Piotr Naskrecki's Blog, page 2

Mozambique Diary: Red-headed flies

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 showy 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 strikingly 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 many 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.

Filed under: Macrophotography

Dermatobia Redux

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!

Filed under: Flies, Macrophotography, Video

Puppy-killing scientist smuggles rainforest babies in body cavity

I am pretty sure that taking this very photo in Belize was the beginning of my adventure.

I almost got away with it – for five days I had covered my body and slathered insect repellant onto my skin with an almost religious zeal, but on the last day I faltered. I was in Belize, teaching macrophotography at the Bugshot workshop. The course was almost over, and so I relaxed and decided to shoot some red-eyed tree frogs in the rainforest around the lodge. I rolled up my sleeves but, because I had misplaced my insect repellant and was too lazy to look for it, I did not put any DEET on. Big mistake. As I photographed the frogs, clouds of mosquitos, perhaps sensing a new, unprotected warm body, went to town on my arms and face. But, this being my last day in Belize, I decided to ignore the little vampires and kept taking pictures. Later that day my arms were quite itchy, but it was nothing new or unusual.

That’s a nice-looking butt – I knew that something was amiss when a strange tube started poking out of my skin. This turned out to be a bot fly’s breathing tube.

Things started veering off course after I got home. Some of the mosquito bites kept itching and, rather than disappearing, started to get bigger. It didn’t take me long to realize that I had brought with me, embedded in tiny holes in my skin, larvae of the Human bot fly (Dermatobia hominis). This was not the first time for me to have this parasite. What was new was the number of these animals that had made my body their home – at least six of them were feeding on both my arms, with four spaced only a millimeter apart on my right forearm. In the end, only three of them survived the first week. One of the surviving larvae was on my elbow. It was a nasty little thing, very active and painful. It had to go. But I decided to keep the two remaining larvae. As strange as it sounds, I felt bad about killing them, but I also had never seen an adult bot fly, and this was my chance.

Human bot flies are well known to entomologists and people living in warm, tropical parts of Central and South America. I cannot think of any of my biologist friends working there who didn’t have a torsalo living in their skin at some point or another, often in such very inconvenient places as the eyelid, the upper lip, or the top of the head. These get extracted through a variety of methods that often involve suffocating the larva with glycerine jelly, raw steak, or duct tape, and then pulling or squeezing the larva out of the skin. These methods usually work, but there is always a risk of leaving a part of the bot’s body in the wound, which may lead to infection. On those occasions where I needed to remove a larva, I preferred to use a suction venom extractor, which enlarges the opening of the wound (warble) and pulls the larva out, still alive and in one piece. I only discovered this method, first described 13 years ago (Boggild et al. 2002. Clin. Infect. Dis. 35: 336-8), after a visit to my doctor. Her solution was to perform a surgery by cutting my arm open. I said “thanks, but no thanks” and did my own research on furuncular myasis.

A mature larva of the Human bot fly (Dermatobia hominis) is an impressively armored animal. And yet it caused relatively little discomfort when feeding, deeply embedded in the skin of its host, me.

Human bot flies (D. hominis), despite their name, are not interested in our species only. They will gladly feed on other primates, as well as ungulates and other large mammals. Similarly, other members of the bot fly family (Oesteridae), who preferentially target small mammals, will occasionally find themselves on humans. But we get infected with D. hominis more often than with other bot flies because of this species’ unusual strategy of dispersing its eggs. Rather than laying them on the ground in the vicinity of mammalian burrows, the way other bot flies do, the D. hominis female catches and lays her eggs on other exoparasites: mosquitos, ticks, and deer flies. The eggs hatch while on the intermediate host and drop onto the skin of the ultimate host, often a human, when they sense its body heat. Frequently they will use the hole made by the mosquito to enter the skin but they can also use a hair follicle to get inside. Even the newly hatched larvae are covered with spines that point up, which makes pulling them out from the warble very difficult.

The puparium of the Human bot fly. The tufts on the front of the body are the anterior spiracles that allow the animal to breathe as it matures  underground. As the puparium ages it changes color from light brown to black. Remarkably, the spiracles stay the same, orange color.

Once in the skin, the larva undergoes three molts and in 7-10 weeks grows from the size of a grain of sugar to that of a peanut. Throughout this time the warble enlarges and occasionally bleeds, but otherwise it is relatively painless, unless the larva decides to munch on nerve endings. These wounds rarely get infected as the larva very likely produces antibiotic secretions. Once fully grown, the larva crawls out of the warble and falls to the ground, where it quickly buries itself and turns into a puparium. The wound usually heals completely within a couple of days. All in all, not a big deal. But some people, for whatever reason, don’t like to have a squishy, almost harmless animal living in their skin.

A mature Human bot fly (Dermatobia hominis). Although we don’t think about them as such, these flies are beautiful rainforest animals, as much a part of that ecosystem as howler monkeys and Morpho butterflies.

A mounting body of research indicates that many parasites have evolved a way of manipulating the behavior of their hosts. A parasitic horsehair worm will make its otherwise terrestrial grasshopper to jump into the water, where it then ruptures the grasshopper’s body and swims away. Parasitoid wasps who have just left the emaciated body of a caterpillar will be actively protected by their brain-washed host. Humans also fall victim to parasitic manipulation – there is evidence that toxoplasmosis, a disease caused by protozoan Toxoplasma gondii, makes men less intelligent and prone to take greater risks (it has to do with increasing the likelihood of ending up as food for large cats, Toxoplasma’s ultimate host; inexplicably, the effect on women is a statistically significant increase in their intelligence.)

After I had decided to keep two of my botflies and let them reach maturity, I began to wonder – have the generations of entomologists, who let these flies live in their skin as a kind of geeky right of passage, inadvertently selected for a strain of bot flies that manipulate human behavior towards letting the flies live? Or do I just have toxoplasmosis?

A newly eclosed Human bot fly, with traces of the ptilinum on its head, a reversible pouch that gets inflated with hemolymph to help the young fly break free from the puparium.

In any case, the flies survived in my skin for nearly 10 weeks, successfully emerged, pupated, and are now enjoying a brief life as adults. Brief, because adult bot flies have no functional mouthparts and cannot feed, which means that they only live for a few days. They are quite pretty – I would go as far as to say that, among insects, they undergo one of the most dramatic transitions from ugly to cute during their development.

It was an interesting experience and I am glad that I managed to bring these insects to maturity. But rest assured that the next time I am in Belize my bottle of DEET will never leave my pocket.

Stay tuned for a video with some awesome sequences showing the development of my bot fly!

 

A composite photo showing the stages of the Human bot fly’s development. The size difference between the first and the third larval instars is particularly striking.

 

Postscript

I let my bot flies live and I went to great pains to make sure that they survived their inadvertent exodus from their native land of Belize. Will this endear me to people who wanted to crucify me for killing a puppy-sized spider a few months ago? I am guessing, no. Do I give a crap? Take a guess. Incidentally, now that the dust has mostly settled, I can repeat that I did not kill the puppy-sized spider – another scientist collected and preserved it – although this bit of information somehow didn’t register with the online media. There was no point in clarifying this because it is completely irrelevant to the issue of scientific collecting – I have killed and preserved my share of specimens, and I will always defend biologists who have the unpleasant duty to do so.

Postscript 2

Gil Wizen has written about his experience of raising a dipteran child on his blog.

Filed under: Flies

So long, 2014

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!

Filed under: Macrophotography

Mozambique Diary: Not all flies fly

Tsetse fly (Glossina sp.) from Gorongosa feeding on my blood. Luckily, tsetses in Gorongosa do not carry the dreaded sleeping sickness.

After a long hike in the scorching heat of the African savanna the cool, shady patch of tall miombo forest looked like heaven to us. I was in the southern part of Gorongosa, looking with a few friends for some elusive species of arthropods. But we were having little luck finding any and after several hours of strenuous walking the morale was low. As we stepped under the dark, inviting canopy of the forest, the drop in the temperature was palpable and we all relaxed, slowed down the pace, and the mood in the group immediately improved. But then, suddenly, somebody yelped “Ouch!” and at the same moment I felt a painful pin-prick at the back of my neck. Crap, tsetse flies! We looked around – they were everywhere. Clouds of them. We could see groups of dozens clumping on vegetation, taking into the air the instant they noticed the movement of our bodies. We ran.

A painting (undoubtedly the first and only) of a bat fly (Penicillidia sp.) burrowing in the fur of a Long-winged bat (Miniopterus).

Tsetse flies have long had a reputation for being one of the scourges of Africa, alongside malaria, crocodiles, and the plague of locusts. And deservedly so – some species of tsetses, all members of the genus Glossina, are vectors of nasty protozoans, including Trypanosoma brucei, the cause of the deadly sleeping sickness. Luckily for us, Gorongosa tsetses carry a different Trypanosoma species, T. congolense. This protozoan does not affect humans but unfortunately causes the chronic Nagana disease in cattle and horses, which explains the nearly complete absence of these animals around the park and in almost the entire region of central Mozambique. But knowing that tsetse bites are not going to kill us did not make them any more pleasant. Tsetses are large flies, about the size of a bee, and their skin-piercing mouthparts are much thicker than those of a mosquito. In other words, it hurts like hell when one jabs you with its proboscis, and you flail your arms like a madman to shoo it away while the fly escapes unharmed.

Members of the family Streblidae, such as this Raymondia sp., collected from the Hildebrandt’s horseshoe bat (Rhinolophus hildebrandtii), often exhibit interesting adaptations in their wing morphology, such as the ability to fold them longitudinally along the back. This presumably helps them move swiftly in the pelage of their hosts.

But count yourself lucky. Imagine instead that you cannot shoo them away. You try to smack one but it runs, hides in your hair or some place where you are not able to reach, and it continues to bite. It only leaves your body to give birth somewhere in your house but then immediately runs back, guided by your scent and body heat. Oh, and imagine that this fly is the size of your fist (or a small puppy). Welcome to the world that bats are forced to live in.

Tsetses are members of a large group of flies, the superfamily Hippoboscoidea, all of which are exclusively hematophagous – blood is the only food that they are interested in. The tsetse family (Glossinidae) is the most basal (unsophisticated, one might say) member of this lineage of insects – they are always looking for a blood meal but never evolved the ability to stay with their tasty host. Bats are unlucky to have been colonized by two much savvier families of flies, the Nycteribiidae and Streblidae. These insects know the value of a good host and, once they landed on the furry back of a bat, they never leave it again. Over millions of years of coevolution with their mammalian hosts the bat flies have undergone a remarkable transition. From a free-flying ancestor, most likely very similar to today’s tsetse flies, emerged several lineages of highly modified, often completely wingless, spider-like creatures. Their body became flattened and very hard, making it almost impossible to squash them against the skin. In the family Nyctiberiidae the head turned into a small appendage that can be safely tucked away in a protective groove on the back and all traces of wings completely disappeared. These flies cannot survive for long outside of their host’s body and only feel at home when scurrying at an alarming speed in its dense fur. Their feet are armed with large claws that make it almost impossible to dislodge them from the hair of their host. They really don’t look like flies and when a friend spotted one on the body of a bat she called me to collect the bat’s “pet spider.”

In the closely related family Streblidae the wings may or may not be present, but even in the winged species the body is modified for squeezing through the fur, and members of the subfamily Ascopidterinae go even further in their commitment to the host. Much further. Once a female lands on a bat she sheds her wings and legs (yes, legs) and burrows head-first into the skin. Once there, her head and thorax sink into her own abdomen, and the skin of the bat overgrows her body. She becomes one with her host.

Penicillidia bat flies (Nycteribiidae) are some of the most unusual members of the order Diptera and hardly resemble their winged relatives. This individual was collected from a Long-winged bat (Miniopterus natalensis) in Gorongosa, Mozambique.

Female bat flies, like their relatives tsetse flies, are remarkably good mothers. The great majority of insects relies on what ecologist call “r-selection” in their reproduction – they lay hundreds or thousands of eggs, betting on one or two of them making to the adulthood. Bat flies, on the other hand, rely on “K-selection” – like humans, they prefer to invest a lot in a much smaller number of offspring, hoping that they will all make it to the reproductive age. They are larviparous – instead of laying eggs the female gives birth to a single, fully developed larva, who immediately turns into a pupa. While in her mother’s body, the larva feeds on “milk glands”, analogous to the mammalian mammary glands (if they were located in the uterus), and develops safely protected from the elements and predators. When the time comes for the mother to give birth she walks off the bat’s body and attaches the larva to the wall of the bat’s roosting place, usually a cave (which explains why bats that roost in rolled-up leaves and other less permanent places have fewer ectoparasites). Then she turns back and runs towards her host, guided by the smell and the heat of its body.

The recent Ebola crisis brought back the attention of the medical community to bats as potential reservoirs of the virus. Although there is no evidence that bats are in fact harboring the virus, there seems to be some correlation between instances of the outbreak and the presence of large numbers of bats in the affected areas. While reading the literature on both Ebola and bat flies I found it rather curious that nobody has tested bat flies for the presence of the virus – these are relatively very long lived (195 days on average) insects, who always stay (as pupae) at the roosting sites of bats, even when the hosts leave to forage elsewhere. They often move from one host species to another and, this point makes me really wonder why nobody has seriously looked at these flies as potential vectors, occasionally drop on and bite people. We know that they harbor a slew of pathogens – a recent study conducted in Gorongosa National Park on bats Rhinolophus landeri and Hipposideros caffer showed that flies living on these animals are vectors of Trypanosoma species that are ancestral to those that cause Chagas disease. Add to this the fact that one of the first cases of Marburg disease in Zimbabwe (caused by a virus related to Ebola) was caused by a bite of an arthropod (by default all unidentified bites seem to be classified by the medical community as “spider bites” and spiders in the area were tested, predictably unsuccessfully, for Marburg). It is far more likely that the bite was caused by a fly that fell off a bat.

A friend of mine recently expressed her dismay at “lowly” parasites. I beg to differ – if anything, parasites, including bat flies, are incredible examples of evolution at its best, organisms capable of both adapting to life in the most hostile of environments (the very substrate you live on wants you dead!) and resisting diseases that live inside your body. I cannot promise that I will not try to smack the next tsetse fly that lands on me but at least I promise that I will do it in the most respectful, considerate way.

Louse flies (Hippoboscidae) are closely related to bat flies and equally modified for ectoparasitic lifestyle. This Lipoptena sp. was collected from a Nyala antelope while it was being fitted with a GPS collar. Louse flies are parasites of large mammals and birds, and some are considered serious pests of sheep.

Filed under: Bats, Flies, Gorongosa, Insects, Mozambique

African Bats: Conservation in the Time of Ebola

A guest post by Jen Guyton

Banana bats (Neoromicia nana) are tiny, insectivorous bats. Their name comes from the preferred roosting habitat of this species – furled leaves of banana plants.

The last fragile wing finally came free from the threads of my mist net. I sank into the sand on the riverbank, took a deep breath, and tugged off my yellow deerskin gloves. Eight cotton bags wiggled as they hung from the line that tethered my mist net to a tree. We’d gotten a swell of banana bats (Neoromicia nana), tiny creatures, no heavier than a large grasshopper, that are thought to roost in the furled leaves of banana plants. They had come in low over the river like a pack of tiny, flittering wolves, hunting the gnats and mosquitoes that hovered in a veil over the water. I’d had to work fast, because the longer the bats stayed in the mist net, the more tangled they became. Some even chewed their way through the nylon thread, escaping in a flurry of teeth and leaving behind a yawning hole for me to mend, its edges fringed with fragrant urine. Now, I just had to wait for my subjects to leave me a few fecal pellets in the cotton bags so that I could analyze their diet.

I looked with relief at Kaitlyn, my assistant for the day, as we took swigs of our beers. I watched the net billow and catch the moonlight, shining silvery-black like a benighted spider web, and listened to the sound of elephants crashing their way through the dense riverine vegetation in the distance.

Out of the corner of my eye, I saw Kaitlyn startle and look down. “I think something just peed on me,” she said, sounding perplexed. I shone my headlamp above her and was greeted by the glittering eyes and bulging cheeks of a large bat, hanging from the branch of the tree above us and happily chomping away on a piece of fruit. From the white patches below its ears and its fawn-colored fur I recognized it as an Epauletted fruit bat, a member of the genus Epomophorus.

A painting of the female Wahlberg’s epauletted fruit bat (Epomophorus wahlbergi) that peed on Kaitlyn

I ran to grab my hand net, a long mesh bag on a circular frame with a handle. The bat was a dozen feet above us, and I didn’t have the handle extension sections, so I quickly duct taped the net to a mist net pole. I raised the net slowly, very slowly, sure that the bat would see me coming and take flight. But it continued to munch merrily, and it disappeared into the net with little more than a metallic peep! of protest. As I collected a fecal sample from it, Kaitlyn cleaned the urine from her clothes.

***

Little collared fruit bat (Myonycteris torquata) from Ghana, a species implicated in harboring the Ebola virus.

Stories like these have gotten me into trouble lately. “I study bat communities in Africa,” I’ll say, only to be greeted by wide eyes and mouth poised to speak the word that’s on everyone’s mind: Ebola.

Luckily, I work on the other side of the continent, thousands of miles from where Ebola has now taken almost 5,000 lives. My field site in Mozambique, on the southeastern coast of Africa, is safe from bat-borne diseases, as far as we know. But it’s no secret that bats have been implicated frequently in emerging zoonotic diseases – diseases of animal origin – that are now cropping up among humans: rabies in the Americas, Marburg virus in Africa, Hendra virus in Australia, and Nipah and SARS viruses in Southeast Asia are all harbored by bats.

The recent Ebola outbreak, too, has tenuous ties to our fluttering friends: scientists have found its antibodies in several species of West and Central African fruit bats. We can’t be sure, though, that they are “reservoir” species – organisms that consistently maintain a virus in their bodies without showing signs of illness. This would allow the bats to harbor Ebola, giving it the opportunity to spill over into humans. But, since we haven’t isolated live virus particles from the bats, all we know is that at some point in their lives,they were infected with or exposed to the virus that left its signature on their immune system.

So far, there’s no record of a bat transmitting Ebola to humans. Humans can get it from other humans, and we have solid evidence that people have become infected through ape carcasses, scavenged and eaten. People in parts of Africa eat bats too, but whether humans can catch the bug directly from bats is still a mystery. Some bat-borne diseases need to pass through what’s called an “intermediate” host – another species that amplifies the virus, allowing it to multiply and become more virulent – before humans can catch it. That is true of Hendra virus, which is found in Australian flying foxes. Contact with the bats poses little known threat to humans, but four people have died after interacting with sick horses. The horses, it seems, fed on fruits from trees where bats roosted.

A colony of Egyptian fruit bats (Rousettus aegyptiacus) from Nzerekore, Guinea, where many people have recently died of Ebola. This species has also been suspected of being the virus’ carrier but so far no live Ebola virus has been isolated from any species of African bats.

All of this adds to bats’ undeservedly bad reputation. Their mystical association with vampires, nocturnal habits, their seemingly erratic flight pattern, a slew of spooky superstitions, and now a misperception that bats are unusually disease-ridden have earned them a less-than-exalted place in the human consciousness. In some cases, this negative image arouses persecution. In 2007, hysteria stemming from a Marburg virus outbreak in Uganda led to mass extermination of Egyptian fruit bats, leaving heaps of them piled on the floor of the forest. This wasn’t an unprecedented reaction – people have been slaughtering vampire bats in Peru since the 1960s in an effort to control rabies, and a few years ago, the four human deaths from Hendra virus in Australia led to widespread culling of flying foxes.

Wahlberg’s epauletted fruit bat (Epomophorus wahlbergi) from Gorongosa National Park in Mozambique

But does reducing bat populations actually help reduce the risk of bat-borne diseases jumping to humans? Surprisingly, the answer is: probably not. In fact, there’s evidence that it could make things worse. In Uganda, the fruit bat extermination led to a much larger outbreak of Marburg, which is closely related to Ebola, among humans. As it turned out, fruit bats recolonized the caves from which they’d been exterminated, and the new population had a much higher prevalence of Marburg infection than the exterminated one. We’re seeing a similar effect in the Peruvian vampire bats – rabies prevalence is higher in populations that are subjected to culling by a poison called “vampiricide”, which preferentially kills adult bats. That’s probably because killing adults removes individuals that have already been exposed to the disease, making them immune. That allows “susceptible” juveniles, with no immunity, to proliferate, and the infection spreads like wildfire.

Fruit bats like bananas – even when they are being measured, photographed, or otherwise molested by a researcher.

It’s not clear whether bats really are different from other animals that could potentially carry diseases, or whether we’re just paying more attention to them now; there’s currently a debate raging among scientists about whether bats are special as disease reservoirs. Some say yes. This may be because many bat species are very social, which would allow pathogens to spread easily. Or, it could be that bats have a long evolutionary relationship with some virus families. Some scientists hypothesize that it’s linked to bat physiology: an unusual immune system, or the remarkably high body temperatures that bats experience during flight, could play a role in their ability to survive infections and, in the end, become reservoirs of pathogens.

Others argue that the numbers just don’t add up and that bats aren’t any more disease-ridden than other mammal groups. Given that bat research is on the increase it could be the simple result of a twisted treasure hunt: the harder we look, the more we find.

What we do know is that bats are special in a lot of other ways, and they deserve a boost in popular image. They’re the only mammals that have evolved true flight. They’re also one of the few groups, along with some whales, shrews, and birds that use echolocation – the ability to “see” a landscape using reflected sound waves. The combination of flight and echolocation allows them to fill a special role as nocturnal predators of aerial insects, with the potential to suppress insects like mosquitoes or some agricultural pests that aren’t active during the day. That does us humans an important service, and scientists have estimated that bats save U.S. agriculture $53 billion dollars in pest control every year. The high diversity of bats – they’re the second most diverse mammal group after rodents – allows them to fill a number of other important roles in ecosystems, such as dispersing the seeds of rainforest trees or pollinating flowers, including the agave used to make tequila.

We don’t yet know as much about bats and their diseases as we should, but the little evidence we do have suggests that killing bats will actually worsen the problem. It also suggests that the same things that are driving some bats toward extinction are also driving spillover events. Deforestation, for example, forces bats to find new homes in cities and increases the probability of their contact with humans. And eating bats gives their pathogens even easier access to people. We can reduce those risks if we protect bat habitats, halt culling efforts, and convince people to stop hunting and eating bats. None of these are trivial endeavors, but we need to try. In the time of Ebola, bat conservation is more important than ever.

Peters’s epauletted fruit bat (Epomophorus crypturus) from Gorongosa National Park

Filed under: Bats, Guest post, Mammals

Treehoppers

Nobody really knows what the strange structures on the head of the Bocydium treehopper are for. They don’t use them in courtship and seem pretty ineffective for defense.

“I need to have my vision checked” was the first thought that popped into my head when my eyes met a treehopper of the genus Bocydium sitting on a thin branch in the Braulio Carillo National Park in Costa Rica, where I was researching several newly discovered katydid species. I had seen many mind-boggling organisms during my years as a tropical entomologist, but this thing looked like something that had just disembarked from a tiny interstellar spaceship. All the parts expected of a self-respecting insect were there – six legs, compound eyes, two pairs of wings – but what was the deal with the huge modernist sculpture on the head?

For ants, a colony of treehoppers is like a pasture full of cattle. They protect the insects and collect their nutritious honeydew. An ant can elicit the production of a droplet of honeydew by gently stroking a treehopper (in this case a Costa Rican Harmonides sp.) with her antennae.

Treehoppers, members of the family Membracidae, are distant relatives of cicadas and aphids, and just like them they feed on liquids that flow through vascular tissues of plants. Such diet is extremely rich in carbohydrates, to the point that the excess must be expelled by the treehoppers. They do so in the form of honeydew, sugary water, dripping off the end of their abdomen, a substance that other organisms, ants mostly, find both delectable and worthy of fighting for. For this reason ants frequently form mutualistic relationships with treehopers, and defend them against potential predators in exchange for nutritious droplets. Some ants are even capable of asking for honeydew by gently tapping or stroking the treehopper’s abdomen, to which the insect responds by dispensing the drink. In addition to ants, certain wasps and flies also take advantage of this resource, but do not seem to repay in any way.

This mutualistic relationship with ants can influence the maternal behavior of some species. In many treehoppers the female guards the eggs and newly hatched brood, shielding them with her body and fending off predators. But if ants are constantly present, assuming the role of the brood’s guardians, then there is no need for her to stick around and protect her children. Instead, she can move on and lay another clutch of eggs on a different part of the host plant. Treehopper species that lead solitary life and don’t display maternal guarding of the brood are unlikely to attract ants’ protective interest as it is simply uneconomical for the ants to travel long distances to collect honeydew from a single insect. Thus, in some cases, developing nymphs of solitary species join “herds” of communal treehoppers, thus gaining the benefit of ants’ services.

Treehoppers are excellent parents – this female Thorn treehopper (Umbonia sp.) is shielding her eggs with her body; if necessary she can also use her powerful legs to kick and ward off potential predators.

But treehoppers are by no means helpless and, in the absence of ants, can defend themselves quite effectively using deceit, amazing body armor, and kickboxing (or at least an insect version of it). Nearly all species of treehoppers carry a massive, often intricately shaped and beautifully colored shield-like thoracic structure known as the helmet. In most cases its function is that of crypsis – many species resemble thorns, tiny leaves, or random bits of vegetation. Others use their helmet and bright coloration to turn into perfect replicas of stinging wasps, albeit they of course remain completely harmless.

Members of the tribe Hoplophorionini, however, go beyond such passive defense and have evolved powerfully muscled, spiny legs, which they are not shy to use on a wasp or any other predator that makes a mistake of straying too close. They kick and flap their wings, which is usually enough to drive away a predator several times their size. In those species where the female guards a large group of children, who usually position themselves in a long line all along a branch of their favorite plant, the insects employ a complicated language of acoustic signals – the nymphs can “talk” to the mother by sending substrate-borne vibrations, alerting her to an approaching enemy so that she can come running and ward the predator off. Acoustic communication is also used among adults to find mates, stake territories, or warn others about predators. Some species eavesdrop on other treehoppers to look for richer or safer pastures.

Two extreme examples of treehopper morphology – Membracis zonata, showing disruptive coloration that conceals the fact of being an insect, and Cladonota ridicula, a perfect imitator of a dead speck of vegetation.

Entomologists had always assumed that trehoppers’ helmet was a simple outgrowth of the pronotum, or the dorsal plate of the first segment of the thorax. Pronotal modifications can be seen in other groups of insects (beetles or grasshoppers, for example), and thus it was only logical that treehoppers represented merely an extreme case of such a development. But a study published in 2011 by Benjamin Prud’homme and his colleagues (pdf) challenged this view. It provided tantalizing evidence that the awesome structures that treehoppers carry on their bodies are essentially a third pair of wings that had evolved to play a very different function. By carefully studying the embryonic development of treehoppers and mapping the expression of certain Hox genes (genes that control the development of serial structures, such as an insect’s body segments), they were able to show that the helmet of treehopers starts as a pair of tiny wing-like structures that later expand and fuse above the body. In some cases they even retain traces of hinges that are present at the base of normal insect wings.

And thus we know how, but not necessarily why. Some entomologists have suggested that the otherworldly shapes of Bocydium and other insane treehoppers are examples of ant mimicry, or simply serve to turn the body of an otherwise helpless insect into an equivalent of unpalatable fishhooks. But there might be another explanation – what if these structures are sophisticated satellite antennas and the treehoppers use them to stay in touch with the mothership? Probably not. Or maybe?

What possible function can these massive horns play in this Costa Rican treehopper Umbelligerus sp.?

A portrait of a Costa Rican treehopper Poppea capricornis.

Filed under: Behavior, Costa Rica, Hemiptera

What to do?

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

Take Our Poll

Filed under: Macrophotography

Mozambique Diary: Rescuing a Dragon

A guest post by Jen Guyton

In my lap was a specter, one of the most elusive animals in sub-Saharan Africa. I’d been waiting years to see it, and now it was weighing abrasively on my thighs like a sack of bricks stuffed into a giant pinecone. It wiggled and unfurled its roly-poly body just enough to reveal an eye like sticky caviar, its tongue whizzing in and out and reinforcing the illusion that this scaly orb was a dragon come to life.

But it was a warm-blooded, placental mammal, confirmed by the tiny body double that was furled in her spiny grasp, suckling at the teats exposed on her underbelly. The mother and her pup were ground pangolins (Smutsia temminckii), one of eight species belonging to the mammalian order Pholidota, found only in Africa and southeast Asia. Though often called scaly anteaters, pangolins are unrelated to the Vermilingua, the suborder containing true anteaters. Actually, pangolins aren’t closely related to much of anything; these animals are unique, clinging to a long, isolated branch on the tree of life.

Safe at last – rescued from poachers, a Ground pangolin and her baby boy are going back to Gorongosa National Park to be released back into their habitat.

We were in Gorongosa National Park, Mozambique, and someone had told us about her. There was a man in a village across the river, the whispers went, selling her for the low price of 22,000 meticais (about $700 USD). Like rhinos, pangolins have fallen victim to a deeply-held misconception that their keratinous scales hold medicinal magic: that they can cure skin disease, reduce swelling, or even conquer cancer. I’ll tell you now: save yourself the money and the risk of jail time, and just chew on your nails – they are chemically and physiologically the same.

One day and a sting operation later, the pangolin was in my lap. Park rangers, working with the local police, arrested the poachers and rescued the animals. We were driving them out into the core of the park, where we’d release them, safely distant from grasping human hands. Though the pinecone plates of a pangolin’s back can and do stand up to being chewed on by lions, these animals are no match for a human that’s interested enough to simply pick one up and carry it off. Their only other defense is their smell, an indescribable odor that originates from a noxious-smelling acid secreted from glands below the tail.

I ran my hands along the pangolin’s scales. They were grooved and brittle-chipped, crooked and mud-splattered like fingernails that had seen many years of working with the land. In Asia, the scales of confiscated pangolins bear the circular scars of punches used for medicine. Even the artful hand of evolution, which had crafted this unique armor from a plush pelt, couldn’t save them.

Bipedal and armed with massive claws, a Ground pangolin could easily be confused with a carnivorous Jurassic raptor. But these gentle mammals feed exclusively on termites and ants, and their only defense is a thick armor of keratinous scales.

As she unrolled herself from her fortress, a second head surfaced, tiny and pale. It was her male pup, the only one that will be born until he reaches sexual maturity in two years. He was born in captivity, a side effect of stress, and an unrealized bonus prize for the poacher. His scales were half-baked, pliable, and the dark shriveled stump of an umbilical cord poked from his round belly. He moved in the shivering stutters of an infant still unsure about the world.

As the pup crawled up my arm, the mother thrust out a hooked hand to right herself. Her claws, the length of my own fingers, gripped my jacket like rusty nails and tore a gaping hole in the material as they bore into my side. I jumped, and she rolled back into a ball, her pup safely inside. These formidable sickle-claws are used to tear open termite mounds and ant nests, shredding the hard earth in search of scrambling adults and doughy larvae. The pangolin laps them up with its sticky-salivating tongue, longer than its own body and the longest relative to body size of all known mammals. Because pangolins lack teeth entirely, keratinous folds line their stomachs with inverse armor, grinding the insects to bits with the help of ingested pebbles.

Having spent a month in captivity, the pangolin, her baby tenuously clinging to her back, takes the first steps as a free animal.

We finally reached an appropriate site: far from the park’s perilous edges, the forest bulged above a tapestry of termite mounds. We set her gently on the ground, and waited.

Pup clinging to her back, she stood and sniffed the air, taking a few moments to orient herself to her new and safer home before choosing a bearing. Her scales clack-clacking, she ambled away on her hind feet like a drunken Velociraptor, tail out and claws curled against her chest. It’s hard to walk on all fours when you’ve got scythes for hands.

In Chinese mythology, pangolins are wayfarers. It’s said that they travel the world by digging through the core of it, tying the earth together with a vast underground labyrinth. In Cantonese, they’re called chun-shua-cap, “the animal that bores through the mountain.” I’d like to think she’s safely reached the Alps by now.

Text and artwork ©Jen Guyton 2014

If you would like to learn more about pangolins, and threats they face from the illegal wildlife trade, read a recent expository piece on the CNN website.

Safe under his mother’s armor, a young pangolin will stay with her until his own scales are large and strong enough to provide protection from predators.

Filed under: Gorongosa, Guest post, Mammals, Mozambique

Involuntary Bioslaughter and Why a Spider is Dead

“Hey, where is the spider post?”, you may be asking if you arrived at this page by following one of the thousands of links that sprung up overnight in the online media and social circuits. In the fine tradition of online publishing I took the liberty of pulling a “bait-and-click” switcheroo, and turning the hysteria surrounding the Goliath birdeater’s story into a teaching opportunity. And thus, please bear with me, and read this post to the end (where you will find the original post about the spider) before banging out an angry comment in ALL CAPS.

For some reason, probably related to the proximity of Halloween, my blog post about the Goliath birdeater spider received an inordinate amount of attention, and has been republished, reinterpreted, outright stolen, and vilified all over the Internet. This one post on my obscure blog is now receiving in excess of 120,000 unique visits every day, and comments are pouring in. Alas, most of them are somewhat less than positive, and I am beginning to wonder if I really am a “HORRIBLE person” who “will destroy the earth.” (I must admit that some of the trolls were touchingly tactful – they might have said ” F&*K you, a$$hole”, but they modified the foul words as not to offend my sensibility.) But why the vitriol?

Museum collections are priceless not only because of their role in scientific discoveries, but for igniting the fascination with the natural world in future generations of researchers, artists, and conservationists.

You see, while talking to a reporter I explained that one of the specimens I describe in the blog had been collected and placed in a museum. This, combined with my comment of having seen this species only a handful of times, triggered a tsunami of self-righteous outrage at my murderous act which, according to the most vocal individuals, is bound to drive this species to extinction. In fact, I really fear for the Smithsonian Institution, this nation’s preeminent natural history collection. If a single spider collected by a scientist causes such an outrage then, surely, the 126 million specimens in its holdings will warrant burning it to the ground and crucifying all scientists working there.

But in all seriousness, why was the specimen collected? First, a bit of a background about the expedition to Guyana during which this took place. I was there with a group of biologists and Guyanese students at the invitation of the Ministry of Amerindian Affairs and the Environmental Protection Agency of Guyana. Our job was to conduct a comprehensive survey of animals and plants of the newly created Community Conservation Area, train Guyanese students in the methodology of biological surveys, and collect specimens for the Center for the Study of Biological Diversity at the University of Guyana. These specimens are used to both create permanent documentation of the species composition of a never before explored area of the country, and to train a new cadre of scientists and conservation professionals in identification and morphological diversity of organisms. And before you point out various alternative methods of documentation (photographs, sound recordings, non-destructive DNA samples), let me assure you that there is no substitute for the collection of physical specimens.

What about this particular spider? As I mention in the post below, Theraphosa blondi is indeed the largest spider in the world (although its legs are not foot long, as some media reported), and thus it makes a perfect specimen for teaching spider morphology. It is also a very common species, not protected or endangered, and collecting of a single individual poses absolutely no threat to its survival (a scientist picking up one spider is no different from a bird doing the same; if a stochastic event such as this can drive a species to extinction then this species is already doomed.) In fact, you can purchase Goliath birdeaters in many pet stores in the US or online for $20-100 a piece. But they are shy and elusive, and thus I was thrilled every time I saw one during a small handful of encounters with this species. Once the animal was properly euthanized and preserved, something that is never done lightly, it was carefully labelled and deposited in the collection in Guyana where to this day it serves as an important teaching tool. And, years from now, the same specimen may provide new data on spider anatomy, genetics, evolution etc. In addition to the spider, we also collected vouchers of 857 other species of animals and plants (excluding birds and large mammals), which are now deposited across various research institutions in Guyana, Venezuela, and the US.

The Endangered Katydid (Paracilacris periclitatus) – this species may already be extinct due to the loss of its habitat, but we know of its existence because I collected a few individuals and described the species.

Collecting and preservation of physical specimens is an integral, irreplaceable element of biological sciences. There is hardly a branch of biology that does not rely on the examination of organisms’ bodies (the only exception I can think of is ethology, and only some variants of it), be it for the purpose of their identification, understanding of the functions of their respiratory system, or the speed of transmission of neural signals. Museum collections, where specimens are preserved for future scientists, are a special, very important case. There specimens are often deposited not for a particular, clearly defined research project (such as when a geneticist examines thousands of fruit flies to measure the expression of a particular gene). Rather, collections serve as both a documentation of the current state of species composition in a particular time period or an area, or as a library of morphological and genetic diversity across a wide range of species. We cannot anticipate what questions will be asked, and answered, using specimens deposited in such collections. For example, the ban on the use of DDT, a horrible environmental pollutant, was based on the discovery made in ornithological collections that bird egg shells have been getting progressively thinner, thus leading to high mortality of birds, ever since the chemical began to be used. The spread of chytrid fungus that is wiping amphibian species across the globe was understood by examining specimens dating back a hundred years. Closer to my own research, the world’s only cave katydid is now listed as Endangered by the IUCN Red List and thus receiving a greater attention from conservationists, because I found 70-year old, unidentified specimens of this species, collected by a scientist who had no idea what a remarkable animal he was catching.

What do these beautiful animals have in common? You killed them. Or similar species. Our houses are death traps for countless organisms who are attracted to artificial lights and die inside. I found members of each of these species in the light fixtures of my house.

Can collecting specimens for scientific research threaten a species’s survival? The short answer is no, there is absolutely no evidence that any scientist has ever driven a species to extinction. Famous New Zealand 19th century ornithologist Water Buller is sometimes accused of having collected birds to extinction, but a close examination of the numbers of specimens collected by him proves that his work had no impact on the birds’ populations; rather, his bird collection is now a sad repository of species exterminated in New Zealand by moronic, purposeful introduction of alien species and destructive agricultural practices on the islands.

And this is the key – species are never lost as a result of scientific collecting, but almost invariably because of the destruction of their habitat, or due to competition from alien species introduced by humans. And this loss of species is happening on an unimaginable scale – by some estimates 16,000 species quietly go extinct every year, some even before scientists have a chance to describe and name them. And this is why if I see something that may be new to science, even if I suspect that it might be rare and threatened, I will collect it and deposit it in a museum. Some years ago I found a new species of katydid in South Africa. I knew that its population was tiny and on the brink of disappearance. In fact, this species is now probably extinct. Not because I collected a few individuals, but because its only population was located in a tiny patch of a native yellowwood forest within a massive pine plantation, a patch that was already being cut down to be replaced by more non-native trees grown for timber. Had I not collected a few specimens of this animal, we would have never known it existed. Now, at least its tombstone has a name – Paracilacris periclitatus, The Endangered Katydid.

I could go on and on about why scientific collecting is needed, but I want to mention one last thing. Every single one of us is guilty of involuntary bioslaughter – we kill thousands of organisms without realizing that we do it. Look into the light fixtures of your house or the grill of your car, they are full of dead insects and spiders. That highway that you drive to work – each mile of it equals millions of animals and plants that were exterminated during its construction (and if you live in areas of particularly high endemism, California or New Zealand for example, its construction probably contributed to pushing some species closer to extinction). That tofu that you eat because meat is murder – it probably comes from Brazil, where massive plantations stretching from one horizon to another have replaced its once thriving rainforest and led to the disappearance of thousands of species.

A mile of highway kills more organisms that an entire generation of scientists. First during its construction, then when it turns into a conveyor belt to hell for any organism unlucky enough to step on or fly over it.

It is very easy to fixate on an individual case of an organism being deliberately euthanized. We do it because it is convenient emotionally – it is much easier to feel superior when we can point a finger at somebody who does it consciously, even if for a good, justifiable reason, but we don’t like to think about those trillions of animals and plants that we kill by virtue of simply going to a grocery store.

And now, enjoy the story of the Goliath birdeater.

 

The sound of little hooves in the night

When I go out at night into the rainforest to search for katydids I don’t like to have any company. Not that I am particularly antisocial, but tracking skittish and cryptic animals is an activity that’s better done alone. I walk slowly, trying not to disturb anything and anybody, slowly scanning the vegetation and the forest floor in the light of my headlamp. Every now and then I turn the light off to fully immerse myself in the ambient sounds of the forest, which often helps me pinpoint a faint trill made by a katydid’s wings. A few years ago I was deep in the rainforest of Guyana doing just that – listening to the sounds of the night in a complete darkness – when I heard the rustle of an animal running. I could clearly hear its hard feet hitting the ground and dry leaves crumbling under its weight. I pressed the switch and pointed the light at the source of the sound, expecting to see a small mammal, a possum, a rat maybe. And at first this is what I thought I saw – a big, hairy animal, the size of a rodent. But something wasn’t right, and for a split second the atavistic part of my brain sent a ping of regret that I didn’t bring any companion with me on this particular night walk. But before that second was over I was lunging at the animal, ecstatic about finally seeing one of these wonderful, almost mythical creatures in person.

Goliath birdeater (Theraphosa blondi) from Suriname, displaying the full arsenal of its defenses – urticating hair, enormous fangs, and a loud hissing noise.

The South American Goliath birdeater (Theraphosa blondi) is the largest spider in the world. For all the arachnophobes out there this is probably a good excuse to pave over large swaths of the Amazonian rainforest, but for the rest of us this species is one of biodiversity’s crown jewels. Although far from being the largest member of the subphylum Chelicerata – this honor belongs to horseshoe crabs – Goliath birdeaters are ridiculously huge for a land arthropod. Their leg span approaches 30 cm (nearly a foot) and they weigh up to 170 g – about as much as a young puppy. They truly are Goliaths, but are they bird eaters? Alas, the truth is a bit less exciting. Although definitely capable of killing small birds, they rarely have a chance to do so while scouring the forest floor at night (however, there is some anecdotal evidence that they may feed on bird eggs if they run across a nest). Rather, they seem to be feeding on what is available in this moist and warm habitat, and what is available is earthworms – lots of them.

Goliath birdeater in its natural habitat in Suriname.

But how do they get to be so big? Apparently, according to one study (Makarieva et al., Proc. R. Soc. B [2005] 272), it has to do with their metabolic rate, which is lower than in the Goliath birdeater’s relatives. This allows it to function with lower levels of oxygen reaching its tissues and organs than those required by smaller, more active spiders. In other words, the bigger the body the more difficult it is to provide oxygen to all its parts if the metabolic rate is to remain constant. Regardless of the reason, because of its gargantuan size, the Goliath birdeater is probably the only spider in the world that makes noise as it walks. Its feet have hardened tips and claws that produce a very distinct, clicking sound, not unlike that of a horse’s hooves hitting the ground (albeit, admittedly, not as loud). But this is not the only sound this spider makes.

Every time I got too close to the birdeater it would do three things. First, the spider would start rubbing its hind legs against the hairy abdomen. “Oh, how cute!”, I thought when I first saw this adorable behavior, until a cloud of urticating hair hit my eyeballs, and made me itch and cry for several days. If that wasn’t enough, the arachnid would rear its front legs and open its enormous fangs, capable of puncturing a mouse’s skull, and tried to jab me with the pointy implements. The venom of a birdeater is not deadly to humans but, in combination with massive puncture wounds the fangs were capable of inflicting, it was definitely something to be avoided. And then there was a loud hissing sound. For a long time the source of the sound was a mystery, but now we know that it is produced by “setal entanglement” – some of the hairs (setae) on the legs are covered with microscopic hooks that scrape against other, feather-like setae, producing the loud warning hiss.

With the leg span of nearly 30 cm, the Goliath birdeater is an animal that should be treated with respect, even though it is pretty much harmless to humans.

A couple of years after my first encounter with Theraphosa blondi I was in South America again, walking alone at night in the rainforest of Suriname. Suddenly my foot brushed against something big and moving, and I nearly tripped. I froze, expecting a snake. “Nah, it’s just another Goliath birdeater. Aren’t you a cutie pie?”

Update: You can now purchase high quality prints of all images appearing in this post – just click on the image. For commercial use please contact Minden Pictures with inquires regarding licensing of these photos.

A Goliath birdeater from Guyana, the first individual of this species that I ever encountered (possibly T. stirmi). Her opisthosoma (abdomen) is nearly bald because most of the urticating hairs ended up in my eyes and mucus membranes – now I know better than to put my face too close to these animals.

Filed under: Arachnida