lq-yang 的日誌

Grey herons often stand motionless in shallow water, waiting with great patience for opportunities to harvest accidental passers-by in immediate proximity to them like fish and shrimps. The ancient Chinese superstitiously interpreted this seemingly passive hunting mode as the birds believing that Heaven would keep their prey within easy reach of them and that it would be in their karma whether they could really have the godsends. Hence the rather bizarre name karma-believer (信天缘) for the birds.

However, as it turns out, the so-called karma-believers don't come exclusively from birds. My very recent observations of a kind of spider that I identify as Asceua torquata (thanks to the kind help from Dr. Pakawin Dan) reveal that this species of spider, whose biology hasn't yet been documented, actually shares a strikingly similar hunting mode with the birds, although the two species dwell in rather different habitats.

Asceua torquata is an ant-eating spider that has a distinctive triangular marking on abdominal dorsum as one of its most easily recognizable characteristics. During nightly huntings, they first choose a position on the trunk of a tree where there are always visible signs of ants traveling to and fro. Once a vantage point has been chosen, the hunter will stay there literally motionless exactly as grey herons normally do while hunting. The surprise attack starts only when an unlucky victim is making an imminent head-on approach towards the undetected ambusher. The most curious twist is: if the ant should approach the spider by the flank, the predator will immediately shy away as if scared of the prey. So what's the strategy behind an apparently false sign of weakness? Well, as an aside note, this might be a fantastic example for a study of predator-prey interactive dynamics. Anyway, in a successful ambush, the spider typically pounces with deadly agility upon the approaching ant, almost instantly subduing it with its venomous chelicerae.

So there are karma-believers in birds and there are their arachnid counterpart. It might also be a reasonable conjecture that there are potential counterparts in a variety of other species. But do they really believe in karma as interpreted by the ancient Chinese? Or they're actually the opposite? This seems to be an interesting question to ponder.

During the many hiking/photography trips that I took in my local hills and mountains, starting from as early as six years ago, I have seen a good lot of intriguing scenes of peculiar insect behaviors but only a very few of them linger particularly vividly in my memory. The logic seems like this: what is to be expected might sometimes still be interesting but never to the point of being unforgettably fascinating. I have, for example, observed many times the curious scenes of spider wasps carrying spider victims. It was interesting each time. But even before the first time I seized the opportunity of seeing such a predator vs. prey scene, I had already read from books and therefore always expected such behavioral displays of spider wasps. So later happenings strictly following the script gave me no real surprises as the expectation itself acted paradoxically as a spoiler that spoiled the grander joy of an unexpected discovery. But have you read/known that a tiny fly with a body length of barely 3mm could even fly simultaneously carrying a killed ant? As for me, I myself had totally no such preknowledge and this is probably why it simply astonished and fascinated me seeing it happen before my very own eyes! On that particular morning, by pure accident while passing a scrubland, I spotted a tiny metalic-green fly (around 3mm in body length) with a pair of robust-looking antennae, standing motionless like a zombie, on the leaf of Ampelopsis cantoniensis, accompanied bizarrely by an obviously dead ant lying on the back under its hind-legs. The fly was immediately recognized as a soldier fly because I had previously spotted and identified with the help from a dipterist the individuals of apparently the same species. But what's the story behind the scene? Did the soldier fly kill the ant? Or they're both dead somehow, perhaps by some mysterious kind of external force? I was sunken deep in a bewilderment. And the fly kept the same motionless position until finally the overwhelming curiosity drove me to touch and check the aliveness of this itsybitsy creature by a handpicked fallen leaf. The fly flew instantly and almost equally instantly landed on a nearby leaf of Millettia dielsiana. Voila! The flight covered a distance of only about 20 centimeters but the most amazing part was it actually landed with the ant! So have you ever seen a fly fly simultaneously carrying an ant? As for me, yes! And it was so amazing!
Nature is so full of wonders! Stay curious and beware that knowledge may turn out to be a killjoy!