"What does signature mean? Supposedly these are the added touches that make the crime personal to the killer." - Pat Brown
Any crime fiction aficionado proud of his memorabilia of smart thrillers know that a crime scene often carries signature of the killer. A near-neurotic compulsion to leave unique footprints adds to the alluring aura of a planned crime, demanding above-average intelligence to demystify. Ironically enough, it also becomes an extremely effective weapon to catch the killer. If they commit serial offences, it becomes straightforward at times for intuitive readers too to find the missing link based on such repetitive deep-seated psychological patterns. These imprints are nothing but 'signatures'.
It is totally different from leaving fingerprints by mistake per se. A #signature is not a scattered evidence or clue. It cannot be always decoded with criminal profiling and is not an absolute requirement to give fruition to the modus operandi. Rather it is that emotion-driven added exhilaration some offenders (generally psychopaths) derive by teasing the intelligence of the forces of law and order.
However, this trait popularized by crime fictions does not score in thematic consistency with the raw data. The world of inductive and deductive reasoning rather suggests that the real crime scene behaviours are fairly diverse and complex. Nevertheless, ritualistic tendencies which also become the offender's calling card cannot be totally dismissed even in reality.
I didn't expect to find any personalized signature in a forest though. Granted that very interesting #evolutionary tricks are being performed all around in nature and even though I never underestimated it, I didn't know any better until I saw it in #invertebrates in its most visual-driven form, though not remotely as sinister in purpose.
Here is the one shown by a Signature Spider whom I came across while exploring dense evergreen forests of Thattekad in Western Ghat foothills.
They are also known as Writer Spider due to the authentic nano-structures of silk fibres in their #webs.
It is quite possible that your arachnophobic mind has ordered you 'Go get rid of this insect' (Spiders are not #insects though, they belong to a different group called #Arachnida) before as variants of them are commonly seen in gardens amidst tropical and temperate climate. However, I haven't seen such a well-formed stabilimentum (the white opaque Zig-Zag Web presumably stabilizing the structure) in one before. This Writer Spider was looking particularly hauteur, perhaps the Bard among its lots!
However, the 75 different species of this #spider appear virtually indistinguishable from one another, even though typically females are 3-4 times larger than males and exhibit sexual cannibalism post mating, i.e. the females consume the male Signature Spider. They are otherwise non-aggressive, not much venomous either, generally harmless to humans, but the big ones can deliver occasional painful bite when seized, causing blisters.
All things are bound together
The incredibly complex social structure and intimate life of spiders are stories worth telling, but that's for another time. I am here going to focus more on the Stabilimenta, that many believe serves the spider exceedingly well as a #camouflage in concealing the spider's presence, thereby minimizing the possibility of predator exposure. Another interesting theory is that they display a somewhat flower-like appearance to deceive other insects and render warning for birds in order to prevent them flying into their webs, thereby inadvertently destroying the intricate but fragile structure. Rebuilding and repairing obviously result in a crucial waste of time, energy and resource.
“Fiction is like a spider's web, attached ever so lightly perhaps, but still attached to life at all four corners. Often the attachment is scarcely perceptible."
But it was this very zig-zag pattern that attracted my attention in that tropical deciduous forest and made me wonder whether this structure was injudiciously helping large birds with good eyesight, who are also fond of eating spiders, to spot it better.
Typically, camouflaged animals resemble their background. Here the stabilimentum rather marked it distinct. And hence, made the spider rather exposed.
Are there any trade-offs involved then? To lure insects into its magnificently woven clutch comes with a price as their signatures make them also vulnerable to get caught? After all, these spiders are able to catch and eat insects twice as large as their own sizes! So is this another great balancing act by nature?
The plot thickens
A frisky and temperamental eagle flew above our head. I was already sweating profusely while the hired car was driving us through the teak, rubber and mahogany plantation. While exploring the #biodiversity hotspot of Thattekad Bird Sanctuary on foot by following the narrow trails, the heat soared. Darkness accumulated even under broad daylight and the #forest climate appeared as overwhelmingly stiffening. Not a good omen for bird watching, so decided to spend some more time with the master craftsman and more closely I tried to observe its ambush strategy while being very careful about not to disturb it.
I was stepping inside her home after all. The spider was actually sitting on a hollow centre of the web, adjoining two legs as a singleton unit, as if to appear as a four-legged creature! Fascinating, must be for a reason, huh?
If you intently look at the above photograph, you can notice that the hairs on their legs intertwined when the legs were thus enmeshed. These leg hairs act as a natural UV reflector along with the radiant M or W (inverted M) chain pattern of white silks of the stabilimentum. Many perceive these patterns as X (as a Cross), thus it is also called St. Andrews #CrossSpider in Australia after a saint who was believed to be martyred on a cross of similar shape. It enjoys many other names across geography.
Irrespective of their variants, this reflector ability enables them to appear extra bright, thereby enticing bees, flies and wasps who are instinctively attracted to light, thanks to phototaxis. You may want to watch this video which nicely explains phototaxis and why bugs are attracted to lights.
For nocturnal insects who typically depend on moonlight's constant angle to tread through and maintain a steady flight, the Signature Spider's bright silk tends to distort their navigational sense. They easily feel disoriented and try to follow the way paved by the artificial light, rather than the moon, which is the greater artificial light, by the way! And that's how starts the endless spiral dance, the beginning of their tedious end.
More so, because spiders generally strike with an extremely slow-motioned approach. If a spider strikes fast, the herbivorous insects (arthropods) they typically prey upon are sometimes caught unaware, but the target's escape rate is also pretty high with quick fidgety movements.
Interestingly, Signature Spider always sits at the middle of the web and wraps up the victim by white silk, its very signature! Through this signature it immobilizes the prey by emanating #neurotoxin and rotates it like a spinning top before administering the fatal bite. For smaller preys, they conserve energy and do not follow this convoluted silk-wrapped strike. A simple bite is adequate along with the injection of digestive enzymes. As a protection mechanism, they also shake the web rapidly at times and temporarily dissolve their 'Signature' to perplex the predator before daintily turning to the back of the web through the hollow in the middle or dropping from the web altogether!
There is no such thing called impartial jury
I have used the mood of classic noir as a setup, perhaps only because I was just not prepared then for the possibility of viewing an in-your-face evolutionary baroque.
Now I look back at the moment when finally, I looked around. A dull heavy air of apprehension was dangling under the forest sky. The scent of primal battles between many victors and victims, with survival being the cardinal necessity on an absent moral high-ground, seemed eerily beautiful for few moments.
'Autograph please', the true fan inside me whispered so before getting lost in other thrillers written by nature.
PhotoStory Date: 23.05.2012
Place: Thattekad, Kerala
Words and Photographs: Amrita Ghosh
Resource Credit: Video of Why bugs are attracted to lights? @SmarterEveryDay
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