Marang Trail - The Magic Of Spiders At Night

Marang Trail

South, Singapore

February 2015

Ant Mimicking Spiders (Myrmarachne)

This Myrmarachne Spider avoids being eaten by predators by appearing like an ant rather than a spider. This defense is two-way: Ants are not as palatable as spiders to most general predators, and spider-specialized predators might not recognize these spiders as food.

For mimicry to work optimally, though, spiders must inhabit places with plenty of ants. Not the easiest task, since ants eat spiders. And the poor vision of ants helps. Because these ant-mimicking spiders do not smell like spiders, nor do they smell like ants. In fact, they do no smell like anything at all - They are stealth spiders!

Another one spotted hiding in a curved leaf strung together by its web - See the intricate outlay of threads just to hold the leaf together?

 

Pale Spitting Spider (Scytodes pallida)

The Pale Spitting Spider (Scytodes pallida) has a unique habit of spitting a glue-like and possibly toxic substance at its prey to render them immobile prior to envenomation. Behavioural studies demonstrate that the spider regulates its spit expenditure when offered prey of variable sizes and struggling intensities. 

Moving about on a plant with leaves devoured by grasshoppers into artistic patches, this Sac Spider spreads its long legs over the gaps to balance itself...

 

Though it is produced in venom glands in the chelicerae, the fluid contains both venom and spider silk in liquid form. The venom-impregnated silk not only immobilizes prey such as Silverfish by tying it down, but has a venomous effect as well. In high-speed moving pictures, the spiders can be observed swaying from side to side as they "spit", catching the prey in a crisscrossed "Z" pattern. It is crisscrossed because each of the chelicerae emits half of the pattern. The spider usually strikes from a distance of 10–20 mm and the whole attack sequence is over in a little under 1/700th of a second. After making the capture, the spider will typically bite the prey with venomous effect, and wrap it in the normal spider fashion with silk from the spinnerets.

  

Orb Weavers (Araneidae)

The typical orb-weaver spiders (family Araneidae) are the most common group of builders of spiral wheel-shaped webs often found in gardens, fields and forests. Their common name is taken from the round shape of this typical web, and the taxon was formerly also referred to as the Orbiculariae. However, orb-webs are also produced by members of other families.

Orb-weaving spiders make their webs at night time and usually take them down in the morning. They eat the silk, leaving only the base line to rebuild on. Constructing the web uses a lot of the spider's energy due to the large amount of protein required, in the form of silk and after a time the silk will lose its stickiness and becomes inefficient at capturing prey. Eating their web is a way for the spider to recoup some of the energy used in spinning. The silk proteins are thus "recycled".

An orb-weaver with some web debris and an egg pod on its web...

An  Argiope versicolor (Multi-coloured St Andrew's Cross Spider) flexing itself on its web without its trademark "X"...

A male Argyrodes flavescens (Red Silver Spider) on its own web for once...

Comb-Footed Spiders (Theridiid) are entelegyne (have a genital plate in the female) araneomorph ecribellate (use sticky capture silk instead of woolly silk) spiders that often build tangle space webs and have a comb of serrated bristles (setae) on the tarsus of the fourth leg.

The large golden orb-weavers (Nephilidae) and the long-jawed orb weavers (Tetragnathidae) were formerly included in the Araneidae; they are indeed closely related to them, being part of superfamily Araneoidea. Their webs are similar to those of the typical orb-weavers, but tend to be less sophisticated and often have an irregular instead of a neat spiral arrangement of the prey-capturing threads.

Members of the species Tetragnatha are stick-like spiders with long legs and well-developed jaws. They build delicate orb-webs with open hubs. The webs are suspended horizontally or in an inclined plane. The male jaws are particularly elongated and are equipped with a spur each. These are instrumental in locking the jaws of the female during mating.

Like many species of the superfamily Araneoidea, Nephila Spiders have striped legs specialized for weaving (where their tips point inward, rather than outward as is the case with many wandering spiders). Their contrast of dark brown/black and green/yellow allows warning and repelling of potential predators to whom their venom might be of little danger.

A Nephila Spider with its freshly-caught dinner...

Golden orb-weavers reach sizes of 4.8–5.1 cm (1.5–2 in) in females, not including legspan, with males being usually 2/3 smaller (less than 2.5 cm, 1 in). They are also the oldest surviving genus of spiders, with a fossilized specimen known from 165 million years ago.

The intricate layout of colours with patches, stripes and spots...

Neoscona punctigera (Ghost Spider)

The last time that Merlion Wayfarer spotted this was in 2012, among the long grass in Punggol. At that time, it was evening, and the spider was dormant. (See "Ghost Spider - Happy Halloween!")

(File Photo)

This time round, it was refreshing to note how active it is at night. Awaken from its daytime slumber, this Ghost Spider was moving about. With its flexible joints, one gets the impression that it is sorting out how not to stumble over its own legs.

Waving its long legs about to increase the perception of its body size - A sign of aggression... 

Sources

• "An ant-mimic spider escapes ant attention by being nearly odorless" (18-Nov-2013) by alexwild from myrmecos.net at http://www.myrmecos.net/2013/11/18/an-ant-mimic-spider-escapes-ant-attention-by-being-nearly-odorless/.
• "Golden silk orb-weaver" from Wikipedia at http://en.wikipedia.org/wiki/Golden_silk_orb-weaver (18-Feb-2015).
• "Mangrove Big-Jawed Spider" by Joseph K H Koh from A Guide to Common Singapore Spiders at http://habitatnews.nus.edu.sg/guidebooks/spiders/text/Tetragnatha_josephi.htm (18-Feb-2015).
• "Orb-weaver spider" from Wikipedia at http://en.wikipedia.org/wiki/Orb-weaver_spider (18-Feb-2015).
• "Regulation and non-toxicity of the spit from the pale spitting spider Scytodes Pallida (Araneae: Scytodidae)" by Clements, R. and Li, D. from ScholarBank@NUS at http://scholarbank.nus.edu.sg/handle/10635/101550 (18-Feb-2015).
• "Spitting spider" from Wikipedia at http://en.wikipedia.org/wiki/Spitting_spider (18-Feb-2015).
• "Theridiidae" from Wikipedia at http://en.wikipedia.org/wiki/Theridiidae (18-Feb-2015).

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Sungei Buloh - The Lizard Chomping Spider

Sungei Buloh Wetlands Reserve
North, Singapore
January 2015

Spiders Galore!

It seems to be the spider season now. At the new portion of Sungei Buloh, hundreds of  Araneidae spiders (orb-weavers) were spotted. It was almost as plentiful as at least one web every 2-5 steps!

The mangroves provide an abundant supply of food, as many of the occupants are being having their breakfasts/brunches/lunches...

Argiope versicolor (Multi-Coloured St Andrew's Cross Spider) with their "cross" legs (4 pairs of 2 legs each)...

Criss-cross webs (see the squares within  the web) of these spiders...

Nephila pilipes (Golden Web Spider) Female on its radial web with some gold strands...

The Lizard Meal

The most gastronomical experience Merlion Wayfarer spotted today was a hungry Fishing Spider (genus Dolomedes, family Pisauridae) well-hidden among the multiple layers of a fern. If not for a sharp-eyed fellow photographer who spotted the contrast of the light tan of the wiggling lizard tail, it will have remain hidden.

Almost all Dolomedes species are semi-aquatic, and hunt by waiting at the edge of a pool or stream. Upon subduing their prey, they inject venom with their hollow jaws to kill and digest the prey. 

One hour after the initial spotting of the spider, when Merlion Wayfarer came back to the same spot, only about 1.5 cm of the lizard had been consumed.

The Birds

Dollarbirds (Eurystomus orientalis) got their name from the two silvery white circular patches on each underwing, that flash as they fly. These look like shining American silver dollar coins. Feeding alone or in pairs, they are frequently seen perching on high vantage points like dead trees or telephone wires, keeping a lookout for a passing meal...

The Mudflats

Waders or shorebirds are so-called because they wade in the shallow water in search of food. Plovers and sandpipers are common waders found in the reserve. With their different bill length and feeding habits, they are able to tap on different food sources found in the mudflats. This enables them to co-exist in the same habitat.

Egrets at the reserve are white and more slender than herons in appearance. They are frequent visitors during the migratory season. The Little Egret is often seen dashing about, chasing after its prey in the shallows.

 

An Egret keeping a lookout at the edge of a shallow pool created by a mudskipper...

The Milky Stork (Mycteria cinerea) is a large wading bird in the stork family Ciconiidae. Free-ranging from the Jurong Bird Park, the pair here can often be spotted in the mudflats feeding on fish and amphibians.

Others

Arhopala athada (Vinous Oakblue) resting on a leaf. The "blue" in its name refers to a shimmering blue patch at the bottom of its wings.

Weaver Ants' nests are among the most complex ants' nests. The ants choose living leaves to build nests. These provide well camouflaged protection from predators and the elements. To create their neat nest, chains of worker ants form along the edge and pull the edges together by shortening the chain by one ant at a time. Once the edges are in place, an ant holds one of their larvae in its mandibles and gently squeezes it so the larvae produces silk. The silk is used to glue the leaf edges together. The larvae have special glands to produce lots of strong silk. 

Grasshoppers have antennae that are generally shorter than their body and short ovipositors. They also have pinchers or mandibles that cut and tear off food. Known as long-horned grasshoppers, many katydids exhibit mimicry and camouflage, commonly with shapes and colors similar to leaves...

The crab looks at the really HUGE mudskippers basking in the shade. Many crabs here in the mangroves are burrowers, digging holes at the base of mangrove trees and in mud lobster mounds. At high tide during the day, tree-climbing varieties are often seen clinging to tree trunks just above the water line. They remain motionless to avoid both aquatic predators in the water, and airborne predators such as birds.

The Callosciurus notatus (Plantain Squirrel) is extremely adaptable, occurring in a wide range of habitats including secondary and coastal forest, mangrove, plantations, parklands and semi-urban areas. It is easily identified by the two cream and black stripes on the sides, and the orange belly.

Like all members of the reptile class, lizards are cold-blooded. That means their bodies do not generate stable internal temperatures like those of birds and mammals, warm-blooded animals. Cold-blooded creatures depend on the environment around them to control their body temperature. Lizards bask in the morning sun to raise their internal body temperature and stimulate their metabolism. They position their body to soak up maximum sunlight, spreading themselves to create more surface area. As their internal temperature warms up, their muscles become limber, which is crucial for hunting and escaping predators. If a lizard becomes too warm, it will move into a shady spot or burrow into cool soil.

The Varanus salvator (Malayan Water Monitor) can be found in many parts of South East Asia. Often found near water, it is known for its good swimming abilities and agile speed when moving along land.

Both males and females of the Calotes versicolor (Crested Tree Lizard) have a crest from the head to nearly the tail. Usually a dull brown, grey or olive with speckles or bands, but these lizards can can be seen in other colours such as bright green. These colour changes reflect readiness to mate and defend their territories.

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