Madla Cave meshweaver facts for kids
Quick facts for kids Madla Cave meshweaver |
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Cicurina madla is a very rare type of spider also known as the Madla Cave meshweaver. It lives only in Texas, United States. This special spider is found in just a few caves in Bexar County. It's one of several tiny animals that live only in these caves and are considered endangered. Another spider, once called Cicurina venii, was later found to be the same species as C. madla.
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What Does the Madla Cave Spider Look Like?
The Cicurina madla spider is quite unique. It has no working eyes, so it can't see! These spiders are usually a creamy white color.
Female spiders are about 4.8 to 6.7 millimeters long. That's roughly the size of a small grain of rice. Their body has two main parts:
- The cephalothorax (head and chest part) is 2.3 to 3.3 millimeters long.
- The abdomen (belly part) is 2.5 to 3.4 millimeters long.
The fourth leg on these spiders is the longest, measuring about 2.5 to 3.4 millimeters. Female spiders also have special parts called spermathecae that are long and thin. Male spiders have a special part called a palpal bulb with a narrow, long cymbium and an oblong tegulum.
How Scientists Study Cave Spiders
In 2004, a scientist named Cokendolpher created a "troglomorphy index" (TI). This index helps scientists understand how well an animal is adapted to living in caves. It measures how long a spider's legs are compared to its body. Spiders with longer legs usually have higher TI values, meaning they are more adapted to a cave life.
C. madla spiders, including the ones once called C. venii, have TI values above 2.0. This shows their legs are quite long, which is typical for cave-dwelling creatures. Scientists can tell C. madla apart from other spiders in the same area by looking at their TI index, their DNA, and the unique shapes of their body parts.
Where Did the Madla Cave Spider Get Its Name?
Cicurina madla was first officially described by a scientist named Willis J. Gertsch in 1992. In the same year, Gertsch also described another spider, calling it Cicurina venii. He said this spider was found only in Bracken Bat Cave.
The Mystery of Cicurina venii
Only two C. venii spiders were ever collected, and one of them is now lost. The entrance to Bracken Bat Cave is now blocked, so no one can get in. It's also on private land.
In 2018, scientists studied Cicurina spiders from Texas caves. They found that the only known C. venii specimen was actually the same species as C. madla. So, they decided to combine the two names, and now C. venii is considered the same as C. madla.
Scientists think that the C. venii specimen might have been mislabeled or put in the wrong container, and it was actually from Government Canyon Bat Cave. Or, if it really was from Bracken Bat Cave, it means C. madla lives in an even wider area than first thought. The World Spider Catalog, a big list of all known spiders, agrees with this change.
Protecting the Madla Cave Spider
The tiny animals living in the karst caves of Bexar County, like the Cicurina madla spider, are called troglobites. This means they spend their entire lives underground in caves. It's hard for scientists to know exactly how many of these spiders there are because their homes are often hard to reach. Also, the spiders themselves are very small and good at hiding.
Dangers to Cave Spiders
All these cave-dwelling species face similar dangers:
- Habitat Loss: Their homes are destroyed when caves are filled in or dug up for quarries.
- Pollution: Water flowing into the caves can become polluted, harming the spiders.
- Water Flow Changes: Any changes to how water flows through the caves can affect their environment.
- Human Interference: People directly disturbing the caves can also cause harm.
- Invading Species: Some caves are even taken over by harmful insects like the red imported fire ant.
In August 2012, a C. madla spider was found in a natural hole during the construction of a highway underpass in Northwest San Antonio. This discovery actually stopped the $15-million highway project! Biologists have found at least 19 cave features in that area. At least five of these could be home to more of these rare spiders. This shows how important it is to protect these hidden underground worlds.
