Many people I know have installed one of those non-selective electronic insect shocking devices on their verandas. My neighbour bought and installed one at his back door. From then on sitting on my stoep in the evening wasn’t a pleasure any more. The bright violet light that lures the insects to their death was like a gaping wound in the soothing darkness of the night. I found it disturbing to listen to the audible crackling as scores of marvelously created creatures, of whose lives we know so little, were being executed. Counting the number of crackles I determined that on average over 80 insects were electrocuted every minute, which would total almost 50 000 by the light of dawn.
A local co-op informs me that farmers buy these devices to control fruit flies in their orchards. This is counterproductive as fruit flies are only active during the warm part of the day, but night-pollinators which ensure good crops would be decimated. So the next day I went over to enquire why he operated the thing. “For the flies and mosquitoes,” he replied.
When I pointed out that flies don’t fly at night and that mosquitoes were not attracted to lights he admitted that he did not know much about insects. Inspecting the heap of ash under the device, I extracted the remains of many night-pollinating moths, parasitic wasps and a few beautiful large insects, with long spotted wings that he did not know of. They were ant lions.
Fascinating world of ant lions
Many of us think we are familiar with ant lions as little pot-bellied insects with their huge sickle-shaped jaws. As children most of us stirred them with a piece straw out of their conical pits of soft sand, in which they trap ants and other unsuspecting insects. If we ever watched them shuffling above ground, we may even have noticed that they have only one gear: six-wheel drive in reverse. But there is more to them than meets the eye. For instance, just like caterpillars are the larvae of butterflies, these little pot-bellies are only the larvae of much larger and different adult insects with long, delicate wings resembling slender, slow-flying dragonflies.
But unlike dragonflies they are able to fold their wings over their bodies. The larva has neither a mouth nor anus as it doesn’t actually eat the prey it catches. Its jaws are actually curved hypodermic needles which are thrust into the bodies of its victims to suck out their body fluids, discarding the rest of the corpse. This liquid diet produces very little waste and is kept inside its body until it is excreted as a small white pellet when it develops into an adult.
Not all ant lions make pit traps as some live beneath the sand surface where they ambush passing prey. Recently I found a big free-living ant lion larva in a tree. It had peculiar fringe-like projections around its body to conceal itself on the bark. It was highly mobile and could move in any direction, enabling it to stalk its prey among the leaves and branches. Some larvae and adults have the front parts of their thorax bizarrely elongated into a thin giraffe-like neck, while others seem to have borrowed their heads from a butterfly, complete with big eyes and long antennae with a knob on the end. Others resemble a wasp or praying mantis. Despite their beauty they are all voracious predators of other insects.
Ant lion varieties
Ant lions belong to the order of Neuroptera, which also contains the delicate and smaller lacewing, to which they are closely related and whose larvae also have similar large, sickle-shaped sucking jaws. Adult lacewings, which are often light green, have long, gossamer wings with numerous prominent veins. Some lacewings have an insatiable apatite for plant lice and go by the name of aphid wolves. They are such gluttons that from the moment they’re born they will cannibalise each other, which forces their mother to lay her eggs on the tips of long silken stalks, each like a balloon on a string, to protect her offspring from each other. They come in such a bewildering variety that to name them must have been a challenge as can be seen from a few descriptive examples such lacewings, spoonwings, threadwings and ribbonwings.
The Neuroptera are all farmer friends but, like all predators, they may be the first allies to fall victim in the crossfire of the pesticide war against pests. Any field sportspeople who walks with heavy boots over the delicate insect world in search of the big stuff are unlikely to notice that the most incredible and fascinating miracles of creation are right beneath their feet. – Abré J Steyn
For more information contact Abré J Steyn on 083 235 4822.