An Orchard Orb Weaver in Houston, Texas

— This article by Jerry Cates and Troy Bell, first published on 15 December 2012, was last revised on 27 December 2012. © Bugsinthenews Vol. 13:12(02).

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001. Ventral habitus

On 8 November 2012 Troy Bell wrote:

“Hi Jerry, I found this spider in the back yard and was wondering what species it might be.

Attached is a top/bottom photo of it.

Love your website “Bugs in the news”

Thanks for your time

Troy Bell”

Troy, a retired R&D Technician and Product Engineer with Compaq (now a part of Hewlett Packard Computers), currently volunteers with the Houston Museum of Natural Science as a Paleontological prepper and Paleo-CSI field worker. Several times a year he lends a hand to Robert T. Bakker, curator of paleontology at HMNS, traveling to North Central Texas to dig up and prepare fossil remains of reptiles, mammals, and amphibians from the Permian era. Many of the fossils he’s helped unearth and prep are now on display at HMNS. At other times, he and a paleontologist/geophysicist friend assist Thomas Yancey, professor of paleontology at Texas A&M University, with his field research on wood-boring mollusks from the Eocene era.

Clearly, Mr. Bell is possessed of a curious mind, and is no stranger to the world of science. As the excellent images he sent me of this spider attest, neither is he a stranger to the art of photography (he realized, for example, that the only way he would be able to get his camera, a Sony DSC-H10, to focus on the spider instead of the leafy background, was to insert a sheet of white paper below the web). But inasmuch as he was not familiar with the orchard orb weaver, he had to get to the bottom of its identity. So, let’s get on with that:

The genus Leucauge, to which this spider belongs taxonomically, is represented widely throughout the tropical and subtropical world, and presently contains 168 recognized species, many of whom are confined to fairly restricted locales. Two of these — Troy’s Leucauge venusta (Walckenaer, 1842)  and a similar but slightly different spider, Leucauge argyra (Walckenaer, 1841) — are known to be found in North America. Like many if not most spiders of the world, both have undergone something of a taxonomical roller-coaster ride over the past 160+ years. In Ubick’s Identification Guide to North American Spiders north of Mexico, published in 2005, the latter species, Leucauge argyra, which — in the United States — is found primarily in Florida (though, as mentioned below, it has been observed elsewhere along the Gulf Coast, including, for example, Katy, Texas), is identified as Plesiometa argyra. That was the name given to the species by F.O.P.-Cambridge in 1903. But the spider involved was first described by Walckenaer in 1841, who placed it in the genus Tetragnatha. Between that year and 1903 it was re-described under different names a total of five times. By 2005 it had been re-described six more times, four of those under variant names, as the following history, adapted from Norman Platnick’s World Spider Catalog, version 13.0, testifies:

01. Tetragnatha argyra Walckenaer, 1841 (orig. descr. male & female).
02. Linyphia aurulenta C. L. Koch, 1845 (orig. descr. female).
03. Linyphia ornata Taczanowski, 1874 (orig. descr. male & female).
04. Meta a. Keyserling, 1881 (descr. male & female).
05. Argyroepeira argyra McCook, 1894 (descr. male & female).
06. Argyroepeira a. Keyserling, (descr. male & female).
07. Argyroepeira a. Simon, 1894 (descr. male).
08. Argyroepeira aurulenta Simon, 1897.
09. Plesiometa argyra F. O. P.-Cambridge, 1903 (descr. male & female).
10. Leucauge argyra Banks, 1909.
11. L. a. Petrunkevitch, 1930 (descr. male & female).
12. L. aurulenta Archer, 1951 (descr. male & female, removed from synonomy with L. venusta).
13. Plesiometa argyra Archer, 1951 (descr. male).
14. Leucauge argyra Levi, 1980 (descr. male & female, synonomy with Plesiometa argyra asserted).
15. L. a. Nentwig, 1993 (descr. male).
16. Plesiometa argyra Dierkens, 2010 (descr. male).
17. Leucauge argyra Álvarez-Padilla & Hormiga, 2011 (descr. male & female).

In 2005, though some authorities considered it synonymous with Leucauge argyra, it was then generally recognized as Plesiometa argyra. I used that name, in fact, in an article I published in 2008 that featured one of these spiders that had been photographed by Allison M., in Katy, Texas. In 2011, however, new investigations led arachnologists to once again assign it to the genus Leucauge, causing the generic name Plesiometa to fall into disuse (it had held but this species, alone). L. argyra differs from Troy’s specimen, Leucauge venusta, in that — among other things — the latter’s pair of triangular orange/yellow markings on the ventral abdomen are replaced by two longitudinal bands of much the same color. One of these days I must revisit that old article and republish it here, under its current taxonomical name.

By comparison, Troy’s female specimen of the other — the second species in the genus Leucauge that is found in the U.S. — the orchard orb weaver Leucauge venusta, has been described some 31 times over the same period, though 61% of the time — and exclusively since 1951, disregarding Archer’s synonym, L. mabelae — under the presently recognized taxonomical name. The listing below, adapted from Norman Platnick’s World Spider Catalog, version 13.0, shows that this species has been described in the scientific literature under as many as nine distinct binomials since it was originally described by Walckenaer in 1841. That original description placed it in the genus Epeira, which itself has a colorful history, beginning in 1805 when Walckenaer first coined it to embrace those spiders we now consider the common orb weavers (grouped presently under the Araneidae family). Clerck, in 1757, had coined the generic name Araneus for many of these spiders, of which Epeira is now considered a junior synonym.

01. Epeira venusta Walckenaer, 1841: (orig. descr., male).
02. Linyphia (L.) argyrobapta White, 1841: (orig. descr., female)
03. Epeira hortorum Hentz, 1847: (orig. descr. female).
04. Tetragnatha 5-lineata Keyserling, 1864: (orig. descr. male & female).
05. Argyroepeira hortorum Emerton, 1884: (descr. male & female).
06. Argyroepeira hortorum Keyserling, 1893: (descr. male & female).
07. Argyroepeira venusta McCook, 1894: (descr. male & female).
08. Argyroepeira hortorum Emerton, 1902: (descr. female).
09. Leucauge venusta F. O. P.-Cambridge, 1903: (descr. male & female).
10. L. hortorum Banks, 1909:
11. L. argyrobapta Petrunkevitch, 1911:
12. L. v. Petrunkevitch, 1930: (descr. male & female).
13. L. v. Saito, 1933:
14. L. hortorum Franganillo, 1936: (descr. male).
15. L. v. Kaston, 1948: (descr. male & female).
16. L. mabelae Archer, 1951: (orig. descr. male & female).
17. L. v. Archer, 1951: (descr. male & female).
18. L. v. Wiehle, 1967: (descr. male & female).
19. L. v. Levi, 1980: (descr. male & female, synonomy [with L. mabelae?]).
20. L. v. Coddington, 1990: (descr. male).
21. L. v. Hormiga, Eberhard & Coddington, 1995: (descr. male).
22. L. v. Dondale et al., 2003: (descr. male & female).
23. L. v. Álvarez-Padilla, 2007: (descr. male & female).
24. L. v. Álvarez-Padilla & Hormiga, 2008: (descr. female).
25. L. v. Kuntner, Coddington & Hormiga, 2008: (descr. male).
26. L. v. Paquin et al., 2008: (descr. male & female).
27. L. v. Álvarez-Padilla et al., 2009: (descr. male & female).
28. L. v. Dimitrov & Hormiga, 2010: (descr. male & female, synonomy).
29. L. v. Dierkens, 2010: (descr. male & female).
30. L. v. Álvarez-Padilla & Benjamin, 2011: (descr. male & female).
31. L. v. Álvarez-Padilla & Hormiga, 2011: (descr. male & female).

As noted earlier, and shown in the above list, another confusing taxonomical name that has become widely distributed in the scientific literature is Leucauge mabelae. This spider is often described in spider identification books under the common name of Mabel (or Mabel’s) Orchard Spider. For many years (from 1951, when it was originally described by Archer, until 1980, when Levi’s revision established it as synonymous with Leucauge venusta) this was thought to be a separate species. Since 1980, however, it has been recognized as a conspecific variant, differing only in exhibiting a brown coloration where the typical L. venusta is predominantly green in color.

An earlier article on another female of the typical Leucauge venusta was published in BugsInTheNews in 2007, and featured a specimen photographed by Christine, in The Woodlands, Texas.

Leucauge venusta is easily distinguished from many if not all of its co-generic relatives by the arrangement of its visible markings, but it would be foolish to suggest that we can be absolutely certain of this particular specimen’s taxonomical identity citing nothing but those characters. A microscopic examination of the genitalia, both of the male and the female (we know this is a female for two reasons, first because — see fig. 108 — it lacks an obvious bulb on the distal tip of its palps, and second because — see fig. 111 — it is in possession of a sclerotized epigynum) is required to arrive at such a determination, and such an examination is impossible from these photographs alone. The best that can be said is that it has all the outward appearances of L. venusta, and we cite as our authority the dichotomous key published by Herbert W. Levi in Ubick, et al., 2005, with the few caveats I’ve mentioned above.

The orchard orb weaver is a small spider that puts itself and its modest web in places where prying human eyes don’t ordinarily go. There, among the leafy boughs of trees and shrubs in the forest, and within the back yard haunts of residential neighborhoods, even when we do look, we rarely let our eyes dwell for long on the minutiae we find in such places. Such smallish organisms, those thing are. How could they be of much consequence in the over all scheme of things?

So functioneth the mind of man. I write these words as a confessedly frequent victim of such thinking. It is part of the human condition. Simple but persistent curiosity, embedded in minds determined to learn more and more each day, is a certain antidote for the human condition. The most fortunate amongst us, who are endowed with a goodly dose of that antidote, gladly take their medicine every day.

Whenever I pause to smell the flowers, I study the immediate surroundings to see what mysterious and interesting creatures can be found there. Driven by such a mood, surveying my own back yard in Central Texas — particularly in mid-summer — I may find one or two of these small, beautiful spiders, nestled among the lowest branches of a Pyracantha or a cedar elm. Always they impress me with their understated elegance. Never does the spider or its web flaunt its presence. The out-of-the-way web it builds is oriented, atypically for its larger folk, in the horizontal plane; as a result we humans are not as likely to realize we’ve bumped into one in the field, the way we are when we come across the in-your-face webs of ordinary orb weavers like the yellow garden spider or the arabesque orb weaver. Both of the latter, you know, brazenly stretch their webs directly across our garden paths — the former during the day, the latter at night —  as though begging for a tête à tête encounter.

Although the diminutive orchard orb weaver is adorned with bright colored splotches, it usually hangs upside down in its web, with its bright orange spots showing upward and to the side. I suspect (with but the scarcest bit of evidence) that the orange markings on its ventral abdomen are specially intended to attract its favorite prey — small dipterans such as fruit flies. These, while flying by and looking down, would see what appears as a potentially nutritious morsel of berry or fruit. Venturing closer, then attempting to pass through the orbicular snare under which the spider hangs, their goose, as it were, gets cooked. In life, he who has the appetite sometimes becomes the main course…

My hypothesis is based strictly on the observation that this spider’s orange ventral markings are not directly coincident with its epigynum (it is, as earlier mentioned, a female; the male of the species is much smaller, and rarely seen except early in the year, while fidgeting impatiently at the edge of a virginal female’s web), as similar markings tend to be with most ordinary orb weavers. With those spiders the markings may assist the male in precisely positioning his sperm-charged pedipalps during copulation. These two characters are so distant from one another, as fig. 108 makes clear (the epigynum is in the exact center of the image), that their functionality during mating seems doubtful. But anyone who happens upon one of these spiders in the field is immediately drawn to the sparkle of orange from the markings on its belly. Just as would be a fly, looking for a berry to taste.

More to come…

100. Lateroventral habitus

101. Ventroposterior habitus

102. Ventral habitus

103. Lateroposterior habitus

104. Lateroposterior body

105. Lateroposterior habitus

106. VFL body

107. VFL habitus

108. Pedicel & epigynum

109. Ventral abdomen

110. Ventral body

111. Ventral carapace

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Taxonomy:

• Kingdom Animalia (an-uh-MAYHL-yuh) — first described in 1758 by the Swedish taxonomist Carolus Linnaeus (1707 – 1778), using the Latin word animal = “a living being,” from the Latin word anima = “vital breath”, to refer to multicellular, eukaryotic organisms whose body plans become fixed during development, some of which undergo additional processes of metamorphosis later in their lives; most of which are motile, and thus exhibit spontaneous and independent movements; and all of whom are heterotrophs that feed by ingesting other organisms or their products;
• Phylum Arthropoda (ahr-THROPP-uh-duh) — first described in 1829 by the French zoologist Pierre André Latreille (1762 – 1833), using the two Greek roots αρθρον (AR-thron) = jointed + ποδ (pawd) = foot, in an obvious reference to animals with jointed feet, but in the more narrow context of the invertebrates, which have segmented bodies as well as jointed appendages;
• Subphylum Chelicerata (kuh-liss-uh-RAY-tuh) — first described in 1901 by the German zoologist Richard Heymons (1867 – 1943) using the Greek noun χηλη (KEY-lay) = a claw, talon, or hoof + the Greek noun κερας (Ser-as) = an animal’s horn + the Latin suffix ata — which by convention is suffixed to the names of animal subdivisions — to refer to animals that have specialized appendages before the mouth that they use in feeding, capturing and securing prey and that — in the case of spiders — are further equipped to inject venom and digestive agents into their prey; 
• Class Arachnida (uh-RAKH-nih-duh) — first described in 1812 by the French naturalist and zoologist Jean Léopold Nicolas Frédéric Cuvier (1769 – 1832), usually referred to as Georges Cuvier, using the Greek noun αραχης (uh-RAH-kes) = a spider, in reference to all eight-legged arthropods, including such disparate animals as ticks, mites, scorpions, harvestmen, solpugids, and spiders;
• Order Araneae (uh-RAY-neh-ee) — first described in 1757 by the Swedish entomologist and arachnologist Carl Alexander Clerck (1709 – 1765), who used the Latin word aranea = a spider or a spider’s web, to refer to eight legged arthropods that spin webs;
• Suborder Opisthothelae (oh-PIS-thoh-THEH-lee) — first described in 1990 by the American arachnologists Richard C. Brusca and Gary J. Brusca, who used the Greek words οπισθεν (oh-PIS-thehn) = behind, at the back, yet to come + θηλη (THEE-lee) = nipple or teat, to distinguish this grouping of spiders from the more primitive spiders in the suborder Mesothelae, in that certain characters (e.g., tergite plates, ganglia in the abdomen, and — in particular, inasmuch as the suborder name is a direct reference thereto — median-positioned spinnerets) of the latter are absent in the former; thus spiders in this suborder have spinnerets positioned at the hindmost portion of the abdomen;
• Infraorder Araneomorphae (uh-RAY-nee-oh-MOHR-fee) — distinguished from the mygalomorphae by having opposing fangs that open and close perpendicular to the spider body’s longitudinal axis, in a pinching action, whereas, in the mygalomorphae (e.g., tarantulas and trapdoor spiders), which have fangs that open and close more nearly in alignment with the spider body’s longitudinal axis.
• Series Entelegynae (inn-TELL-uh-jiy-nee) — araneomorph spiders which, unlike the Haplogynae, have hardened, i.e., sclerotized, female genitalia. Foelix (2011) points out that “entelegyne spiders have more complex reproductive organs (with an epigyne and separate fertilization ducts in the female)…” and that “Male entelegyne genitalia are very diverse…“; the entelegynae series is presently divided into 19 distinct superfamilies, though 7 entelegyne families are of uncertain placement (incertae sedis) and thus not included in the recognized superfamilies;
• Superfamily Araneoidea (AHR-uh-nee-OY-dee-uh) — 15 families of entelegyne spiders;
  • Family Anapidae (Simon, 1895) — 38 genera containing 150 species (Platnick, WSCv13.0); generally small (less than 2 mm long) rain forest spiders that mostly inhabit ground level detritus; many are orb weavers whose diminutive webs are 3 cm or less in diameter; most are native to New Zealand, Australia and Africa, though several genera are native to Japan, China, & Korea; the species Comaroma simoni and all three species of the genus Zangherella occur in Europe; in the United States, the species Gertschanapis shantzi (Gertsch), and Comaroma mendocino (Levi) are found in California;
  • Family Araneidae (Simon, 1895) — 169 genera containing 3,031 species (Platnick, WSCv13.0); known generally as typical orb weavers, thus the most common group of spiders that craft spiral, wheel-shaped webs from whose shape their common name is derived; these spiders have eight roughly similar eyes, generally hairy or spiny legs that lack stridulating organs; they are cosmopolitan, and worldwide comprise 168 genera and 3,006 species in 168 genera;
  • Family Cyatholipidae (Simon, 1894) — 23 genera containing 58 species (Platnick, WSCv13.0); unknown before the late 19th century, these are mostly sheet web spiders that live in moist, high-elevation forests in Africa, Madagascar, New Zealand, and Australia; one species (Pokennips dentipes) native to Jamaica;
  • Family Linyphiidae (Blackwall, 1859) — 589 genera containing 4,419 species (Platnick, WSCv13.0); distributed worldwide, exceeds all families in terms of total recognized genera, second only to the Salticidae in terms of total recognized species; because these spiders are small and poorly known their taxonomy is in a constant state of flux; they are often described as sheet weavers and money spiders, the former for the shape of their webs, the latter from superstitious belief that encountering one of these spiders under certain circumstances portends of good fortune;
  • Family Mysmenidae (Petrunkevitch, 1928) — 23 genera containing 123 species (Platnick, WSCv13.0); small spiders distributed worldwide; in North America confined to subtropical southern U.S., Mexico, and Central America; includes, in America, the genus Mysmenopsis, comprised of tiny, tropical and subtropical kleptoparasitic (parasites by theft) spiders that mostly live in the funnel-webs of diplurid spiders, with a few well-known exceptions;
  • Family Nephilidae (Simon, 1894) — 4 genera containing 61 species (Platnick, WSCv13.0); distributed worldwide in the tropics and subtropics, all of which are distinguished from other orb weavers for their habit of only partially renewing their webs, while other orb weavers generally rebuild their webs daily;
  • Family Nesticidae (Simon, 1894) — 9 genera containing 209 species (Platnick, WSCv13.0); scaffold-web spiders, distributed worldwide, mostly associated with caves or overhangs; closely related to the Theridiidae family (comb-footed spiders), possessing as with the theridiids a comb, on the tarsi of leg IV, which is used to draw silk from the spinnerets;
  • Family Pimoidae (Wunderlich, 1986) — 3 genera containing 37 species (Platnick, WSCv13.0); considered remnants of a formerly more widely distributed grouping of spiders; distributed presently along the west coast of North America, in the Alps, the Apennines, and the Cantabrian Mountains of northern Spain, and in the Himalayas; in North America one genus (Pimoa) is recognized, comprised of 13 species;
  • Family Sinopimoidae (Li & Wunderlich, 2008) — 1 genus containing 1 species (Platnick, WSCv13.0); Sinopimoa bicolor, whose taxonomical status is in dispute;
  • Family Symphytognathidae (Hickman, 1931) — 7 genera containing 66 species (Platnick, WSCv13.0); generally small spiders; distributed in the tropics of Central and South America, Australia, Africa, Japan, and Southeast Asia;
  • Family Synaphridae (Wunderlich, 1986) — 3 genera containing 13 species (Platnick, WSCv13.0); distributed along the Mediterranean coastline of southern Europe, in Madagascar, the Canary Islands, Croatia, Egypt, the Ukraine, and Turkmenistan;
  • Family Synotaxidae (Simon, 1894) — 14 genera containing 82 species (Platnick, WSCv13.0); distributed in Central and South America, New Zealand, and Australia;
  • Family Tetragnathidae (Menge, 1866) — 47 genera containing 957 species (Platnick, WSCv13.0); distributed worldwide; generally known as long-jawed orb weavers that weave small to medium sized orb webs with open hubs, widely separated radii and spirals, no signal lines, and no retreats;
  • Family Theridiidae (Sundevall, 1833) — 121 genera containing 2,350 species (Platnick, WSCv13.0); three-dimensional space-web builders, generally known as cobweb, tangle-web, or comb-footed spiders;
  • Family Theridiosomatidae (Simon, 1881) — 16 genera containing 89 species (Platnick, WSCv13.0); generally known as ray spiders that build cone-shaped webs;
• Family Tetragnathidae (teht-ruh-NATH-uh-dee) — first described in 1866 by the German entomologist Franz Anton Menge (1808 – 1880) who, following a convention established by earlier scientists who used the Greek word τετρας- “tetras-” = four + -γναθος, “-gnathos” = jaw, which means, of course, “four-jaws,” and thus appear to refer more to a Solpugid than a spider. Because the jaws of tetragnathid spiders are paired like those of all other spiders, the etiology of the word τετραγναθος, as applied by early writers — as early as the 2nd century BC by Aelian, and the 1st century BC by Strabo and Pliny, then much later, by the French arachnologist Latrielle in 1804 — to these spiders in particular, is somewhat obscure; Ubick et al., 2005, p. 323, sheds some light on the mystery, and the reader may wish to consult that resource for more details.
• Genus Leucauge (lew-CAWGE) — first described in 1841 by the British zoologist Adam White (1817 – 1878) using the Greek words λευκος (LEW-khos) = bright/white + καυμα (KOW-mah) = embers, to refer to the silvery white dorsal abdomen, in combination with the brightly colored ventral abdomen of many of the members of this genus, often having small, isolated, bright red or yellow spots on a black or green field; comprised of 168 species (Platnick, WSCv13.0) distributed throughout the tropics, worldwide;
• Species venusta (vih-NOOS-tuh) — first described in 1842 by the French civil servant and scientist Charles Athanase Walckenaer (1771 – 1852) using the Latin venustus = lovely, graceful; distributed from Canada to Brazil, common along the East coast and parts of the central US; its web is typically oriented to the horizontal plane, the spider hanging upside-down at the web’s hub, its brightly colored ventral abdomen facing upward;

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References (for a list of all of Jerry’s references to scientific literature, including children’s books, click here):

• Beccaloni, Jan. 2009. Arachnids. Univ. Calif. Press.
  
• Comstock, John Henry. 1912. The spider book: a manual for the study of the spiders and their near relatives. University of Michigan.
• Emerton, James H. 1902. The Common Spiders of the United States. Kindle, hardcopy, and paperback editions.
• Foelix, Ranier F. 2011. Biology of Spiders, Third Ed. Oxford Univ. Press.
• Gertsch, Willis J., 1979. American spiders. Von Nostrand Reinhold Company.
• Herberstein, Marie Elisabeth (Ed.). 2011. Spider Behaviour: Flexibility and Versatility. Cambridge University Press.
• Howell, W. M., and R. L. Jenkins. 2004. Spiders of the Eastern United States: A Photographic Guide. Pearson Edu.
• Jackman, John A. 1999. A Field Guide to Spiders & Scorpions of Texas (Gulf Publishing Field Guide Series). Gulf Press.
• Kaston, B. J. 1978. How to know the spiders (The Pictured key nature series). WCB McGraw Hill.
• Levi, Herbert W., and Lorna Levi. 1987. Spiders and Their Kin (Golden Guide). Golden Press, New York.
• Platnick, Norman I. 2012a. The World Spider Catalog, Version 13.0;  FAM. TETRAGNATHIDAE Menge, 1866: 90 [urn:lsid:amnh.org:spiderfam:0032]. American Museum of Natural History.
• Platnick, Norman I. 2012b. The World Spider Catalog, Version 13.0; Currently Valid Spider Genera and Species. American Museum of Natural History.
• Preston-Mafham, Rod. 1996. The Book of Spiders and Scorpions. Barnes & Noble.
• Ubick, Darrell, and Pierre Paquin, Paula E. Cushing, V. Roth (Editors). 2005, Spiders of North America: An Identification Manual. American Arachnological Society.

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