Zygoballus sexpunctatus

Zygoballus sexpunctatus is a species of jumping spider which occurs in the southeastern United States where it can be found in a variety of grassy habitats. Adult spiders measure between 3 and 4.5 mm in length. The cephalothorax and abdomen are bronze to black in color, with reddish brown or yellowish legs. The male has distinctive enlarged chelicerae (the mouthparts used for grasping prey) and front femora (the third, and typically largest, leg segments). Like many jumping spiders, Z. sexpunctatus males exhibit ritualized courtship and agonistic behavior.

Zygoballus sexpunctatus
Female
Male
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Subphylum: Chelicerata
Class: Arachnida
Order: Araneae
Infraorder: Araneomorphae
Family: Salticidae
Genus: Zygoballus
Species:
Z. sexpunctatus
Binomial name
Zygoballus sexpunctatus
(Hentz, 1845)[1]
Z. sexpunctatus is endemic to the southeastern United States.
Synonyms[1]

Attus sexpunctatus Hentz, 1845

Etymology

The specific name is derived from the Latin sex meaning "six" and punctum meaning "spot".[2] This is a reference to the six spots typically occurring on the abdomen of the male.[3]

History and taxonomy
Hentz's original figure of the male

The species was first described by entomologist Nicholas Marcellus Hentz in 1845 in the Boston Journal of Natural History.[4] Hentz named the species Attus sexpunctatus and described it as follows:[5]

"Black; cephalothorax with the two posterior eyes near the base, which is wide and suddenly inclined at nearly a right angle with the upper surface, cheliceres with a strong inner tooth, and a long, curved fang; abdomen with six dots, and a line in front, white; feet, 1. 4. 2. 3., first pair with enlarged thighs and quite long."

Hentz classified A. sexpunctatus in the subgeneric group Pugnatoriae, which consisted of jumping spiders whose first pair of legs were the longest, followed by the fourth pair. Later entomologists abandoned this classification, which Hentz himself admitted was "somewhat artificial".[5] In 1888, with the recognition of Zygoballus as an independent genus, American arachnologists George and Elizabeth Peckham renamed the spider Zygoballus sexpunctatus.[6] Specimens of Z. sexpunctatus are housed at the Museum of Comparative Zoology, the British Museum, the Milwaukee Public Museum, the American Museum of Natural History, and the Muséum National d'Histoire Naturelle. No type specimens are known.[7]

The genus Zygoballus contains approximately twenty species distributed from the United States to Argentina. Zygoballus is classified in the subfamily Dendryphantinae of the family Salticidae (jumping spiders).[8]

Description
Mouthparts of male (ventral view): 1 = chelicerae, 2 = maxillae, 3 = labium

According to arachnologist B. J. Kaston, adult females are 3.5 to 4.5 mm in body length, while males are 3 to 3.5 mm.[9] The Peckhams' earlier description, however, gives a length of 3 mm for females and 3 to 4.5 mm for males.[10]

Male carapace and chelicerae (lateral view)

The cephalothorax of Z. sexpunctatus is bronze to black in color.[10][11] Like all Zygoballus spiders, the cephalothorax is box-like in shape, being widest at the posterior lateral eyes.[6][12] Numerous white or pale blue scales cover the clypeus ("face") and chelicerae.[10][13] This covering extends around the sides of the carapace, ending beyond the posterior median eyes.[3] In males, the labium is two-fifths as long as the maxillae, and as wide as it is long.[6] The chelicerae of males are greatly enlarged and obliquely oriented, with each chelicera having a prominent inner tooth and a long, curved fang.[5]

The legs are reddish brown, or sometimes yellowish,[10] with the femora of the anterior (first) pair being darker and enlarged, especially in the male.[3][11] The anterior legs have three pairs of long spines on the ventral surface of the tibia and two pairs of spines on the metatarsus.[10] The Peckhams give the following measurements for the lengths of the legs of a male specimen, starting with the anterior pair: 3.7 mm, 2.2 mm, 2 mm, 3 mm.[6] In females, the fourth pair of legs are the longest.[10] The pedipalp in the male has a single tibial apophysis which tapers gradually.[14]

The abdomen is bronze to black with a white basal band and two white transverse bands. The transverse bands are often broken to form six spots. Some or all of these spots may be lacking, however.[3][10]

Epigyne (ventral view). Scale equals 0.1 mm.

Zygoballus sexpunctatus is similar in appearance to Zygoballus rufipes, with whom its range overlaps. The male can be distinguished from Z. rufipes by the large spot of white scales at the beginning of the thoracic slope (which is lacking in Z. rufipes), and by the longitudinal division present on the bulb of the pedipalp (Z. rufipes has a transverse division).[3][10] The female can best be distinguished by the form of the epigyne (the external genital structure).[3]

Habitat and distribution

The range of the species extends from New Jersey to Florida and west to Texas,[15] although it is most commonly found in the southern states.[3] Hentz collected his original specimen in North Carolina.[5] In 1909, the Peckhams reported that the species had been collected from North Carolina, Florida, Texas, Louisiana, and Mississippi.[10] A seven-year survey of spider species in western Mississippi reported the abundance of Z. sexpunctatus as "uncommon".[16] A one-year survey in Alachua County, Florida, reported the species as "rare".[17]

Specimens have been collected from several ecosystems, including old fields,[16][18] river terrace forests,[19] flatwoods,[20] Florida Sand Pine scrub,[20] Slash Pine forests,[21] Appalachian grass balds,[22] and rice fields.[23] Robert and Betty Barnes reported the species as occurring in broomsedge fields throughout the southeastern Piedmont.[24] The species is typically found in the herb stratum (among grasses and other short plants) and may be collected with a sweep net.[19]

Behavior
Ritualized agonistic behavior between Z. sexpunctatus males

Male Zygoballus sexpunctatus spiders are known to exhibit elaborate courtship displays.[25] As a male approaches a female, it will typically raise and spread its first pair of legs and vibrate its abdomen.[12][14] If the female is receptive, it will often vibrate its abdomen as well.[12] The specific patterns of courtship behavior, however, vary between individuals.[25]

Z. sexpunctatus males exhibit ritualized agonistic behavior when encountering other males of the same species.[25] This behavior may include many of the same elements as courtship, such as raising and spreading the first pair of legs and vibrating the abdomen.[12] During agonistic display, males will also extend their pedipalps and fangs.[13] Lethal attacks between males appear to be rare, however.[12]

Diet and ecology

Like most spiders, Zygoballus sexpunctatus is an opportunistic feeder, feeding on a wide range of invertebrate prey. The spider's diet typically includes small insects such as aphids and young caterpillars.[15][26] They have also been known to eat mosquitoes and numerous kinds of small spiders.[13][27]

Mud dauber wasps, which capture and paralyze spiders as a source of food for their larvae, have been shown to prey on both male and female Z. sexpunctatus spiders.[28]

Life cycle

In a study of spider populations in western Tennessee, Zygoballus sexpunctatus spiderlings were reported to hatch from egg sacs in mid summer. The spiders hibernated through the winter in an immature form and reached sexual maturity around late April.[19]

  • Larval stage
  • First instar
  • Immature male
  • Immature male
gollark: Why gibson when it's obviously lyricly?
gollark: Possibly 9, actually. Or 11.
gollark: Obviously I wrote 13.
gollark: #7 looks like Tux1 *badly* trying to imitate someone like HelloBoi.
gollark: No, #9 is obviously citrons.

References
  1. "Taxon details Zygoballus sexpunctatus (Hentz, 1845)". World Spider Catalog. Natural History Museum Bern. Retrieved 2016-07-23.
  2. Glare, P. G. W., ed. (2000). Oxford Latin Dictionary. Oxford: Clarendon Press. pp. 1520, 1750. ISBN 0-19-864224-5.
  3. Comstock, John Henry (1920) [First published 1912]. The Spider Book. Garden City, New York: Doubleday, Page & Co. pp. 696–99.
  4. Platnick, Norman I. (2009). "Salticidae Blackwall, 1841". The World Spider Catalog, Version 10.0. American Museum of Natural History. Retrieved December 21, 2009.
  5. Hentz, Nicholas (1845). "Descriptions and Figures of the Araneides of the United States". Boston Journal of Natural History. 5: 198–202.
  6. Peckham, George; Peckham, Elizabeth (1888). "Attidae of North America" (PDF). Transactions of the Wisconsin Academy of Sciences, Arts, and Letters. 7: 89.
  7. Prószyński, Jerzy (2006). "Zygoballus Peckham et Peckham, 1885". Catalogue of Salticidae (Araneae). Museum and Institute of Zoology, Polish Academy of Sciences. Retrieved 2009-11-24.
  8. Hedin, Marshal C.; Maddison, Wayne P. (March 2001). "A Combined Molecular Approach to Phylogeny of the Jumping Spider Subfamily Dendryphantinae (Araneae: Salticidae)". Molecular Phylogenetics and Evolution. 18 (3): 386–403. doi:10.1006/mpev.2000.0883. PMID 11277632.
  9. Kaston, B. J. (1972). How to Know the Spiders (2nd ed.). Dubuque, Iowa: W. C. Brown Co. p. 266. ISBN 0-697-04899-3.
  10. Peckham, George; Peckham, Elizabeth (1909). "Revision of the Attidae of North America" (PDF). Transactions of the Wisconsin Academy of Sciences, Arts, and Letters. 16: 355–646.
  11. Ressler, I. L. (1918). "Spiders of the Family Attidae Collected in the Vicinity of Ames, Iowa". Proceedings of the Iowa Academy of Science. 25: 230–231.
  12. Hill, David Edwin (2009). "Interactions of Male and Female Zygoballus sexpunctatus Jumping Spiders (Araneae: Salticidae) in Greenville County, SC, USA". Open Source Movies. Internet Archive. Retrieved December 20, 2009.
  13. Hill, David Edwin. "Gallery of Salticid Behavior: A Collection of Digital Photographs that Represent Interesting, or Little-known, Aspects of Salticid Behavior". The Peckham Society. Retrieved December 20, 2009.
  14. Maddison, Wayne P. (1996). "Pelegrina Franganillo and other jumping spiders formerly placed in the genus Metaphidippus (Araneae: Salticidae)". Bulletin of the Museum of Comparative Zoology. Harvard University. 154: 215–368.
  15. Howell, W. Mike; Ronald L. Jenkins (2004). Spiders of the Eastern United States: A Photographic Guide. Boston: Pearson Education. pp. 339–340. ISBN 0-536-75853-0.
  16. Young, Orrey P.; Timothy C. Lockley; G. B. Edwards (1989). "Spiders of Washington County, Mississippi". Journal of Arachnology. 17 (1): 27–41.
  17. Murrill, W. A. (April 1942). "Spiders of Alachua County, Florida". The Florida Entomologist. 25 (1): 7–9. doi:10.2307/3493048. JSTOR 3493048.
  18. Berry, James W. (1970). "Spiders of the North Carolina Piedmont Old-Field Communities". Journal of the Elisha Mitchell Scientific Society. 86 (3): 97–105.
  19. Gibson, Walter William (1947). "An Ecological Study of the Spiders of a River-Terrace Forest in Western Tennessee". Ohio Journal of Science. 47 (1): 38–44.
  20. Corey, David T.; Taylor, Walter K. (1989). "Foliage-Dwelling Spiders in Three Central Florida Plant Communities". Journal of Arachnology. 17 (1): 97–106.
  21. Edwards, G. B. (December 1982). "The Arboreal Salticidae of Florida" (PDF). Peckhamia. 2 (3): 33–36.
  22. Toti, Douglas S.; Frederick A. Coyle; Jeremy A. Miller (2000). "A Structured Inventory of Appalachian Grass Bald and Heath Bald Spider Assemblages and a Test of Species Richness Estimator Performance". Journal of Arachnology. 28 (3): 329–345. doi:10.1636/0161-8202(2000)028[0329:ASIOAG]2.0.CO;2.
  23. Heiss, J. S.; Meisch, M. V. (March 27, 1985). "Spiders (Araneae) Associated with Rice in Arkansas with Notes on Species Compositions of Populations". The Southwestern Naturalist. 30 (1): 119–127. doi:10.2307/3670665. JSTOR 3670665.
  24. Barnes, Robert D.; Barnes, Betty Martin (1955). "The Spider Population of the Abstract Broomsedge Community of the Southeastern Piedmont". Ecology. 36 (4): 658–666. doi:10.2307/1931304. JSTOR 1931304.
  25. Davis, John D. (1974). "Courtship Displays as Isolating Mechanisms in Some North American Jumping Spiders of the Genus Zygoballus (Araneida, Salticidae)". Bulletin of the Association of Southeastern Biologists. 21 (2): 50. (Abstract only).
  26. Warren, L. O.; W. B. Peck; M. Tadic (July 1967). "Spiders Associated with the Fall Webworm, Hyphantria cunea (Lepidoptera: Arctiidae)". Journal of the Kansas Entomological Society. 40 (3): 382–395.
  27. Hill, David Edwin (2009). "Behavior of Zygoballus sexpunctatus Jumping Spiders in Greenville County, SC, USA". Open Source Movies. Internet Archive. Retrieved December 20, 2009.
  28. Muma, Martin H.; Jeffers, Walter F. (June 1945). "Studies of the Spider Prey of Several Mud-Dauber Wasps". Annals of the Entomological Society of America. 38 (2): 245–255. doi:10.1093/aesa/38.2.245.

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