|C. citricola from Portugal|
Cyrtophora citricola, also known as the tropical tent-web spider, is an orb-weaver spider in the family Araneidae. It is found in Asia, Africa, Australia, Costa Rica, Hispaniola, Colombia, and Southern Europe. In 2000, it was discovered in Florida.
C. citricola is in the orb web spider family, but its orb webs are considered atypical. Its webs are mesh-like, with a horizontal appearance. The spider has developed distinct and specific prey-capturing techniques using its unconventional webs. The difference in C. citricola's web silk is from physiological changes in its spinning apparatuses. The spider can be social, and its webs are often built in large matrices next to one another.
C. citricola is nocturnal, only performing necessary tasks during the day. During the day, it remains idle and tries to stay out of sight from predators. Most of its foraging and prey capture happen at night. At times it may also have to ward off other spiders in the colony that may try and claim its web.
C. citricola's color can vary greatly. Many spiders sport a black and white pattern while others are brown. Males often appear black. Male and female spiders have a sexual dimorphism. The body length in females normally reaches 10 mm, while males are only 3 mm long.
The common name for C. citricola, “tropical tent-web,” derives from Peter Forsskal's first observations. The spider was first seen in citrus trees and Forsskal described their horizontal webs as nets. 
Peter Forsskal discovered C. citricola in the Arabian Peninsula posthumously naming it Aranea citricola in 1775. It was classified in the Araneidae family because it creates orb-webs. Between 1776 and 1864 the spider was classified under the genus Epeira, another synonym for Aranea, more commonly known as Araneus. The spider was later moved from the genus Aranea genus to Cyrtophora by Eugene Simon in 1864. This decision was made because C. citricola orb webs differ from those constructed by the genus Aranea. C. citricola webs are horizontal and tent-shaped which are similar to other spider's webs in the genus Cyrtophora. Like others in the Cyrtophora family, C. citricola's 2nd, 3rd, and 4th legs have a shorter combined patella and tibia length than femurs within the same legs. Additionally, it shares the same bent-back eye pattern: a typical family defining trait. C. citricola differ from the Manogea genus of orb-web spiders due to its broader cephalic structures.
C. citricola is apart of the family Araneidae because they share three common characteristics. The male palpal faces the mesal direction. The male spider's palpal has an exoskeleton on their bulbous known as a radix. The spider has a thin reflective layer of tissue in the posterior set of its eyes called the tapetum. C. citricola differs from “derived araneids” such as Theridion and Linyphiidae because it lacks smaller aciniform brushes in their median spinnerets. C. citricola is apart of the argiopoid clade because there is a sexual dimorphism between males and females. The sexual dimorphism present in C. citricola separates them from members of the Araneinae subfamily including Nuctenea, Cyclosa, and Mangora. C. citricola is apart of the Cyrtophorinae subfamily and shares the sexual dimorphism trait with the Argiopinae, Gasteracanthinae, and Micratheninae subfamilies. Within the argiopoid clade, C. citricola is a member of the argiopine clade because the upper section of its exoskeleton is hairy. This trait distinguishes C. citricola from the Gasteracanthinae and Micratheninae subfamilies. Within the argiopine clade, C. citricola is a member of the Cyrtophorinae family, which includes the genera Cyrtophora and Manogea. Cyrtophorinae's subfamily defining features are its embolus, the palpal bulb's open duct, running in the counterclockwise direction, and its non-adhesive orb-webs.
Cyrtophora citricola is a medium brown color, however, there are darker brown spots on the abdomen. In Florida male spiders are black, while females vary in their coloring and can camouflage in their webs. The females have white trichobothria. In Turkey, they usually appear brown with grey hair. C. citricola has a distinctive horizontal bifurcation at the posterior abdomen. C. citricola is different from its other relatives because it has two pairs of dorsal tubercles and a pair of posterior tubercles. C. citricola typically has seven denticles. The opisthosoma has two dorsal pairs of protuberances and two posterior lobes.
They are active from the middle of summer to the beginning of fall. Adults mate between June and September.
Cyrtophora citricola build tent-webs that have a horizontal orb web and a network of webs above it web resembling a tent. These webs can be built alone or as part of a colony. The spiders exhibit advantages living in colonies, but there is no selection towards either solitary or colonial living. Within colonies, the horizontal orb webs are solitary and maintained by individuals. Other Araneidae species have a triad complex on their posterior spinnerets which produce a gluey thread material for the webs from the piriform glands. C. citricola lack a triad complex and is unable to make gluey thread web material so it creates a distinct non-sticky, mesh-like web.
C. citricola creates a thick silk strand barrier above the orb and a thinner barrier below the orb. The silk above the web is used to deflect insects onto the orb web below. The webs above and below the horizontal orb webs are communal and maintained by the colony. The horizontal orb web and silk are not sticky. The orb webs appear as a fine mesh curtaining, made of radii and a non-adhesive structural spiral. This is different than the typical Araneidae family webs, as they lack a viscid spiral. These webs are durable, and may have evolved to be created outside of citrus trees. The webs may be large enough to span entire trees and are found on a variety of tree species. C. citricola prefers to build its webs on firm substrates rather than non-firm substrates. Webs built on firmer substrates tend to last for longer periods of time. The webs are strong enough to withstand environmental pressures (i.e. rain and wind). Unlike adhesive webs, which must be respun daily, non-adhesive webs are only repaired when damaged. Most of this damage occurs at the peripheries of colony webs where the costs to create orb-webs is high. The center of these colonies infrequently require repairs, saving the spider the constant investment of respinning the web.
C. citricola typically rest with all of its legs underneath its body when it is not watching over its egg sacs. The spider will sit on the horizontal hub of the web. This positioning occurs during the night and day.
C. citricola participates in web jerking, an act of quickly pulling the radii with a front leg. Web jerking may occur in response to movement in the web and prey capturing. The behavior may allow the spider to accurately find objects in its web, assist in prey location, and transmit signals.
The spider engages in web shaking, motions that cause sudden and rapid shaking of its webs. This shaking is created by a downward motion from the spiders' legs. C. citricola engages in web shaking to dislodge prey stuck in the upper barrier of the web. It may also shake off approaching kleptoparasites.
C. citricola captures its prey in the upper section of the web. The rate of prey per capita due to web deflection is relatively low and may cause spiders to aggregate together. Spiders who live in social aggregates are more efficient at capturing prey than solitary spiders.
The process of prey capturing includes multiple steps. The first step is either biting the prey or wrapping it in silk. The second step is pulling and cutting the prey out of the web. The third step is transporting the prey to the hub of the web by either carrying it in its jaws or rewrapping it and carrying it in silk. The fourth step is feeding on the prey in the hub of the web.
C. citriciola has four attack sequences. In the first variation, the spider wraps its prey and bites it. After biting the prey, the spider removes the prey from the web, rewraps it, and transports it to the hub. The second sequence follows the steps of the first variation but skips the biting stage. The third variation starts with the spider biting its prey and wrapping its prey. Later, the prey is removed and rewrapped before being transported to the web hub. The fourth sequence involves spiders biting and pulling or cutting the prey. The prey is transported to the hub in the spider's jaws. Whether the prey is bitten, wrapped, or both is determined by the type of prey that is captured.
C. citricola preys on moths and flies. These insects are bitten and carried to the hub on silk. Orthopteras are captured eaten by C. citricola using a variety of sequences in its captures. Other common prey include dragonflies, beetles, and pentatomids.
Habitat and distribution
Cyrtophora citricola is found in Asia, Africa, Australia, Costa Rica, Hispaniola, Colombia, and Southern Europe. It is unable to survive in temperature below -1°C. It was also discovered in Florida in 2000. In Florida, C. citricola makes its webs on canal bridges from the east end of Everglades National Park to the east coast. The spider lives in a wide range of environments, but it is most prevalent in olive orchards and undergrowth. C. citricola is also found in tropical agricultural operations.
C. citricola can be found globally unlike its close relatives that are concentrated in specific parts of the world. C. citricola's global presence may be a problem as seen in the Americas. The spider is becoming common in agricultural and urban spaces. It is damaging farm operations. Currently, there are active efforts to remove the spider as its web is known to damage flora.
Cyrtophora citricola exhibits thermoregulative behaviors. This trait is common in web-building spiders, including Nephila clavipes, N. maculata, and Frontinella communis. During the hottest portions of the day, the spider will position themselves so that as little surface area of their body is shown to the sun as possible.
Home range and territoriality
Cyrtophora citricola exhibits territorial behavior over its orb-webs. But tent webs are communal and no aggressive behavior was documented between spiders that travel across these webs. At night there are conflicts between orbless spiders and orb-possessing spiders. These fights occur due to competition for better feeding locations. Larger spiders are typically win in fights over smaller spiders. Invading spiders may come from the colony's periphery, where costs to build webs are often high due to continuous repair and diminished prey capture. Peripheral webs often experience damage from weather and predators whereas central webs remain undisturbed. Conflict arises when an orbless intruder approaches and vibrates the web. This action is a sign of attack and solicits the same response from the defending spider. The vibrations between the attacker and the defender continue for a few minutes. However, the invader rarely captures the web and retreats.
Adult male spiders look for females. These spiders exhibit sexual cannibalism at high rates. Female spiders will often eat males after mating. Females cannibalize males after most successful copulations, up to 100% of the time. Spider age and feeding state have no effect on whether the male will be cannibalized. This sexual cannibalism encourages males to be choosy when picking a female mate. Males prefer to mate younger, well-fed, and virgin females. Females are not as choosy in their male mates, but may prefer well-fed and older males. About 50% of females re-mate within ten days after their first copulation. Sexual cannibalism forces monogamy on the male spiders.
The female begins the mating process. Females traditionally approach the male until they are 1cm from the male. At this point, the male advances quickly towards the female and tries to insert his pedipalp. If successful, copulation begins and lasts for a few seconds. This is the stage at which copulation most often fails.
The male Cyrtophora citricola does not somersault into the female's chelicerae, a maneuver which is common in other cannibalizing spiders. The female bends her cephalothorax and orients herself to attack the male's abdomen while the pedipalp is in the female. The male is eaten and the pedipalp is detached from the female.
The egg sacs of Cyrtophora citricola have a diameter ranging from 12-20mm. These egg sacs are laid in chains of up to 10 sacs in a row on the webs. The eggs are colored bluish- green. Each egg sac contains between 100 and 200 eggs. The eggs are shaped as flat ellipticals. The number of eggs produced depends on various environmental factors, including food availability. Solitary females can produce up to 20% more eggs than females living in colonies. The reduction of eggs in colonies may be due to better parasite protectoin and reduced predation. Females with egg sacs will typically rest directly underneath the egg sac in order to guard them.
Juveniles usually disperse or build their own webs off the maternal webs after four days. Juveniles in larger webs are less likely to leave their mother's web. Mothers feed offspring, but when prey is scarce there is increased sibling aggression. These resource-poor conditions increase the likelihood of early dispersal from the maternal web.
C. citricola prefers to select nest sites and create webs in the forks between branches and leaves.
Cyrtophora citricola may exhibit aggregate social interactions with one another and live cooperatively in groups. This behavior is distinct amongst spiders, as most spiders are solitary. C. citricola make their own individual webs, but these individuals webs are interconnected. The large network of webs with neighboring spiders creates a massive web matrix. Given the large size and visibility of the colonial web, prey who are visually acute may avoiding approaching the colony. If one member of a colonial group senses a nearby predator or prey, they perform a knee jerk on the web. This jerk often begins a chain reaction; up to 75% of nearby spiders may follow suit and jerk their webs as well. Within colonies, there are three zones where spiders may live: the outside, the intermediate, and the inside zones. Spiders living in the intermediate zone have the best rates of prey capture. Larger colonies have higher prey capture rates than smaller colonies do. Spiders in colonies capture prey at higher rates at night compared to day.
C. citricola generally coexist peacefully. They may exhibit aggressive behaviors if another spider tries to take their prey.  Colony living may have evolved because of the foraging benefits of group living for the spiders. Solitary living may be favored when prey is scarce. Conditional sociality is another evolutionary explanation for why group living evolved in this species. One possibility may be protection against parasites or predators. Another possibility is that colonial webs allow juveniles to easily create their first webs.
Some C. citricola live solitarily, alone without other organisms. Solitary spiders have larger webs, produce more eggs, and have more kleptoparasites than colonies. There is no difference in female size and prey capture when comparing colonial and solitary spiders. There are two hypotheses for the limited physical differences between solitary and colonial spiders. The first hypothesis is that spiders can move back and forth between colonial and solitary living throughout their lives. The second hypothesis is that prey capture is similar in both colonial and solitary spiders, allowing for similar physical development. Both hypotheses may explain the many similarities between solitary and colonial spiders.
Argyrodes argyrodes, another species of spider, may steal Cyrtophora citricola's prey and eggs.  In addition, Holocnemus pluchei, also known as daddy long-legs, has been found to build their webs off of C. citricola's webs. Holocnemus pluchei exhibit aggressive behavior towards C. citricola and are observed eating C. citricola juveniles. C. citricola will drop to the ground if attacked, in an attempt to camouflage. C. citricola may also pull all of its legs inwards towards its abdomen.
Argyrodes gibbosus often acts as a kleptoparasite to C. citricola, stealing prey that the C. citricola caught. Argyrodes gibbosus is known to switch strategies depending on where the host is located. Prey is stolen when the host is in the hub of the web. Argyrodes gibbosus was seen waiting for the C. citricola to go foraging before consuming their eggs.
Pediobius pyrgo is a type of wasp that lays its eggs in C. citricola egg sacs. The wasp is present in the Iberian Peninsula and in the Canary Islands. Philolema palanichamyi is another type of wasp that lays its eggs in C. citricola egg sacs. The wasp affects these spiders primarily in the Canary Islands and can parasitize around 40% of egg sacs. Wasp larvae feed on the spider's eggs and each larva will devour significant portions of the egg sacs. The incubation takes approximately seven weeks. Wasp larvae often cause a large portion of parasitized spider egg-sacs to die. Parasitization approximately decreases emerging spiderling populations by 60%.
Protective coloration and behavior
C. citricola can change its abdomen's color to blend in with the environment. The coloring of the female Floridian spiders allows them to appear as brown, dead leaves when sitting in their webs, preventing potential predators from spotting them.
Ornamental trees, fruit trees, and various flowering plants in the genus Eugenia including Eugenia coronata, have high concentrations of Cyrtophora citricola. These plants and trees may experience incomplete death when C. citricola's webs span over their leaves. This may be due to the thickness of the webs that can restrict airflow to the leaves. As a result, some authorities have opted to use high-pressure water sprayers and chemical controls to exterminate colonies.
C. citricola is problematic for many agricultural operations in South American including coffee and citrus plantations. It is listed as an important agricultural pest in the Dominican Republic due to its devastating impact on citrus trees. Additionally, it is increasingly common in the Southern states of North America. In Florida, the spider has become a common backyard nuisance.
- Leborgne, R.; Cantarella, T.; Pasquet, A. (1998-05-01). "Colonial life versus solitary life in Cyrtophora citricola (Araneae, Araneidae)". Insectes Sociaux. 45 (2): 125–134. doi:10.1007/s000400050074. ISSN 1420-9098. S2CID 12052536.
- Rypstra, Ann L. (1979). [http://link.springer.com/10.1007/BF00293677 "Foraging flocks of spiders: A study of aggregate behavior in Cyrtophora citricola Forsk�l (Araneae; Araneidae) in West Africa"]. Behavioral Ecology and Sociobiology. 5 (3): 291–300. doi:10.1007/BF00293677. ISSN 0340-5443. S2CID 37651094. replacement character in
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- Forsskal, Peter (1775). Descriptiones Animalium – Avium, amphiborum, insectorum, vermium quæ in itinere orientali observavit Petrus Forskål.
- Simon, Eugène (1892). Histoire naturelle des araignées. /. Paris: Roret. doi:10.5962/bhl.title.51973.
- Natural History Museum Bern. "NMBE - World Spider Catalog". wsc.nmbe.ch. Retrieved 2020-12-15.
- Scharff, Nikolaj; Coddington, Jonathan A. (1997-08-01). "A phylogenetic analysis of the orb-weaving spider family Araneidae (Arachnida, Araneae)". Zoological Journal of the Linnean Society. 120 (4): 355–434. doi:10.1111/j.1096-3642.1997.tb01281.x. ISSN 0024-4082.
- Levi, Herbert Walter (1997). "The American Orb Weavers of the Genera Mecynogea, Manogea, Kapogea and Cyrtophora (Araneae: Araneidae)". Bulletin of the Museum of Comparative Zoology at Harvard College. 155: 215–255 – via biodiversitylibrary.
- "Colonial Tentweb Orbweaver Cyrtophora citricola". entnemdept.ufl.edu. Retrieved 2020-10-20.
- Elverici, Mert; Teksam, Ilyas; Özkütük, Recep Sulhi; Kunt, Kadir Bogaç (2012-12-20). "Cyrtophora citricola (Araneae: Araneidae: Cyrtophorinae), a first record for Turkey". Arachnologische Mitteilungen. 44: 7–9. doi:10.5431/aramit4402.
- "araneae - Cyrtophora citricola". araneae.nmbe.ch. Retrieved 2020-10-20.
- Yip, Eric C.; Levy, Tanya; Lubin, Yael (2017-07-28). "Bad neighbors: hunger and dominance drive spacing and position in an orb-weaving spider colony". Behavioral Ecology and Sociobiology. 71 (8): 128. doi:10.1007/s00265-017-2357-6. ISSN 1432-0762. S2CID 23620793.
- Peters, Hans M. (1993-10-01). "Functional organization of the spinning apparatus of Cyrtophora citricola with regard to the evolution of the web (Araneae, Araneidae)". Zoomorphology. 113 (3): 153–163. doi:10.1007/BF00394856. ISSN 1432-234X. S2CID 44616019.
- Brenes, Ruth Madrigal (August 2012). "Substrate selection for web-building in Cyrtophora citricola (Araneae: Araneidae)". The Journal of Arachnology. 40 (2): 249–251. doi:10.1636/Hi11-30.1. ISSN 0161-8202. S2CID 86047610.
- "The Predatory Behavior of CYRTOPHORA" (PDF). Arachnol.
- Blanke, R. (1972). "Untersuchungen zur Okophysiologie und Okethologie von Cyrtophora citricola Forskal (Araneae, Araneidae) in Andalusien ". Forma et. Functio. 5: 125–206 – via Florida Department of Agriculture and Consumer Services.
- Sewlal, Jo-Anne Nina; Starr, Christopher K. (2011-05-23). "Preliminary Survey of the Spider Fauna of Great Inagua, Bahamas, W.I." The International Journal of Bahamian Studies. 17 (2): 3. doi:10.15362/ijbs.v17i2.137. ISSN 2220-5772.
- "Tropical Tentweb Spider - Cyrtophora citricola, Gorongosa National Park, Mozambique" by Judy Gallagher is licensed under CC BY 2.0 license. Copyright
- "Cyrtophora citricola (Tent-web spider)". biodiversityexplorer.info. Retrieved 2020-10-20.
- www.biointeractive.org https://www.biointeractive.org/classroom-resources/mate-choice-spiders. Retrieved 2020-10-20. Missing or empty
- Yip, Eric C.; Berner-Aharon, Na’ama; Smith, Deborah R.; Lubin, Yael (2016-06-01). "Coy Males and Seductive Females in the Sexually Cannibalistic Colonial Spider, Cyrtophora citricola". PLOS ONE. 11 (6): e0155433. Bibcode:2016PLoSO..1155433Y. doi:10.1371/journal.pone.0155433. ISSN 1932-6203. PMC 4889064. PMID 27249787.
- Yip, Eric C.; Rao, Dinesh; Smith, Deborah R.; Lubin, Yael (2019). "Interacting maternal and spatial cues influence natal – dispersal out of social groups". Oikos. 128 (12): 1793–1804. doi:10.1111/oik.06531. ISSN 1600-0706.
- Mishra, Abhinav; Rastogi, Neelkamal (2020-09-01). "Unraveling the Roles of Solitary and Social Web-Making Spiders in Perennial Ecosystems: Influence on Pests and Beneficials". Proceedings of the National Academy of Sciences, India Section B: Biological Sciences. 90 (3): 567–576. doi:10.1007/s40011-019-01126-5. ISSN 2250-1746. S2CID 199369382.
- Rypstra, Ann L. (1979). "Foraging Flocks of Spiders: A Study of Aggregate Behavior in Cyrtophora citricola Forskål (Araneae; Araneidae) in West Africa". Behavioral Ecology and Sociobiology. 5 (3): 291–300. doi:10.1007/BF00293677. ISSN 0340-5443. JSTOR 4599237. S2CID 37651094.
- Lubin, YD (1974). "Adaptative advantages and the evolution of colony formation in Cyrtophora". Zoological Journal of the Linnean Society. 54: 321–339. doi:10.1111/j.1096-3642.1974.tb00806.x.
- Leborgne R, Cantarella T, Pasquet A (1998). "Colonial life versus solitary life in Cyrtophora citricola". Insectes Sociaux. 45: 125–134. doi:10.1007/s000400050074. S2CID 12052536.CS1 maint: multiple names: authors list (link)
- Blanke, R (1972). "Field studies on the ecology and ethology of Cyrtophora citricola Araneidae in Andalusia". Forma et Funcio. 5: 125–206.
- Pasquet, Alain; Leborgne, Raymond; Cantarella, Theresa (2010-04-26). "Opportunistic Egg Feeding in the Kleptoparasitic Spider Argyrodes gibbosus". Ethology. 103 (2): 160–170. doi:10.1111/j.1439-0310.1997.tb00015.x.
- Chuang, Angela; Gates, Michael W.; Grinsted, Lena; Askew, Richard; Leppanen, Christy (2019-09-02). "Two hymenopteran egg sac associates of the tent-web orbweaving spider, Cyrtophora citricola (Forskål, 1775) (Araneae, Araneidae)". ZooKeys (874): 1–18. doi:10.3897/zookeys.874.36656. ISSN 1313-2970. PMC 6733805. PMID 31537957.
- Canals L, Mauricio; Solís M, Rigoberto (2013). "¿Es la araña "tigre", Scytodes globula, una predadora efectiva de la araña del rincón, Loxosceles laeta?". Revista médica de Chile. 141 (6): 811–813. doi:10.4067/s0034-98872013000600021. ISSN 0034-9887. PMID 24121589 – via via Florida Department of Agriculture and Consumer Services.
- Serra, C.A.; Jorge, P.E.; Abud-Antun, A.J.; Alvarez, P.; Perguero, B.; Serra, C.A.; Jorge, P.E.; Abud-Antun, A.J.; Alvarez, P.; Perguero, B. (2003). "Invasive Alien Species in the Dominican Republic: Their Impact and Strategies to Manage Introduced Pests". doi:10.22004/AG.ECON.256720. Cite journal requires
- Álvares, É.S.S. & De Maria, M. (2004). First record of Cyrtophora citricola (Forskål) in Brazil (Araneae, Araneidae). Revista Brasileira de Zoologia 21(1):155-156 PDF doi:10.1590/S0101-81752004000100026
- Edwards, G.B. (2012): Cyrtophora citricola (Araneae: Araneidae), a Colonial Tentweb Orbweaver Established in Florida. DPI Entomology Circular 411:. PDF
- Platnick, Norman I. (2009): The world spider catalog, version 10.0. American Museum of Natural History.
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