Signature Spider

Description:

Argiope luzona (Walckenaer, 1841). The spider in the above pictures is a young adult female. It is approximately 6.5 mm. long (excluding legs), but will eventually grow, if it survives, to around 25 mm. In the last couple of years, I have been trying to learn as much as I can about the interesting life of this kind of spider, especially the web decorations for which it is well known. Just a short time ago, I would probably have called the stabilimentum (web decoration), shown here, a "linear stabilimentum", because that is what it looks like when viewed from just a short distance, as in the secong photo above. However, I would have been wrong (and I often was). Adult female Argiope luzona spiders do not make "linear stabilimenta" - they only make "cruciate stabilimenta" (web decorations which form a cross or part of a cross). Before you start thinking that a linear (straight line) decoration could be part of a cross and I am just playing with the terminology, please look at Notes below.

Habitat:

This Signature Spider was spotted in our backyard. Its web was moored between two Banana Plants (Musa x paradisiaca L.) known throughout much of the Philippines as Saging, but in the local dialect, where I live, it is called Batag. Plant information - http://www.stuartxchange.org/Saging.html............

Notes:

In order to avoid ambiguity, the scientists who study this kind of spider have developed terminology for describing web decorations, very carefully. In the case of adult female Argiope luzona spiders, the zigzag silk lines which make a cross or part of a cross are called "arms". If two arms join together (at the hub of the web), as is the case here, the resulting decoration is called a "Two-arm Continuous Cruciate Stabilimentum". If the two arms do not join at the hub, the decoration would be called a "Two-arm Discontinuous Cruciate Stabilimentum". If you look carefully at the first photo above, you will see that there is a join at the hub, making this decoration a "Two-arm Continuous Cruciate Stabilimentum". At first, it all seems to be a bit of a mouthful, but it is done for good reason and the nomenclature soon becomes fairly easy to use and understand.