05 Oct Spiders – art of making the kill
Spiders (Order: Araneae, Class: Arachnida) are probably one of the more evolved group of arthropods. They have developed a highly diverse set of skills and strategies for hunting. Some stalk and run down their prey, while some wait in place for their prey to wander by, using stealth and camouflage. Many others use silk and sticky webs in very innovative ways to trap their meal. A few of the highly specialised spiders belonging to the genus Portia are known to display intelligence in their ability to choose different tactics for hunting and also in developing new ones. Among spiders, it is truly an art when it comes to making the kill and they are quite adept at it.
Jumping spiders ( Family: Salticidae )
These are very active hunters. Their highly developed sense of vision and speed help them sight and choose their targets, which they then stalk and run down, to make the kill. They are akin to the tigers of the big mammal world. Here’s one, stalking a pair of house flies.
Once locked on, jumping spiders are very fast and latch on to their prey with one quick dash and grasp. Here’s another, with a long-legged fly kill.
Crab spiders ( Family: Thomisidae )
These are also active hunters and don’t build webs. They rely on stealth and camouflage to get the job done. They sit inside or below the petals of flowers and wait for an unsuspecting prey to wander by. Here’s one, that has positioned itself nicely.
A surprise attack needs to be a well calculated one. Not possible at all times. Here’s a butterfly which has landed on a flower with the crab spider lurking in the shadows. However, the butterfly escaped this time, with the spider deciding not to go in for the kill.
The bee here, wasn’t as lucky. Moving from flower to flower, feeding on the nectar, it ended up on one, where-in the spider was waiting and met its end.
Lynx spiders ( Family: Oxyopidae )
These guys are also ambush hunters. At times, hiding in flowers to attack pollinating insects, very similar in behaviour to the crab spiders. And at other times, they stay camouflaged on the plant stalks or barks. They too have varied diets. Here’s one with a small wasp.
And another one here that has ambushed a caterpillar.
Orb weaver spiders (Family: Araneidae )
These are the so to say traditional spiders that build webs. Many others belonging to the family Nephilidae, are also web building spiders. Some really big webs are built by the likes of the Giant wood spiders. Positioning themselves at the centre of their silky stage, they wait for any flying insect or such to fall and get stuck in it. The vibrations of the struggling prey gets carried to the spider along the interconnected strands of silk. As soon as the spider senses this, it darts to the hapless prey and kills it instantly. Some do pack their food up using silk, to store away for later use. Here’s a signature spider doing just the same.
Ornamental tree-trunk spiders ( Herennia multipuncta, Family: Nephilidae )
These spiders also build webs, but much smaller when compared to the orb weavers. They are found on the trunks of trees where they build a small patch of web using the bark of the tree as support. Hunting strategy is very similar to other web weaving spiders, waiting for a wandering prey to get caught up in the web. Here’s one which has caught a moth of some kind and feeding on it.
Net casting spiders ( Family: Deinopidae )
Among web builders, the net casting spiders are very innovative. They build a relatively small web which looks like a fishing net. With the web held by its front legs, the spider hangs down, close to the ground or any other surface, waiting for its prey to pass under it. With big, googly eyes, it has very powerful vision. As soon as it sights a potential prey wandering below and within reach, it throws down the web, stretching it to two to three times its size, onto the prey and captures it.
This is just about a small part of the amazing diversity that the spiders display. A whole group of different families of spiders, commonly known as the trap-door spiders build highly advanced and specialised mechanisms to catch their prey. Then, there are the ones of the genus Dolomedes that are fishing spiders. Lying in wait at the edge of small streams they look for the ripples of water to convey the movement of prey which they then quickly reach to and capture. Here’s one, waiting on floating leaf litter…
Spiders are indeed a very highly efficient, very characteristic and intriguing group of arthropods. So varied are their habitats and so varied are their styles of hunting that it is always very enriching to see and learn more about them.