Jump to content

Pholcus phalangioides

From Wikipedia, the free encyclopedia

This is an old revision of this page, as edited by Kekaze (talk | contribs) at 08:50, 1 December 2020 (Separated the initial blurb of information as I felt that it would not make sense in terms of flow for it all to be jumbled into one paragraph.). The present address (URL) is a permanent link to this revision, which may differ significantly from the current revision.

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 humans and 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 as females are slightly larger than the males of the species. The body length of this species varies between male and females. Males tend to range around 6 to 10 mm with the average male being around 6 mm in length. On the other hand, the average female ranges 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, their 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, is 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 P. phalangioides can be divided into two parts: the prosoma and the opisthosoma. The prosma is commonly known as the cephalothorax. The opisthosoma is considered the 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 P. phalangioides 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 differing intervals; younger spiders tend to molt much more often. During molting, 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 exuviae.[2]

Lifespan

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 (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 of the arachnid 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 of populations results in an increased importance placed on the role of genetic drift, more specifically the founder effect, on population structure. Although some gene flow does exist between populations, 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 will 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 P. phalangioides is not suited for survival in cold environments, and thus it prefers the warmth of the indoors and can often be found inside human dwellings. 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

Pholcus phalangioides feeding on species of fly in its web

Similar to other members of the family Pholcidae, the daddy long-legs spider is a carnivorous predator that feeds on insects, other spiders, and other small invertebrates. Unlike many other spiders, who simply feed on prey that have gotten stuck in their webs, these spiders 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] Cannibalism is often used as a last-resort means for obtaining nutrients for survival. Different variations of cannibalism are observed in nature - most often used when resources are scarce and an individual needs to propagate its genes into future generations.

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. Social species of spiders are known to remain in the communities in which they were born in for their entire life. They feed and live communally, usually sharing webs and resources. The extent of the daddy long-legs spiders 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

Much like most other species of spider, P. phalangioides 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 P. phalangioides has been well studied is the Portia fimbriata jumping spider species of the genus Portia. This mimicry takes the form of the jumping spider producing certain specialized vibrations near the edge of the web of P. phalangioides. These vibrations cause the P. phalangioides 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, P. phalangioides 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 P. phalangioides, thus subduing them in many instances. In addition to employing mimicry, these jumping spiders are also particularly good at preventing P. phalangioides from inducing their whirling defense mechanism, which tends to be an effective way for P. phalangioides spiders to defend themselves from predators.[13]

Defensive behaviors

The primary defense strategy done by daddy long-legs spiders in moments of predation is 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 P. phalangioides. 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 P. phalangioides does not rely on vision for predation. 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 P. phalangioides spider raises up on its long legs. The spider patiently waits until the exact moment in which the prey touches one of its legs. At that moment, the P. phalangioides 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 its prey, P. phalangioides 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 web of P. phalangioides aren’t safe. Often, the prey will trip over the edges of the web, thus providing P. phalangioides with an optimal time to attack. P. 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]

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 the human 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

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 near 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 are 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]

Reproductive System

Male Genitalia

Overall Genital System Structure

The genital system of an adult, male daddy long-legs spiders is located in the ventral portion of the opisthosoma and can be characterized by a large pair of testes and thin, twisted vasa deferentia which become thicker upon nearing the genital opening of the male pedipalp. These vasa deferentia distally fuse creating the ductus ejaculatorius of the spider. The ductus ejaculatorius is composed of lumen which contains large quantities of spermatozoa and other secretions. This variety of secretions is not seen in subadult males whose lumen only contains dense secretion matrix. Ventrally surrounding specific portions of the genital tract are apullate silk glands, and overall, the genital system is bordered by parts of the midgut gland. All stages of spermatogenesis are apparent in the adult testes, and the spermatozoa are coiled. In order to reach this stage with a fully formed male genital system, P. phalangioides must first go through two subadult phases.[19]

Stages of Genital Development

The first stage occurs roughly four weeks prior to the daddy long-leg’s final molt. Unlike adult males, young males possess a broad tarsus that does not appear to consist of any internal structures or appendages. Their pedipalps are greatly bent at a joint connecting the between the tibia and patella. The testes at this point in the young male’s life appear very similar to those of the adult males both in terms of physical structure and presence of all stages of spermatogenesis. This spermatogenesis takes place in cysts which contain spermatids. During this time, there is very little observable secretory activity in the testes. In a similar manner to the adult genital system, the vas deferens in young males is connected to the distal, thin part of the testis. The distal portion of the vas deferens is incredibly narrow and is not characterized by the presence of spermatozoa or other secretions. On the other hand, the proximal region consists of a thick epithelium and intricate luminal region containing spermatozoa.[19]

The second stage of development is observed two weeks prior the spider’s final molt. At this point, the pedipalps of the spider are only partially bent, and the internal structures of the tarsus can be seen. The testes are dimensionally very similar to those of subadult stage one males and adult males. Spermatozoa and other secretions are now extensively present in proximal portion of the vas deferens. The distal portion of the vas deferens has also become thinner and is now twisted in a tube-like shape. Like the stage one males, these males still do not appear to contain any sort of secretions or spermatozoa in the distal portion of the vas deferens. This is in contrast to adults where spermatozoa are present in all regions of the vas deferens.[19]

Spermatogenesis

Spermatogenesis for males of the P. phalangioides species commences weeks before maturity and continues throughout their lives.[19]

Female Genitalia

Many female spiders possess sac-like structures where sperm from the male spider is stored; however, females of the P. phalangioides species do not have these receptaculum seminis.[20] Instead, the posterior wall of uterus externus, or genital cavity, serves as the site of sperm storage. The females have two accessory glands located in the dorsal part of the uterus externus. These glands release a secretion into the uterus externus which functions as a matrix to hold the male spermatozoa and seminal fluid in place upon copulation.[21][22]These accessory glands are composed of multiple glandular units, they themselves consisting of two secretory and envelope cells each. The inner and outer envelope cells surround the secretory cells and serve to create a cuticular ductule or canal that runs from the secretory cells to the two pore plates located on the uterus externus. These pore plates are the exit sites for the aforementioned glandular secretion into the uterus externus.[22]

Mating Behaviors

Courtship

Male courtship in daddy long-legs spiders can be observed in four different steps: abdominal vibrations, tapping of the female’s web, web jerking, and tapping the female’s legs. In order to mate with the females, the males must perform courtship in a manner which will not result in the female assuming that the male is prey. Otherwise, the male would be attacked.  

As the males approach the females, they begin to do a series of rapid dorso-ventral vibrations with their opisthosoma. This only occurs once the females have noticed the presence of the males. The males then use the ventral portion of their tarsus to begin tapping on the web of the female either by alternating between legs or tapping with the legs at the same time. This tapping can last up to twenty minutes as the male inches closer to the female. Then, using claws on their tarsus, the males hook onto the web and perform rapid jerk movements using their legs. This back-and-forth movement serves to increase and subsequently decrease tension in the web. On average, this jerking lasts for a few minutes with each jerk lasting less than half of a second. In between sequences of jerking, the males continue to move closer to the females. The males then tap on the female’s legs with their cephalothorax positioned downwards for, on average, eight minutes. At this point, receptive females will take on a specific position in which they are motionless with their opisthosoma turned horizontally and their legs extended outward.[23][21] Before coupling, many of the males will use their pedipalps to cut certain parts of the web closest the female.[21]

Copulation

Copulation begins as the males use their chelicerae to rapidly move back and forth across the female’s ventral body surface. This is an attempt to grab hold of the female’s body and mount onto their epigyne. For some males, it can take up to 100 attempts to properly mount. Once mounted, the males pull the females closer to them resulting in rotation of the female opisthosoma from a horizontal to vertical position. At this point, the male is able to insert his palpal parts into the genital cavity of the female. During the multiple insertions, the male pedipalps are twisted into different motions in a synchronous fashion with the procursi being inserted deeply into the female genital cavity to release sperm into the uterus externus. As the coupling duration lengthens, the amount of palpal insertions decreases. The duration of copulation is dependent upon whether or not the female daddy long-legs spiders have previously mated with any males. If the females have, second males are only allowed to engage in copulation for a few minutes. On the other hand, first males are able to copulate for anywhere between 16-122 minutes.[21] Once the mating has finished, the females often act aggressively towards the males in an attempt to drive them off.[23]

Male Competition

Because palpal, or genital bulb, movements from the males result in the displacement of spermatozoa and other seminal fluid from the female uterus externus, sperm competition exists between males of the P. Phalangioides species. A rival male can attempt to displace the sperm of another male from the female’s genital cavity by copulating with her; however, because the copulation duration is greatly decreased in second males, and thus there is less time to displace a rival’s sperm, it is unlikely that the spermatozoa of rival, second male would greatly outnumber those of the first male in the uterus externus.[21]

Sexual Selection

It is hypothesized that female daddy long-legs spiders will choose which males to mate with based on the morphological characteristics and movement of the male’s palpal bulbs, or pedipalps. All spiders in the family Pholcidae have distinctive pedipalps consisting of a procursus and fused sclerites. The procursus is unique to the pholcid spiders. This tarsal structure can be characterized by its multiple apophyses, lamellar processes, and its conspicuous zone. This zone becomes inflated upon insertion into the female and is crucial to female stimulation.[21]

Biomedical Applications

Medicinal Benefit

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. [24] 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.[25][7]

Antibacterial Activity

A multitude of studies over the past decade have illustrated that certain antimicrobial biomolecules found in the spider silk of daddy long-legs spiders are able to elicit an inhibitory effect on drug-resistant human pathogens including gram-positive bacteria L. monocytogenes, gram-negative E. coli, Staphalococcus aureus, Bacillus subtilis, and Pseudomonas aeruginosa. 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 serve as a natural anti-microbial agent in the future.[26][7][27]

Biological Imaging

Spiders are capable of spinning a multitude of unique silks. These silks vary in the compounds and proteins that they consist of and in their use for the spider. One specific type of silk, known as dragline silk, is of particular interest to researchers due to its high elasticity, toughness, and large tensile strength. In fact, this silk has been shown to be significantly stronger than steel of the same weight. Dragline silk is what you can observe a spider using to, for example, dangle from a ceiling. It serves as the spider’s attachment to its web should it need to retreat from predators or just go back in general. This silk also forms the radial spokes of a spider’s web.[28][29]

To examine the potential role of this dragline silk in biological imaging, researchers from National Yang-Ming University collected this type of silk from a population of Pholcus phalangioides. A resin was then dripped onto the fibers of the silk, and as it condensed, it was molded naturally into a dome or lens shape. By shining a laser onto this lens, the researchers were able to generate high-quality photonic nanojets (PNJs), or high-intensity scattered beams of light. These photonic nanojets could be adjusted by manipulating the amount of time that the silk spends in contact with the resin. This adjustable spider silk-based lens could be used in the future for biological tissue imaging.[29]

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. ^ 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. (January 2001). "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.
  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 20 November 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. ^ "Daddy Long Legs". Spider Research. Retrieved 20 November 2020.
  19. ^ a b c d Michalik, Peter; Uhl, Gabriele (29 June 2005). "The male genital system of the cellar spider Pholcus phalangioides (Fuesslin, 1775) (Pholcidae, Araneae): development of spermatozoa and seminal secretion". Frontiers in Zoology. 2: 12. doi:10.1186/1742-9994-2-12. ISSN 1742-9994. PMC 1182384. PMID 15987506.{{cite journal}}: CS1 maint: unflagged free DOI (link)
  20. ^ "receptaculum seminis". TheFreeDictionary.com. Retrieved 21 November 2020.
  21. ^ a b c d e f "(PDF) Male pedipalp morphology and copulatory mechanismin Pholcus phalangioides (Fuesslin, 1775) (Araneae, Pholcidae)". ResearchGate. Retrieved 21 November 2020.
  22. ^ a b Uhl, Gabriele (1994). "Ultrastructure of the Accessory Glands in Female Genitalia of Pholcus phalangioides(Fuesslin, 1775) (Pholcidae; Araneae)". Acta Zoologica. 75 (1): 13–25. doi:10.1111/j.1463-6395.1994.tb00958.x. ISSN 1463-6395.
  23. ^ a b Bartos, M. (2005). "Quantitative analyses of male courtship behaviour in Pholcus phalangioides". www.semanticscholar.org. Retrieved 22 November 2020.
  24. ^ "A closer look at spider webs – Inside Ecology". Retrieved 20 November 2020.
  25. ^ 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.
  26. ^ Mirghani, M.; Kabbashi, N.; Elfaki, F.; Fahmi, M. Z.; Zulkifli, B. (2012). "BT-201: INVESTIGATION OF THE SPIDER WEB FOR ANTIBACTERIAL ACTIVITY". undefined. Retrieved 20 November 2020.
  27. ^ Vijimole, P.J. (13 July 2020). "INVESTIGATION OF THE PHOLCUS PHALANGIOIDES SPIDER WEB FOR ANTI BACTERIAL ACTIVITY" (PDF). European Journal of Pharmaceutical and Medical Research. 7(8): 732–737.
  28. ^ "Why is spider silk so strong?". Scientific American. Retrieved 20 November 2020.
  29. ^ a b "Spider silk can create lenses useful for biological imaging". ScienceDaily. Retrieved 20 November 2020.