Mostly nature and photojournalism of amateur standard.

By: Amir Ridhwan

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Sunday, 29-Apr-2007 14:36 Email | Share | | Bookmark
Lycosidae Family Part 2: Pirata and Pardosa

Old skin after molting
Pirata, both genders
Pirata, male
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I'm going to continue with another 2 genera related to the wolf spider. Several genera of Lycosidae are semi-aquatic like Pirata and Pardosa. They are mostly found near the edges of ponds and small streams, lurking among the water vegetations. Being super predators, they are very difficult to be noticed unless you are looking for them. The camouflage colors blend well with the surrounding and they are dormant most of the time, moving just occassionally. These spiders can move on the surface of water and even dive to avaoid hazard.



A Pirate Spider (genus Pirata). Kampung Pelindung, Kuantan.



This one spotted at Taman Gelora, Kuantan.

In general Pirata (commonly known as Pirate Spider) has a dark tuning–fork mark starting from the fovea and goes to the lateral eyes. This mark has light-clored surroundings making it apparent. The abdomen are spotted with banding which makes an appearance of segments. Upon close inspection you may note short dark hairs at each legs.



A female (far) and a male (near). Kampung Pelindung, Kuantan.

Pirata builds a vertical tube in moss with the upper endhas and opening from which it darts at passing insects. The lower end goes into the water where the spider will retreat at the sign of danger. Their camouflage makes them blend well with the surroundings and often can be detected only when they scurry away on water surface.



Pardosa is the largest genus in the family with 40 species recorded in Soth East Asia. They are distributed worlwide and often seen at marshes or ditches, sometime among grass. Males have very large hairy palps. You can identify them from the pattern on its carapace as shown here.


Pardosa. Taman Gelora, Kuantan.

To find these spiders, try going to ponds, marshes and non-concrete ditches. The spiders might be basking on the banks or lurking among the vegetations. They are quite easy to spot once you found the first. Remeber to identify them from the pattern on the carapace and abdomen. There is another type of spider that is semi-aquatic, a spider that I have been searching without any success still. It's the fishing spider which can catch and haul a small fish ashore.

How semi-aquatic spiders walk on the surface of water.
They can walk on water due to the water surface tension. The molecules of H20 are connected to one another by the van der Waals forces which is quite weak. That gives water its liquid property. But at the edge where water meets another medium with different density such as air, the molecules behave like a barrier akin to a thin film of one molecule depth. The pressure exerted by water's greater density to air creates the surface tension in which Pirata and Pardosa spiders take advantage of. From the photo of Pardosa below you can see the spider legs seems to be toucing an elastic film abover the water.

To answer Boogey's inquiry, if the pressure exerted by an object is above the threshold the surface tension can hold, the tension will break and the object will dip. As you might remember from physics class some 40 years ago, pressure exerted by an object depends on its mass, acceleration in a given direction and the surface area of impact. A needle might float due to the tension when it hit the water surface flat and slowly but may sink if it come in vertically with its sharp point having minimal surface area, hence maximum pressure.


The mass of this Pardosa is carefully balanced between its 8 limbs as to not overly exerting too much weight into the water surface. They do not float like ships because bouyancy is not involved. It's just Newton's Third Law.


Monday, 23-Apr-2007 14:05 Email | Share | | Bookmark
1st Anniversary at Fotopages

Honeybee
Weaver ants
Lynx spider
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I purposely delay my weekend posting so I can have it today to celebrate this special day. For a year I have been actively involved with digital photography which has changed my life for an entire year. Now I am looking forward for weekends so I can go for a photography outing which is much to my wife's disapproval. For this, I am blessed by having such an understanding wife. Ehemm...

I got my first digital camera a year ago- an Olympus E-500 with a Zuiko 14-45mm kit lens and a Sigma 55-200mm. At first I thought of taking bird photographs but later realized that 200mm is not good enough, even with a 2x crop factor. Hence I slowly turn to taking photographs of insects. The Sigma is not very sharp so the only merit is its long focal length enabled me to take some decent photos of insect-in-flight.

A few months later I purchased a Zuiko 35mm f3.5 macro lens. It is so far the best lens I have and the one I most frequently use. It took me about 2 months to be completely comfortable using it. Ever since then I have slowly specializing into macro photography and most of my subjects are insects. My zoon lenses are starting to get neglected.

Some time last year I have started to get fascinated with spiders. So my photography got more tunneled into capturing the image of spiders. It was first inspired when I found a full grown male lynx spider. From the macro image I can see the spiny legs clearly which is so amazing. Since then I made it a mission to get as many spider photo as I can.

As for this anniversay, I want to talk on some of my favourite photos so far. This is the lynx spider photo that triggered me the hunt for spiders. It is from the family of Oxypidae. I was looking for macro subject in a public park in Puchong when this guy suddenly crawl in front of me. I sqeezed to get this angle and close enough to get a proper magnification. Technically, it is nothing to be proud of but this particular image has quite a sentimental value. It is the inspirator.




This is a Theridula caudata adult with its offspring. I noted them on a small tree by the road side in Bukit Fraser. These are very small spiders and to encounter this bunch of little critters is ecstatic.




The weaver ants. I photographed them on a tree below my apartment. It seems they are carrying a carcass of a black ant. It was quite challenging to follow their fast pace and given the super shallow DOF, I wasted a lot of shot.




Mating Tetraganithids. I was in Bukit Belacan which is one of my favourite spot for spider hunting. This couple seems to be having a really good time. It is a popular myth that female spiders eat the male after making out. Only if the male is too exhausted to retreat after copulation, the female might just take the smaller male for snack.



The FRU lady. This stunning law enforcer turned a lot of heads during the anti-toll hike demonstration in front of Sunway Pyramid earlier this year. It seems that the police force is taking an unorthodox approach of the "Mesra Rakyat" campaign.




The young devotee. It was during the Thaipusam festival this year in Batu Caves. This young lad is carrying offerings to Lord Murugan. From the color of his pants, it seems he is worshipping the God of War.




Pathway to Robinson Fall. It is one of the well known waterfalls in Cameron Highlands. I went there early in the morning but did not reach up to the actual waterfall. This is one of my few feeble attempts at photographing scenery.



My anniversary resolution is to take up ikelah's advise on giving raw a chance. I've been using jpeg 1/12 compression most of the time. Now that I have bought a new 2GB 133x CF card, it might be worth going raw. I might also take a look atthe upcoming Olympus E-510 which would be the ideal dslr for macro photographers. Sorry N and C, with the current progress of digital photography, Olympus seems to spearheading its way into top-end technology and high quality glasswares. Henceforth I have pledged to continue using the Four-Thirds system.

Here in one of my early shots using raw. It's kind of neat that you can edit it freely later provided you have the time and patience. For me, I prefer more shooting than editing.



Saturday, 14-Apr-2007 08:27 Email | Share | | Bookmark
Lycosidae Part 1: The Wolf Spider

 
 
 
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Lycosidae is a large family of mostly ground hunters commonly known as the wolf spiders. Most are seen running on the ground in open areas and perhaps the most common of spiders in our area. We can spot them between grass, near tree roots and occassionally on low stalks of vegetation. They are probably known as wolf spiders because of the way they run down their prey. Though they can be numerous in an area, they actually do not hunt in packs like wolves.


A typical wolf spider between short grasses. Puchong.


The trademark of Lycosidae is it's eye arrangment which in the order of 4-2-2. The front row consists of 4 small eyes of almost equal size. The other 2 pairs of eyes which are in the posterior are larger. Some species have a pair of the larges eyes in the anterior thus making the front 4 eyes look like a moustache. The color is usually brownish with patterns on the carapace and sometimes bands on the legs. Overall length of the cephalothorax and abdomen is about 1 cm in most common species.


Wolf spiders often run and hide between vegetations. Lembah Beringin.


Like other hunting spiders, Lycosids do not weave webs to catch prey. Thys hunt for small insects among vegetations and pound their preys like wolves do. Some species however build web retreats among grasses or in a ground hole. These retreats are not to catch prey but mainly used as a refuge against hazards.


A mother carrying her egg sac. Bukit Fraser.


It is not uncommon to find a female wolf spider carrying its egg beneath its abdomen. If you take a careful walk at a grassy area such as a soccer field, you have a very good chance to find some wolf spiders running around and some might even carry egg sacs.


A mother with spiderlings on the abdomen. Puchong.


After the egg hatched, the mother will cut a hole at the sac so the spiderlings can crawl out. The spiderlings will hang on the mother’s abdomen until they come to the first molting stage where they shed their skin to grow. During this period, the mother continues to hunt with the babies on her back. A baby that is accidentally dropped will try to crawl back to its mother’s body or else will face the wilderness alone unprotected. The spiderlings feeds on reserved egg yolk and drink from dew drops that are caught on their mother’s body.

Though it is quite easy to identify a Lycosid based on the eye arrangement, color and body shape, I found it very challenging to isolate a specific genus. This is partly because there is so much similary in physical appearance between the genus and they are usually differed on minute details such as the number of claws and stripe pattern.


Saturday, 7-Apr-2007 15:17 Email | Share | | Bookmark
When Mars meets Venus

Lynx spider
Nephila pilipes
Leucauge
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Every year we estimate thousands of species on earth gone into extinction, of these many have never even been discovered by science. While many people romance the demise of the dinosours, tasmanian tiger, dodo and mammoth, we often did not realize the thousands of species of arthropods that go into extinction in the last hundred years. Arthropods are facing a more serious threat to their survival compare to the highly symphatized mammals and birds. The invention of pesticide and irresponsible chemical disposal to the environment take their toll by eliminating these little ones effectively. Some, like the giant trapdoor spider Liphistius malayanus which is endemic to Bukit Fraser, might soon go extinct if their natural habitat is contaminated and destroyed to make room for 5-star resorts.

We can do our part by supporting the conservation effort put forth by the government and many NGOs. We can boycott products that were manufactured at the expense of living endemic arthropods such as sourvenirs made from petrified insects. We can teach others, especially our youngs, to appreciate nature thus realizing that we only borrow the earth from our descendants to come. The simplest thing is perhaps to just dispose hazardous chemicals in a proper manner. Note that to many creatures on earth, the laundry detergent is very hazardous.

Fortunately the little crawlers are not that hopeless and just be sitting ducks. They have survived thousands of years here before the meddlings of man and only now the challenge is a but different. To ensure their continuous survival as a species, they do just what other organisms do- reproduce. Like human, it starts with courtship and ends with mating.



Male Lynx (left) closing in.


Mating of Lynx spiders. Once the male has identified the female, he will stalk her until he gets a good chance to mate. Females are generally larger than the male (as shown here) and would fend off the male's courtship at first. Once the male can come close enough, it grips the female in an embrace while delivering the sperm through its pedipalps (short front limbs used to handle food). Puchong.



Courtship among Nephila pilipes aka the Giant Golden Orb Weaver. The female is so much larger than the male. Before mating, the male would offer a wrapped prey to the female and while she's eating, he will inject sperm into her. To lay eggs, the female will dig a hole in the soil beneath her web and deposit the egg sac there before burying it, a unique practise among orb weaving spiders. Bukit Tinggi.




This is the mating of Leucauge spiders. The female is greenish while male is reddish. Courtship goes for a few minutes between these two expert orb weavers where they dangle close two each other akin to dancing. Once they are close enough, the male holds her and mating happens. Bukit Fraser.



A member of the family Tetraganthidae courting. I remember observing them in this position for about an hour. I could not say if they are from genus Opadometa or Leucauge. Bukit Belacan.


After a while.



Arachnid love dolls. Species still not identified. Gunung Soga, Batu Pahat.



Friday, 30-Mar-2007 13:43 Email | Share | | Bookmark
Hunters hunting.

 
 
 
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Apart from web weavers, there are hunting spiders which use stealth and speed to hunt. They come from the tiny sand spiders to the largest spider on earth- the goliath bird-eating spiders. Although spiders are generally assocciated with webs, the hunters are as equally fascinating as their method of attack and defense can be unlike what we would expect.

Among the more popular hunters are the well-known tarantulas. Although most people expect that they are native to South America, we do have tarantulas in Malaysia. Infact some of them like the Velvet Tarantula can only be found in Peninsular Malaysia but facing the danger of extinction due to poaching. I am yet to find one but it certainly on top of my Most Wanted list.

All hunting spiders are venomous though most of them are harmless to human. They are usually very mobile and have very good camouflage ability. Some are very colorful like the jumping spiders of genus Siler which can be found having 3 to 4 vibrant colors. The Myrmarachne and Porfia have very weird appearance as you shall see soon in upcoming entries.

OK, here are hunters that I captured them during meal time.


A crab spider from family Thomisidae eating a damselfly. Its venom is very potent to insects even those much larger than itself. They are truly masters of camouflage. Puchong.



A lynx spider of family Oxyopidae. They are very nimble and can leap to the air to catch flying insect. Bukit Fraser.



One of those on top of my sought-after list is the ant mimmicking spider. They are from the same Salticidae family as the jumping spider. This Myrmarachne maxillosa has just captured a Pholcus spider. Batu Pahat.



A Salticidae jumping spider with a big prize. Puchong.

Thank you visitors for your comments. I am off to my hometown Kuantan for the weekend and will try to get some good images for you.


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