Grasshoppers are generally known for their jumping ability. Anyone who has tried to catch one will know that this is an invaluable defence mechanism for getting away from predators. But what if you don’t need to get away from predators? The koppie foam grasshopper, Dictyophorus spumans, is such a creature for few, if any, predators would choose to eat one of these as a meal. So it is quite happy walking casually along in the open, with only the occasional low hop if really pushed (and hence nice and easy to photograph).
What makes the koppie foam grasshopper so unappetising is its diet. Unlike other grasshoppers that eat rather innocuous plants (though few grasshoppers solely eat grass), this one enjoys eating toxic, distasteful and noxious plants, such as members of the milkweed family. It then has the ability to keep the toxins in its body, an ability known as sequestration. Should a predator then decide to make a meal of this grasshopper, it will end up rather worse off than just a bad stomach-ache.
The key for the grasshopper is to let the predator know that it is going to be worse off for eating it. It is rather late for the grasshopper if the predator only discovers this after its meal. The grasshopper therefore develops this gaudy black and red coloration, which says to any potential predator “don’t even think about it”. In scientific terms it is known as “aposematic coloration”. The common name in Afrikaans for these insects also reflects this distinctive colour combination: rooibaadjie (red jacket).
But just in case a predator has not learnt this colour-coded signal yet, the koppie foam grasshopper has another surprise in store and one that bequeaths it the English common name. If grasped it releases a toxic foam from glands just behind its head, which has a repugnant smell and usually accompanied by an audible hissing sound. This foam contains similar toxins to the main body of the insect and will often prove irritable to the creature that has had the misfortune to bite at it. This is usually enough to ensure that the grasshopper is quickly released and then the bright coloration will remind its would-be predator not to try that again.