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Mozambique Diary: Pardalota

Pardalota reimeri, probably the most colorful and one of the rarest katydids in the world. The individuals I observed in Quirimbas are the first record of this species in 103 years.

Pardalota reimeri, probably the most colorful and one of the rarest katydids in the world. The individuals I observed in Quirimbas are the first record of this species in 103 years.

Ever since I can remember I have been having a recurring nightmare: I am in some incredible location – usually somewhere in the tropics, there are amazing insects everywhere, often those that I have been dying to find, but I need to leave immediately and have none of my collecting gear – not a single vial, no net, no camera (not everybody can relate, I realize, but entomologists know what I am talking about). And last month I finally got to live through this bad dream.

A defensive display of Pardalota reimeri – these katydids feed on highly toxic plants and is likely that their bodies are loaded with poisonous alkaloids.

A defensive display of Pardalota reimeri – these katydids feed on highly toxic plants and is likely that their bodies are loaded with poisonous alkaloids.

Before coming to Gorongosa I flew to the northern town of Pemba where a newly opened campus of the University of Lurió trains Mozambican students in biology and engineering. It was supposed to be a strictly-business trip, meeting lecturers and students, and for this reason I did not bring with me any collecting or sound recording equipment, and only the most basic photo gear. But my friend Harith had a better idea and decided to take me on a short trip to Quirimbas National Park, famous chiefly for its spectacular marine life. Some of his students were working on insect and amphibian faunas of the park, and I said, “Why the hell not.” The seemingly easy trip turned briefly into hell after our Mitsubishi truck decided to part ways with its clutch right in the middle of nowhere. After a long while a friendly driver in a passing car went to fetch a tow truck for us, and eventually we made it to the park.

An unidentified, aposemtically-colored tiger moth found on the same plants as Pardalota.

An unidentified, aposemtically-colored tiger moth found on the same plants as Pardalota.

The first thing that I noticed was the wall of insect sound. The lush miombo forest reverberated with loud katydid calls, ones that I did not recognize. They were unusual for a couple of reasons. One, it was the middle of a hot, African day, and katydids tend not to like it, preferring to call under the cover of the night. And two, the calls were continuous, low frequency, and very complex. They were telling everybody with ears, “Here I am, come and get me.” And when you do that you better have a good trick up your sleeve to protect yourself, as katydid ladies are not the only ones listening: birds, lizards, monkeys, they all love big, juicy insects.

The katydids were calling from high in the trees and I was afraid that I would not be able to catch, or even see them. But then one flew down from the canopy and landed right in front of me. When I saw what it was, my heart skipped a beat – it was Pardalota reimeri, the Holy Grail for katydid aficionados (there are a few of us out there). This species had been known only from the original type series, described in 1911 and preserved in a museum in Berlin. What is special about this species is that even those old, dried husks retained vivid, crazy colors, unlike those of any other known katydid species. And colors as awesome as this indicate an equally awesome biology.

I caught the katydid and he immediately went into a defensive mode: he opened his bright purple, black and white wings, and exposed his neon-orange abdomen and cervical membrane; he lifted his hind legs that had yellow and black markings, remarkably similar to those of toxic chrysomelid beetles. This was either a daring bluff, or this thing was seriously poisonous. All around me other males continued to sing.

A video of a P. reimeri nymph – although the insect is not feeding it gives the perfect illusion of the front end of a fuzzy caterpillar chewing on a leaf.

What to do? Here I was, surrounded by a remarkable entomological discovery, but with no way to collect, preserve, or record it. I decided to exploit Harith’s students and we fanned out looking for the insects. Soon we discovered where they sang – they were only calling from, and feeding on, two species of trees, both known to produce potent chemical defenses, including some powerful psychoactive alkaloids. This almost certainly explained their aposematic coloration. We also found nymphs of this species, which turned out to be incredibly hairy. In fact, when I first saw one I thought I was looking at a fuzzy caterpillar feeding on a toxic plant – its movements were an uncanny imitation of the front end of a caterpillar chewing on a leaf, even though I was looking at at the katydid’s butt. It wasn’t shocking then when a minute later I noticed very similar looking caterpillars feeding on the same plant and, also on the same plant, tiger moths (well known to be toxic) wearing colors very similar to those of the katydids’. Having nothing else at my disposal I pointed my Canon 6D at the canopy and used its video recording feature to record the sound of the singing males. I collected as many individuals as I could, stuffing them into Ziplock bags, hoping to be able to get decent photos and proper sound recordings later on.

In the end I managed to collect enough material and data to write a short note about the biology of this species. But not being able to do a very good job at data and specimen collecting in the field was not a pleasant experience. I have already learned never to go anywhere without my headlamp, a GPS, and a camera, and now I am adding to this list an ultrasonic sound recorder and a large set of vials with 96% ethanol. On the second thought, maybe also an extra clutch for a Mitsubishi and a satellite phone. And some beer, for emergencies.
Two nights later I had a nightmare about Quirimbas.

A female P. reimeri cleaning her foot.

A female P. reimeri cleaning her foot.

Who was Per Brinck?

Brinckiella elegans – a beautiful species from Western Cape Province of South Africa. Females of all species in this genus, and males in at least one, are completely wingless. This is rare among katydids and I still don’t have a good explanation for this loss of the ability to both fly and produce courtship calls.

Brinckiella elegans – a beautiful species from Western Cape Province of South Africa. Females of all species in this genus, and males in at least one, are completely wingless. This is rare among katydids and I still don’t have a good explanation for this loss of the ability to both fly and produce courtship calls.

Taxonomists, myself included, are often asked how we choose names for the organisms we discover and describe. Some are surprised to learn that species are often named after people, but that is also inappropriate to name species after yourself (albeit I know of one such case*). Naming species and genera after people is in fact so common that taxonomists rarely pause to ponder who Welwitsch (Welwitschia), Scudder (Scudderia), or Wahlberg (Clonia wahlbergi, Aquila wahlbergi, Arthroleptis wahlbergi and more) might be or have been. 

As I am sitting in front of my miscroscope, preparing a description of yet another African katydid of the genus Brinckiella, I realize that it never occurred to me to find out who Brinck was, the person after whom the genus was named in 1955. All I know is that he was one of the editors of a monumental, 15-tome treatment of the results of an expedition across southern Africa in 1950-1951. It was during this expedition that a single, tiny green katydid was collected, later to be named after its collector Brinckiella viridis by a French entomologist Lucien Chopard.

For some reason I assumed that Brinck, whoever he was, must be long dead – somebody who published a 15-tome treatise in the early 1950’s would have to be at least 120 by now, right? Well, yes and no. Professor Per Brinck has indeed died. But he only died two months ago, at the age of 94 in his home in Oland, Sweden. He was that country’s leading ecologist, one of the founders of the Nordic Foundation Oikos and editor of the journal Oikos. He was also a an expert on whirligig beetles (Gyrinidae) and dragonflies. He might have liked to receive a copy of my revision of the genus Brinckiella, which I published with my friend Corey Bazelet a few years ago. Alas, I never thought of it and now it’s too late.

An so, next time you run across an insect’s weird name that sounds like it might have been named after somebody, make an effort to find out who that person was. That – let’s pick a random patronym – Naskreckiella may bear the name of somebody very interesting, you just never know.

B. karooensis occurs in karoo vegetation along the western coast of South Africa.

B. karooensis can be found only on karoo vegetation along the western coast of South Africa.

 

*) Wall’s krait (Bungarus walli), a highly venomous snake related to cobras, was named by Frank Wall, a British officer and a medical doctor working in India in the early 1900s. His paper is a delight to read, here is an excerpt where he justifies naming the species after himself:

“[...]At the Club in the afternoon I was pursued by an urchin who produced another specimen which, to my satisfaction, I found to exactly accord with the morning one, and after getting home while dressing for dinner the same boy brought me a third, identical in the peculiarities first noted. Thus in one day I acquired three specimens of a snake hitherto unknown ! I may mention that the day’s bag exceeded 100 snakes of all kinds ! These three Kraits were all small. Since this I have obtained 8 of the same species, and though I believe it a breach of ethics for any naturalist to call a species after himself, the fact that this is the first new snake I have discovered in 11.5 years’ hard collecting, may be pleaded as sufficient excuse for commemorating the event and attaching my own name to it.”

Wall, F. 1907. A new krait from Oudh (Bungarus walli). J. Bombay Nat. Hist. Soc. 17:155-157.

The amazing Glass katydid

A young nymph of Glass katydid (Phlugis teres) from Suriname sitting on the tip of my finger.

A young nymph of Glass katydid (Phlugis teres) from Suriname sitting on the tip of my finger.

Once again things have been slow on my blog as I am trying to finish a million little things before my upcoming departure for Mozambique. I will be arriving there at the beginning of the rainy season, which means tons of insects and other invertebrates, a multitude of frogs, and hopefully some great new stories for this blog.

One of the animals that I hope to see there is a pretty, yet unnamed katydid from Mt. Gorongosa, which I first found last year in the mid-elevation rainforest on the mountain slopes. I am now working on its formal description and will post its photos as soon as the paper is out. In the meantime I thought I would present one of its close relatives, the amazing Glass katydid from Central and South America, a member of the genus Phlugis (Listroscelidinae).

As they age, Glass katydids begin to lose their transparency, and older nymphs and aduls acquire pale green coloration.

As they age, Glass katydids begin to lose their transparency, and older nymphs and aduls acquire pale green coloration.

I coined the name Glass katydid after seeing for the first time young nymphs of Phlugis teres, a species found in Suriname, who display remarkable, nearly complete transparency of their bodies. These minute insects truly look as if they were made of glass and, peering closely, it is possible to see most of their internal organs, including the entire tracheal system. Unfortunately, these katydids lose most of the transparency as they get older, and eventually acquire pale green coloration, occasionally marked with brown accents.

It would seem that something so seemingly fragile cannot feed on anything other than dew and rose petals, but in fact Glass katydids are agile, powerful predators. Unlike most of neotropical katydids, the genus Phlugis includes many diurnal species that use their excellent vision to find prey, and their hunting technique is very clever. Glass katydids are sit-and-wait predators who spend most of the day sitting upside down on the underside of large, thin leaves, usually at the edge of the rainforest or in open, shrubby habitats. They prefer leaves that are fully exposed to the sun so that any insect landing on its upper surface will cast a dark, sharply defined shadow. And that shadow is what Glass katydids are waiting for – it tells them whether the insect is a hard beetle (not good) or a soft fly (excellent), and if the insect looks like a good meal they launch themselves from under the leaf and onto its surface, and capture the victim with their long, very spiny legs in a blink of an eye.

In addition to being some of the most sophisticated and fastest orthopteran predators, Glass katydids are famous for the sound they produce – their call exceeds the frequency of 55 kHz, which is about three times the frequency a human ear is capable of hearing. A closely related genus Archnoscelis holds the record of producing the highest frequency call among all invertebrates – a whopping 129 kHz, twice the frequency of echolocation of most bats, and about 10 times more than the hearing ability of most adult humans. Another reminder that the ability to look cool and do amazing things seems to be inversely correlated with the body size.

Their huge eyes are a good indication of Glass katydids’ mode of hunting – they are diurnal sit-and-wait predators of small flies and other soft insects. This newly discovered, yet unnamed species from Costa Rica hunts small flying insects along the edges of mid-elevation rainforest.

Their huge eyes are a good indication of Glass katydids’ mode of hunting – they are diurnal sit-and-wait predators of small flies and other soft insects. This newly discovered, yet unnamed species of Phlugis from Costa Rica hunts small flying insects along the edges of mid-elevation rainforest.

Music in my head

Male Carolina ground crickets (Eunemobius carolinus) are the hardiest of all my garden's musicians, and may continue to woo females with their song well into late November.

Male Carolina ground crickets (Eunemobius carolinus) are the hardiest of all my garden’s musicians, and may continue to woo females with their song well into late November.

I have always wanted to be a musician. Not that I have any particular musical talents (and never learned to read music), but my fascination with sound was definitely one of the reasons for becoming an expert in the taxonomy of orthopteroid insects, nature’s preeminent musicians. Few things are more pleasant to me than sitting on the deck of our house near Boston on a warm summer evening – a high frequency sound recorder in one hand, a glass of gin & tonic in the other – and getting lost in the hypnotic chorus of about a dozen species of katydids and crickets that share our garden with us. (The best part of this activity is that I can call it “data collecting”.) Now that the summer is sadly over, all I have is the memory of beautiful garden soundscapes, and a bunch of recordings. There are still some strugglers out there – just the other night I found a Sword-bearing conehead (Neoconcephalus ensiger) singing on the lawn in front of our house – but let’s face it, it will be very quiet very soon. And thus I thought that this might be a good time to put all of this year’s recordings together into one composite soundscape, and relive the aural painting that I am privileged to experience every summer.

Some of the cricket species I recorded in or near my garden. The number under each name represents the sequence of joining the musical performance in the composite recording below.

Some of the cricket species I recorded in or near my garden. The number under each name represents the sequence of joining the musical performance in the composite recording below.

Some species, such as the ubiquitous Carolina ground cricket (Eunemobius carolinus), produce calls that are not especially musical, but rather reminiscent of a buzz made by overtaxed power lines. Others, like the Treetop bush katydid (Scudderia fasciata), make irregular, high frequency clicks that show no discernible rhythm. But, as I listen to the evening’s ambience, a repeating pattern begins to emerge. Snowy tree crickets (Oecanthus fultoni) stridulate in a way that is both highly rhythmical and melodious (Joni Mitchell fans will recognize this species in the song “Night Ride Home”), while the frequency-modulated chirps of Field crickets (Gryllus veletis) add a nice, if somewhat irregular, punctuation.

Some of katydid neighbors. Just like with the crickets, the number under each name represents the sequence of joining the musical performance in the composite recording below.

Some of katydid neighbors. Just like with the crickets, the number under each name represents the sequence of joining the musical performance in the composite recording below.

As the night falls more and more species join in. A Two-spotted tree cricket (Neoxabea bipunctata) utters short, piercing cries, usually in sonic pairs, sometimes in series of threes or fours. And although I cannot hear it, I know that the Drumming katydid (Meconema thalassinum), a relatively recent arrival to North America from Europe, is banging one of his hind legs against the bark of the large oak in our garden, creating a percussive line for the rest of the ensemble. Why this species has lost its ability to stridulate and instead evolved a drumming behavior is a mystery, but it is likely that the shift was driven by either a predator or a parasite the had used its (originally) airborne calls to find the singing males and do unspeakable things to them.

And finally, later at night (and later in the season), the True katydid (Pterophylla camellifolia) adds its voice to the chorus. This spectacular insect, whose song is recognizable to anybody who’s ever lived on the East Coast of the US, is the northernmost member of a largely tropical lineage of katydids, the Pseudophyllinae. Despite them being very large and remarkably common insects (you can hear true katydids in the middle of Boston and other large cities), few people ever get the chance to see one – they spend their entire lives high in the canopies of the tallest trees, and are encountered only occasionally, for example when a gust of strong wind knocks them down onto the ground. I have lived surrounded by True katydids for the last 20 years, but can count all my encounters with them on the fingers of one hand. Incidentally, if you ever wondered where the word “katydid” came from, listen to this species’ call. The more northern populations (and thus the ones that the Pilgrims first heard, and apparently were afraid of) have a call consisting of 2-4 syllables that can be interpreted as the sound “ka-ty-did” (or, as the legend goes, “katy-she-did-it”, thus betraying the identity of some murderous lady).

My foot has been tapping since the tree crickets started calling, and now, with the strong beat of the True katydid, I can’t help but imagine melodic lines filling the spaces in between the pulses. I sip my drink and let the mind wander.

A sonogram of a composite recording of most of the orthopteran species singing in my garden. On a good night I can hear them all, but here I decided to add them one by one to the recording to make each species' song stand out. Click here to listen to this soundscape. Please note that some species (esp. Scudderia and Microcentrum) may not be audible to a certain group of listeners (I am talking about you, men 35 or older; I count myself incredibly lucky for still being able to hear all my local species – but who knows for how long). It will help if you listen to this recording through headphones or external speakers; most built-in computer speakers may not be able to reproduce all frequencies (esp. the low frequency drumming of Meconema). (If you would like to see an animated sonogram with species names appearing as they join the chorus, click here; it is a large file, suitable only for a fast connection.)

A sonogram of a composite recording of most of the orthopteran species singing in my garden. On a good night I can hear them all, but here I decided to add them one by one to the recording to make each species’ song stand out. Click here to listen to this soundscape. Please note that some species (esp. Scudderia and Microcentrum) may not be audible to a certain group of listeners (I am talking about you, men 35 or older; I count myself incredibly lucky for still being able to hear all my local species – but who knows for how long). It will help if you listen to this recording through headphones or external speakers; most built-in computer speakers may not be able to reproduce all frequencies (esp. the low frequency drumming of Meconema). (If you would like to see an animated sonogram with species names appearing as they join the chorus, click here; it is a large file, suitable only for fast internet connections.)

Mozambique Diary: The fat coneheads of Gorongosa

Conehead katydid Lanista annulicornis (a.k.a. L. africana) showing its huge, sharp mandibles designed for cutting and crushing grass seeds. They also do an admirable job on human skin.

Conehead katydid Lanista annulicornis (a.k.a. L. africana) showing its huge, sharp mandibles designed for cutting and crushing grass seeds. They also do an admirable job on human skin.

A few years ago I was at the Museum of Natural History in London to examine several type specimens of African katydids. One of them was the holotype of a conehead katydid Lanista africana, a species described by the infamous 19th century entomologist Francis Walker. (Stories abound about the quality of his taxonomic work, such as the time when he described the same set of insect species twice, each time giving them different names. This, of course, is not unusual and happens to this day, but in his case it was the same box of specimens which he first described in the morning, and then again after lunch, without realizing that he had already given them names.) What caught my eye was an inscription on the label attached to the specimen. In addition to the typical 19th century exactitude in the locality information (“From Africa”) it bore the following note – “Lived 18 months without food.”

The body of the Conehead katydid Pseudorhynchus pungens looks just like a blade of grass and few predators can spot them.

The body of the conehead katydid Pseudorhynchus pungens looks just like a blade of grass and few predators can spot them.

Now, without getting into speculations as to why anybody would torture a poor katydid for so long, I was of course highly skeptical about the veracity of such a statement. Eighteen months? That seemed unlikely, to say the least, considering that the average lifespan of an adult katydid is only a few months. But that was before I had a chance to see a live individual of Lanista.

Gorongosa National Park is defined by its extensive grasslands and woodland savannas, just the kind of habitat that African conehead katydids love. If you walk through the tall grass here (and you better have an armed ranger with you if you decide to do so – it is surprisingly easy to miss an elephant hiding a few feet away) chances are that the first insect you see will be a conehead katydid scurrying away. Fourteen species of coneheads can be found here, and one of them is the aforementioned Lanista africana (Which, incidentally, is now known as L. annulicronis. Shockingly, L. africana turned out to be a synonym of L. annulicornis, a species described earlier by – who else? – Mr. Francis Walker.)

When I caught my first Lanista I was surprised at how fat and heavy it felt. Since I needed to preserve a few specimens of this species for the Gorongosa synoptic collection and my own work, I dissected them and discovered that their entire body was absolutely loaded with fat tissue. It was difficult to discern any internal organs in the abdomen because the layer of thick, white fat filled every bit of space – these guys were in a serious need of liposuction. All katydids that I had seen up to that point were rather lean – where did all that fat come from and why did they have it?

African coneheads, as opposed to their New World counterparts, are almost exclusively herbivorous, and the food that they are particularly fond of are grass seeds. Grass seeds are loaded with carbohydrates and lipids, and if you can feed on them effectively you will start storing fat very quickly. (That tasty Big Mac that goes straight into your hips? It is mostly the bun – pure carbs – that does the damage.) Coneheads’ mandibles are seed grinding machines, very sharp and propelled with powerful muscles – this is why coneheads have such huge, elongated heads. Few insects are as good at stripping the husk of a grass seed and getting to the tasty kernel as a conehead katydid.

Conehead katydids' mortal enemy, the Black-bellied Bustard (Lissotis melanogaster) – I have watched this bird slowly walk in tall grass and expertly pick katydids and grasshoppers that were invisible to me.

Conehead katydids’ mortal enemy, the Black-bellied Bustard (Lissotis melanogaster) – I have watched this bird slowly walk in tall grass and expertly pick katydids and grasshoppers that were invisible to me.

Grasslands in Africa are seasonal – the seed bonanza of the rainy season quickly turns into near starvation of the dry one – but if you can store enough energy to survive those few very lean months then your chances of producing the offspring at the onset of rains, perhaps even a second generation of the species in the same year, are greatly improved. I strongly suspect that this is what the coneheads of Gorongosa are doing. The individuals I am seeing now, at the peak of the dry season, are significantly thinner than those I saw here just a few months ago, but I believe that they belong to the same generation. And while I am not going to test it, I now find it more believable that an individual with all its fat reserves intact may be able to survive for a very, very long time without food. And, incidentally, the one species of katydids that is routinely eaten by people in Africa is a conehead Ruspolia consobrina, whose body also contains high levels of nutritious fats.

The genus Ruspolia is represented in Gorongosa by at least six species, some of which may be new to science. R. consobrina is one of few katydids that are routinely eaten by people in Africa.

The genus Ruspolia is represented in Gorongosa by at least six species, some of which may be new to science. R. consobrina is one of the few katydids that are routinely eaten by people in Africa.

The large, elongate head of the conehead katydid Pseudorhynchus hastifer hides powerful grinding muscles and help this animal blend in among blades of grass.

The large, elongate head of the conehead katydid Pseudorhynchus hastifer hides powerful grinding muscles and helps this animal blend in among blades of grass.

They can count, too

A male Treetop bush katydid (S. fasciata) from Woburn, MA.

A male Treetop bush katydid (S. fasciata) from Woburn, MA.

In March of 1882 a little known journal that had been founded only two years prior was about to go under – nobody wanted to read it, and its owner was tired of putting any more money into it. But an enthusiastic entomologist named Samuel H. Scudder, who at that time, after many years of doing various unpaid jobs, was finally holding the prestigious position of an Assistant Librarian at Harvard University, had recognized the potential of that publication and decided to save it. He edited the journal until 1886, ensuring that it would gain prominence and a much greater readership. Thanks to his enthusiasm the journal had survived, and later became somewhat influential in the academic circles.

But in addition to his penchant for saving obscure publications from oblivion, Scudder was one of the most prolific and influential American zoologists. His list of papers and books includes 791 titles (!), and many of them deal with my favorite group, the Orthoptera. Because of his contribution to the taxonomy of orthopterans, 24 species of grasshoppers and katydids carry his name (scudderi), as does one  genus, the elegant Scudderia, also known as the Bush katydid.

A female Fork-tailed bush katydid (S. furcata) from Boston ovipositing between the two layers of a leaf's epidermis.

A female Fork-tailed bush katydid (S. furcata) ovipositing between the two layers of a leaf’s epidermis.

I always knew that one species of Scudderia was common in my backyard, the Fork-tailed katydid (S. furcata), and its short, high-pitched clicking calls can be heard almost every night from the deck of the house. But a few nights ago I noticed a different call coming from the garden, and was pleased to find a new neighbor – the Treetop bush katydid (S. fasciata). Bush katydids are graceful, delicate creatures that feed on leaves and flowers of a variety of plants, and in our garden they seem to be particularly fond of bee balm flowers and a few other ornamentals. They spend their entire lives either high in the canopy or in tall bushes, and never descend to the ground. Female bush katydids lay eggs on the vegetation, but do it in a truly masterful way. Rather than laying eggs on the surface of leaves or bark, which many arboreal katydids do, they perform the almost impossible feat of splitting the leaf in two – along its thin edge! – and insert the eggs between the two layers of the epidermis. Obviously, in order to fit there, the eggs must be really thin, and in fact they are so thin as to be virtually translucent when they are initially deposited. They harden and darken as they age, but remain remarkably two-dimensional. Well hidden inside the leaf’s tissue, eggs of Scudderia are probably at a much lower risk from parasitoid wasps, which often wipe out most of katydid egg clutches.

The counting katydid, Scudderia pistillata – males of this species add one syllable to each subsequent "click", and the male with the highest number of syllables has the highest chance of attracting a female. This individual is from Sanbornville, NH.

The counting katydid, Scudderia pistillata – males of this species add one syllable to each subsequent “click”, and the male with the highest number of syllables has the highest chance of attracting a female. This individual is from Sanbornville, NH.

Bush katydids have also one very interesting feature – they apparently can count. Males of the Broad-winged bush katydid (S. pistillata) produce several types of call, but only one is designed to attract females. It usually starts with a typical single phrase, with only a few syllables (to the human ear these sound like a slow “chirp”), but each subsequent phrase adds one more syllable. It has been shown that females preferentially mate with males who produce the highest number syllables at the end of a calling bout. This is probably because longer phrases require more energy to produce, and thus are an honest indication of the male’s health and the ability to invest in his offspring.

Bush katydids are hardy creatures, and I sometimes find them well into late October. Their pretty nymphs are also some of the first katydids to appear in the late spring. They can be identified by their color patter, which often has vivid emerald and orange accents, and by the presence of a small “cone” on the top of their head (this “cone” disappears in adult katydids).

This is how it's done: the female first chews off the edge of the leaf, and then uses her mouthparts to carefully guide her ovipositor in between the two layers of the epidermis.

This is how it’s done: the female first chews off the edge of the leaf, and then uses her mouthparts to carefully guide her ovipositor in between the two layers of the epidermis.

Not surprisingly, the beautiful Scudderia is one of my favorite genera of North American katydids, and its members are deserving bearers of the name of one of America’s greatest naturalists. Oh, and the journal that Samuel Scudder saved from oblivion? It was Science.

Nymphs of bush katydid can be recognized by their bright, emerald green coloration and the presence of a small "cone" on the head.

Nymphs of Scudderia can be recognized by their bright, emerald green coloration and the presence of a small “cone” on the head.

S_pistillata_song

The song of S. pistillata – notice how the number of syllables increases in each subsequent phrase. Click here to hear it. (Based on a recording from the Singing Insects of North America.)

Helmeted katydids

Helmeted katydid (Phyllophora boschami) from Pogera gold mining camp in the Enga Province of Papua New Guinea.

Helmeted katydid (Phyllophora boschami) from Pogera gold mining camp in the Enga Province of Papua New Guinea.

Porgera, a gold mine in the highlands of Papua New Guinea, is not a pleasant place for a biologist, especially if you are aware of the massive environmental damage of its operations, or the frequent human right violations that this mining camp is known for. But we had no choice but to sleep with the enemy, and ask for the mine’s help in helicoptering us into the remote highlands of PNG where our team was surveying animals and plants. Luckily, the heavily guarded fortress of Porgera had one redeeming quality – at night I was allowed to wander around our sleeping quarters and look for insects. This, being New Guinea, guaranteed that even a place as dismal as a mining camp was bound to reward me with something interesting. And I was not disappointed – not only did I find a lot of insects, but one of them turned out to be new to science. (Yes, I am aware of the irony of a mining camp being the type locality and the site of the only known population of Pandangraecia porgera Naskrecki and Rentz, 2010.) But the insect that really stood out in the crowd was a katydid Phyllophora boschmai, a member of a remarkable lineage of my favorite insects.

The body of helmeted katydid nymphs, like in this Phyllophora sp. from Eastern Highlands Province of PNG, is almost entirely covered by the helmet-like pronotum.

The body of helmeted katydid nymphs, like in this Phyllophora sp. from the Eastern Highlands Province of PNG, is almost entirely covered by the helmet-like pronotum.

The Phyllophorinae, known as the helmeted katydids (the names hooded katydids or box katydids are also used) are found primarily on New Guinea and nearby islands, although a handful of species venture into northeastern Australia, and a few places in the Philippines, Sri Lanka, and Taiwan. What immediately sets them apart is their size – many species are massive, and one, Siliquofera grandis, is the largest living katydid, with the wingspan of over 8 inches (20 cm)! Their morphology is also unusual – the pronotum, the part of the thorax immediately behind the head, is greatly expanded into a huge, helmet-like structure that covers the thorax and parts of the wings; in nymphs the pronotum may cover the entire body. This type of the pronotum usually indicates that the katydid is an exceptionally loud singer since the pronotum can act as a resonator and an amplifier of the call produced by the sound-producing apparatus at the base of the wings. But this is where things get interesting. If you were to peek under the huge pronotum of a helmeted katydid, you would find nothing. No sound-producing organs, no stridulatory file, nothing. These katydids cannot sing.

Some helmeted katydids, such as this Sasima versteegi from the Western Province of PNG, are huge.

Some helmeted katydids, such as this Sasima versteegi from the Western Province of PNG, are huge.

It appears that the huge pronotum is there solely as a defensive mechanism, protecting the softer, more vulnerable parts of the body. Why helmeted katydids have lost the ability to sing is still a mystery, especially considering the fact that they are a highly derived group, closely related to some of the loudest singers in the family, the Mecopodinae. But the real question is, how do males and females find each other?

In katydids, the acoustic communication – attracting each other with a song produced by rubbing their wings – is the only way (that we know of) for the two sexes to get together as these insects lack pheromonal communication or any other way to send long distance signals (some katydids use substrate vibrations to communicate, but this only works over short distances). But helmeted katydids are not entirely silent, either. They have evolved unique stridulatory structures at the base of their legs that allow them to produce loud, rustling noises, which both males and females use as a defense mechanism if they happen to be assaulted by a predator (click here to listen to the defensive stridulation of a helmeted katydid). These structures, however, cannot be used to attract the opposite sex in the dense vegetation of the New Guinea rainforest, and the mechanism by which the sexes locate each other is completely unknown.

The sternocoxal stridulatory apparatus of a helmeted katydid. The first segment (coxa) of the last pair of legs is covered with dense, parallel ridges that rub agains a series of pegs on the surface of mesosternal lobes on the ventral side of the thorax. The sound produced in this way is noise-like, typical of a defensive stridulation.

The sternocoxal stridulatory apparatus of a helmeted katydid. The first segment (coxa) of the last pair of legs is covered with dense, parallel ridges that rub agains a series of pegs on the surface of mesosternal lobes on the ventral side of the thorax. The sound produced in this way is noise-like, typical of a defensive stridulation.

But it wouldn’t be, if only I had the presence of mind to watch them more closely. While in Papua New Guinea I captured a male and a female of Phyllophora sp., and placed them in a large mesh cage. I kept looking at the pair, waiting for something to happen, but then it was dinner time and I was hungry and, long story short, when I came back the two were already relaxing with a cigarette in hand – I missed the whole thing! And it probably was quite a spectacle – I knew that they had successfully mated because the female now carried what looked like a pair of white testicles, a nuptial gift from the male. In many katydid species the male produces a similar gift, known as the spermatophylax, that the female later consumes. Why they do it is another story, but in an essence this is to prevent her from mating with another partner, and to ensure that the male’s sperm has time to enter her body. In this way the edible spermatophylax, which encapsulates a pair of small vesicles containing sperm, is indeed, from the functional point of view, a pair of autonomous testicles that the male attaches to the female.

What looks like a pair of testicles at the base of a female's ovipositor is the spermatophylax, a nuptial gift produced by the male during mating. It consists mostly of nutritious carbohydrates and proteins, and is subsequently consumed by the female. Its presence ensures that the male's sperm has enough time to enter the females genital opening, and effectively prevents her from mating with another partner, at least for some time. The nutrients in the spermatophylax also contribute to the fitness of his and her offspring.

What looks like a pair of testicles at the base of a female’s ovipositor is the spermatophylax, a nuptial gift produced by the male during mating. It consists mostly of nutritious carbohydrates and proteins, and is subsequently consumed by the female. Its presence ensures that the male’s sperm has enough time to enter the females genital opening, and effectively prevents her from mating with another partner, at least for some time. The nutrients in the spermatophylax also contribute to the fitness of his and her offspring.

And so the mechanism of the helmeted katydids’ long range communication remains a mystery. I never had a chance to watch these insects again, but hope to be able to return to New Guinea at some point, and finally document their courtship ritual, dinner be damned.

P.S. David Rentz, who also participated in the PNG katydid survey, has revised Australian Phyllophorinae, and wrote a post about these insects on his excellent blog BunyipCo.

Although mostly nocturnal, some species, such as this Phyllophora sp. from New Britain, can be found during the day on understory vegetation.

Although mostly diurnal, some species, such as this Phyllophora sp. from New Britain, can be found during the day on the understory vegetation.

A molting female of Phyllophorella woodfordi from the Solomon Islands.

A molting female of Phyllophorella woodfordi from the Solomon Islands.

A nymph of Sasima versteegi is a perfect mimic of mossy vegetation of the humid, lowland rainforest on New Guinea.

A nymph of Sasima versteegi is a perfect mimic of mossy vegetation of the humid, lowland rainforest of New Guinea.