Tuesday, February 23, 2010

The Pale Spitting Spider, Scytodes pallida.



Of the 69 families of spider found in South East Asia, several of them possess very interesting characteristics such as the ability to catch fish, mimic other animals or blend so well with the surrounding. Yet one of the most remarkable ability belongs to the Scytodidae family which is range attack.


Known as the spitting spider, scytodid is quite common in Malaysia. The can be found in primary and secondary forests and even near human dwellings. A few weeks ago I had one individual crawling next to my PC keyboard before vanishing between the junks on my table. But the best place to find one is probably secondary forests where I had most encounters. It is pretty common in Bukit Kiara arboretum near Kuala Lumpur and I found quite a number in Hutan Lipur Soga Perdana in Batu Pahat.




Now a bit about the anatomy of the spitting spider. While most spiders have 8 eyes, the scytodid has only 6. There are less than 10 families of spider with 6 eyes which also include the common daddy long legs (Pholcidae). Generally 6-eyed spiders are nocturnal and hunt at night but I have seen several individuals which hunt during the day.


In one occasion I was blessed with the opportunity to witness a spitter attacking a jumping spider. It crawled slowly to the prey and fired several jet of glue until the jumping spider was immobilized. Then it moved slowly behind the prey to deliver a bite at the limbs. This is a series of photos I took of the action. Since I just happened to stumbled upon this scene, there was no time to do proper camera setup and to record everything. I wish I captured the glue trail flying from the spitter’s fangs to the prey but that may be too much to wish for.


The first attack is by glueing the enemy.



Then the bite at a more secured part of the enemy's body.



OK, not I'm sure what's the intention here, perhaps injecting digestive enzymes.



Some species of spitting spiders tend to make human house as habitat. They prey on moths, silverfish and other small insects in the house. This can be beneficial and perhaps welcomed in homes. As pest predator, spiders are very effective and most of the time avoid being visible to human. Several houses in a village I visited in fact welcomed spiders and the villagers did not even clean the webs at the ceiling of their houses. I also noticed that while there were mosquitoes outside the house, the interior was virtually free from blood suckers and cockroaches. Seems like both human and the spider have established a symbiotic relationship.


Are they dangerous to human? I suppose a single cockroach is a lot more hazardous in many ways- eating our food and leave their droppings everywhere. Spiders keep this kind of house pest at bay and they have no business with our food or sucking our blood like mites. The fact that they are hunters means that the spitting spiders do not weave any web except as a retreat, usually when nesting. At the cost of making our house looks unkempt, they are the free pest control agents who hunt relentlessly.


Retreat is made by curling the tip of a leaf. Somehow they like that kind of leaf.


Another interesting behaviour of S. pallida is the mother carries the eggs with her jaw. She would build a retreat by curling a leaf and stay there until the eggs hatch. Maternal care of the eggs is crucial to avoid mould infection on the eggs as well as protecting it from predators. But by being encumbered, the mother herself is vulnerable and consequently becomes the prime target for predators such as the jumping spider Portia labiata which prefers to attack spiders with eggs. To offset this advantage, S. pallida has a remarkable anti-predator mechanism where upon sensing the presence of P. labiata (by the chemical cues from its drag line), a mother S. pallida can shorten the embryonic period of the eggs and make them hatch faster. While this may cause higher mortality rate among the hatchlings, the mother will then be free to protect herself and the surviving spiderlings with her defensive spitting.



A mother will carry and protect the eggs at the cost of her life.



The Pale Spitting Spider has a wide distribution across the South East Asia with records in Malaysia, Indonesia, Philippines and up to Papua New Guinea.

7 comments:

  1. This spider looks so different and strange under your macro lens.

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  2. My goodness, a spider tagged you home !!

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  3. Amazing that spiders have ranged attack, i thought they only had melee weapons. Great captures on the attacking process!

    "OK, not I'm sure what's the intention here, perhaps injecting digestive enzymes."- thats a very 'safe' guess.. haha

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  4. Awesome..love the parts where it attacked the jumper!

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  5. great stuff you got here, mind helping me out, thanks.
    http://wai-yien.blogspot.com/

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  6. Bonjour à tous, qui a utilisé le Mitigeur cascade avant? Nous devons acheter un nouveau pour notre maison en ce moment, si vous savez à ce sujet, se il vous plaît nous en informer. Ou peut aussi être sur les Robinet infrarouge.

    ReplyDelete