This entry is just for brooklinegirl.

[dira]

I've been reading a book on locusts (title: Locust) and periodically I try to explain to someone how great it is. I can't really do it justice in paraphrase so here, as promised,

In entomology in general, and acridology in particular, we often resort to qualitative differences in structures that most people would find peculiar are best, and perverse at worst. We spend a lot of time peering at grasshopper penises.

The genitals of a male grasshopper are elaborate structures, comprising a number of elegantly working parts. The external features include a couple of hinged plates, or "doors" at the tip of the abdomen that are the grasshopper's equivalent of a foreskin, protecting the more delicate internal structures. Also on the exterior of the creature's abdomen are a pair of small, variously shaped protuberances called cerci. Some look like clubs, others like hooks, others like tiny cowboy boots. The internal or concealed genitalia are a bit more amorphous. We refer to these structures as the phallic complex, which is not a psychological condition but a mass of variously membranous, leathery, and hardened features. In grasshoppers, the phallic complex is tucked away inside the tip of the abdomen, being prudently encased by the external plates and extruded only when mating is imminent. The phallic complex includes the penis, or more technically speaking the aedeagus, which is the organ that enters the female and through which sperm pass. Actually, I suspect that there is a bit of prudishness and squeamishness in using the term penis in entomology--it sounds more clinical and technical to rename a structure that appears so flamboyant compared to our own. Lying above the aedeagus is the epiphallus, a hardened structure that probably plays a role in ensuring a proper fit of the male and female genitals during copulation.

The explanation of why the male genitals of grasshoppers are so intriguing to taxonomists is fairly simple. To being, these structures exhibit remarkable consistency within species but spectacular variation among species, even in cases where two kinds of grasshoppers seem to be otherwise similiar in size, form, and color. The basis for these differences is probably, at least in part, a function of reproductive isolation. For a species to evolve and sustain genetic integrity, its members shouldn't be trying to mate with other species. Species often have distinct body forms and colors that allow prospective mates to readily identify their own kind. Some grasshoppers use elaborate courtship rituals to ensure that the prospective mate is the "right one." Not so for the spurthroated grasshoppers--a subfamily named for the conical protuberance that arises from between their front legs, giving the impression of an enlarged Adam's apple or "spur throat." Species in this taxonomic group (of which spretus is a member) are similar in appearance and undiscriminating in their foreplay.

For the spurthroated grasshoppers, sex is a lover's leap. Males often hop onto almost any moving object of approximately the right size and color of a prospective mate, including females of other species and sometimes even other males. In the latter case, consummating the relationship is, of course, hopeless. But in the former case, mistaken matings would seem possible. However, with his weirdly contorted genitals, the male is not able to insert his aedeagus into just any female. When a mismatched male is not summarily kicked off by the female, he spends several minutes tediously probing with his genitalia. But the elaborately sculpted tip of his penis simply doesn't align properly with her genital tract.



Lockwood, Jeffrey A. Locust: The Devastating Rise and Mysterious Disappearance of the Insect That Shaped the American Frontier. New York: Basic Books, 2004, pp.155-156.