Archive | November 2012

A bump in the road

A partially corrupt RAW file. This type of damage is often the result of a physical flaw of the hard drive, and cannot be repaired.

I have been photographing earwigs recently, and this reminded me of another group of hexapods, the members of which often have big, pincer-like cerci, the diplurans. “I’ll write a post about them”, I thought, “now, let’s see what kind of pictures I have.” I started looking and located a bunch of shots of diplurans that I took in 2006 in Ghana, but when I tried to open the files I received a Photoshop error telling me that the files were in an unrecognizable format. This usually means that the file is corrupt. Other files opened, but were partially garbled.

“No problem, I’ll just get the backup files.” Same error. Second backup, same error, third backup, same error. I began to worry. I am pretty good about keeping all my files backed-up, on multiple, physically separated drives, but the system has clearly failed me.

My normal file-saving procedure while in the field is as follows:
1. Copy files from CF/SD cards to the hard drive on my laptop
2. Catalog image files in iViewPro, rename them, discard crappy shots
3. Add keywords and captions to the files
4. Copy the annotated files to two separate, portable hard drives
5. Back home, copy the files from the laptop to a separate, stationary hard drive (HD1)
6. Copy the content of this drive to two additional, separate drives (HD2 & HD3), occasionally I add a fourth drive (HD4) to the lineup.

After this is done I feel that the files are safe, and I reuse the portable hard drives for another project. Until a few years ago I would have also burned DVDs with an extra copy of the files, but as the files got bigger, and more numerous, I abandoned the practice, opting instead for adding another hard drive to the backup.

All my backup files had the same type of corruption, which must have originated on the first drive, and was copied to other drives.

What must have happened in the case of my corrupt dipluran shots was either a copying error during the process of transferring files from the laptop to HD1 drive, or file corruption on the HD1 following the transfer. Regardless, the damaged files were then duplicated to drives HD2-HD4. So, it seems, all is lost.

Luckily, not. Back in 2006 I still burned DVDs with file backups, using the original files from the laptop as the source. I pulled them out, and sure enough, uncorrupted, original files were there. Alas, going back to using DVDs as a backup is simply not an option. During my recent trip I shot 352GB of images, which translates to 42 DVDs (DVD+R, 8.5GB each), or about 14 hours of burning and swapping DVDs (assuming 20 minutes per disk.) What are my options then?

For one, I will be copying my files from the camera’s card simultaneously to at least two separate drives. You can do it directly in the Finder (or Explorer), or use a dedicated program, such as Photo Mechanic (this program also allows for renaming files while copying them.) Second, I will no longer reuse the portable drives that hold the files copied from the cards in the field. These drives are becoming so cheap that they are now a very sensible alternative to large, external, independently powered hard drives (I may even consider keeping the CF/SD cards with the original shots and not reusing them; some photographers already do it.) And third, I will add storage space to my Dropbox account. There is no way I can keep all my photos there, but at least I can safely store the most important shots. The experience of losing some of my original files was a reminder that no single backup method is 100% safe, but hopefully a combination of several methods will reduce the chances of a disaster similar to what I saw today.

As for the diplurans, I think I will need to write another post about them later on. These are very cool animals, close relatives of insects, and they deserve a proper writeup. They have an interesting reproductive behavior and a sophisticated maternal care, and give us a glimpse of what the early chapters of the insect evolution might have looked like.

Dipluran (Japyx sp.) from Ghana. I was lucky to have an extra, uncorrupted copy of the original Canon RAW file on a data DVD made immediately after taking the photos.

A biblical arachnid

The male Atewa dinospider (Ricinoides atewa) from Ghana has a huge second pair of legs, which are probably used in male-to-male combat. [Canon 1D MkII, Canon MP-E 65mm macro, Canon MT-24EX twin light]

In 1837 a small fossilized beetle was discovered in Carboniferous deposits of England, and its description was promptly published in “The Bridgewater treatises on the power, wisdom and goodness of God as manifested in the creation.” Unfortunately, two things were wrong with this publication. As it turned out, the creature was not a beetle, but a member of a previously unknown group of arachnids. Only a year later, French entomologist F.E. Guérin-Méneville described a living species of the same group, now known as Ricinueli, and thus turned the animal into a “Lazarus taxon”. This biblical name is applied to groups that were first described as fossils (i.e., all members are presumed dead), only to be subsequently discovered as extant organisms. Coelacanth is another example of such an animal, as is the recently found new order of insects, Mantophasmatodea.

And, speaking of biblical references, one species of Ricinulei, Pseudocellus krejcae, should be considered both a “Lazarus taxon” and a “Jesus Christ species” (two guys who apparently met at some point) as it is known only from a single specimen found walking on the surface of the water deep in a cave in Belize.

Immature dinospiders, like this Cryptocellus sp. from Costa Rica, are usually brightly colored. [Canon 1Ds MkII, Canon MP-E 65mm macro, Canon MT-24EX twin light]

Ricinulei are often referred to as hooded tick-spiders, but I prefer a name invented by a friend of mine, the dinospiders. Since the initial discovery of living dinospiders in West Africa 175 years ago we have learned quite a bit about these cryptic animals. Further paleontological evidence has confirmed that they indeed date back at least 319 million years, and their closest living relatives are probably anactinotrichinid mites. Their distribution also points to their origin before the breakup of the Gondwanaland, and these days they are known only from tropical and subtropical regions of the Americas, and a relatively narrow area in West Africa. Only 68 species are recognized, making the Ricinulei the smallest order of arachnids.

At first sight the appearance of dinospiders may be underwhelming – most species are under a centimeter long, dull brown – until you notice one peculiar characteristic. These animals, a closer inspection reveals, don’t have a head. In the place where a spider or a daddy longlegs has eyes and mouthparts, dinospiders have nothing. The front of the body, where you would expect to find a mouth, ends in a vertical plate. (When I found my first dinospider I was convinced that it had been damaged, and was missing a critical part of the body.) Of course, they have to feed somehow. The plate that covers the front of the body (cucullus), can be lifted to reveal a pair of small, pincer-like chelicerae and the mouth opening. They have no distinct eyes, however, although this does not stop them from being extremely sensitive to light.

Dinospiders are surprisingly long-lived and can take several years to mature. [Canon 7D, Canon MP-E 65mm, 3 speedlights Canon 580EXII]

Most of the species are found in the soil and leaf litter of tropical forests, but a few are also found in caves. Little is known about their diet, but some species feed on ant larvae, termites, and dead invertebrates; cave species apparently also feed on bat guano. Their reproduction, in typical arachnid fashion, involves a complicated sperm-transfer mechanism. The male loads one of his legs up with sperm, and then inserts it into the female genital opening. The female usually lays only one egg, which she then carries until a tiny, six-legged baby hatches. Only after a few months does the larva turn into a nymph, and grows an additional pair of legs, making it an honest, eight-legged arachnid.

I had always been fascinated by these animals, and thus was ecstatic to discover a new species of dinospiders in the ancient and seriously threatened Atewa forest in Ghana, which I named, predictably, Ricinoides atewa. To make it even more exciting, this turned out to be the largest dinospider species in the world, growing to the whopping 11 mm long! How many taxonomists can claim that they discovered the largest species in an order?

Neotropical dinospiders, like this Cryptocellus sp., are smaller and distinctly “fuzzier” than their African counterparts. [Canon 1D MkII, Canon MP-E 65mm macro, Canon MT-24EX twin light]

What happens on the fourth Thursday of November

Winter moths on my kitchen window, a sure sign that Thanksgiving is near. [Canon 7D, Canon 24-105mm]

The fourth Thursday of November is upon us, and this can mean only one thing – winter moths are coming! A few days ago, while trying to decide if this year we should have a turkey or two turkeys for dinner, Kristin looked up from the menu list she was working on and said, “Thanksgiving moths should be here soon.” I never realized it, but this is a much more appropriate name for these insects, members of the family Geometridae, which begin to flutter around the lights of our house around this time of year. Sure enough, that very night the first Winter moth (Operophtera brumata) came to the light of the kitchen window, and their numbers have been picking up since.

Winter moths are interesting animals. Unlike most species of moths and butterflies, they are strongly sexually dimorphic. In fact, while the male looks like your typical, grayish-brown geometrid moth, you will be hard pressed to recognize the female as a member of the same order of insects. She is plump and flightless, with wings reduced to tiny lobes that often resemble tufts of hair. Her mouthparts are reduced (not much to feed on for a moth at the end of November), and the only clue that she is in fact a moth comes from the scales that cover her entire body.

A caterpillar and adults of the Winter Moth (Operophtera brumata). [Canon 7D, Canon 100mm macro, 3 speedlights Canon 580EXII]

In the coming days we will be seeing more and more mating pairs, until the arrival of permanent freezing weather kills them all off. But their eggs, safely hidden in the bark of maples that grow around our house, will hatch next spring, and thousands upon thousands of small, green caterpillars will commence their prodigious pooping on our deck at the end of April. Some years there are so many of them that the foliage of our maples is almost completely gone by the end of May. The incredible abundance of this moth is a clue to the fact that this species does not really belong here. It is an invasive species that arrived from Europe in the 1930’s, and has since spread across the entire North American continent. And because it does not have too many natural enemies here, it is able to breed in numbers higher than those of many native moths. A closely related, native species, O. bruceata, is rarely seen in similarly high densities.

Female Winter Moth (O. brumata) on the tree trunk of a maple tree in front of our house. [Canon 7D, Canon 100mm macro, speedlight Canon 580EXII]

Winter moths (Operophtera) are not the only moths that come out around this time, and also not the only ones with remarkable morphological differences between males and females. I found another geometrid moth, the Fall Cankerworm Moth (Alsophila pometaria), yesterday on a tree trunk in Estabrook Woods. These animals are even stranger, with females completely devoid of any traces of wings, and resembling a velvet sausage running on long spindly legs.

Although winter moths are not the only insects active at this time of year, and some insects remain active even during freezing weather, their appearance reminds me of two things. First, that the insect season is truly over, and they are the last things to come to the lights of our house until spring. And second, that this Thursday night I will assume the appearance of a winter moth female, stuffed to the breaking point like a sausage, and definitely incapable of flying.

Female Fall Cankerworm Moth (Alsophila pometaria) from Estabrook Woods, MA. [Canon 7D, Canon MP-E 65mm, 3 speedlights Canon 580EXII]

No pockets, no problem

I was walking to my car earlier today and reached into my pocket to get the car keys. While pulling them out I spilled everything that was in it: some change, a couple of business cards, my office keys. And I thought: where did people put these things before the invention of pockets? Of course, these things had not existed before pockets were invented, but it made me recall a day in Guinea when I saw a young fisherman collecting mole crickets for bait. He was catching them, piercing them with a piece of plant fiber, and then weaving the fiber into his hair. Brilliant!

An auditory cyclops

Chinese mantis (Tenodera parasinensis) – notice a narrow, oval opening between its hind legs (click on the photo to enlarge) [Canon 7D, Canon 100mm macro, 3 speedlights Canon 580EXII]

Although these days most of our life is spent in front of devices that cram the world into a convenient, two-dimensional space, the moment when we peel our eyes off the screen brings the realization that we still live in a universe that has a pesky third dimension. Sights, sounds, and smells come to us from all directions, and our sense organs use a number of sophisticated methods to locate their sources. We may not know it, but every second that we are awake our brains are hard at work, performing complicated calculations, triangulating, comparing arrival time differentials, and measuring particle velocity in signals that reach our eyes, ears, and nostrils. This usually helps us avoid walking into a lamppost, jump away from a barking dog, and know that the smelt-ee is not always the delt-ee. But in order to capture the distance and  directionality of a signal, we need at least two sensors separated from each other, and this is the reason why virtually all animals have at least two eyes, two nose holes (or a forked tongue), and two ears. Virtually all animals, but not all – some have only one ear.

The single ear between the hind (metathoracic) legs of a Chinese mantis [Canon 7D, Canon 100mm macro, 3 speedlights Canon 580EXII]

It is quite reasonable to ask what good would a single ear do: sure, you will hear the noise of a roaring lion at night, but you will not be able to tell where the animal is. Hearing the noise getting louder, but not having the information about its location, you are as likely to run towards it as away from it, and natural selection has made sure that such confused individuals don’t get to pass their genes onto the next generation. And yet one animal, the wonderful praying mantis, somehow manages to go through life with a single, cyclopean ear.

For the longest time nobody realized that mantids can hear at all. Scientists had poked and prodded their bodies for hundreds of years, and nobody found anything that resembled the typical, paired organs that are used by animals to detect sound waves. It wasn’t until 1986, when David Yager and Ronald Hoy jammed a metal probe directly into the nervous system of a praying mantis and discovered, by measuring nerve cell activity, that these animals were amazingly good at perceiving certain sound frequencies. Only then did they figure out that the mysterious hole between the last pair of a mantis’ legs is an ear – a single one.

Subsequent experiments confirmed the long-standing principle of hearing – despite its sensitivity, the mantids’ single ear was no good for detecting the direction of sound. Why have it then? The clue comes from the range of frequencies their ear is attuned to. They are the same frequencies, ultrasounds between 25 and 100 kHz, that bats use to locate their flying prey. Mantids, it turns out, can hear bats hunting in the air. Many mantids are good fliers, and males will often fly at night, following pheromonal trails emitted by the females. But mantids are not nearly as fast and skillful in the air as are bats, and in trying to fly away from a bat they would invariably end up in becoming its meal. From the survival point of view, it makes far more sense to simply dive bomb to the ground the moment a hunting bat is detected, and disappear into the grass or bushes. And for this to do a mantis does not need to know where the bat is, all it needs to know is that the bat is out there.

Additional confirmation of the role of the mantids’ single ear comes from the sexual dimorphism in the ear development. In many mantids it is only the male who flies, and in these species females have strongly reduced ears, or none at all. Ears are also absent in wingless and flightless species of mantids.

Leaf mantis (Choeradodis rhombicollis) in flight (Costa Rica) [Canon 10D, Canon 100mm macro, 2 speedlights Canon 580E + MT-24EX twin light]

Solifugids – arachnid teddybears (with big teeth)

The body of a solifugid is covered with long hairs. These are sense organs, capable of detecting the tiniest changes in the temperature, humidity, or air movement (South Africa) [Canon 5D, Canon 100mm, speedlight Canon 580EX + Canon MT-24EX twin light]

Like everybody else, I have a soft spot for things that are fuzzy and look at me with expressive, big eyes. But of course being furry and having eyes isn’t necessarily equivalent to being cuddly, as I learned during a painful lesson delivered to me once by a silky anteater, whom I had foolishly picked up from a branch in Costa Rica – turns out that its claws were not only good for ripping termite mounds open, they also worked great on human skin. And so when I saw my first solifugid, arguably the hairiest of all arachnids, it wasn’t too difficult to resist the temptation to pet it and snuggle against my cheek. In retrospect, probably a good decision.

The “head”, or propeltidium, of a solifugid is a giant ball of muscles that power their huge chelicarea, and the first pair of “legs” (pedipals) are usually held in the air, sensing for prey and danger. (Mozambique) [Canon 7D, Canon 100mm macro, 3 speedlights Canon 580EXII]

Solifugids (Solifugae) are the arachnid equivalent of a honey badger, the tireless, famously cantankerous African mammal. Like the badger, they are lonesome, opportunistic predators, constantly on the run, looking for something, anything, to sink their jaws in. They are big and they are fast. Really, really fast. Most are nocturnal and hate being exposed to the light (hence their name, Solifugae, Latin for “fleeing from the sun”.) But some are active in the middle of the day, although still preferring to stay in the shade as much as possible. This, of course, sometimes leads to comical misunderstandings – when you see a giant, hairy arachnid chasing you in the desert (and I can attest to the fact that it does happen!), be assured that it is after your shadow, not you per se. Just let it curl up against your leg, and all will be fine.

Solifugids are efficient hunters, capable of overpowering very large prey. Before swallowing their food they must macerate it very well, using a “cheliceral mill.” [Canon 5D, Canon 100mm, Canon MT-24EX twin light]

Solifugids are found across the globe, mostly in hot, dry environments (curiously, they are absent from both Australia and Madagascar.) A handful of species live on the verges of wet, tropical forests, but these are rare (in all my years of working Costa Rica I have only seen one solifugid.) Little is known about the physiology of these animals, but they appear to be extremely tolerant of wide temperature changes, from near freezing to over 50°C (122°F), which is an adaptation to the daily temperature changes in the desert environment. At the same time, a solifugid may drop dead the moment it is exposed to the sun after being dug out from its burrow, likely indicating that their adjustment to extreme temperatures must be conducted in a gradual fashion.
Unlike spiders, with which they are often confused, solifugids are not venomous. Probably not venomous. Those species that have been studied in detail lack venom glands, but there is some anecdotal evidence of possible envenomation of large prey items by these arachnids. Bites from solifuigids may also cause localized pain and swelling in humans, further indicating injection of toxins or histamines. Regardless, they are efficient killers of insects and other small animals, including frogs and lizards. They pursue their prey relentlessly. I once watched a solifugid going after an insect that hid under a rock, and never before had I been as grateful for being large as at that moment: these animals do not know the meaning of the words “tired” and “give up.”

The evolutionary history of soifugids is murky. Few fossils unequivocally recognized as solifugids exist, but it appears that they may be at least 300 million years old. Their closest relatives are also uncertain, but most arachnologists agree that they are closely related to pseudoscorpions. Among other arachnids they are unmistakable: their chelicerae (“jaws”) are so huge and muscular that it is easy to confuse them with the entire head of the animal. Solifugids are also equipped with strange, mushroom-like organs on the underside of their fourth pair of legs, known as the “racuquet organs” or malleoli. Their function is not entirely clear, but they seem to be extremely sensitive organs of smell, and play a role in both detection of prey and finding a mating partner. Solifugids look as if they had five pairs of legs, but the first pair, the pedipalps, is in fact an element of the mouthparts. At the tip of the pedipals solifugids have unique suctorial organs that, like the suction cups on the arms of an octopus, help them catch and hold their prey.

I like solifugids, I like them very much. But I can understand why some people may be afraid of them. To be completely honest, solifugids are the only animals that I have never caught with my bare hands (and I have caught a lot of animals with my bare hands, vipers and scorpions included.) I know that they cannot really hurt me, even if they are mildly venomous (of which there is no firm evidence), but their gremlinish body and behavior tap right into my primordial fear of the agile and the unknown. Maybe next time I will try to pet one. Maybe.

The underside of solifugids’ last pair of legs carries strange organs known as malleoli. Their exact function is not known, but they appear to be very sensitive scent organs. [Canon 7D, Canon 100mm macro, 3 speedlights Canon 580EXII]