Gasteracantha cancriformis
| Gasteracantha cancriformis | ||||||||||||
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Gasteracantha cancriformis ( Florida ) |
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| Scientific name | ||||||||||||
| Gasteracantha cancriformis | ||||||||||||
| ( Linnaeus , 1758) |
Gasteracantha cancriformis is a species of spider from the family of the true orb- web spiders (Araneidae), which is native to North and Central America and the Caribbean . The species name " cancriformis " is Latin and means "cancer-shaped" when translated.
distribution
The distribution area extends from California to Cuba and south to Central America and also includes some Caribbean islands such as Jamaica or Cuba.
anatomy
Females have a body length of 5 to 9 mm, the abdomen ( opisthosoma ) is 10 to 13 mm wide. The opisthosoma has a white to orange basic color, in some parts of the distribution area it has a black basic color. It shows six spike-shaped elevations that are colored red or black and protrude diagonally at the edge of the opisthosoma. The tops of these elevations can also be different, e.g. B. orange, colored.
This spider species shows a great regional diversity of different colors and spine shapes in its area of distribution. The top of the opisthosoma is brightly colored from white to orange and has characteristic black crater-shaped points that are mirrored. These points are arranged in four rows. Viewed from the front part of the body, the first row has ten points, the two in the middle two points each, and in the rear part of the opisthosoma there is another row with ten points, whereby the two middle rows are only very small. Since the black coloring of the points runs out of the crater rim, in some specimens the black coloring of closer points partially run into one another. In some animals there are also further black colorations in the middle of the opisthosoma that look like additional points.
As with many spider species, Gasteracantha cancriformis shows a pronounced sexual dimorphism : males are considerably smaller than females and have a body length of 2 to 3 mm. In contrast to the females, they are only a little longer than they are wide. The opisthosoma is gray in color and the spots are white. They also don't have the same spines as the females. These are only indicated and only visible four or five times.
Behavior and way of life
Life expectancy
The animals have a life expectancy of three months (males) to one year (females). Males die just six days after mating with a female, usually in spring. The female only lives until the cocoon is made in the autumn or winter months.
Reproduction
Reproduction could not yet be researched in nature, but only under laboratory conditions. Since research was only carried out on one female and one male, it cannot be determined whether this spider species is polygamous or monogamous in nature and whether a female mates either with only one or with several males. In nature, several males sometimes appear near the female web.
The male's courtship behavior consists of drumming on the female's net with a rhythm of four short, repetitive beats. After the male has approached the female, it is tied up by the female with spider silk. This is followed by the pairing process, which takes about 35 minutes. The male then remains in the net to repeat the pairing a few more times.
The cocoon contains 100 to 260 eggs and is usually assembled on the underside, rarely on the surface of a leaf near the web. First the female spins a loose fabric with few threads, which is attached to the underside of the leaf with stronger threads and lays her eggs in it. Then the cocoon is spun with white and yellowish threads and then covered with some very strong, dark green threads, all of which point in the same direction. Finally, a canopy is woven to connect the cocoon to the leaf. Then the female dies.
The young hatch in winter and after two to five weeks are already fully grown and spread out.
Network construction
One documented net was approximately 30 centimeters in diameter. It is re-spun by females every evening and usually hangs slightly inclined to the vertical. It is built as a symmetrical wheel about one to six meters high. To do this, the female first spins a frame from a vertical thread between two suitable objects and completes it to form a triangle. Radial threads are spun in this frame, which then serve as a support for the approximately twenty concentric circles. After a greater distance to the innermost circle, a fine web is built in the middle, which serves as a base for the spider. The female sits down on this base of the net with the opisthosoma facing up and lies in wait for prey.
The adult males do not build safety nets, but hang on a thread near a female. Up to three males have been found near a female.
food
All kinds of small, flying insects can be used as food, such as B. fruit flies , whiteflies , beetles and smaller moths .
Synonyms
Due to the different colors of the opisthosoma from white to orange and the different shapes and colors of the sting, this spider has been described several times under various species and generic names. Levi described all of these names as synonyms for Gasteracantha cancriformis in 1978 .
Individual evidence
- ↑ a b c d e f g h i Factsheet from University of Michigan Museum of Zoology , accessed July 11, 2008
- ↑ a b Description page spinybacked orbweaver from University of Florida Institute of Food and Agricultural Science , accessed July 3, 2013.
- ↑ Field observations of Gasteracantha cancriformis (Araneae, Araneidae) in a Florida Mangrove Stand (PDF; 145 kB), in: The Journal of Arachnology 17, pages 119-120, 1989
