BY ALPER ÖZKAN (MSN/PhD)
d_ozkan@ug.bilkent.edu.tr
Three types of animals are virtually guaranteed to be interesting: parasites within ordinarily free-living groups; specialized predators derived from herbivores and scavengers; and oddballs that are given their own higher taxa, distinct from anything else and often attracting strong controversy on where exactly they belong (Buddenbrockia, for example, was only recently recognized as a cnidarian, but you wouldn’t guess that from looking at it, because what it looks like is a worm, while the atavistic, clawed bird the hoatzin is still the subject of heated debate). Orthoptera, the taxonomic home of crickets, grasshoppers, katydids, grigs and their kin, doesn’t have much in the way of the former (although tiny, deaf ant inquiline crickets do exist, resembling nothing so much as bullets with legs) or the latter—but it does have carnivores, and they are exceptional. Let’s have a look at some.
Orthoptera is, fortunately, one of those groups that has a classification system that makes sense even to me, being split neatly into the crickets (Ensifera, dagger-bearers) and grasshoppers (Caelifera, chisel-bearers—both names refer to the sharp ovipositor, longer in crickets than in grasshoppers, which the females use to lay eggs within soil or plants). Typical backyard hoppers belong to the very apex of the grasshopper side, which also contains the locusts—though these, rather than distinct species unto themselves, are the swarming forms of solitary grasshoppers. This characteristic allows locusts to lie low for some period of time before whipping up their legendary swarms—the extinct Rocky Mountain locust, which formed the largest swarms of all (one swarm reportedly covered an area of some 500,000 square kilometers, or about two-thirds of Turkey, corresponding to an estimated 3.5 trillion insects), was in fact once thought not to be extinct at all, but merely incapable of mustering the population densities required for locusting. The grasshopper clade also contains the bizarre sandgropers, a convergent equivalent to the distantly-related mole crickets: larviform despite never actually being larvae (orthopterans do not undergo complete metamorphosis, hatching from their eggs as miniature versions of the adult), these insects cannot fly or jump but are prodigious burrowers.
Although sandgropers do ingest animal matter, grasshoppers in general adhere to the “peaceful herbivore” image that they project—but crickets are different. All are omnivorous to some degree, and the meat-eating habit has been refined to perfection in predatory katydids. These green, jumpy, grasshopper-like crickets are often defended by an impressive array of spines (sometimes complemented with the ability to spit or squirt blood at a distance), and their armaments are equally useful in grasping prey insects and even small lizards, which they make short work of with their massive, multipurpose chewing mouthparts. Some have rather evocative names, like the dragon-headed katydid (not predatory, but still one of the very few insects I am genuinely unsettled by) or the red-eyed devil (which does live up to its name, biting to draw blood if provoked), and an Australian species even mimics the reply calls and body language of female cicadas to lure males to their doom, just as Photuris fireflies mimic the flashes of other species in order to devour would-be suitors!
The most famous predatory crickets, however, belong to the superfamily Stenopelmatoidea, which includes Jerusalem crickets, king crickets, raspy crickets and weta. (My preferred name for the whole lot is crickhopper: that is what Gryllacridoidea, another name for the group, means in Latin, and it’s too good a name not to be used—and yes, I also think that grylloblattids and mantophasmids should rightfully be called crickroaches and mantistick insects.) Heavyset and well-armored, these ground-dwelling crickets will eat anything they come across, and one of them made quite a name for itself in the “Japanese Bug Fights” video series: while the more aggressive insects immediately pounced upon their enemies or attempted to flee the arena, the placid cricket was evidently unaware that it was in a fight to the death, treating the event like an all-you-can-eat buffet and casually chewing down its still-living opponents. It remains a fan favorite despite its absence in later seasons, which were devoted to the Manticora beetle and the emperor scorpion crushing everything to oblivion. (Note to bug death-match organizers: I’m not exactly the sensitive type when it comes to the practice of insect fighting, but when your “insect” is a scorpion and/or has trouble fitting into the arena, it’s just plain cruel to let it “fight” others.)
Oh, and since this is the first column of the season, I think introductions are in order: I write, so far as I am able, on biology and history, and if you have any relevant topic in mind, do feel free to mail it to me.