On the benefits of random collecting

A female Cederberg cave katydid (Cedarbergeniana imperfecta) preening her antennae.

A female Cederberg cave katydid (Cedarbergeniana imperfecta) preening her antennae.

In 1911, after a short and apparently unsatisfying stint as a lawyer, Keppel H. Barnard left his native London and joined the staff of the South African Museum in Cape Town. First a mere lab assistant, he quickly ascended the ranks, in 10 short years reaching the position of the museum’s director, which he held until his retirement in 1956. Barnard’s life was dominated by two seemingly opposite passions. One was the study of aquatic animals, and during his productive career he laid the foundations of modern African ichthyology, carcinology, and malacology. But I probably would have never even heard of him if it wasn’t for his second obsession – mountaineering. In September 1925 his insatiable desire to scramble pointy rocks lead him to the ragged peaks and caves of Cederberg, a mountain range of red, Ordovician sandstone, about 150 km North of Cape Town. Once there, his zoological predilection kicked back in, and made him look into every nook and cranny to collect specimens for the museum. In narrow caves known affectionately as the Wolfberg Cracks he encountered large, spider-like insects, with spindly, striped legs and 6-inch antennae. But neither he nor anyone else knew what to make of them, other than that they might have been katydids.

Sandstone spires above Wolfberg Cracks, one of the few caves where cave katydids can be found.

Sandstone spires above Wolfberg Cracks, one of the few caves where cave katydids can be found.

For 70 years those specimens had sat in a dark corner of the museum until, after a string of my increasingly incessant letters, they were packed with a bunch of other unidentified material and shipped to me, then a young student of entomology working on a revision of southern African katydids. One glimpse at the specimens and I knew that they were special. Not surprisingly they were new to science — an always welcome but not unexpected occurrence. But the fact that the insects had been collected from caves was intriguing — no other katydid had ever been found in such a habitat. Could those be the first such animals? Their morphology certainly seemed to suggest it. Extremely long appendages and pale coloration are the hallmarks of troglophiles, organisms living in caves, and the new katydids fit this pattern.

Resembling large spiders, cave katydids exhibit typical morphological characteristics of cave animals, which relay mostly on tactile information when moving around.

Resembling large spiders, cave katydids exhibit typical morphological characteristics of cave animals, which relay mostly on tactile information when moving around.

To add to the mystery, all specimens were immature, and I could only speculate about what the adults might have looked like. I published a formal description of the new katydids, giving them the scientific name Cedarbergeniana imperfecta (immature katydid from Cederberg; now I wish I had named them after Barnard), but ever since I have been dying to find out more about their behavior and biology. Do they really live in caves? What do they eat? Can they sing? Are they solitary, like virtually all katydids, or do they live in groups, like cave crickets?

Cave katydids are gregarious, found in multi-aged groups of 20-30 individuals.

Cave katydids are gregarious, found in multi-aged groups of 20-30 individuals.

In the years that followed I have been able to visit Cederberg many times, and collected a lot of data about their biology. Yes, they truly are cave dwelling katydids, the world’s only, and yes, they are highly gregarious, often found in clusters of 20-30 individuals of various ages. The caves they prefer are cold, maintaining the chilly temperature of 12°C (54°F) throughout the year. Their habitat cannot be occupied by bats or hyraxes, which probably quickly do away with the tasty, surprisingly very slow-moving insects, thus limiting the number of available caves (interestingly, when exposed to higher temperatures they become phenomenal jumpers). I know now what sound they produce – a short, ultrasonic click. All their close relatives (katydids of the tribe Aprosphylini) produce long, continuous trills, but such a call would probably cause a lot of reverberation in a cave environment and thus make it difficult for a female to locate a singing male. I also know what they eat, a mystery that had bugged me after seeing the nearly sterile interior of the cave – they leave the cave at night to forage on grasses and other plants growing at the mouth of the cave. This behavior makes them, in technical parlance, trogloxenes.

Last month, during a short visit to Cederberg with my friend Jen Guyton, I approached Wolfberg Cracks with some trepidation. For one, it is a tricky climb and, having witnessed another friend tumble down the mountain and break several bones while looking for cave katydids, I did not want the same thing to happen to me or, especially, Jen – it would be hard to explain why young females who accompany me to the cave always end up falling off cliffs. But I was also worrying about the katydids themselves. Corey Bazelet, my collaborator at the University in Stellenbosch, and I have recently completed the IUCN Red List assessment of South African katydids, and the Cederberg cave katydid unquestionably ranks as Endangered. It is known only from a tiny handful of locations in the Cederberg Mountains, a possible relic of colder climates of the Pleistocene, having found shelter in the cooler environment of the caves. With, what now seems to be unavoidable global climate change, and an already well-documented warming up of southern Africa, I fear that its days are numbered. But, luckily, today cave katydids are doing very well. Jen and I found them to be thriving; I even found an additional, small cave where I had not seen them before.

A male nymph and adult female of Cederberg katydid (Cedarbergeniana imperfecta).

A male nymph and adult female of Cederberg katydid (Cedarbergeniana imperfecta).

We climbed back down safely and stopped at a little gift shop at Sandrifft, the highest vineyard in Africa and the legal owner of the Wolfberg caves, and picked up a few bottles to toast to the survival of K.H. Barnard’s incidental discovery, the result of his random collecting that lead to the description of the world’s only cave-dwelling katydid and now, with its proclamation as an Endangered species, its increased protection. If the chances of the katydids’ survival are in any way related to the amount of toasting, they will be just fine.

The contrasting coloration of the cave katydids allows them blend in among the colorful rocks of Cederberg during their rare forays outside the caves.

The contrasting coloration of the cave katydids allows them blend in among the colorful rocks of Cederberg during their rare forays outside the caves.

A cave katydid cleaning his foot; their tarsi are incredibly sticky, allowing these insects to walk upside down on the smooth celing of their cave.

A cave katydid cleaning his foot; their tarsi are incredibly sticky, allowing these insects to walk upside down on the smooth celing of their cave.

Uo, the rain caller

A portrait of uo, or the Mexican burrowing toad (Rhinophrynus dorsalis) from Belize.

A portrait of uo, or the Mexican burrowing toad (Rhinophrynus dorsalis) from Belize.

We climbed deeper into the cave, approaching a site of a Mayan ritual. Here – Abel, our half Mayan guide explained – in this pitch-black underground chamber in one of Belize’s countless limestone caves, ancient Mayans performed gruesome bloodletting rituals, slicing women’s tongues and men’s genitals to entice gods to relieve dry, parched fields with life-giving rains. He pointed to razor-thin slivers of obsidian laying among shards of broken clay pots. In the light of my headlamp I could see a few piles of ash that looked as if the fire went out only a few hours ago, but in fact they had burned hundreds, perhaps over a thousand years before I was born, and the complete lack of air movement, or any other disturbance, preserved them perfectly.

The blood rituals seemed to work, and rains came back every year. Why the Mayans thought that the gods would get a kick out of people injuring themselves is a mystery (I guess gods all over the world have similar tastes.) But, as it turns out, the Mayan self-mutilation might have been for nothing because another creature was already working on their behalf, calling to Chaac, the Mayan god of rain.

Resembling a small balloon, uo is surprisingly agile as it runs and hops on the forest floor.

Resembling a small balloon, uo is surprisingly agile as it runs and hops on the forest floor.

Uo, as the rain-calling animal is known among the Mayans, an onomatopoeic name based on its strange courtship song, is a frog. But it is difficult to tell by just looking at it as it is a frog like no other. When I saw it for the first time it took me a second to make sense of the fist-sized black and red balloon with short, stubby legs. It seemed that an animal like this could not possibly be able to walk, but in fact these frogs are remarkably agile and can even jump. But what it is really good at is digging.

The mouth of uo is very small and surrounded by cushion-like pads.

The mouth of uo is very small and surrounded by cushion-like pads.

Uo, or the Mexican burrowing toad (Rhinophrynus dorsalis), as it is known among herpetologists, is the only member of a relatively basal (“primitive”) family of amphibians, the Rhinophrynidae. Its closest living relatives are equally strange, strictly aquatic clawed frogs of South America and Africa (Pipidae). Rhinophrynus are found in low laying forests from the southernmost tip of Texas to Costa Rica. Among frogs they are unique in having their tongue attached to the back of the mouth the way we, mammals, do – in all other frogs the tongue is attached at the tip, and is flipped forward and upside-down when hunting.

Rarely seen on the surface of the ground, uo is a strictly fossorial frog, emerging only at the onset of torrential rains of the wet season.

Rarely seen on the surface of the ground, uo is a strictly fossorial frog, emerging only at the onset of torrential rains of the wet season.

Looking at the face of this animal it is difficult to see any resemblance to a typical frog. Uo’s mouth is tiny and surrounded by strange cushion-like pads. Electron microphotography revealed that every single cell around the mouth of the frog is armed with a keratinous spike, which likely protects the mouth when the frog pushes forward through the soil. Like most fossorial frogs, uo buries itself backward, using its short but powerful hind legs as shovels. It also inflates its body rhythmically as it goes deeper into the soil to widen and stabilize the sides of the burrow. But once fully dug in, the frog can move forward, pushing its snout towards termite and ant colonies, the source of its food. Apparently nobody has ever seen uo feeding, as it all happens underground, but it seems that it hunts by sliding the tongue along special grooves in its toothless mouth and swallows the prey – stinging ants and biting termites – alive and whole. To minimize the effect of the aggressive insects, the esophageal lining has leaflike projections that vastly accelerate food digestion.

Perhaps not the most graceful of frogs, uo’s morphology is perfectly adapted to fossorial lifestyle and hunting for social insects.

Perhaps not the most graceful of frogs, uo’s morphology is perfectly adapted to fossorial lifestyle and hunting for social insects.

When I was in Belize last week, teaching photography at BugShot, it was clear that the rain god Chaac had already heard the call of uo, and was very generously spilling his rain-filled gourds onto the earth. After a few days my black backpack turned moldy white, and my laptop flickered and died. Mosquitos seemed to target mostly the corners of my eyes and deposited several botfly larvae onto my skin, but seeing the amazing uo made it all worthwhile.

A male uo.

A male uo.

Mozambique Diary: Webspinners

An adult female of a yet unidentified webspinner from Gorongosa National Park.

An adult female of a yet unidentified webspinner from Gorongosa National Park.

It has been a busy couple of months for me – first organizing a month-long biodiversity survey in Gorongosa National Park, then dealing with various aspects of our newly created E.O. Wilson Biodiversity Laboratory. But now that I am home I can process all the photos taken in Mozambique and, finally, write a few long overdue blog posts.

Our second biodiversity survey of the park started with a week of sampling in the Sand Forest, an interesting plant community near Chitengo, the park’s main camp. While somewhat underwhelming at first glance, this stunted forest that grows on remarkably infertile, pale and sandy soils, produced some of the finest discoveries of the survey. It was also an exciting place to be, on the account of roaming elephants (who really didn’t like people invading their private feeding ground) and a radio-collared male lion (who, I was told by our lion researcher Paola Bouley, might actually “like” people).

Males of many webspinner, such as this cosmotropical Oligotoma saundersii, are fully winged. Their wings can easily flex in half over the top of the body to help them move backward in the narrow silky corridors.

Males of many webspinner, such as this cosmotropical Oligotoma saundersii, are fully winged. Their wings can easily flex in half over the top of the body to help them move backward in the narrow silky corridors.

The first thing that I noticed was that many tree trunks in the forest were covered with extensive carpets of silk. This was great because for the last two years I had been searching in Gorongosa for the elusive webspinners (Embiidina), an order of semi-social insects that build intricate silk corridors on trees and rocks. No species of webspinners has ever been recorded from Mozambique but I knew that they had to be there. To be precise, I did find a webspinner once in Gorongosa, but it was an introduced, Asian species Oligotoma saundersii, which has a nearly cosmotropical distribution. But the animals on the trees of the sand forest were clearly something very different.  For one, they were huge. I am used to webspinners being tiny, brownish insects that you look for with a magnifying glass. But one adult female that we collected was pitch black and nearly 25 mm long, which probably makes her the largest webspinner in the world (the largest webspinner that I could find a record of is the South American Clothoda, which grows to 20 mm.) But despite their size these insects were not easy to find. I ripped through dozens of their silky colonies but found only a handful of specimens. Only later did I realize that during the day these insects were hiding deep in the crevices at the base of the tree or in debris-filled nooks between branches.

The thin sheet of silk acts as an invisibility cloak, protecting foraging webspiners from their principal enemies, ants.

The thin sheet of silk acts as an invisibility cloak, protecting foraging webspiners from their principal enemies, ants.

Webspinners have fascinated me for a long time. They are one of those animal groups that don’t attract much attention because of their small size and unassuming physique but, once you learn about their biology, they become very hard to ignore. The webspinners’ most obvious claim to fame is their ability to spin silk. But how do they do it? Spiders spin silk from spinnerets located at the tip of their abdomen (opisthosoma), but all insects (caterpillars, ant larvae, gryllacridid crickets, to name a few) have them located on their mouthparts. Or so the entomologists thought. And so strong was this conviction that early morphological descriptions of webspinners included silk-producing tubercles on the labrum which, upon closer inspection, turned out to be purely imaginary – as it happens, webspinners possess unique silk-producing, glands on their front tarsi, and not on their mouths. This explains their characteristic behavior of constantly waving the front legs – they are spinning silk, but the individual strands as so microscopically thin as to be completely invisible to the human eye. Only once hundreds or thousands of individual strands have been spun together do they begin to appear as a thin sheet of soft silk. The proteins that make up the spider and moth silk are some of the strongest organic compounds, resistant to breaking and very flexible. In contrast, the webspinners’ silk is remarkably weak and tears quite easily. This may have to do with its primary function – rather than being used to capture prey or protect a fragile developing pupa, it is merely a cloaking device that makes the insects invisible to ants while the webspinners graze lichens that cover bark or rocks. I have watched ants walk right on top of webspinners separated only by a diaphanous sheet of silk, while the webspinners were happily grazing on lichens, completely unperturbed by the presence of their deadly enemies.

The second function of the silk is the protection of eggs, which the female covers with silk and guards them until they hatch. She stays with the eggs mostly to chase away parasitoid scelionid wasps and plokiophilid bugs, and her presence increases the survival of eggs by 50%. But once the eggs are about to hatch the mother must remove the silk, otherwise the nymphs will not be able to emerge. She then stays with her children until they are ready to fend for themselves, initially masticating their food and spinning the silk corridors. She then leaves to start another colony.

The front tarsi of webspinners are strongly enlarged to accommodate silk-producing glands.

The front tarsi of webspinners are strongly enlarged to accommodate silk-producing glands.

Interestingly, some webspinners are the only social insects that are inquilines within the societies of other social animals – two species of Oligotoma from India build their societies inside colonies of a social spider Stegodyphus sarasinorum (but continue to spin their own silk). Another, Oligotoma termitophila, lives in termite colonies in Sudan.

So, what’s next for my Mozambican webspinners? Next time I am in Gorongosa I plan to look into their biology, and figure out what their colony structure and dispersal patterns are. The species also needs to be identified and described, which I should be able to do once I bring the specimens back from Mozambique (we hit a little snag with the export permits). I also plan to look for other species on Mt. Gorongosa. Who knows, I may also be able to find the webspinners’ closest relatives, the amazing zorapterans.

Silken galleries of webspinners covering trees in the Sand Forest of Gorongosa.

Silken galleries of webspinners covering trees in the Sand Forest of Gorongosa.

Mozambique Diary: Amphisbaenians

Most people would hardly look twice at this small, pink “worm”, but this amphisbaenian (Chirindia swynnertoni) from Gorongosa probably looks like the now extinct ancestor of all snakes.

Most people would hardly look twice at this small, pink “worm”, but this amphisbaenian (Chirindia swynnertoni) from Gorongosa probably looks like the now extinct ancestor of all snakes.

Having drawn the short straw at the phenotypic lottery I have always felt a special kinship with creatures that most people dismiss as too small, too creepy, too unattractive. Because these are (I tell myself) the hallmarks of the truly interesting organisms, ones that have followed the less-trodden paths of unusual specialization, remarkable adaptations, evolutionary ingenuity.

One such organism, about the existence of which I learned as a young child from an old zoology textbook, was Bipes, an amphisbaenian. It was a chimeric, strange creature, with the appearance of a pink snake, but equipped with a pair of shovel-like legs at the front end of its long body. There was a striking resemblance between that creature and a picture of a dragon that I had seen in the illustrated edition of the Old Testament from my Sunday School (which, incidentally, offered its classes on Monday nights), and I was instantly hooked.

Although it looks like a soft and squishy, the amphisbaenian’s head hides a strong skull that allows it to push through even the hardest soil.

Although it looks soft and squishy, the amphisbaenian’s head hides a strong skull that allows it to push through even the hardest soil.

Amphisbaenians are reptiles, but so unusual that for the longest time they were considered a separate order of these animals. For one, they look nothing like a vertebrate – the last couple of times that somebody brought me an amphisbaenian they were under the impression of having collected an earthworm (unlike Bipes, most species are legless.) Their annulated body is usually pink or covered with irregular, white and dark blotches, a clear indication that these animals don’t care about how they are perceived by others. And for a good reason – why bother with the looks if your entire life is spend underground and you yourself are blind. Better to invest the energy that would have been spent on the irrelevant appearance into things such as a thick skull and powerful thoracic muscles that will allow the animal to push effortlessly though the soil in search of prey.

My assistant Ricardo Guta looking for insects and other animals in the habitat of the Gorongosa amphisbaenian.

My assistant Ricardo Guta looking for insects and other animals in the habitat of the Gorongosa amphisbaenian.

Recent phylogenetic studies revealed that amphisbaenians are not a separate, primitive order of reptiles, but rather a highly derived, supremely modified lineage of lacertiform lizards. It is very likely that the next step in this transition to a subterranean lifestyle was the complete loss of limbs and girdles, a dramatic reshaping of the skull, the loss of eyelids and, eventually, the emergence of a brand new group of animals, the snakes. In fact, the most basal (primitive) snakes, the Typhlopidae and other related families, look remarkably like the amphisbaenians.
A few days ago I was in the southern part of Gorongosa, checking out sites for the second biodiversity survey of the park, and there, in a dry, crumbling log, I found a beautiful little amphisbaenian, Chirindia swynnertoni. This species is rarely seen, and thus I promptly followed a recommendation of a field guide to amphibians and reptiles of East Africa: “Anyone finding a worm-lizard [amphisbaenian] should take it to a museum.” I still haven’t had the heart to preserve it for the Gorongosa Synoptic Collection, and instead I have been watching it for days, transfixed by its amazing ability to squeeze into the hardest soil with the body that looks like an overcooked string of pasta, and with a baby-pink face of a newborn. It has been feeding on termites and ant larvae, crushing the insects with its tiny yet powerful jaws. And I find it fascinating (and somewhat rewarding) that from so seemingly unassuming a beginning came a lineage of animals that has terrified the human psyche since the time of Eden.

Gorongosa amphisbaenian (Chirindia swynnertoni)

Gorongosa amphisbaenian (Chirindia swynnertoni)

My life is now complete

A wingless form of zorapteran (Zorotypus hubbardi) from Sapelo Island, GA

A wingless form of zorapteran (Zorotypus hubbardi) from Sapelo Island, GA

When I set off for a long weekend on Sapelo Island in Georgia to teach insect photography at the BugShot workshop, it never occurred to me that the trip would culminate in completing a life-long quest. I am not one to keep bucket lists of things to see or do but, as an entomologist, I always hoped to personally collect all extant orders of insects. The most conservative classifications list about 28 orders of these animals, while others divide the class into more ordinal taxa (for example, Vitaly M. Dirsh divided the Orthoptera into 14 separate orders; thankfully nobody paid any attention to such craziness.) Regardless of the semantics, over the years I have collected all major lineages of insects, including such rarities as the Mantophasmatodea (in fact, I collected the second live specimen ever found; the first one was collected by Namibian entomologist John Irish about 10 minutes earlier), Grylloblattodea, or Strepsiptera. But one group has consistently eluded my grabby hands – the Zoraptera.

Warm, humid, and festooned with Spanish moss, the oak forest of Sapelo Island, GA, is an ideal habitat for the Zoraptera.

Warm, humid, and festooned with Spanish moss, the oak forest of Sapelo Island, GA, is an ideal habitat for the Zoraptera.

Described in 1913 by Italian entomologist Filippo Silvestri, Zoraptera are the least diverse order of insects – only 39 species are known, all in the genus Zorotypus (Mantophasmatodea have fewer species, but are divided into multiple genera and families.) As far as rare insects go, Zoraptera may appear somewhat underwhelming in their size and morphology – most species are only about 3 mm long, usually pale yellow or brown, blind and wingless. Their preferred habitat is also not very sexy as Zoraptera are found mostly in rotten logs across tropical and subtropical parts of the world, feeding on fungal hyphae or springtails. They are rather picky in their selection of habitat, and will only survive in logs that have reached the “Zorapteran stage” of decomposition – nothing more, nothing less (the five-stage classification of log decay was introduced in 1959 by E.O. Wilson, who to this day considers himself a zorapteran aficionado). Looking for Zoraptera is akin to looking for a grain of salt in a sugar bowl – in a log teaming with ants, termites and springtails you need to be able to spot a nearly microscopic, whitish insect that runs frantically in all directions, whose body proportions are only slightly different from those of a newly hatched termite nymph. It took me several hours of ripping through decaying logs and enduring countless stings of trap-jawed ants (Odontomachus) before I noticed an eensy dot of an insect that looked a little different. Even as I was putting it in a vial I was not quite sure that it was really a zorapteran, but my suspicion was confirmed the moment I looked at it through the macro lens of my camera.

Most zorapterans are pale, wingless and blind. Winged forms only appear if the decaying long in which they live can no longer support the population of these insects.

Most zorapterans are pale, wingless and blind. Winged forms only appear if the decaying log in which they live can no longer support the population of these insects.

But of course one should not judge the Zoraptera by their unassuming demeanor, for their behavior and reproductive biology are some of the most interesting among all insects. First, despite their name (zor [Gr.]=pure, aptera=wingless), winged forms are found in all species, albeit they only appear when the time comes to leave the log when it shifts from the “Zorapteran” to “Passalid stage” of putrefaction. And, once a new, nicely rotten habitat is found, the wings fall off. This type of behavior is not unique to the Zoraptera (aphids display a similar wing polymorphism), but what happens next is.

Zoraptera are not truly social, but often live in groups of 30+ individuals of various ages. But, unlike termites and ants, all individuals in the colony can reproduce, at least in theory. The colony is strictly patriarchal – the dominant individual is always the oldest male who maintains a harem of females and fights off younger males. Only when the senility kicks in, younger males have a chance to take over the top spot. This type of a male-dominated society is unique among arthropods, where it is always the females who control both reproduction and individual status in the colony.

Even more interesting is the way males inseminate the females. All across the animal kingdom males tend to be rather generous with the dispensation of their reproductive cells (to put it mildly), while females are frugal with their eggs, and choosy when it comes to mating. But in Zoraptera things are different – to inseminate the female the male produces only one (one!) sperm cell. And not just any sperm – the zorapteran spermatozoa are about 3 mm long, which, if you recall, is the average body length of the entire animal. Not surprisingly, males of these insects are not particularly eager to mate and it is the female who does most of the courting. Why this happens is not entirely clear, but most likely the single, giant sperm cell fills the female spermatheca (a sperm storage space that allows the female to inseminate eggs long after the copulation) and precludes her from mating with other males.

I wish I could have spent more time in Georgia – it would have been nice to see armadillos in a form other than flattened pancakes on the highway. On my drive from Savannah to Atlanta I counted 27 carcasses of these animals killed by cars.

I wish I could have spent more time in Georgia – it would have been nice to see armadillos in a form other than flattened pancakes on the highway. On my drive from Savannah to Atlanta I counted 27 carcasses of these animals killed by cars.

As I drove back from Savannah to Atlanta, counting armadillo roadkill (27), I couldn’t help but wonder what the bar scene of our species would look like if men produced only one, 6 feet long reproductive cell during each mating. In the end, I am happy for the zorapteran males, but will keep my millions, thank you very much.

Zorapteran (Zorotypus hubbardi), the only species of the order Zoraptera found in the United States.

Zorapteran (Zorotypus hubbardi), the only species of the order Zoraptera found in the United States.

Glass katydid

Glass_katydid Last night the Harvard Museum of Natural History held an event to celebrate a new book on Gorongosa by E.O. Wilson and yours truly, and the opening of a photo exhibit highlighting the park’s biological richness. During the evening I met a talented glass sculptor, Wesley Fleming. Turned out that Wesley is yet another artist who uses my photos to inspire his creations. He presented me with a beautiful glass katydid, which he designed based on the photos from one of my books. (Incidentally, a while ago I wrote about a real life glass katydid.)

Please visit Wesley’s website and marvel at his incredible glass sculptures.

Glass_katydid2

Almost mammals

A female ball blattodean (Perisphaerus lunatus) from northern Cambodia begins to unfurl to reveal long, powerful legs.

A female ball blattodean (Perisphaerus semilunatus) from northern Cambodia begins to unfurl to reveal long, powerful legs.

I was rummaging one day through the leaf litter on the forest floor in northern Cambodia, looking for insects, when a small, perfectly round ball rolled from a leaf above, bounced off my head, and landed on the ground in front of me. I picked it up to have a closer look, not sure if the object was an animal or a plant. It was about the size of a pea, but black, and very hard. It was an animal, as betrayed by the clearly visible segmentation of its body, but several groups (crustaceans, millipedes, and armadillos, to name a few) use a very similar tactic, and I was not sure which one I was holding (I quickly ruled out armadillos.) After a few seconds a pair of big eyes with two short antennae between them cautiously peeked from a crack that opened on the mysterious sphere. It was a blattodean, but one I had never seen before. Later I identified it as the ball blattodean (Perisphaerus), an interesting animal that experiments revealed to be, thanks to its tight armor, virtually impervious to attacks by ants and other small predators. In fact, the combination of the hard cuticle that forms its exoskeleton with its powerful muscles makes it impossible to unroll the animal without damaging it.

Ball blattodeans of the genus Perisphaerus and several related genera are probably the only organisms other than mammals that exhibit suckling behavior. Young nymphs of these insects have long, almost proboscis-like mouthparts that allow them to access a series of special “mammary” glands on their mother’s underside and suck nutritious fluids.

Ball blattodeans of the genus Perisphaerus and several related genera are probably the only organisms other than mammals that exhibit suckling behavior. Young nymphs of these insects have long, almost proboscis-like mouthparts that allow them to access a series of special “mammary” glands on their mother’s underside and suck nutritious fluids.

Rolling your body into a tight, hard ball is a neat trick, perfected by only a few other insects, but there is something else about Perisphaerus that makes it unique among not only insects, but also almost all other animals. Blattodeans, a large, ancient lineage, represented by nearly 5,000 species, is a truly fascinating example of the evolution of parental care and social behavior. Within insects, where good parenting usually amounts to not eating your young, blattodeans display levels of devotion and parental sophistication otherwise found only in birds and mammals. Dr. Louis M. Roth, the late Harvard entomologist who during his long and productive life uncovered many secrets of blattodean biology, was the first to realize the unusual nature of Perisphaerus. While studying these insects he noticed that females were often accompanied by nymphs clinging to their legs, and some of these youngsters had their heads stuck to the underside of their mother’s body. Careful examination revealed something strange – the mouthparts of the nymphs were very long, almost proboscis-like, a trait unknown in blattodeans, whose mouthparts are of a simple, biting type. Looking carefully at the female Roth also noticed that between the bases of her legs were small, glandular openings, and that’s where the young ones were sticking their heads. Could it be that the mother were actually suckling her young? Up to that point only mammals were known to display this type of behavior, but suddenly it appeared that a similar one might have evolved at least one more time in the history of the animal kingdom. The evidence for this is still largely circumstantial, but what we know about blattodeans certainly supports such a possibility. Many species of these insects give birth to live young, and in a few cases the female feeds them until they are ready to start foraging on their own. In the case of the Pacific blattodean (Diploptera punctata) the female develops an equivalent of the mammalian placenta, and feeds the embryos growing inside her abdomen with a rich mix of proteins, lipids, and carbohydrates. But a female with “mammary glands” and nymphs with sucking mouthparts take the maternal care among blattodeans to a completely new level.

North American forest blattodean (Parcoblatta penssylvanica) carrying an ootheca – a hard, nearly indestructible purse that protects the eggs from predators, parasitoids, and desiccation.

North American forest blattodean (Parcoblatta penssylvanica) carrying an ootheca – a hard, nearly indestructible purse that protects the eggs from predators, parasitoids, and desiccation.

A couple of years after my first encounter with Perisphaerus I found myself, in the middle of the night, following through a bamboo thicket a group of fanatical herpetologists who were intent on catching a particularly elusive, possibly new to science frog. We were in New Britain, a large island that is a part of Papua New Guinea, and I knew that I had a good chance to run across Perisphaerus again. Sure enough, the very moment I heard a triumphant scream that announced the capture of the unfortunate amphibian, I saw the mysterious blattodean scurrying around my feet. And it was a pregnant female. She gave birth to about 10 young a few days later, and during the two weeks when I kept her in a small container the nymphs always stayed with her, hidden under her body, their mouthparts firmly between her legs. Every now and then she would have a bite of a fruit, but the young ones never left her side or fed independently. And yet they grew. I separated a couple of nymphs from their mother and offered them the same conditions and food I was providing her with – they were dead within three days, while their siblings continued to thrive. This short observation convinced me that the female feeds her young with something secreted by her body, and that they completely depended on it, just like mammalian offspring does. My admiration for insects ratcheted up yet another notch.

Table Mountain blattodean (Aptera fusca) from South Africa is a species that exhibits an extended maternal care.

Table Mountain blattodean (Aptera fusca) from South Africa is a species that exhibits an extended maternal care.

Of course, not all blattodeans display the same degree of nurturing and maternal sacrifice, but there is not a single species in this group that does not at least try to give its children a safe start in life. The least the female blattodean can, and most do for their eggs is to encase them in a hard, chitinous purse that protects the eggs not only from physical injuries and desiccation, but also creates a very effective barrier to predators and parasitoids. Usually such a container, known as the ootheca, is carried by the female until the eggs are almost ready to hatch. She will then burry or glue it close to the source of food, usually a fruit or some particularly tasty leaf, and the young hatch a few days or weeks later, ready to start independent life. In more advanced species the female never lets her eggs go, and while she still protects them in an ootheca, she carries it until the very day the young ones are going to hatch. Others take it a step further and, after forming the ootheca and filling it with eggs, suck it back into their abdomen. There, protected by both the ootheca and their mother’s belly the young ones complete their development. Their hatching takes place inside the mother’s abdomen, giving the impression of live birth (such false live birth is known as ovoviviparity.) And finally, there are species, such as the Pacific Diploptera punctata that are truly live bearing.

A large, shield-like pronotum protects the head and front legs of the giant blattodean (Blaberus giganteus) from Guyana.

A large, shield-like pronotum protects the head and front legs of the giant blattodean (Blaberus giganteus) from Guyana. This species is ovoviviparous, which means that eggs are carried by the mother until they are ready to hatch and the nymphs are ready to start independent life.

I have always been fascinated by these animals: the simple elegance of their bodies, their devotion as parents, their dominance in tropical ecosystems, their ancient origin, all this made me want to learn more. But for a group so rich in species and so abundant in many terrestrial ecosystems, we know shockingly little about blattodeans. There are probably no more than 20-30 scientists worldwide who study the 5 thousand or so species we already know about (an equal number of new species of blattodeans most likely still awaits discovery.) At the same time thousands of students and researchers around the world work on mammals, a group with a comparable number of species. As it turns out, the two may have a number of astonishing similarities in their reproductive behavior. Perhaps some of the mammal specialists could be enticed to broaden their taxonomic horizons, and help us learn more about one of the most intriguing groups of animals that ever walked the Earth? Entomologists could really use some help here.

Wood blattodeans (Cryptocercus) took their family life to the next level, and these insects live in small, multi-generational societies. Females feed their offspring symbiotic protozoans, which these insects need to be able to digest cellulose, their main source of food. From here it took only a small evolutionary step towards eusociality, which we see in a lineage of blattodeans known as termites.

Wood blattodeans (Cryptocercus) took their family life to the next level, and these insects live in small, multi-generational societies. Females feed their offspring symbiotic protozoans, which these insects need to be able to digest cellulose, their main source of food. From here it took only a small evolutionary step towards eusociality, which we see in a lineage of blattodeans known as termites.