Reader André Schuiteman, who works at Kew Botanical Gardens and has previously contributed biology photos and stories here, sends the following pictures and a tale about death in nature:
On December 2010, during a brief excursion to Cuc Phuong National Park in Vietnam, about 80 km south of Hanoi, I came across the most unusual caterpillar I had ever seen. [He now thinks it's a species of Orgyia, a tussock moth, or something closely related.] As shown in the photographs, it sported a luxuriant and colourful coat of long and short hairs, partly arranged in tufts, some resembling miniature shaving brushes, others bouquets of white eyelashes. It was sitting on a leaf of which it had evidently eaten quite a bit. As I was admiring the creature, I noticed that I wasn’t the only one who had taken an interest. A rather ordinary-looking fly was walking around it and clearly seemed to disturb the caterpillar, which tried to crawl away. Suddenly the fly curved its abdomen forward under its body, walked up to the rear end of the caterpillar and, raising itself on its hind legs, inserted its abdomen in the victim’s fur. I write ‘victim’, as there can be little doubt that this was one of those parasitic flies that lay their eggs on caterpillars.
All this took place slightly above eye-level, which made it awkward to photograph. I happened to have my camera with macro-lens ready, but the flash was still in the bag. As I didn’t want to lose an opportunity, I photographed it with natural light, which explains the shallow depth of field. Unfortunately, the photo of the moment of oviposition is highly unsharp because either the leaf or I moved too much.
As I walked on I felt sorry for the beautiful caterpillar, knowing that it almost certainly was going to die an extremely unpleasant death (slowly being eaten alive by a maggot). Should I have interfered? This moral dilemma occupied me for a while. Nature is wonderful, but full of horrors, most of which go unnoticed.
To bring up a bit of historical (and religious) context here, we have the famous quote from Darwin written in a letter to American botanist Asa Gray on May 22, 1860, using observations like the above as evidence against a beneficent God:
With respect to the theological view of the question; this is always painful to me.— I am bewildered.— I had no intention to write atheistically. But I own that I cannot see, as plainly as others do, & as I shd wish to do, evidence of design & beneficence on all sides of us. There seems to me too much misery in the world. I cannot persuade myself that a beneficent & omnipotent God would have designedly created the Ichneumonidæ with the express intention of their feeding within the living bodies of caterpillars, or that a cat should play with mice.
Ichneumonids are not flies, but wasps (mostly parasitic ones) in the order Hymenoptera, along with bees and other more familiar wasps.