June 20 till August 2, 2009
Maid of Honour, Dark Crimson Underwing, Night Peacock Eyes – all names that bode well for romantic stories. How different the word “moth” sounds – by and large associated with the butterfly’s black, dusty stepsister. And yet, the natural behaviors of these not always nocturnal insects are actually quite remarkable. Moths have several ways of defending themselves against enemies. The dark colored forewings found on most species provide them with camouflage by day, and while their often-iridescent rear wings are mostly hidden, fanning them can repel an aggressor. Even noise can be used as a line of defense – the Death’s Head Hawkmoth, for example, lets out a whistle-like shriek. Most moths defense tactics are more passive: if despite their camouflage they are discovered or even touched, some will resort to a simple but effective fall. Playing dead while simultaneously flying out of sight is extremely sophisticated. Thaumetopoeidae – otherwise known as “processionary caterpillars” use another effective technique that includes moving in single-file columns of sometimes hundreds more than a hundred animals, leaving tiny, poisonous hairs along the way – places even larger mammals such as foxes or boars avoid.
Though night moths have a fairly reliable sense of smell, their orientation towards light has been a clear disadvantage since at least the invention of electric light: endlessly circling streetlights damages their fragile insect bodies, which are sensitive to heat and UV-rays. The orientation and movement of an organism toward the source of a light is called “postive phototaxis” – though the reason for this movement is a mystery to this day. According to one theory, moths use the moon as orientation while flying, and this sensitivity is disrupted by the much closer electric lamp. This causes them to spiral endlessly around the object in circles, trapping the moths in a movement they cannot free themselves from. Another theory traces the behavior to an optical phenomenon: the area directly next to a source of light appears blackest to the eye (an effect otherwise known as “Mach bands”), so the moths continually seek protection in what they perceive as the darkness surrounding the light. Observation, however, also leads us to conclude that the insects’ flight path is oriented towards the brightest spot as a way of avoiding trees and plants, meaning light signals a clearing or gap for them. As deceptive as light’s brightness is, the instincts driving the moth are a mystery in themselves, be it attraction driving them to follow it or an impulse to flee. Creatures of the night buzzing around artificial light: the moth gives the viewer room for empathy. Their mysterious behavior continues to fuel the imagination, as it has since the dark poetry of the 19th century.