (23 June 2016). "Pholcus phalangioides". Monaco Nature Encyclopedia. Retrieved 21 October 2020.
  3. ^ Daddy Long Legs – Queensland Museum
  4. ^ FAMILY PHOLCIDAE – Daddy long-leg Spiders
  5. ^ a b c d "Longbodied Cellar Spider". Penn State Extension. Retrieved 21 October 2020.
  6. ^ a b Shahbuddin, M.; Puat, N. A.; Mirghani, M. E. S.; Raus, R.A. (2016), Ibrahim, Fatimah; Usman, Juliana; Mohktar, Mas Sahidayana; Ahmad, Mohd Yazed (eds.), "Natural Silk of Pholcus Phalangioides, a Common Home Spider Species for Wound Healing Applications", International Conference for Innovation in Biomedical Engineering and Life Sciences, vol. 56, Singapore: Springer Singapore, pp. 216–221, doi:10.1007/978-981-10-0266-3_45, ISBN 978-981-10-0265-6, retrieved 21 October 2020
  7. ^ a b c Roozbahani, Hassan; Asmar, Mahdi; Ghaemi, Naser; Issazadeh, Khosro (1 July 2014). "Evaluation of Antimicrobial Activity of Spider Silk Pholcus Phalangioides Against Two Bacterial Pathogens in Food Borne". International Journal of Advanced Biological and Biomedical Research. 2 (7): 2197–2199. ISSN 2383-2762.
  8. ^ a b c d e "BioKIDS - Kids' Inquiry of Diverse Species, Pholcidae: INFORMATION". www.biokids.umich.edu. Retrieved 21 October 2020.
  9. ^ "Opisthosoma - an overview | ScienceDirect Topics". www.sciencedirect.com. Retrieved 21 October 2020.
  10. ^ "Pholcidae Definition and Examples - Biology Online Dictionary". Biology Articles, Tutorials & Dictionary Online. Retrieved 21 October 2020.
  11. ^ Schäfer, Martin A.; Hille, Axel; Uhl, Gabriele B. (2001-01). "Geographical patterns of genetic subdivision in the cellar spider Pholcus phalangioides (Araneae)". Heredity. 86 (1): 94–102. doi:10.1046/j.1365-2540.2001.00815.x. ISSN 1365-2540. {{cite journal}}: Check date values in: |date= (help)
  12. ^ Jackson, Robert R.; Rowe, R. J. (1 January 1987). "Web-invasion and araneophagy by New Zealand and Australian pholcid spiders". New Zealand Journal of Zoology. 14 (1): 139–140. doi:10.1080/03014223.1987.10422692. ISSN 0301-4223.
  13. ^ a b c Jackson, Robert R. (1990). "Predator-prey interactions between jumping spiders (Araneae, Salticidae) and Phokus phalangioides (Araneae, Pholcidae)". Journal of Zoology. 220 (4): 553–559. doi:10.1111/j.1469-7998.1990.tb04734.x. ISSN 1469-7998.
  14. ^ Heuts, B. A; Witteveldt, M; Dionisio Pires, L. M; van Wageningen, F (13 June 2001). "Long-duration whirling of Pholcus phalangioides (Araneae, Pholcidae) is specifically elicited by Salticid spiders". Behavioural Processes. 55 (1): 27–34. doi:10.1016/S0376-6357(01)00157-7. ISSN 0376-6357.
  15. ^ a b Jackson, R. R.; Brassington, Roxanne J. (1987). "The biology of Pholcus phalangioides (Araneae, Pholcidae): predatory versatility, araneophagy and aggressive mimicry". Journal of Zoology. 211 (2): 227–238. doi:10.1111/j.1469-7998.1987.tb01531.x. ISSN 1469-7998.
  16. ^ "Anatomy of the Skin". www.utmb.edu. Retrieved 21 October 2020.
  17. ^ Zobel-Thropp, Pamela A.; Mullins, Jennifer; Kristensen, Charles; Kronmiller, Brent A.; David, Cynthia L.; Breci, Linda A.; Binford, Greta J. (2019). "Not so Dangerous After All? Venom Composition and Potency of the Pholcid (Daddy Long-Leg) Spider Physocyclus mexicanus". Frontiers in Ecology and Evolution. 7. doi:10.3389/fevo.2019.00256. ISSN 2296-701X.{{cite journal}}: CS1 maint: unflagged free DOI (link)
  18. ^ "Have you heard this one?". Department of Entomology. UC Riverside. Retrieved 16 December 2019.
  19. ^ Blamires, Sean J.; Tseng, Yi-Hsuan; Wu, Chung-Lin; Toft, Søren; Raubenheimer, David; Tso, I.-Min (24 May 2016). "Spider web and silk performance landscapes across nutrient space". Scientific Reports. 6. doi:10.1038/srep26383. ISSN 2045-2322. PMC 4877650. PMID 27216252.
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