I am pleased to announce that I will be joining macrophotography legends Alex Wild, John Abbott, and Thomas Shahan in a tropical insect photography course in Belize later this year. The workshop will be held September 22-29, 2013. Today is the first day of registration – hurry up, it usually sells out very fast, and is limited to 20 participants.

A male Tobacco cricket (Brachytrupes membranaceus) singing at the entrance to his burrow. The shape of the opening acts as an amplifier to his already very loud song. [Canon 7D, Canon 16-35mm, Canon MT 24EX twin light]

We spent the last night of the recon in a remote outpost of park rangers, a place that happened to sit on top of deep, sandy soils. And such soils are just what the Tobacco crickets (Brachytrupes membranaceus) love, and they make it loud and clear. At around 7:30 pm, just after it got really dark, the entire camp suddenly erupted in incredibly loud, buzzing racket when about a dozen cricket males started singing at the entrances to their burrows. They were very easy to locate, but getting too close to one was painful. Listening to a singing Tobacco cricket from a distance of a meter or less is akin to staring into a bright lightbulb – for a while, once you turn your eyes away, you still see the light and not much more, and the cricket’s song leaves your hearing similarly dulled and almost unable to perceive any other sounds for a few seconds.

Singing males always face the burrow and dive in at the slightest disturbance. [Canon 7D, Canon 16-35mm, Canon MT 24EX twin light]

Tobacco crickets get their name from their preference for young tobacco plants, and in some areas of Africa they are considered pests. Unlike most crickets and other orthopterans, these insects gather and store food in their burrows, and are able to preserve it so that mold does not destroy it. They are also unusual in a well-developed maternal care. The female, which has a strongly reduced ovipositor, lays the eggs in her burrow and cares for them and the newly hatched nymphs until they are ready to forage on their own. All in all fascinating creatures, which also taught me to look for large holes in the ground before setting up a tent, and move as far away from them as possible.

A male Cataloipus cognatus munching on grass. [Canon 6D, Canon 100mm macro, 3 x Canon 580EXII]

Despite the strangely persistent misconception, the sound of grasshoppers is not produced by rubbing their legs together (in fact, no insect makes sound in this way), but rather by dragging the inner side of the hind femur against a thick vein on the front wing (depending on the group, either the femur or the vein is armed with a row of stridulatory pegs). But this ability to produce loud songs is far less common among grasshoppers than it may appear to somebody who grew up in Europe, one of the few places in the world where members of the vociferous subfamily Gomphocerinae dominate the grasshopper fauna. I was surprised how few grasshoppers sing in North American or Australian meadows, and tropical grasshoppers of South America and Africa are almost all silent.

Females of C. cognatus are much larger than the males; they are also completely silent, whereas males produce a loud mandibular stridulation. [Canon 6D, Canon 100mm macro, 3 x Canon 580EXII]

Just to be sure I caught a few more individuals, and some made the sound while others didn’t. Then I noticed that the silent ones were all females, while all males were producing the sound. Since I don’t have a microscope here in the Chitengo camp (yet, one is coming soon, fingers crossed), I could not look at the structure of the sound-producing apparatus. But I recorded the sound and looked at its oscillogram, which revealed a clean, evenly spaced pattern of pulses, which is indicative of the presence of a distinct stridulatory file. This, combined with the fact that only males produce sound, seems to suggest that the sound might be used not only as a defensive signal, but rather that it may play a role in courtship. If this true, and I will try to confirm it by watching the courtship behavior of this species, it would make a very interesting case of independent evolution of courtship stridulation in eyprepocnemidine grasshoppers.

An oscillogram of the mandibular stridulation of C. cognatus; click here to listen to the sound.

A colony of Lander’s horseshoe bats (Rhinolophus landeri) – notice the orange hairs in the armpits of the flying male.

Tomorrow marks the first official day of the Gorongosa Biodiversity Survey on the Cheringoma Plateau. All participating scientists are arriving, and the following morning we will depart for the first, northernmost site. But even before we get to those remote and unexplored areas, some of us have been already collecting interesting data.

Earlier today Jen Guyton, the expedition’s bat and rodent specialist, discovered a large colony of bats in an old, abandoned concrete water tank on the outskirts of the Chitengo Camp. It was too good of an opportunity to learn something new about bats of Gorongosa to pass by. Armed with a large butterfly net Jen had descended deep into the dark and rather odoriferous structure, and soon emerged triumphant with half a dozen bats fluttering in the net. She immediately identified them as Horseshoe bats (Rhinolophus), members of the family Rhinolophidae.

Two color morphs of Lander’s horseshoe bats (Rhinolophus landeri) found in Gorongosa.

These mammals get their common name from the characteristic, horseshoe-shaped noseleaf, an intricate structure on their faces that is the source of their echolocation signals. The ultrasonic signals of horseshoe bats are unusual in their relatively long duration and constant frequency, as opposed to more typical, short signals of shifting frequency found in most other insect-feeding bats.
Our bats turned out to be Lander’s horseshoe bats (Rhinolophus landeri), and the Chitengo colony had two color morphs of this species, one of which had a beautiful golden fur, which reminded me of that of the Amazonian Lion Tamarin. Lander’s horseshoes appear to feed mostly on moths, and can be identified among related species of the genus by tufts of distinct orange hair in the armpits of adult males (see photo).

In the coming days and weeks we will undoubtedly see more bat species and other amazing organisms. I will try to post updates from the field as often as I can, but it remains to be seen if my cellphone modem works in the areas were we will do our work. Stay tuned.

Mammalogist Jen Guyton examining a freshly caught Lander’s horseshoe bat.

The best time to see Atlantic horseshoe crabs (Limulus polyphemus) is on the nights of the full and new moon in May and June.

I am still in Mozambique, and will be here for a few more weeks, but I simply must take a quick break from describing African nature to highlight a spectacular phenomenon that is taking place right now along the eastern coast of North America – the mass spawning of the Atlantic horseshoe crabs (Limulus polyphemus). Watching these magnificent animals is to me one of the most beautiful natural events that one can witness, and I encourage everybody living on the East Coast to take a trip to the beach this and next month (this year the best time to see them are nights of May 24th, and June 9th and 23rd.) What follows is a short excerpt from my book “Relics” (Chicago University Press 2011), describing my experience of watching horseshoe crabs on the beaches of the Delaware Bay.

“As hundreds of biting flies did their best to drain us of every drop of blood, my friend and fellow photographer Joe Warfel and I stood on the beach, waiting for the spectacle to begin. The sun grew dim, and the high tide was nearing its peak. There were a few people on the beach when we first arrived, but by now they had all disappeared, and we were the only witnesses to what was about to unfold. I started to tell Joe how strange it was that nobody else stayed to watch, but swallowed a fly and decided to quietly enjoy the rest of the evening. First came the big females. Nearly all had males in tow. In the dimming light we could see spiky tails of hundreds more as they tumbled in the waves, trying to get to the dry land. By the time the sun fully set, the beach was covered with hundreds of glistening, enormous animals. Females dug in the sand, making holes to deposit their eggs, nearly 4,000 in a single nest, while the males fought for the privilege of fathering the embryos. Fertilization in horseshoe crabs is external, and often multiple males share the fatherhood of a single clutch. Equipped with a pair of big, compound eyes (plus eight smaller ones), capable of seeing the ultraviolet range of the light spectrum, male horseshoe crabs are very good at locating females even in the melee of waves, sand, and hundreds of other males.

Delaware Bay is the best place in the world to see these magnificent animals. On a good night one could easily see 100,000 horseshoe crabs.

Horseshoe crabs have been around longer than most groups of organisms that surround us now. A recent discovery in the fossil deposits of Manitoba, an interesting little creature named Lunataspis aurora, proves that horseshoe crabs quite similar to modern forms were already present in the Ordovician, 445 million years ago. By the time the first dinosaurs started terrorizing the land in the Triassic (about 245 million years ago), horseshoe crabs were already relics of a long-gone era. And yet they persisted. Dinosaurs came and went, the Earth changed its polarity and climate many times over, but horseshoe crabs slowly plowed forward. Yet during this time they changed surprisingly little. Species from the Jurassic were so similar to modern forms that I doubt I would notice anything unusual if one crawled in front of me on the beach in Delaware. Somehow horseshoe crabs had stumbled upon a lifestyle and morphology so successful that they were able to weather changes to our planet that wiped out thousands of seemingly more imposing lineages (dinosaurs and trilobites immediately come to mind.) But despite claims to the contrary by creationists and other lunatics, they kept evolving. Modern horseshoe crabs, limited to three species in Southeast Asia and one in eastern North America, differ in many details from their fossil relatives. We know, for example, that many, if not most of fossil horseshoe crabs lived in freshwater, often in shallow swamps overgrown with dense vegetation, and some might have even been almost entirely terrestrial. Currently only the mangrove horseshoe crab Carcinoscorpius rotundicauda from the Malayan Peninsula routinely enters rivers, and is the only species to lay eggs in fresh or brackish water.

Even Sir David Attenborough, a man who probably witnessed more natural spectacles than any other human being, is fascinated by the spawning of horseshoe crabs. Here he demonstrates the improper way of holding a horseshoe crab (never hold them by their telson) while on the beach in Delaware during the filming of the BBC series “Life in the Undergrowth”.

The following morning Joe and I found the beach covered with horseshoe crab eggs. Well-rested and ready to start a bright new day the flesh-piercing flies attacked us with a renewed enthusiasm. Flailing our arms and swatting dozens at a time we went about flipping crabs stuck on their backs in the sand, and started to look for particularly big clutches of eggs. Although females burry the eggs in the sand, the returning tide washes out many of them. Freshly laid eggs are small, not larger then half a grain of rice. Surprisingly, the eggs grow as they develop, eventually becoming more than twice as large. This, of course, is impossible. The “growth” is an illusion, the result of the production of an external, thin membrane by the developing embryo. A fully developed egg, which at this stage has spent two weeks in the sand, resembles a tiny glass aquarium, with a petite horseshoe crab twirling inside, impatient to break the walls of its miniature prison. Once free, the larva (or at least the lucky ones) catches a wave back into the ocean and will spend about a week floating freely, before settling on the bottom of the shallow shore waters to begin life akin to that of its parents.[…]“

Tiny horseshoe crab larvae, known as the trilobite larvae, twirling in their aquarium-like egg shells. Soon they will break free to begin a short pelagic period, after which they settle on the bottom of the ocean to begin a lifestyle similar to that of their parents.

Just like their distant relatives, scorpions, horseshoe crabs display green fluorescence under the ultraviolet light.

Atlantic horseshoe crabs on the Prime Hook Beach near Milford, Delaware.

There are still a few slots available for BugShot 2013, a great opportunity to learn macrophotography in the rainforest of Belize from Alex Wild, Thomas Shahan, John Abbott, and yours truly. It is going to be a great event, at a fantastic location. You will not only discover the carefully guarded secrets of some of the best insect photographers in the world (e.g., what cameras they really use, how they drug their insects so that they sit absolutely still etc.), but you will also learn a lot about insect biology and behavior, and visit a variety of Neotropical habitats.

Head on the BugShot.net to grab one of the few remaining spaces.

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 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.

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 fast internet connections.)

A conehead katydid (Ruspolia consobrina) found in a Maputo hotel.

Last night I arrived in Mozambique’s capital Maputo. It was almost midnight when I finally got to my hotel, tired to the point of barely being able to keep my eyes open after more than 20 hours on the plane. But the scent of tropical, humid air was too much for me to resist, and so I put on my headlamp and took a quick stroll around the hotel’s grounds. 

It is the wet season now, and although it did not rain last night the atmosphere felt very humid. But it quickly became apparent that the hotel’s garden had been sprayed with pesticides, as evidenced by almost no insect activity on its beautifully manicured lawns. Across the street from the hotel insects were flying around street lamps and several species of crickets and katydids could be heard in a distance; I even heard the unmistakable call of a pamphagid grasshopper. “Oh, well”, I thought, and at that moment a large katydid flew in from across the fence and landed on the wall in front of me. It was a female conehead katydid (Ruspolia consobrina), a species I knew well from Gorongosa. After a few minutes I found a second individual, trapped in the foyer of the hotel.

Coneheads of the genus Ruspolia are handsome insects, with bodies resembling blades of grass, which makes sense as these are the plants they mostly feed on. Their mandibles are massive and strangely asymmetrical, a feature they share with several other grass-feeding katydid genera. Why is one mandible, usually the left one, much larger than the other is unclear, but it likely helps with stabilizing and cracking seeds of grass that these insects like to eat. And because they feed on such nutritious food, bodies of Ruspolia can get very fat. Combine it with the fact that coneheads can occur in large, almost plague-like numbers in certain parts of Africa, and it is not surprising that they feature prominently in the diet of many African peoples. They high fat content also allows coneheads to survive long periods of low food availability, or even starvation (a topic I covered in an earlier post).

I quickly snapped a few pictures of the katydid, happy to see it minutes after my arrival, and collapsed on the bed on the verge of total exhaustion. Of course I woke up a couple of hours later, unable to fall back asleep because of the time change and so, here I am, writing this blog well before sunrise – a first for me.

Coneheads (R. consobrina) are highly polymorphic – these three individuals are from the same population in Gorongosa National Park.

Intimate portraits: A queen ant (Polyrhachis armata)

My arrival in Johannesburg has brought a welcome respite from the unbearable winter of New England, and tomorrow I fly to Gorongosa National Park to begin preparations for the official opening of the E.O. Wilson Biodiversity Laboratory on March 27th. Stay tuned for updates and photos!

But there is something else that I am very excited about. Last year I was invited by Alex Wild to teach an insect photography workshop in Belize, the famous BugShot, and this year we are doing it again. This time the workshop will take place on Sapelo Island in Georgia, a place I have never been to but always wanted to visit. Insect life is bound to be spectacular – among other things I expect to find there Brunneria borealis, North America’s largest praying mantis and the world’s only fully parthenogenetic species of these insects. There are webspinners (Embioptera) there, two species of sylvan katydids (Pseudophyllinae), and over 100 species of other orthopterans. This is going to be good.

High-speed macrophotography: Periodical cicada (Magicicada septendecim)

The workshop will take place on May 22-25 and there are still a few empty slots left. If you want to learn macrophotography, perfect your technique or learn a new one, or simply find out amazing facts about invertebrates, then you should join entomologists and photography experts Alex Wild, John Abbott, and myself on this fun adventure. Visit the BugShot website to find more details.

Wide-angle macro: Sylvan katydid (Celidophylla albiomacula)

Time lapse macrophotography: A molting katydid (Enyaliopsis petersi)

Ambient light macrophotography: Atlantic shield-back (Atlanticus testaceus)

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.

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 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.

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.

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.

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.

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.

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.

This morning, in my bathroom, I was faced with a dilemma.

It was an interesting, busy year, which explains in part why I have been neglecting this blog recently. I am not going to give a month-by-month account of 2014 but thought that a few highlights might be in order.

Early in the year I made a brief visit to Quirimbas National Park in northern Mozambique where I found Pardalota karschiana, one of the most remarkable and beautiful katydids in the world.

The most important event of 2014 for me was, unquestionably, the opening of the E.O. Wilson Biodiversity Laboratory in Gorongosa. This facility, which I now direct, is quickly becoming a hub of renewed scientific and educational activity in Mozambique. Here our technician Ricardo Guta is teaching kids from nearby schools about insects of Gorongosa.

I have my first encounter with the African lungfish. This animal appears to be more resourceful than I ever suspected. Here a PBS cameraman John Benam and producer James Byrne witness its amazing ability to escape.

In April E.O. Wilson and I published “A Window on Eternity“, a book on the biodiversity of Gorongosa and the efforts to restore this unique place on Earth.

During a BugShot macrophotography workshop on Sapelo Island in Georgia I find my first zorapteran!

Back in Gorongosa, with the help of our mammalogist Jen Guyton, I learn how to shoot bats in flight.

A short trip to Belize in September gives me a chance to meet Uo, the mythical rain caller.

A successful sting operation leads to the rescue of a pangolin and her baby from a poacher – I finally get to see and touch the animal I had been dreaming of seeing all my life.

The internets go batshit crazy over a single specimen of a common arthropod collected for scientific research.

That’s about it – I am looking forward to 2015, which promises to be even more exciting. Watch this space and thank you for reading!

Raising two dipteran children was an interesting experience. It was embarrassing on a few occasions, when both of my arms started bleeding profusely in public; painful at times, to the point of waking me up in the middle of the night; and inconvenient during the last stages of the flies’ development, when I had to tape plastic containers to my arms to make sure that I will not lose the emerging larvae. But other than those minor discomforts it was really not a big deal. Perhaps my opinion would have been different had the bot flies decided to develop in my eyelids, but I actually grew to like my little guests, and watched their growth with the same mix of pleasure and apprehension as when I watch the development of any other interesting organism under my care.

Having two bot fly larvae embedded in my skin have also made me ponder once again the perplexing element of the human psyche that makes us abhor parasites but revere predators. Why is it that an animal that is actively trying to kill us, such as a lion, gets more respect than one that is only trying to nibble on us a little, without causing much harm? I strongly suspect that it has to do with our genetically encoded sense of “fairness” – we perceive parasites as sneaky and underhanded, whereas predators attack us head-on and thus expose themselves to our retaliation. They are brave, or so we think. This, of course, is a very naive and anthropomorphic interpretation of nature. A lion is no “braver” than a bot fly, who has to skillfully hunt mosquitos to assure the dispersal of her eggs and risk more dangers than a lion, a top predator with no natural enemies. Most importantly, to a bot fly we, humans, are a renewable resource – it is in the bot fly’s best interest that we live a very long life and thus can be “reused” – hence the minimum amount of suffering that this species causes. To a lion we are nothing more than a one-time meal. But we should not judge either species for their actions – there is no “good” or “bad” in nature – nature is amoral.

I am saying this to prepare you for a short video that I have made about my experience of raising a bot fly. I don’t want you to think that it is “creepy” or “weird”. It is simply a documentation of an interesting organism, who happens to develop in the skin of large mammals. But please be forewarned that this video includes a few sequences that some viewers may find disturbing. If you don’t want to have nightmares about things living inside you (which they already do, by the way), please don’t watch it. But if you are prepared to be open-minded and appreciate God’s wonderful creations in all their amazing glory, enjoy the show!

Red-headed flies (Bromophila caffra) are striking and common animals in East and southern Africa, but little is known about their biology.

Two months, that’s how long I have been neglecting this blog. Some people had even sent me messages to check if I were still alive. But I am alive and the reasons for my silence were good – until last week I was in Mozambique, working at the Wilson Lab and busily preparing for the next biodiversity survey of Gorongosa National Park. While there I had precious little time to write or take photos, but I did manage to take some shots of a few interesting critters. It is the rainy season in Gorongosa now and insect life is exploding. I had set up an ultraviolet light in front of my office to collect all members of my target groups (orthopteroid and dictyopteroid insects) and to cherry-pick the more interesting species from orders that we don’t yet collect systematically. On some nights the sheet was sagging under the weight of hundreds of species of insects and for a while mysterious redheads kept coming to the light.

Red-headed flies, which in Mozambique emerge at the end of the rainy season, like to hang in clusters on leaves.

I recognized them from my earlier trips to Gorongosa as Red-headed flies (Bromophila caffra) – large, slow moving insects, reluctant to take to the air, and much happier to hang in clusters from low tree branches. They are truly striking animals, showy and clearly unconcerned about attracting anybody’s attention, including that of potential predators. There were many birds and grabby vervet monkeys in the camp, who not so much as looked in the direction of the flies who slowly spun in clusters on leaves.

Adult Red-headed flies feed on dung and other decaying organic matter.

But for an insect as conspicuous and common as the Red-headed fly, shockingly little is known about its biology. In fact, the last scientific paper that mentions it by name (according to an extensive MetaLib cross-database search) is from 1915, and it does so only to compare the fly’s strikingly red head to another species. As already pointed out in an excellent post about this species by Ted C. MacRae, there exists only anecdotal evidence that the larvae of this species might be feeding on the roots of Terminalia trees, potentially sequestering toxic cyclic triterpenes, which would explain the adult flies’ aposematic coloration. But, as is the case with so many African invertebrates, nobody really knows.

There is also another possibility. One morning while in Gorongosa I woke up to find my arms covered with big, painful blisters. The night before I had spent a couple of hours searching for insects in tall grass and remembered seeing many contrastingly colored, red and black beetles of the genus Mylabris. “Oh, that’s why they are called blister beetles!”, it dawned on me, a little too late. While walking through the grass I must have brushed against some of these insects, and a mere touch against my skin caused the blisters, which lasted for over a week, to appear. The beetles themselves are highly toxic, deadly even, and no bird or other vertebrate will try to eat them. It is therefore quite possible that the flies are fakers – not toxic at all but simply counting on predators’ reluctance to try a potentially harmful meal. This phenomenon, known as Batesian mimicry, is common in the animal kingdom and I strongly suspect that the flies are an example of it.

I strongly suspect that Red-headed flies are Batesian mimics of blister beetles of the genus Mylabris. These beetles not only cause painful, long-lasting blisters but are also potentially deadly toxic.

When I return to Gorongosa next month the flies should still be around. It will also be the time when many young house geckos (Hemidactylus mabouia) are hanging around the lights of the camp, having hatched in January and February. It might be a bit evil on my part, but I think I will do some feeding experiments to see if the lizards, which at that point should still be naive about the flies, have any adverse reaction to eating them. Watch this space.

One peculiar morphological characteristic of the Red-headed flies is the absence of the ocelli, which are typically found on the head of other flies.

A silhouette of the first ghost mantis (Phyllocrania paradoxa) recorded from Gorongosa National Park in Mozambique.

I have been working in Africa for quite a while and during this time I have seen my share of iconic animals that epitomize the awesome continent’s fauna. There are still, of course, many that I yet need to meet in person – aardvark, “hairy” Trichobatrachus frog, Acridoxena katydid, to name a few – but luck or stubbornness allowed me to witness others. Few things can match the elation of meeting the gaze of a foraging chimpanzee, discovering a toy-like primate poto in the forest canopy over my head, or running into a fight between a hyena and a leopard over a freshly killed kudu. But my first encounter with one of the less known species, the ghost mantis (Phyllocrania paradoxa), was at least as memorable.

A female ghost mantis (Phyllocrania paradoxa) – these insects are such superb mimimcs of dry vegetation that it is often difficult to tell which part belongs to the plant and which to the insect.

It happened during my first trip to Zimbabwe, at the time when the tumor in Robert Mugabe’s brain was still semi-dormant and the country, “Africa’s bread basket”, was experiencing its first and only period of relative political freedom and economic prosperity. I was staying with a group of friends in the suburbs of the recently re-christened capital Harare, vaguely intrigued with, but blissfully ignorant of why so many houses were standing empty, their gauged windows bordered with the mascara of freshly extinguished flames. Africa was new to me, and I inhaled its intoxicating atmosphere and devoured the sights of alien landscapes and even more alien fauna. But I came prepared – for years before my first visit I had been voraciously reading all that I could find about insects and other members of Africa’s smaller majority. The ghost mantis was one of my most desired quarries and I started looking for it the moment I landed. Alas, a month on and with no trace of the animal, it was beginning to feel as if I were really hunting a ghost. I had spent countless hours sifting through the leaf litter, scanning bushes and trees, sweeping my net through all kinds of vegetation – nothing.

One day I stood on the platform of a railway station, waiting for a train to take me to Bulawayo. It was late October, the peak of the dry season, and shriveled leaves were falling from trees onto my head in a rare, merciful breeze. One, fairly large and twisted brown leaf landed on my shoulder. I tried to brush it off but it just sat there, trembling in the wind. I flicked it again. It landed lower on my sleeve. And then the leaf started to climb up my arm. I looked, still not believing. Could it be? No, this is just a piece of withered plant. But it was, finally, a ghost mantis.

No two individuals of ghost mantids are alike, which prevents their principal predators, birds and primates, from learning how to tell them apart from real leaves.

That was 25 years ago and it took me this long to run across another one. In fact, I had more run-ins with the notoriously elusive leopards than with this incredible insect. But this year, in April, I was finally able to confirm ghost mantids’ presence in Mozambique’s Gorongosa National Park (something that I have always suspected), when my friend, entomologist Marek Bakowski, found the first individual during our annual biodiversity survey. Since then I have encountered a few more ghost mantids in the park.

A Gorongosa ghost mantis with a freshly laid ootheca.

A molting ghost mantis.

Thanks to their otherworldly appearance ghost mantids have long been the favorite of amateur insect collectors and, since they can be easily bred in captivity, they have recently become very popular in the pet trade. Now all you need to do to see a live ghost mantis is to pay a few bucks online and one will be delivered to your door. But for an animal so widely kept, shockingly little is known about its biology and behavior in its natural habitat. Nobody is even sure how many species of ghost mantids there are. Three species of the genus Phyllocrania have been described, only to be synonymized a few years ago. All three were recognized as separate species based on the differences in the shape of the leaf-like process on the head, which can vary wildly within the same population. Ghost mantids, like many other insects that rely on leaf-like camouflage, display an ungodly degree of polymorphism, and no two specimens are alike. But the species’ distribution, throughout sub-Saharan Africa and Madagascar, hints at the possibility of distinct, genetically isolated lineages.

Like most praying mantids, the ghost mantis is an ambush predator, a truly superb one. But unlike many others, it is not inclined to attack members of its own species, and I know of no case of the female devouring a male during copulation, as it is often the case in some other lineages of these insects. In Gorongosa ghost mantids are found mostly in the understory of miombo and mopane woodland, and the only time I witnessed one feeding, it was chomping on a grasshopper. Females produce strange, caterpillar-like oothecae, and newly hatched nymphs look and behave like black ants; after the first molt they turn into perfect replicas of dried-up chaff. How males and females find each other, however, is a mystery to me. It is likely that females, like in other highly cryptic mantids, produce sex pheromones to attract their mates.

Next on the list of African biodiversity icons to confirm in Gorongosa, the Devil mantis. I know you are there and I will find you.

Ghost mantids are extremely polymorphic in both their coloration and the shape of the strange processes on their heads.

It is rather amazing that a terrestrial animal as big as this Ringtail salamander (Bolitoglossa robusta) from Costa Rica can spend its entire life without taking a single breath and instead relies entirely on gas exchange through its skin.

Of all the organs in my body, the one that I would be most reluctant to part with (perhaps with the exception of my eyes) are the lungs. It seems that we need them more than anything else. True, we need all the other bits, but lungs seem particularly useful. Without them the brain stops working in a matter of minutes, the vascular system loses its main reason to exist, and the biochemical processes in pretty much every cell come to a grinding halt. Like the hideous inflatable Santa in front of my neighbor’s house, the complex edifice of the human body would immediately collapse if the air supply were to be shut off. It seems that if you are a land-dwelling vertebrate you better have lungs, or you are not going to last very long. And yet, defying common sense, there is a group of terrestrial animals that got rid of their lungs altogether, and in doing so have become widely successful, outcompeting their lunged relatives in both the number of species and their collective biomass. They are the lungless salamanders of the family Plethodontidae.

The Redback salamander (Plethodon cinereus), a small, unassuming animal, common in the eastern United States, is a marvel of evolution, with physiology that makes our own appears laughably inefficient.

I thought of them last month, when freakishly warm weather in Boston forced me to clean up the accumulation of dog poop from the front lawn, which in any other year the snow would have mercifully covered up until spring. The unseasonal warmth also woke up a multitude of creatures that should have been fast asleep, including a couple of Redback salamanders (Plethodon cinereus), which I found under a wooden plank in the garden. Despite the ice crystals glistening in the half-frozen soil, they were surprisingly agile. “Agile” is of course a relative term, especially when talking about an animal whose metabolism is entirely dependent on oxygen passively permeating the skin. Nearly 100% of the oxygen intake and excretion of the carbon dioxide takes place on the surface of the skin of these salamanders, with the throat (buccopahryngeal cavity) accounting for an additional, small proportion of the gas exchange (perhaps for this reason lungless salamanders still retain well-developed nostrils.) Clearly, animals that are incapable of taking active breaths, and thus accelerating or decelerating gas exchange at will, cannot be marathon runners, or runners of any kind. And somehow, by employing various degrees of toxicity and the ability to subsist on low-nutrition diet of springtails and mites, lungless salamanders have managed to become the dominant family of amphibians of the Western hemisphere. Nearly 400 species have already been described and new ones are being discovered every year in both the cool, temperate forests of North America, and in the rainforest canopy of the Neotropics. In some places their numbers are staggering. A recent analysis of the population of the Southern Redneck salamander (P. serratus) of the Ozark Highlands in Missouri put their numbers at 1.88 billion (!) individuals, with the biomass equivalent to that of most whitetail deer in that region – that’s 1,400,000 kg (3,086,471 lb) of amphibian flesh.

Among many adaptations to the arboreal lifestyle are the lungless salamanders’ pad-like feet. Despite the overall similarity, this foot shape has evolved independently in different species of the genus Bolitoglossa.

Although all members of the family Plethodontidae are entirely lungless, their ancestors were not. What prompted the loss is still a mystery, and two competing theories, neither particularly compelling, try to explain it. According to the older of the two, lungless salamanders originated from a lineage that inhabited cold, fast flowing and well-oxygenated streams of the Cretaceous Appalachia (lungless salamanders still dominate the amphibian fauna of that region). The loss of lungs made them less buoyant and thus more capable of maintaining their position at the bottom of the stream while hunting for prey. But some researchers pointed out the lack of geological evidence for cold, upland environments in the Mesozoic Appalachia. Instead, they argue, lungless salamanders come from oxygen-poor tropical waters, where highly humid terrestrial environment proved to be a better alternative. Once on land, dense vegetation exerted adaptive pressure to evolve small, narrow heads, which in turn prevented the animals from filling their lungs effectively, and leading to the reliance on respiration through the skin. If this sounds sketchy to you, you are not alone. Most herpetologists today lean towards the first explanation, with the added argument that the loss of lungs happened early on in the larval development of the aquatic ancestors of the plethodontids. But the truth is, nobody really knows.

The ability to use a prehensile tail, a rarity in the animal kingdom, is one of the most amazing characteristics of the large, arboreal Ringtail salamander (Bolitoglossa robusta) from Costa Rica.

What is not in question is the fact that lungless salamanders rule the forests of North, Central, and parts of South America. Larger species tend to be ground-dwelling, whereas smaller ones live high in the canopy. The arboreal salamanders have evolved a number of cool adaptations to such a lifestyle. The Central American genus Bolitoglossa is famous for its lack of distinct fingers. Instead, these salamanders have pad-like feet that help them move on smooth, wet surfaces of rainforest trees. And although feet in all species of Bolitoglossa look similar, they are the result of two very different evolutionary processes. In smaller species, such as the colorful (and toxic) B. mexicana, the digit-less foot is the result of paedomorphosis – a developmental mechanism during which juvenile characters are retained in adult, reproductive animals. In other words, they have baby feet, and they rely on simple surface adhesion to cling to leaves and branches.

Larger species, such as the Costa Rican B. robusta, also have pad-like feet, but underneath the webbing sit fully developed digits and a complex musculature. The central part of the foot can be lifted, thus creating suction, a mechanism similar to that used by marine cephalopods. But wait, there is more. In addition to having suction cups for feet, this salamander has a prehensile, chameleon-like tail, which it uses to save itself from falling off trees. When I first saw one of these animals a few years ago pull this trick high in the branches in Tapanti National Park, I thought I was hallucinating. And the similarity to chameleons does not end there – just like those reptiles, lungless salamanders sport a long, projectile tongue (in one species the tongue is 80% as long as the body, and salamanders are pretty long animals!) They can eject it with an amazing speed, a mere 117 ms, to catch fast moving prey. And this ballistic tongue projection is an order of magnitude more powerful than that of any muscle in any other living vertebrate species.

All this to say that the next time you find a small, curled up salamander under a rock, look at it with a little more respect. This ancient animal can pull off tricks that would put many Marvel Comics characters to shame. Without taking a breath. Ever.

Ringtail salamander (Bolitoglossa robusta) on a tree branch in Tapanti National Park, Costa Rica.

A really cool sequence of a lungless salamander (Hydromantes) using its projectile tongue (BBC).

The coconut crab (Birgus latro), the coolest, most awesome, most beautiful inhabitant of the Vamizi Island. These animals have adapted to live around humans and the conservation group on the island does a good job of protecting them.

In July 1937 Amelia Earhart’s plane vanished somewhere over the southern Pacific in the general vicinity of New Guinea. Neither the plane nor her and her co-pilot’s bodies were found during the massive search operation that followed. But two years after her disappearance scattered skeletal remains, later identified as those of a tall woman of European descent, were found on the (then) desert island of Nikumaroro, one of the possible crash sites of Earhart’ aircraft. The skeleton was far from complete and many bones were missing, and the suspicion immediately fell on coconut crabs, common on the island. They were accused of carrying the bones and squirreling them away. But recently a group of history buffs called TIGHAR came to the crustaceans’ defense, claiming that these animals did not customarily carry away food into their burrows. They even conducted an experiment by placing a pig carcass on the beach of Nikumaroro and recorded a fascinating time lapse video of the crabs stripping it of its flesh. Crucially, though, no bones were carried away by the coconut crabs. But it still showed very convincingly that, had the crabs found Amelia Earhart’s body, they would have eaten her completely in a matter of days. I certainly find this explanation far more compelling and easier to think about than the alternative proposed by the authors of the pig experiment – that her body was eaten not by the crabs but by her starving co-pilot who might have survived the crash. Why the hell would he ever resort to cannibalism on an island full of large, delicious crustaceans and coconuts? (And what happened to him? Two years after the crash people arrived on the island and, if movies are any indication, they should have found a muscular demigod who had a meaningful relationship with a volleyball.)

Coconut crabs prefer to be active at night and during the dusk. That is when they emerge from their burrows to look for food.

These thoughts ran through my head as I squeezed it into holes in the rugged karst rocks of Vamizi, an island off the coast of northern Mozambique, looking for coconut crabs. Their burrows turned out to be full of coconut shells and other food remains, indicating that a single experiment good science makes not. I had been dreaming of visiting Vamizi ever since my friend Harith showed me a cell phone photo of himself on the island, holding two coconut crabs. All my life I had been fascinated with those magnificent creatures, the largest, heaviest, most awesome of invertebrates that grace the terrestrial surface of the planet. Some years ago I was lucky enough to see these animals alive, first on Guadalcanal, later on Japan’s Okinawa Island, but in both cases they were individuals already captured by somebody else. In those places coconut crabs are on the brink of disappearance due to habitat loss and overharvesting, and I never had a chance to observe them in their natural habitat. Vamizi, however, a tiny speck of paradise in the Quirimbas Archipelago, still appears to have a healthy population of these animals.

Coconut crabs come in two main color forms, a blue and a red one, both of which can be found in the same population.

Coconut crabs survive on Vamizi thanks to a clever campaign developed by the good people of the Vamizi Marine Conservation Research Centre. If, they say to the locals who traditionally used to hunt the crabs, you kill one, a terrible spell will never let you leave the island. In a country that is full of many ridiculous colorful myths, this scary thought has apparently kept many from falling to the temptation of the coconut crab’s meat. How many crabs survive on the island is unknown but apparently during the wet season it is possible to see a dozen or more coconut crabs on a single stroll through the coastal woodland.

I arrived on Vamizi in June, during the cool, dry season, and the locals were not too optimistic about my chances of finding one. (“They sleep now.”) But I didn’t fly to northern Mozambique on the thieving (camera gear was stolen from our checked-in luggage) and occasionally suicidal LAM airlines (go ahead, google it) to leave without seeing a coconut crab. According to Harith the best chance of finding one would be at a place that reliably provides the crabs with their favorite food. No, not coconuts. They prefer something else – fresh garbage.

“Take me to the dump”, I asked Harith as soon as it started getting dark. As we approached the island’s refuse disposal site we heard a sound that I would have never associated with coconut crabs – loud clicking of empty bottles. And there they were. Two giant, surprisingly colorful animals, moving among a big pile of glass, looking for edible bits of organic matter. The setting was not natural, it certainly wasn’t beautiful, but I almost choked up when I saw them. It was at the same time a fulfillment of a life-long dream, to see coconut crabs in the wild, and a sad, disappointing realization that “wild” is a big pile of junk and rubbish, reeking of rotten food and overrun by rats. The Anthropocene, in its full splendor and glory.

The Anthropocene – is this what a “wild” habitat should be?

Over the next few days my outlook had improved as I counted and photographed the crabs, looking for an indication that the population was breeding on the island. A large part of the island is a well-protected nature reserve, full of gorgeous tropical life, including thousands of land crustaceans, small mammals, breathtaking birds, and cool reptiles (including two species new to science, which Harith will soon be describing.) And I won’t even mention the marine life, which puts Vamizi at the top of the list of the most spectacular diving sites of the world. The most reliable proof of the crabs breeding there would have been finding juveniles still in their shells. Coconut crabs (Birgus latro) are oversized, fully terrestrial hermit crabs, that, just like other members of the hermit crab family Coenobitidae, develop as microscopic planktonic larvae in the ocean, and must don an empty snail shell during the first months of their life on land to protect the still soft and fragile abdomen. Only after reaching the size of about 10 mm do they abandon the shell and assume the symmetrical appearance that differentiates them from other hermits (in all other species the abdomen remains asymmetrically twisted throughout their life.)

Coconut crabs are excellent climbers. Also known as robber crabs, they are known to raid bird nests.

I must have picked up and examined about a thousand hermit crabs but, alas, they all turned out to be one of the two local species of Coenobita. A trip to a coconut grove at the opposite end of the island to look for juveniles hiding in the fallen fronds and coconut husks underneath the palm trees was similarly fruitless. That was worrisome. Rats are known to kill juvenile coconut crabs and the island was full of them. We saw rats not only around the houses but also in the most remote, virtually unspoiled natural habitats of Vamizi. One night my friend Max was startled by a gecko that hurled itself towards his head from the very top of a tall tree to escape a rat chasing it on the thin branches. Adult coconut crabs can and will kill a rat, but younger ones don’t stand a chance. Thankfully, the tourism company &Beyond, which operates the phenomenal eco-resort on the island, has been working diligently to improve the situation. To remove invasive species from Vamizi without harming its native populations of samango monkeys and other small mammals they use specially designed rat-only traps, ultrasonic repellents, and other tools to get rid of the nasty aliens.

Every night I spent hours looking for juvenile crabs along the paths in the forest but all I was seeing were very mature adults. On the last night, dispirited by not finding any proof of new blood in the population, I walked further than usual and ended up being out in the field well past 2 AM. Tired and despondent, I decided to have one last tour of the resort staff houses, the most reliable spot for finding coconut crabs at that time of year. There were a few adults milling around but they soon left for their burrows in the forest. That was it. During my four days on the island I did not see any evidence that the animals were breeding. A similar pattern has been seen in other places inhabited by coconut crabs, where the pressure from invasive species, overharvesting, and habitat loss either prevents the animals from breeding or leads to unnaturally high mortality of juveniles. Despite coconut crabs’ longevity (they can live to be 60), with no young crabs surviving the population eventually dies out.

All I can say is that I am glad that I am taller than a coconut crab (albeit not by much!)

I swept the light of my headlamp around, noticing for the first time the fence at the far end of the compound, overgrown with tall, spiky weeds. It occurred to me that I had never checked what lived among them. If I were a young coconut crab, would I want to compete with the adults, and risk being eaten, by feeding at the same spot, at the same time of night? I climbed the fence and crawled through the thicket, long, thorny branches ripping my shirt and cutting my skin. The ground below the weeds was covered with Coenobita hermit crabs, frantically gorging on discarded scraps of food. And there, among the hermits, were the juvenile coconut crabs. They weren’t much bigger than the large hermit crabs C. brevimanus common on the island, about 5-7 cm long. I let out a sigh of relief. The presence of young coconut crabs made it clear that the population was thriving, or at least not dying out. And the help they get from the conservation group working on the island will certainly improve their chances.

The next morning Harith, Max, and I left the island, having learned not only that it had a good population of coconut crabs, but also that eating oysters directly off the sun baked rocks exposed by the low tide really helps you purge your digestive system. I hope to go back to Vamizi sometime soon and do a more thorough assessment of the crabs’ population. And if I ever perish somewhere near to where these gorgeous animals live, I hope that they find me.

The underside of a blue coconut crab.

The edge of the underside of a coconut crab’s thorax looks very reptilian.

I had since forgotten about this brief encounter but recently I ran across an interesting paper describing the behavior used by the net-casting spiders to catch flying insects, which made me think of it again. Net-casting spider, known also as gladiator or ogre-faced spiders, stand out among their silk-spinning kin thanks to an unusual way of catching prey. While most net-making spiders employ a passive, sit-and-wait hunting strategy, deinopids use a small “hand-held” net to actively capture their victims by casting it over them with a remarkable speed. The net is made of tightly packed, non-sticky silk that can be stretched many times over without breaking. Its densely coiled, thin strands work like a very fine, flexible mist-net that bird and bat biologists use to capture their animals. Each tiny loop catches on the spines and protuberances on the victim’s body, enveloping and immobilizing it, allowing the spider to deliver its kiss of death and further wrap it in a layer of silk. 

To detect their prey deinoipids use two separate senses. Their huge eyes provide them with an unparalleled ability to see at night. The light-gathering ability of deinopid eyes is an astounding f/0.58. If you ever used a camera then you know that the “f” number, or the aperture of a lens typically starts at around f/3 and goes up to over f/20 – the lower the number, the greater the ability to gather light. Man-made lenses have high f numbers, which is why we need flashes, tripods, reflectors, and other implements to help the camera gather enough light to create a well-exposed picture. The human eye, with the iris that adjusts its diameter to adapt to different levels of light, spans the range of f/2.1 to f/8.3. The difference between the spider’s f/0.58 and a human’s f/2.1 seems deceptively small but it means that the deinopids’ sensitivity to light is 2,000 times greater than that of the human eye, and hundreds of times greater than that of a cat (f/0.9) or an owl (f/1.1). 

To achieve such an incredible sensitivity, which allows them to spot small insects in pitch black darkness, deinopids have evolved a unique eye structure that disintegrates every day, only to rebuild itself at night. Each of the spider’s big front eyes (technically, posterior-median eyes that moved to the frontal position) has six special light-sensitive structures called rhabdoms, connected with a membrane. The volume of that membrane dictates how much light an eye can gather. At night the membrane is rapidly synthesized, dramatically increasing the light sensitivity of the eye but when the day comes the membrane dissolves, leaving only enough for basic vision.  But why? Wouldn’t it be great to have super vision 24/7?

Several hypotheses have been proposed to explain this phenomenon and the most plausible one is that such an ultra-sensitive membrane ages very quickly, leading to a progressive loss of its sensitivity. It thus makes more sense to reabsorb it when it is not needed and synthesize it anew when it is.

The insects that deinopids catch are quite large compared to the spider’s body and one would think that a single cricket of nearly equal weight would be enough to satisfy it for the night. But no, as soon as the prey is captured the spider begins to eat it, while at the same time setting up its net for another strike. It is possible that the spider’s voracious appetite is driven by the energy-hungry physiology of its eyes, which might have caused some net-casting spiders (the genus Menneus) to forgo the fabulous night vision and reduce their eye size in a process known as regressive evolution.

Remarkably, net-casting spiders can catch insects without ever seeing them or, since spiders have no ears, hearing them. If a flying insect makes a mistake of coming too close behind the spider’s back, it will be met with a blindingly swift backwards strike of the net, deployed with the speed of 60 ms. (To use another photographic reference, the shutter-lag of an average camera, which is the time that elapses between you pressing the shutter button and the camera taking a picture, is between 50 to 200 ms. In other words, these spiders are freaking fast.) Experiments have shown that even blinded deinopids can detected flying prey from two meters away, solely by the sound of the beating wings and precisely direct the strike, all without having ears. It is still unclear how these animals detect sound, but it is likely that the structures responsible for it are trichobothria (“hair”) on the legs of the spider that respond to the movement of air molecules caused by sound waves. The tarsus, or the foot of the spider appears to be particularly sensitive to sound.

All of this is very cool but the thing that really impressed me about net-casting spiders is the incredible effort that females put into building the most beautiful protective shield around their eggs. Last year I was standing in front of my house in Costa Rica, listening to the night chorus of insects and frogs when I noticed a female building an egg sac. It was a perfect orb, suspended on a single strand of silk, and the female seemed to be continuously measuring its smoothness and size with her pedipalps, every few seconds applying a few microscopically thin strands of silk to make it even more perfect. I watched her for a while and took a few pictures, hoping to see over the next few days how she would combine her maternal duties with her hunting activity. Alas, the next morning both the spider and her beautiful maternal work of art were gone, and I will never know if she carried it to a safer location or if a bird swallowed both miracles of evolution. ✦

P. S. If you would like to read more about these spiders and see some really excellent photos and videos, visit Gil Wizen’s blog.