Archive | September 2012

Celebrate blattodeans

Giant blattodean (Megaloblatta blaberoides) was until recently considered to be the largest member of its order. [Canon 7D, Canon 100mm macro, 3 x 580EXII]

In 1994 I took a tropical ecology course in Costa Rica, which was my first exposure to a Neotropical rainforest. The course itself did not convince me to become an ecologist, but at the same time it ignited my fascination with Neotropical biodiversity that has remained strong to this day. While there I made an interesting discovery, or at least I thought I did, because, as it turned out, I was a bit too late.

At the Las Cruces Biological Station near the Panamanian border, I found nymphs of the giant blattodean Megaloblatta blaberoides, which, until recently was considered to be the largest member of this group of insects in the world (a larger species was found in SE Asia a few years ago.) They had a peculiar behavior, which I thought was something previously unknown in this order – they stridulated loudly when disturbed, and the sound they made was eerily reminiscent of that of a rattlesnake, both in its frequency and loudness. I recorded and collected a few individuals, and dissected them to examine their sound-producing mechanism. I found out that they had paired sound-producing stridulatory organs on the ventral side of the abdomen, and made the sound by shaking the last few abdominal segments from side to side in a way very similar indeed to the way a rattlesnake uses its rattle. I took SEM photos of the structures, analyzed the sound recordings (which in fact had the same acoustic characteristics as those of the snakes), and drafted a manuscript about this unusual behavior. But before submitting the paper I decided to contact Dr. Louis Roth at Harvard University, the world’s preeminent blattodean specialist, to share the discovery with him.
I met him at the Museum of Comparative Zoology in a room filled from floor to ceiling with containers holding colonies of live blattodeans. It was feeding time, and he was busy throwing chicken wings into the cages, which I found peculiar because I thought that those insects were exclusively herbivorous. Dr. Roth listened to my story about the stridulation, and then pulled out a paper from a stack of reprints. It was a paper published twelve years earlier by Schal et al. (J. Insect Physiol. 28: 541-552), and it contained everything that I had put in my manuscript, and more. I was crushed. But the experience was also the first of many lessons in how science works, the most important ones being: (1) if you think that your discovery is great then somebody has probably already made it, and (2) do a comprehensive background research before putting anything on paper.

The exhibit at the Harvard Museum of Natural History devoted to blattodeans (which are, apparently, also known as cockroaches.) [iPhone 4GS]

A few years later I made another interesting observation on blattodean behavior, this time truly new, and Dr. Roth and I published our first paper together. We collaborated on a few additional publications, but unfortunately, while working on a large treatment of Costa Rican blattodeans, he passed away in 2003 at the age of 85.

Today a new exhibit that highlights Dr. Roth’s work on blattodeans opens at the Harvard Museum of Natural History. It is a small but beautifully presented celebration of both this scientist’s work and the diversity of a fascinating group of insects. During its preparation the museum was fortunate to be assisted by Marc Socié, a visiting French artist, who created wonderful, unconventional drawings of blattodeans and their relatives. The exhibit will be open for a year, and if you find yourself in Boston between now and the next fall, I urge you to stop by and see it.

One of Marc Socié’s drawings from the exhibit.

Our top predator

House centipedes (Scutigera coleoptrata) are born with only 4 pairs of legs, but eventually develop 15 pairs [Canon 7D, Canon 100mm macro, 3 x 580EXII]

As the days grow shorter and colder, I find myself paying more and more attention to the organisms that I took for granted throughout the entire summer. Suddenly, cricket songs punctuate the unexpectedly chilly nights with hesitation, moths coming to the light on our deck are getting smaller and rarer, and spindly centipedes trapped in the kitchen sink in the morning remind me that I should count my arthropod blessings before winter takes most of them away.

The house centipede (Scutigera coleoptrata) is a particularly welcomed inhabitant of my domestic ecosystem. I have always been fascinated by these animals, and one of my life’s greatest achievements was the ability to convince my wife, who would rather be in the same room with a wild grizzly than a 3 mm long spider, to tolerate and (almost) appreciate their presence. On a few occasions a large centipede ran across the carpet in the living room while we watched TV, and Kristin didn’t bat an eye. (Perhaps 8 legs is that magical number that triggers irrational fear in some people – fewer than or more than 4 pairs is simply not perceived as threatening or creepy, at least not as much.)

House centipede with a cockroach prey; notice the large fangs (forcipules), which deliver the venom that kills the victim, and a prehensile foot holding the cockroach’s leg. [Canon 7D, Canon 100mm macro, 3 x 580EXII]

House centipedes came to North America from the warm, Mediterranean region of Europe, where they can be found in caves and other shady, humid environments. In New England and other places with harsh winters they prefer to spend at least part of the year in houses, and live outside only during warmer summer months. This is why people generally start noticing them in the spring, when these animals look for ways to get out of the house, and then again in the fall, when they come back to spend the winter in the safety of our basements. Their presence in people’s homes is a reminder of the fact that houses are, in an essence, caves inhabited by large mammals. These mammals provide a constant stream of organic debris, which in turn supports a rich fauna of prey species for the centipedes: mites, silverfish, flies, and cockroaches, to name a few of our troglophiles.

Centipedes are the top predators of our domestic ecosystems. They are the equivalent of cheetahs in the African savanna – lean and long-legged chasers of those who scavenge our organic refuse, catching their prey and immediately killing it with one powerful bite. But their weaponry is even more sophisticated than that of the cats. Since the nervous system of insects is not as centralized as that of mammals, crushing the head of the prey would not necessarily kill it. A far more effective method is to inject the prey with venom, which instantly paralyzes it and stops it from struggling. Centipedes do so with a pair of modified legs, shaped like a pair of fangs and connected to venom glands. (Be not afraid, however – these are not capable of piercing our skin, in the unlikely event that you caught one of these things and forced it to bite you; centipedes have absolutely not interest, or capacity, to attack people.)
They also have something else that cheetahs lack – prehensile legs that can wrap around the appendages of their prey, in a way remarkably similar to that in which an octopus handles its victims. Having 15 pairs of long, grasping legs allows centipedes to carry their prey, and even hold one while hunting for another.

If you have seen these animals around your house, count yourself lucky. Their presence assures that no pest species will be able to multiply unchecked, and spread harmful germs from your trash and pipes into the rest of the house. Centipedes may not be the cuddliest of your roommates, but they pay their rent and keep the house clean.

House centipede with a cockroach prey [Canon 7D, Canon 100mm macro, 3 x 580EXII]

Artists take on The Smaller Majority

Okawango reed frog by Pine Roehrs

Last night I saw the amazing David Byrne and St. Vincent in concert, which made me wonder once again what it means to be an artist. It is a person, I have come to believe, who holds a joystick to your endocrine system, and with a flick of a wrist holding a pick (or a pen, a brush, a bow) can control the flow of hormones and neurotransmitters in your body. Or, as we call it, emotions. They do so by altering our sense of reality, and moving us to places we wish we could go to. During the concert I could feel waves of dopamine and oxytocin rising and falling, accompanied by an occasional ripple of endorphins in my brain. Or maybe I was just dehydrated.

Nature photography, on the other hand, is about capturing and documenting reality. Of course, a photograph is never a perfectly objective representation of the scene and, simply by virtue of placing a curved piece of glass between the eye and the world, a photographer distorts the image that our brain then processes and interprets. Clearly, nature photographers can also be artists, and many go a long way beyond simply freezing a moment. But the intention of being faithful to the real world is what most nature photographers consider their guiding principle, and we pride ourselves on preserving fragments of the world as it really was in that one point in time. But to an artist, reality is just the starting point. The image that a nature photographer has so unerringly documented may become a seed of something very different, often revealing aspects of nature that cannot be simply seen – they must be felt.

I am quite proud that a number of artists have used some of my photographs as an inspiration to produce pretty amazing pieces of art. It must be noted that all these artists explicitly acknowledge using my photos as their source of inspiration, some even asked me if I would allow them to do so (alas, this is not always the case, as Alex Wild demonstrates on his blog.)

Here are a few of my favorite pieces.

Ball blattodean by Scott Severance

Red-eyed tree frog by Amelia Bliss Sikes

Monkey frog by Scott Severance

Satanic gecko by “sengkelat

Another take on the satanic gecko by Sharlena Wood

A stunning stained glass window made for the Rama Exhibition

Beanie babies with teeth

Satanic leaf gecko (Uroplatus phantasticus) – despite its unfortunate common name, there is nothing evil about this beautiful lizard [Nikon D1x, Sigma 180mm, flash Nikon SB-28DX]

The island of Madagascar, an ancient chunk of the Indian subcontinent that somehow ended up very close to Africa’s eastern shores, has always been a magnet for biologists. And not surprisingly so: the place is bursting with ancient and endemic lineages, and in some groups of organisms 100% of their species can be found nowhere else. Lemurs usually get the most attention, but other animal groups are equally deserving gasps of wonder, and none more so than the mind-blowing Leaf tailed geckos (Uroplatus.)

When I first held the Giant Leaf tailed gecko (U. fimbriatus) in my hand after catching it in the rainforest of northern Madagascar, it felt as if I were holding a living, breathing beanie baby. It was the size of small puppy, and its skin was velvet-soft and warm. The gecko’s hands grasped my fingers the way a newborn holds its parent’s finger – softly but firmly at the same time. Having this animal sit in my hand was one of the most pleasant tactile experiences of my life.

Giant leaf tailed gecko (Uroplatus fimbriatus), proudly displaying its mouth full of teeth [Nikon D1X, Nikkor 17-35mm f/2.8 IF-ED, fill-in flash Nikon SB-28DX]

Of course, Leaf tailed geckos are not sweet, fuzzy toys – like all geckos, they are efficient killing machines, predators capable of catching and swallowing remarkably large prey. The smiley face of the gecko hides incredibly sharp teeth, and lots of them. Leaf tailed geckos have the highest number of teeth of any amniote (which includes most of terrestrial vertebrates) – their lower jaw can have 97-148, while the upper between 112 and 169. That’s, potentially, 317 teeth! To put it in perspective, other geckos have between 100-180 teeth, while our puny human jaws carry only 32 teeth.

Leaf tail geckos are high masters of camouflage, and this is one of the reasons why so little is known about their biology [Nikon D1x, Sigma 180mm, flash Nikon SB-28DX]

Why so many? Nobody knows for sure, because virtually nothing is known about their feeding behavior in the wild. In captivity they will eat almost anything that moves, but in their native habitat, the wet and humid forests of Madagascar, they may be targeting frogs, which are a remarkably species-rich and abundant group in that part of the world. A huge number of small, sharp teeth is likely to help hold such slippery prey. A higher than usual number of teeth may also be very useful in capturing moths, whose scale-covered bodies are as difficult to grasp as those of wet amphibians.

About 20 species of Leaf tailed geckos are known, including several newly discovered species that await their formal description. Alas, many of these animals are already on the brink of extinction, and some may already be gone. Over 90% of the natural forest habitat of Madagascar has been destroyed, and with it countless species, including several Leaf tailed geckos. Illegal pet trade in these lizards is contributing to the decline but, interestingly, it also contributes to the discovery of the previously unknown species: the largest species of Leaf tailed geckos (U. giganteus), was first collected by amateur herpetologists and its photos appeared in pet trade literature 5 years before the official description, prompting a more scientific interest in this species.

Satanic leaf gecko is a highly polymorphic species, and comes in many different color shades. This species, like many geckos, can also change its color thanks to the presence of chromatophores in its skin. [Nikon D1x, Sigma 180mm, flash Nikon SB-28DX] 

The Eye

The eye of the Red-eyed treefrog (Agalychnis callidryas) from Costa Rica [Canon 10D, Canon MP-E 65mm, speedlight Canon 580EX]

Like the Eye of Sauron, this eye never sleeps. The Red-eyed tree frog (Agalychnis callidryas) from Costa Rica has the upper part of the lower eyelid translucent, allowing the frog to see its surrounding even with the eyes closed. The eyelid carries a pattern of golden lines that obscure the normally highly visible red iris of the eye.

(This image is now available as a high quality print from my new image collection.)

Dangerous candy

Bushhopper Dictyophorus spumans from South Africa, also known as the foam grasshopper, is deadly toxic, and it tells you all about it with its bright coloration [Canon 7D, Canon 14mm]

My first visit to Africa was in 1989, when I went to visit some friends in Zimbabwe. Back then the country was still prosperous and democratic, Toni Childs optimistically sang “No more crime in your lifetime, Zimbabwe”, and nothing indicated the darkness it would soon descend into. I spent a few weeks traveling around the country, getting the first dose of what would soon become an obsession and a deep love for Africa. This was the first time that I saw elephants and other members of the “charismatics megafauna” outside of a ZOO, but the animals that made the greatest impression on me were not mammals, but big, slow-moving grasshoppers that covered nearly every bush and tree around the capital Harare. They were unafraid of me, they were colorful, and they looked …tasty. There was something about these bright, multicolored insects that just made me want to put them in my mouth; they were almost like candies.

Bushhopper Dictyophorus cuisinieri from Guinea defending herself with toxic foam [Canon 1Ds MkII, Canon 100mm macro, Canon MT-24EX twin light]

This, of course, only shows how far we humans are removed from the rest of the natural world, because to any other animal these very characteristics – the slowness, the bright coloration – spell out “you touch me and I’ll kill you!” And surely, the grasshoppers, which I later identified as bushhoppers Phymateus baccatus, were members of the family Pyrgomorphidae, which includes some of the most toxic insects known to man. They feed primarily on Apocynaceae and Solanaceae, plants loaded with toxic secondary compounds, which the grasshoppers are able to sequester and accumulate in their bodies. Among these poisonous metabolites are powerful cardiac glycosides. In very small doses these can be used to treat arrhythmia and other heart diseases, but in larger ones, such as if you ate one of the grasshoppers, will cause heart failure. In fact, there has been a number of cases of children in Zimbabwe and South Africa dying after eating these insects. (There are also known cases of dogs who perished after ingesting these insects, which, I think, shows how similar to humans they have become – to their own detriment; jackals in Africa never eat bushhoppers.)

A nymph of a bushhopper Phymateus viridipes from Mozambique can afford being slow and conspicuous thanks to the toxins in its body [Canon 7D, Canon 14mm, Canon MT-24EX twin light]

But even if you misinterpret the warning coloration, the bushhoppers give you plenty of additional warning. Many species fan their colorful wings when molested, and if this does not get the message across, they begin to squirt blood (hemolymph) through their thoracic respiratory openings, while simultaneously blowing air into it. This behavior instantly produces copious amounts of white foam, which quickly turns yellow and fills the air with acrid smell. All this means that bushhoppers are left alone by most predators who otherwise love gorging on grasshoppers, such as baboons and many birds, and can be found in huge numbers in suitable habitats. Young nymphs of many species are gregarious, and can be found in groups consisting of hundreds of individuals. Such aggregations are vividly colored, and have a much stronger warning effect than a single, small grasshopper nymph would, no matter how strikingly patterned. It is only after the hoppers reach a larger body size (many species are 3 to 4 inches long) that they begin leading a more solitary life, although in most species of the Pyrgomorphidae even the adults prefer to hang around each other.

Bushhopper Phyteumas whellani from Mozambique fans its wings as a warning sign [Canon 7D, Canon 100mm macro, 3 speedlights 580EXII]

Interestingly, close relatives of African bushhoppers are Mexican grasshoppers of the genus Sphenarium, which are not only non-toxic, but also quite tasty and nutritious. Some species of Sphenarium are serious agricultural pests in Oaxaca and other parts of the country, and the most effective way of controlling them is to turn them into delicious “chapulines asados.”

Candy-like colors of the bushopper Taphronota ferruginea from Guinea spell out a loud warning [Canon 1Ds MkII, Canon 180mm macro]

Lantern bugs in action

If you enjoyed the story of lantern bugs and their assorted visitors, you can see a clip from David Attenborough’s fabulous documentary “Life in the Undergrowth” featuring these remarkable animals. Incidentally, the movie shows the same insect individuals, filmed on the very same tree on which I took some of my photos at La Selva Biological Station in Costa Rica. If you have not seen this documentary, you absolutely must do it – it is, by far, the best series about terrestrial invertebrates ever made.

(Thanks to Adrian Thysse for finding this clip and posting it on his blog “Splendour awaits.”)