Sunday, January 13, 2013

Spider Sunday: Orchard Orbweaver

People who think all spiders are creepy, and have no beauty about them whatsoever have never seen an Orchard Orbweaver, Leucauge venusta. This member of the family Tetragnathidae is pearly white or silvery with black, yellow, and red markings, and green legs. It is a truly lovely animal.

The Orchard Orbweaver is one of two species in the genus Leucauge found in North America north of Mexico. The other is L. argyra, found only in Florida. L. venusta occurs from southern Ontario, Canada to Florida, and east to Nebraska and eastern Texas. It also ranges as far south as Panama. I have encountered them in Ohio, Massachusetts, and South Carolina.

Despite its common name, it is not terribly common in orchards, preferring woodland habitats where it builds a horizontal orb web in shrubs, and bushes. Younger spiders have their webs closer to the ground, while adults spin them about 1.5 meters high. The web of an adult spans roughly twelve inches, and features an average of 30 radii (“spokes”) and more than sixty spirals.

The spider hangs upside down in the hub (center) of its snare, displaying a mostly black underside with a red crescent or rectangular spot. Unfortunately, many people mistake the Orchard Orbweaver for a black widow because of that red marking. However, widow spiders are almost never out in their webs during the day, and widows build tangled webs, not orbs.

It is also easy to mistake this species for orb weavers in the genus Mangora, but those spiders spin a vertical orb web, not a horizontal one. The Basilica Spider is also similar, and spins a horizontal orb web, but the orb is pulled into a dome shape. Finally, many sheetweb weavers in the family Linyphiidae resemble Leucauge venusta, but none of them spin orb webs.

Mature females of the Orchard Orbweaver measure 5.5-7.5 millimeters in body length, and males 3.5-4 millimeters. Individuals overwinter as sub-adults, hiding in leaf litter and under loose bark. Adults are found most abundantly in late spring and early summer, perhaps avoiding competition with other web-building spiders that mature later in the season.

The Orchard Orbweaver is shy, and drops from its web straight to the ground if it feels threatened, often disappearing into leaf litter and undergrowth. Don’t let that deter you from looking for it. These are highly photogenic spiders.

Sources: Gaddy, L.L. 2009. Spiders of the Carolinas. Duluth, MN: Kollath+Stensaas Publishing. 208 pp.
Jackman, John A. 1997. A Field Guide to Spiders & Scorpions of Texas. Houston: Gulf Publishing Co. 201 pp.
Jones, Janson. 2011. “Leucauge venusta (Orchard Orbweaver),” Dust Tracks on the Web
Weber, Larry. 2003. Spiders of the North Woods. Duluth, MN: Kollath+Stensaas Publishing. 205 pp.

9 comments:

  1. This tiny beauty is becoming one of my favorite spiders to photograph. Yesterday, May 23, I spent a couple hours in our woods primarily photographing this species. They are truly abundant at this time---but so much smaller than the "typical" summer orbweavers like Araneus species---that they are easy to overlook. There seems to be endless variety in their markings/patterns, too! Thanks for this nice introduction to a remarkable little creature.

    ReplyDelete
    Replies
    1. You are most welcome! At this time of year, depending on what latitude you find them, they are still immature. They are likely to get a little larger than what you are seeing now. I saw some in western Illinois two weeks ago that were definitely not adults yet. They can also be confused with Mangora, which *are* small as adults.

      Delete
  2. I found your site by typing in a description of one of the spiders. I was in the mountains of Tennessee.

    ReplyDelete
  3. Hello. I found this post while searching for information on variations in Leucauge venusta web design. Today I saw two Leucauge venusta not thirty feet away from one another. The first, located at the top of a shrub, had the horizontal orb web I'd come to expect, with a tangle web beneath it. The second, located in a corner of a vertical pole fence, had nothing but a tangle web. In the second case, I assumed that the spider resorted to the tangle web because a corner was not a viable location for an orb web, but there could have been other variables involved. I'd be interested to hear of any similar observations you've made.

    Thanks,

    -Hugh Yeman

    ReplyDelete
    Replies
    1. Interesting observation. Were both specimens female? I ask because I recently learned that when many male orb weavers mature, they lose the capacity to spin normal webs. That said, I don't have anything else to add. I am a dedicated "generalist," and don't always have a great deal of depth on all species I treat here.

      Delete
  4. Hi Bug Eric! I've just come back from hiking, and I took photo of this spider. Can you help me what it is exactly? A friend of mine says, that it is a golden silk spider, but "mine" is completely black. I am very curious. Thank you for your help in advance. :)
    https://lh3.googleusercontent.com/-luqnQQSoMn0/UmrS1batf8I/AAAAAAAABvc/b0Bcdtb8Yao/w263-h350-no/DSCN1912.JPG

    ReplyDelete
    Replies
    1. Zizzer, your friend is correct. The spider is a female Nephila clavipes. I believe the "black" look is just from poor lighting, or perhaps it is simply an older, darker specimen. In the future, please include the geographic location where you found the spider you wish identified.

      Delete
    2. Dear Bug Eric, thank you for your answer! You're right, I should have told you the exact location, I was just very excited and I simply forgot this very important information. :) I took this photo in Brooker Creek Preserve, Tarpon Springs, Florida

      Delete
    3. You are very welcome, Zizzer :-)

      Delete