The Nature of Garden Pests


| June/July 1993



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Just as a weed is any plant growing where we don’t want it, a garden pest is a pest only by virtue of our opinion of it. If aphids preyed on parasitic wasps instead of vice versa, we would rush to order them from slick garden catalogs at an astronomical price per pound and give them the run of our greenhouses. If slugs suddenly became ravenous for dandelions in the lawn instead of lettuce in the garden, we would happily set up little beer busts for them every Friday afternoon instead of trying to drown them in the brew in the dark of night.

Grasshopper (order orthoptera, family acrididae)

Of course, nature being what it is, it’s difficult to separate our feelings about other creatures from our own self-interest. If you’ve watched grass­hoppers consume your entire crop of basil with the avidity of yuppies eating pesto, you might find it hard to care that their hopping ability is roughly equivalent to 6-foot-tall humans with very large thighs leaping 90 feet from a standing position.

On the other hand, if you expect to have to coexist with an extremely large number of grasshoppers this summer, understanding them better might make the relationship more tolerable. You might appreciate knowing that they have a brain in their head, albeit a wee one. It’s little more than a tiny tangle of nerves, actually, with short optic nerves going to the two large, keen compound eyes and the three or so small simple eyes (which are for sensing very short-range images or simple light/ dark shapes). A couple more nerves go to the antennae, with which they might smell as well as feel, and that’s about it. Like the proverbial chicken, a grasshopper can continue to breathe, walk, and fly for quite some time ­without its head— because it has other “brains” in its thorax and ab- domen to control those functions.

If you’ve ever tried to catch grasshoppers, for fish bait, vengeance, or just fun, you might find it useful to know that some of the common garden varieties make themselves scarce by clamping their wings together and dropping straight to the ground in midflight while you, their clever predator, are watching the trajectory traced by their brightly colored underwings and positing a landing place several feet beyond where they have actually come to rest.

Then, if you’ve actually succeeded in catching one of the above grasshoppers, you might be relieved to know that its leg comes off in your hand on purpose; the creature has special muscles for popping off endangered extremeties, and small diaphragms at the joints which close the wound to prevent blood loss or infection. And the disagreeable substance it might have disgorged onto your hand while shedding its leg is not tobacco juice, but the entire contents of its foregut or in some cases a foul secretion from a special gland for offending enemies.

Grasshoppers have a reputation for being improvident, for fiddling away the summer (rasping hind legs on tough forewings to attract a mate) while diligent ants store up grain and such for the winter. We should be grateful. What if they not only ate all the basil they could, but also carried the rest down a hole?





elderberry, echinacea, bee hive

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