Animal Diversity Web

Diversity

Eriovixia includes 21 species of nocturnal orb-weaving spiders occurring in Southeast Asia and Africa. Eriovixia is a group of nocturnal spiders that use their unique morphology and cryptic coloration to mimic dried leaves and other foliage during the day in order to avoid predation. Formerly considered a synonym of Neoscona, Eriovixia species are characterized by their unique abdominal shape and epigynal structures. (Archer, 1951; Han and Zhu, 2010; Javed, et al., 2016; Yin, et al., 1997)

Geographic Range

The majority of Eriovixia species populate forests throughout South and Southeast Asia, from Japan, West to Bangladesh, and South to the Philippines. Three species are found in Eastern Africa. (Archer, 1951; Han and Zhu, 2010)

• Biogeographic Regions
• oriental
  • native
• ethiopian
  • native

Habitat

Eriovixia species weave their webs in between branches and against tree trunks in the forests they occupy. They primarily live in tropical evergreen forests, but some species reside in forests containing a mix of evergreen and deciduous trees. (Archer, 1951; Han and Zhu, 2010; Javed, et al., 2016; Tso and Tanikawa, 2000)

• Habitat Regions
• tropical
• terrestrial

• Terrestrial Biomes
• forest

Systematic and Taxonomic History

Eriovixia species were originally diagnosed as members of the genus Neoscona described by Simon in 1895. In 1951, Archer designated Eriovixia as its own genus using Eriovixia rhinura as a type species. Eriovixia species have also been described using the synonym Simonarachne. (Archer, 1951; Barrion and Litsinger, 1995; Javed, et al., 2016; Mi, et al., 2010)

• Synonyms

  • Simonarachne
  • Neoscona

• Synapomorphies

  • absence of macroseta in the male pedipalp patella
  • epigynum nearly triangular, with copulatory openings wide and opening dorsally
  • Abdomen extends beyond spinnerets, tail-like in apearance

Physical Description

Eriovixia species have highly diverse morphology. However, there are a few key characteristics that unite the genus and distinguish it from other Araneidae genera. The prosoma of Eriovixia species are covered in long soft hairs, and they have a nearly triangular opisthosoma that tapers posteriorly, as well as spiny legs. Females are typically larger than males, and their epigynum has a short scape fused to curved sclerites that bear two copulatory openings. Eriovixia species are generally small, ranging in size from 4 to 9 mm. Coloration can vary by species, but colors are typically muted yellows, grays, and browns that allow Eriovixia species to blend in with dried foliage during the day. Like most Araneidae, Eriovixia species are mildly venomous, although there are no reports of any humans having been bitten by this reclusive nocturnal genus. (Archer, 1951; Han and Zhu, 2010; Javed, et al., 2016)

• Other Physical Features
• ectothermic
• homoiothermic
• bilateral symmetry
• venomous

• Sexual Dimorphism
• sexes alike
• female larger

Reproduction

Upon maturity, males search for a nearby female with whom to mate. Unsuccessful males do not survive their mating attempt, and even males who succeed in breeding are often eaten by the female immediately after copulation. As such, males generally only mate once, while a female may mate multiple times over her lifetime. (Archer, 1951)

• Mating System
• polyandrous

Little is known about the frequency of breeding in Eriovixia species as specimens have not been individually tracked across time. However, reproduction events have been observed at various times throughout the year, and Eriovixia species reside in tropical habitats, suggesting that breeding occurs more than once per year, in no distinct season. (Archer, 1951; Barrion and Litsinger, 1995; Javed, et al., 2016; Tso and Tanikawa, 2000)

• Key Reproductive Features
• year-round breeding
• gonochoric/gonochoristic/dioecious (sexes separate)
• sexual
• fertilization
  • internal
• oviparous

Each female watches over her eggs until they hatch, attaching her egg sac to the underside of a leaf near where she builds her web each night. Once the young hatch, there is no longer any parental investment, and they may be cannibalized by their mother or other spiders in the area. (Yin, et al., 1997)

• Parental Investment
• no parental involvement
• precocial
• pre-hatching/birth
  • provisioning
    • female
  • protecting
    • female

Lifespan/Longevity

Little is known about the average lifespan of Eriovixia species due to their elusive nature. However, what data there is suggests a lifespan of around one year, which is similar to other Araneidae genera. (Archer, 1951; Tso and Tanikawa, 2000)

Behavior

Eriovixia species are nocturnal, dismantling their webs in the morning and rebuilding them each night. During the day, these spiders rest and hide among dried leaves and forest litter. Some species press themselves on the underside of leaves, and others simply rely on their coloration and shape to blend into foliage. Eriovixia species are solitary, and generally do not travel great distances once they have established a prime place to build their webs. Once mature, males venture out more frequently until they find a mate, and may establish a temporary web near hers before attempting mating. (Archer, 1951; Javed, et al., 2016; Tso and Tanikawa, 2000; Yin, et al., 1997)

• Key Behaviors
• nocturnal
• motile
• sedentary
• solitary

Communication and Perception

Nocturnal Eriovixia species have poor vision, especially in daylight. They largely rely on mechanoreception and are quite sensitive to air currents, thanks in part to the hairs on their prosoma, which act like whiskers. (Archer, 1951; Javed, et al., 2016)

• Communication Channels
• tactile
• chemical

• Other Communication Modes
• pheromones

• Perception Channels
• visual
• tactile
• vibrations
• chemical

Food Habits

Eriovixia species are sit-and-wait carnivores. Like all other Araneidae genera, they build a circular web to capture their prey before injecting it with venom and beginning extracorporeal digestion. The most common prey of Eriovixia species are small flying insects, such as Diptera, Orthoptera, and some Hymenoptera species. They also occasionally eat other arachnids that find themselves caught in a web, including smaller individuals of the same species. (Han and Zhu, 2010; Javed, et al., 2016; Mi, et al., 2010)

• Primary Diet
• carnivore
  • insectivore
  • eats non-insect arthropods

Predation

No specific predators of any Eriovixia species are known; However, like other Araneidae genera, they are likely primarily preyed upon by bird species. The most significant anti-predator adaptation of Eriovixia species is their behavior of dismantling their webs each morning and remaining hidden during the day when predators are most active. Secondarily, their abdominal shape and coloration allows them to blend in with foliage, making them even more difficult to spot. (Archer, 1951; Han and Zhu, 2010)

• Anti-predator Adaptations
• cryptic

Ecosystem Roles

Eriovixia species are not known to engage in mutualistic, commensalist, or parasitic relationships with any other species within their ecosystem. Although not considered a keystone group, Eriovixia species, along with other spiders, are important controls on insect populations, reducing the spread of diseases caused by insect vectors. (Archer, 1951; Han and Zhu, 2010)

Economic Importance for Humans: Positive

Eriovixia species serve as important biological controls on pest populations, including agricultural pests and those that carry human diseases. Notably, Eriovixia excelsa in citrus agroecosystems is a control for crop damaging flies. In addition to their role as predators, research has shown silk from Eriovixia species has potential antibacterial effects. This silk can be used to source antibiotics against Streptococcus sp., Pasteurella sp., and Staphylococcus sp. (Keswani, 2014; Tahir, et al., 2019)

• Positive Impacts
• source of medicine or drug
• controls pest population

Economic Importance for Humans: Negative

There are no known adverse effects of Eriovixia species on humans.

Conservation Status

Eriovixia species are not considered protected in any region, and there is no known conservation concern.

• IUCN Red List [Link]

  Not Evaluated

Other Comments

A recently discovered Eriovixia species, Eriovixia gryffindori is so-named because of its striking resemblance to the sorting hat, a magical object from J.K. Rowling's Harry Potter novel series. One synonym for Eriovixia, "Simonarachne," is a patronym honoring the scientist who initially described the group, albeit under a different name. (Javed, et al., 2016)

Contributors

Binyamin Salzano (author), Colorado State University, Genevieve Barnett (editor), Colorado State University.

References

Archer, A. 1951. Studies in the Orbweaving Spiders (Argiopidae). American Museum Novitates, 1487: 1-52.

Barrion, A., J. Litsinger. 1995. Riceland Spiders of South and Southeast Asia. Wallingford, UK: CAB International & International Rice Research Institute.

Han, G., M. Zhu. 2010. Taxonomy and biogeography of the spider genus Eriovixia (Araneae: Araneidae) from Hainan Island, China. Journal of Natural History, 44: 2609-2635.

Javed, A., K. Rajashree, J. Sumukha. 2016. A New Species Of Dry Foliage Mimicking Eriovixia Archer, 1951 From Central Western Ghats, India (Araneae: Araneidae). Indian Journal of Arachnology, 5: 24-27.

Keswani, S. 2014. DIVERSITY, POPULATION AND MICROHABITAT USED BY SPIDERS IN CITRUS AGROECOSYSTEM. Indian Journal of Arachnology, 3: 90-101.

Mi, X., X. Peng, C. Yin. 2010. The orb-weaving spider genus Eriovixia (Araneae: Araneidae) in the Gaoligong Mountains, China. Zootaxa, 2448, No 1.: 39-51.

Tahir, H., A. Sattar, S. Qamar, M. Mukhtar, I. Liaqat. 2019. ANTI-BACTERIAL POTENTIAL OF SILK RECOVERED FROM ERIOVIXIA EXCELSA (SIMON, 1889) SPIDER. Journal of Animal and Plant Sciences, 29: 625-628.

Tso, I., A. Tanikawa. 2000. New Records of Five Orb-web Spiders of the Genera Leucauge, Mesida, and Eriovixia (Araneae: Tetragnathidae and Araneidae) from Taiwan. Acta Arachnologica, 49: 125.

Yin, C., J. Wang, M. Zhu, L. Xie, X. Peng, Y. Bao. 1997. Fauna Sinica: Arachnida: Araneae: Araneidae. Beijing, CH: Science Press.