Signature Spider (Male & Female)

Description:

Argiope luzona, in the Philippines, is locally called “Gagamba X” which translates into “Spider X” in English. Since this is much shorter than the common name “Signature Spider”, I would like to use “Spider X” in this spotting. The female Spider X, shown here, might have helped me to understand, a little better, an aspect of its growth and development which has been confusing me. I will try to explain (obviously not very scientifically, just common parlance). When a female Spider X emerges from its egg sac, as a hatchling, it has already moulted once (inside the egg sac), but is still extremely small – I can’t measure it, but it must be approximately 1 mm. long (excluding the legs). It then grows, through a number of moults, and creates Discoid web decorations, every night, until it reaches about 6 mm. in length. It then stops making Discoids and starts making Cruciate web decorations. I think I am right in saying that in the period when it makes Discoids, the spider is generally referred to as “sub-adult” and when it makes Cruciates, it is called “adult”. It is the adult period which has caused me some confusion. An adult female Spider X, body size < 8 mm. makes only two types of cruciate web decoration (a 2-armed Cruciate Stabilimentum or a 4-armed Cruciate Stabilimentum), but an adult female, body size > 8 mm. makes the entire range of Cruciate Stabilimenta, (1-armed, 2-armed, 3-armed, 4-armed and 5-armed). So, the adult category appears to be divided into two groups. I have observed and taken photos of full-grown adult females (around 25 mm.) and I have only seen gravid females at (or close to) that maximum size. So, now it is time to explain my problem, a little more fully. I have been observing the female in my photos for about two months. During that time, she has made only 2-armed and 4-armed cruciates and she is, obviously, very small, about 7 mm. Therefore, she is clearly in the smaller “category” of adults (both in terms of size and decoration creation). So, I have been thinking that she cannot be mature and ready for mating, because of her small size. I have been assuming that sexual maturity comes with size, but I must be wrong. Why would the male Spider X turn up and construct his web within inches of the female – there is only one possible reason. The female has released pheromones which have led him to her location. So, now I can see that adult maturity could be linked to age rather than size. “Why is she so small?” I can almost hear you asking. I don’t know, but I think that she has built her web in a safe dark corner where there is less chance of predation by Spider Wasps. but there may be a “trade-off” - a shortage of prey insects and that could be a contributing factor to her diminutive size. Note: Great information from a scientific paper written by a group of Philippine academics and published in - https://www.researchgate.net/publication...

Habitat:

The male and female Argiope luzona spiders were spotted in a dark corner of our backyard. Their webs were mainly moored to the stems of *banana plants, but also to some other sundry foliage. The hub of the female’s web was about 2 ft above the ground and that of the male was a few inches higher. *I know that spiders do not have “host plants” in the true sense, but banana plants are a great favourite of Argiope luzona, probably because the spider knows that bananas host a great variety of insects many of which become prey. The bananas, in this spotting are Musa x paradisiaca, generally known in the Philippines as Saging, but in our local dialect, the are call Batag. Plant information from - http://www.stuartxchange.org/Saging.html........

Notes:

These photos were not all taken on the same day. It would be impossible to tell the story of these two spiders in one “snapshot” of time. Pic #1. Shows the relative positions of the male and female spiders. Pic #2. The male, looking down on the female. This is an enlargement, cropped from the first picture. Pic #3. A view of the male, from a better angle. Pic #4. A cropped enlargement from the first picture – sorry, rather fuzzy, but I needed to show the 2-armed cruciate decoration. Pic # 5. A picture of the female, a few days earlier, showing the 4-armed cruciate decoration.