Annual mass migrations of zebras, wildebeest, Thompson gazelles, and other assorted ungulates on sweeping, dry African plains are the source of some of the most evocative and celebrated images of our world at its finest. Cue in the blazing red orb of the setting sun as the endless string of magnificent, heroic silhouettes passes across the horizon and, at the sight of such a pure and epic spectacle of life, your heart is bound to swell with that uplifting feeling of being one with nature. A brief sense of moral outrage may pass through your mind at the recollection of those unscrupulous people who destroy the natural habitats and passageways of the valiant beasts for reasons no other than to plant more crops or graze more cattle. “How selfish we humans are,” you muse, “why can’t we leave nature alone?” I, of course, have exactly the same reaction. But at the same time my entomophilous mind can’t help but notice a strange disparity in our concern for one group of migratory organisms and a total disregard, a raging abhorrence in fact, for others. Africa is a place where many animals move en masse in search of greener pastures, and the one that I find particularly interesting is a small, inconspicuous grasshopper known under the scientific name of Locustana pardalina.
Solitary most of the time, every now and then millions of these insects will band together and, just like the grazing mammals we so admire and love to watch, march across South African karoo to look for more grass. Wingless at first, they hop across parched terrain in huge, reddish waves, but as soon as the animals pass their final molt and grow a pair of sturdy wings the whole group takes up to the air. As they flew over my head against the cloudless sky the spectacle was truly breathtaking. The rustling of thousands of wings filled the air, and each animal took on an almost ethereal quality as the light of the sun filtered through their bodies. I saw this scene only twice in my life, and both times the sight felt to me as majestic as the celebrated migrations of the Serengeti plains. After a while the enormous cloud of insects disappeared over the horizon, and probably found a good patch of greenery, where they landed, and started to feed.
Clearly, I am not a South African farmer, and my description of the swarm of Brown locusts is a departure from the traditional depiction of these insects, where words such as “devastation,” “tragedy,” and “hunger” are frequently evoked. There is no denying that Brown locusts cause considerable damages to cereal crops, which to them are no different from grassy plains that used to exist there before the arrival of organized agriculture. The economic losses and human suffering that they cause clearly justify the efforts to control them, but some of the knee-jerk responses to locust swarms may do more harm than good. Broad-spectrum pesticides used to exterminate locusts kill not only the target species, but also countless other organisms, such as pollinators or beneficial parasitoids that control outbreaks of other pests. To add to the problem it is difficult to predict where and when the next outbreak will take place. There is some evidence of their correlation with the El Niño temperature oscillations of southern Pacific surface waters, on their own difficult to predict events.
[An excerpt from my book “Relics: Travels in Nature’s Time Machine”]