Amongst all denizens of the crawling kingdom, none perhaps evoke such strong and disparate feelings of loathsome fear and unbridled fascination as Spiders.
Love them or loathe them, spiders were here before us – first appearing on the scene some 400 million years ago, before the mighty dinosaurs and long before the early mammals decided to climb down the trees to see what lies beneath – And they are here to stay.
Inhabiting diverse habitats, in a wide range of eco-systems, Spiders are everywhere. From wetlands to deserts, rain forests and even in our homes. They come in a wide variety of shapes and sizes, ranging from the dainty flower spiders, which blend into and hide amongst flower petals, preying upon unsuspecting pollinators lured by the promise of nectar, thus turning the angiosperms very evolutionary advantage to their own benefit, to the mighty monarchs of the eight legged realm, the Tarantulas, which when opportunity presents itself are not loathe to preying upon frogs, lizards and even small snakes.
So, what exactly are spiders?
Simply put, Spiders (Order Araneae, Class Arachnida) are mostly venomous (some species lack venom glands), eight legged, predatory (at least one species, Bagheera kiplingi, a kind jumping spider is primarily vegan) arthropods (joint legged animals), their bodies divided into two (prosoma and opisthosoma) instead of the usual three parts of the average insect anatomy (head, thorax, abdomen), possessing pediplaps, which replace the insect antennae as sensory organs, doubling up as copulatory organs in male spiders. They also posses six to eight eyes and have the dining habits which would make any self respecting Vampire or Ghoul proud.
Lacking jaws, spiders feed by first injecting their hapless prey with venom, in addition to pumping them full of assorted digestive enzymes, effectively dissolving and partially digesting their innards and then proceed to slurp their loathsome (to us) cocktail of insect blood and guts. And just in case that wasn’t already gruesome enough, most web weaving spiders go the extra mile by trussing up their prey like the mummies of old, to cease their struggling, going to the extent of storing up surplus prey in this fashion, whereas the often larger, non-weaving, hunting spiders simply prefer to latch on to their victims in a death grip, as the last of their life ebbs away, while the death struggle ceases.
All spiders possess the remarkable ability to produce silk. Spider silk is liquid protein produced in specialised silk glands found in a spiders abdomen. Each gland is in turn linked to a spinneret which opens on the outside, via a tiny spigot. These silk glands are as varied as the spiders themselves and produce different types of silk, utilised for different purposes ranging from the constructing of snares for entrapping prey, to the formation of sperm webs, egg sacs, silk cocoons, safety lines and in case of burrowing spiders, line the walls of their dug out, underground retreats.
Different kinds of spiders produce different types of web, ranging from the masterful, geometrically precise web constructs of most Orb spiders (Family Araneidae), the silken sheets put out by sheet weavers (Family Linyphiidae) to the untidy, messy webs spun by the (in)famous widow spiders (Family Theridiidae) often playing an important part in their identification.
Spider silk is also remarkably tough, having the tensile strength of steel and about half as strong as Kevlar, used in bullet proof jackets and vests.
Amongst the finest predators of the crawling kingdom, spiders play an important role in the ecosystems they inhabit; they control the population of insects and other arthropods, including important agro-economic pests such as flies, mosquitoes, grasshoppers, crickets, bugs and moths, being themselves preyed upon by a wide variety of predators, ranging from reptiles and amphibians, to birds and even small mammals, thus helping to maintain a delicate natural balance in the innate workings of an eco-system.
Occupying roles which we cannot even begin to comprehend, these amazing organisms quietly go about doing what they do best; help maintain a delicate natural balance in an ecosystem or ‘keep the machinery in working condtion’.
And yet, like most life forms, spiders are fast headed the way of the dodo, with habitat fragmentation, climate change and other factors such as illegal encroachment extracting their toll, plunging many species over the brink by the minute.
In times like these, with global warming and species extinction being household terms and the fate of our doomed wildlife resting uneasily upon the shoulders of uncaring stake holders, it has become crucial to understand the wealth of biodiversity our forests possess before attempting any form of recovery action.
Most Invertebrates often serve as important indicators of the state of the ecosystems they inhabit, their disappearance warning us of impending environmental catastrophes, much the same way as the miners of old were warned of their own impending doom by the death of the canaries they carried into the coal mines, with them.
If these ‘canaries’ of our ‘ecological coal mines’ were to disappear, would we be far behind? 🙂
If you wish to live and thrive, let the spider run alive
– Medieval English Proverb
Thanks to Javed Ahmed for helping me to write this week’s guest blog 🙂 – Krishna Mohan