Those who have been reading this blog with some regularity may have noticed that I find virtually all organisms equally fascinating. But some are more equal than others, and few animals and plants excite me more than phylogenetic relics. These are the last remaining members of lineages that were once dominant, or at least species-rich, but are now represented by only one or a few surviving species, species that still carry the old (plesiomorphic) versions of many of the organism’s characters. Such relics are often relegated to living in places that are inhospitable to their evolutionarily younger relatives, but are able to thrive thanks to their ability to handle extreme conditions (albeit this ability is often a relatively recent development). And though I am now in Gorongosa National Park, a place bursting with all kinds of fantastic African wildlife, before I resume my Mozambique Diary I first must recount an interesting encounter with a Mesozoic singing relic that I had only a few days before leaving for Africa.
Nobody really knows who the first animal singers were. Chances are that the first acoustically active animals were aquatic — grunting placoderm fish, stridulating trilobites, or perhaps pincer-snapping eurypterid sea scorpions — they all have modern equivalents that produce sound underwater. But on land the first organisms that broke the silence were almost certainly small arthropods, whose bodies, encased in rigid plates and tubes of the chitinous exoskeleton, were perfectly suited to become percussive instruments. It is quite likely that a defensive sound production was the initial reason for the evolution of animals’ acoustic behavior, but it did not take long for them to start using sound as an effective attractant during courtship. The unquestionable leading voices of invertebrate love chorus are, and probably have always been, the orthopteroid insects – katydids, crickets, and grasshoppers. Their Permian and Triassic ancestors already had quite sophisticated sound-producing organs on their wings and must have dominated the soundscapes of the Pangean supercontinent. Wings of these fossil insects are often preserved with exquisite detail, allowing us to speculate about the kind of sound they made, and who their modern successors might be. In fact, thanks to a recent study by Jun-Jie Gu you can now listen to a Jurasic song of a katydid ancestor. A handful of direct descendants of these ancient singing insects, members of the largely extinct Mesozoic family Prophalangopsidae, or grigs, are still alive today, and their songs are quite similar to those of their long-gone forbearers.
A few species of grigs can be found in cold, mountainous habitats of eastern Siberia and central China, and three additional ones live in the mountains of western US and Canada. Virtually nothing is known about the Asian species, but the North American ones have inspired research for decades, and we now know more about their behavior than about that of almost any other singing insect on the planet. And what fascinating behavior it is — these innocent-looking insects combine the love of freezing weather and cannibalism with a lust for virgins.
Last week I was in Seattle and decided to try my luck at finding the largest North American grig, Cyphoderris monstrosa. I had precious little time to do this and thus my only option was to look for it in the Cascades, about 70 miles E of the city. Alas, all I had to go by was a single record from 1909, with a vague description of the locality called Stampede, and I figured that it had to be the same place as what is now known as the Stampede Pass, an area covered with thick forest of hemlocks and pines on steep mountain slopes – just the right place for grigs. I got there in the early afternoon but the place did not look particularly inviting – every single road sign was pockmarked with shotgun blasts, what I took for colorful flowers on a meadow turned out to be piles of shotgun and handgun shells, and nearly all roads leading to what looked like a promising grig habitat had a “No trespassing” sign. Hoping that I will make a difficult target in a rainy night I decided to wait until dark and then search for the insects.
The first grig started calling around 10 pm. His call was a high-pitched but rather pleasant warble, somewhat akin to the ring of an old-fashioned telephone. It was coming from a tall hemlock, and I had no other option but to start climbing. Thankfully, grigs are not particularly skittish, and once I located the male I had no troubles getting close to him. I recorded his call and then quickly grabbed him.
In the majority of the animal kingdom the male provides little more than reproductive cells that inseminate the female’s eggs, and hence the profusion of elaborate displays of masculine virility designed to convince the female of the male’s good genes, rather than his suitability for lasting partnership or shared investment in offspring. Usually, all the gullible female gets is a brief, entertaining show and the knowledge that she will never see the guy again. Not so in grigs. The females in these animals want to take home more than just a memory of a good time; they also demand a decent meal, something that will significantly contribute to the production of eggs. Because grigs literally live in their food, a male offering a piece of hemlock or pine, no matter how fresh and tasty, would certainly be given a cold shoulder. Having nothing else to give, the males are forced to make the ultimate sacrifice — they offer females parts of their own bodies to dine on. Like most insects, male grigs have two pairs of wings. The first pair, slightly hardened and modified into sound organs, is used to produce a song that guides the female to him. The second pair, however, is somewhat dispensable, and it has evolved into a pair of big, fleshy organs filled with the male’s blood (hemolymph), and this is what the female grigs lust for.
Once a female locates an interested male, she climbs on his back and immediately starts devouring his wings. While she is busy with her cannibalistic hors d’oeuvre, the male attaches his reproductive organs to those of the female and transfers a packet of sperm. He also leaves with the female a package of nutritious carbohydrates and proteins, known as the spermatophylax, which the female consumes after the mating. It seems that the role of these nuptial gifts is to ensure that the sperm he delivered has enough time to get where it needs to, and it also precludes her from mating again with another male, at least until she is done eating. More importantly, his edible wings and the spermatophylax provide the female with nutrients that she will be able to use to produce her eggs, making the male an active and invested participant in parenthood.
Although both the male and the female will soon be ready to mate again, the male now has a problem — he is not ready to retire quite yet, but he no longer has the tasty wings that attracted his first partner. Luckily for him females are not very good at distinguishing the song of an unmated male from that of one who has already lost his virgin wings (but there is evidence that the females preferentially mate with virgins). And once she climbs the back of a male and realizes that he no longer carries the tasty snack, it is too late. Male grigs have evolved an ingenious, if somewhat insidious, device on their abdomen, appropriately called the gin trap, which effectively locks the female in place and gives him extra time to transfer his reproductive cells. It takes a female a considerable amount of effort to disengage from the male, and there is plenty of time for him to pass on his genes.
I stayed in the forest until midnight, tracking, recording, and photographing grigs. By that time the temperature had dropped significantly and a freezing rain was pouring, which made for very compelling arguments to get back into the car and drive back to Seattle. But I was giddy with excitement of having found the grigs and, an unexpected bonus, not having been shot at.