Archives

Mozambique Diary: The Cat mantis

I decided to christen this impressive praying mantis (Heterochaeta orientalis) the Cat mantis, on the account of its head morphology, but even its defensive behavior reminds me of a cranky cat (is there any other kind?).

I decided to christen this impressive praying mantis (Heterochaeta orientalis) the Cat mantis, on the account of its head morphology, but even its defensive behavior reminds me of a cranky cat. (Is there any other kind?)

Arriving in Gorongosa National Park in Mozambique at this time of the year, when the grasslands are bone dry and green has all but disappeared from the color palette of this immense ecosystem, I did not expect to see too many insects. Sure, there will always be ants and a bunch of grasshoppers, but the bulk of the insect fauna pretty much disappears until the onset of rains in November. The nights are quite cold when the atmosphere is devoid of the buffering layer of humidity and consequently few insects are active around the lights of the camp. But those that do come are often stunning. Some of the first animals that I spotted when I resumed my nightly patrols around the lights of the Chitengo camp were huge praying mantids Heterochaeta orientalis, whose head morphology immediately brought to my mind a scrawny, long-eared house cat, and that’s what I decided to call them. The Cat mantids are probably some of the largest in Africa, with the females’ body length approaching 20 cm. Males are about 15 cm long, which still makes for an imposing insect.

Despite his huge size, a Cat mantis (Heterochaeta orientalis) is virtually impossible to spot in its natural setting of bare branches in the woodland savanna of Gorongosa.

Despite his huge size, a Cat mantis is virtually impossible to spot in its natural setting of bare branches in the dry woodland savanna of Gorongosa.

Little is known about this species’ biology. I have always found Heterochaeta on tall shrubs and bushes in the woodland savanna, albeit finding them is definitely not easy – despite their size they are some of the most cryptic insects of Gorongosa. It is enough to take your eyes off an individual sitting on a branch for a few seconds to completely lose sense of its whereabouts. When resting on a branch these insects hold their long raptorial legs outstretched to the sides in an uncanny resemblance of two dead twigs coming off a larger branch, very unlike the typical “praying” stance of other mantids, who tend to hold their raptorial legs neatly folded under the pronotum. The pointy protuberances on the Cat mantis’ eyes enhance the illusion that this animal is just a dead, spiky stick. Clearly, their main defense mechanism is to remain undetected by either predator or prey.

While resting on a branch the Cat mantis keeps its forelegs outstretched to the side, enhancing the illusion of being just another dead stick.

While resting on a branch the Cat mantis keeps its forelegs outstretched to the side, enhancing the illusion of being just another dead stick.

But in addition to its superb crypsis the Cat mantis has another trick up its sleeve when it comes to avoiding being eaten. When I first tried to pick up one of the individuals that came to the light, it immediately responded by rearing up its body, opening the front legs to reveal a bright patch on the underside, and fanning its wings to flash a beautiful, contrastingly yellow and black pattern. This color combination signifies danger (think wasps and their stingers) and many potential predators may pause before attacking the Cat mantis, giving it time to fly away. The mantis is bluffing, of course, as other than a very weak pinch it can deliver with its long forelegs it does not have any real weapons or chemical defenses.

When cornered the Cat mantis rears up to make itself look bigger and flashes beautifully yellow and black hind wings that normally lie hidden under the cryptically colored front wings.

When cornered the Cat mantis rears up to make itself look bigger and flashes beautifully yellow and black hind wings that normally lie hidden under the cryptically colored front wings.

Ever since I first came to Mozambique I have been marveling at the praying mantis fauna of Gorongosa, which is the richest that I have seen anywhere in the world. My species list is approaching 50, but the actual number is almost certainly greater. Their abundance is also exceptionally high, and it is not rare for me to get 5-10 individuals of praying mantids in a single sweep of an insect net across the tall grassland. What drives this richness is something that I am interested in understanding, but it may be related to an equally high abundance of orthopteroid insects, the main prey item of many mantids.

A male Cat mantis at sunset.

A male Cat mantis at sunset.

Mozambique Diary: The stuff of dreams

Banded-legged golden orb weaver (Nephila senegalensis) from Gorongosa [Canon 7D, Canon 14mm, Canon MT 24EX twin light]

Banded-legged golden orb weaver (Nephila senegalensis) from Gorongosa [Canon 7D, Canon 14mm, Canon MT 24EX twin light]

Isn’t it fascinating that the same thing can be the subject of one person’s worst nightmares, and another person’s wildest dreams and desires? Nothing illustrates this point better than the Golden orb spiders (Nephila), which my wife doesn’t even call spiders – they are simply her Nemesis, clearly intent on luring her into their enormous webs and tangling themselves into her hair.

But today I had the pleasure of going into the field with two great arachnologists, Matjaž Kuntner and Ingi Agnarsson, who came to Mozambique with one dream and one dream only – to see and catch the largest orb weaving spider in the world, Nephila komaci. This species was discovered by Matjaž a few years ago among old museum specimens, but nobody has seen a live individual since. But there is an interesting twist to this story – the reason Matjaž and Ingi chose Gorongosa to look for this Holy Grail of arachnology was a small photo, a thumbnail really, of N. komaci that had appeared on the old Gorongosa’s website five years ago, two years before the species was officially described. We didn’t know where exactly the photo had been taken, but it had to be somewhere in the park.

We set out early in the morning to look for the elusive weaver, hoping that we might find it in the patches of sand forest in the southern part of the park. Alas, after several ours of trampling through the bush we came back empty handed, not in small part because of some confusion as to where the forest was, which made us end up miles away from our intended destination. But playing bait for lions for several hours this morning was not a complete loss, either. The spider men found a few interesting species, including a related species, the Banded-legged golden orb weaver (Nephila senegalensis). These are gorgeous beasts, huge and beautifully colored. Their orbs are often made of brightly yellow silk, hence the common name. A few years ago Simon Peers and Nicholas Godley used the silk of a related species from Madagascar to weave an extraordinary golden cape.

Tomorrow Matjaž and Ingi will continue their search, this time with a GPS and an even stronger desire to lay their hands on the dreamy arachnid.

Getting low and wide – Part 2

Costa Rican dragonfly (Gynacantha tibiata) drying off its wings after the rain. Taken with a Canon 16-35mm lens with an added extension tube Canon EF 12 II; lighting was provided by a twin flash Canon MT-24EX.

Costa Rican dragonfly (Gynacantha tibiata) drying off its wings after the rain. Taken with a Canon 16-35mm lens with an added extension tube Canon EF 12 II; lighting was provided by a twin flash Canon MT-24EX.

A few days ago I posted the first part of an introduction to wide-angle macrophotography, and here is the conclusion.

Illumination. In order for the illusion that you are a lilliput looking at the giant world to work, the background of a wide-angle macro shot should be well and evenly lit, and the frontmost, focal element of the photo should not be in the shade. One of the most difficult problems to overcome in wide-angle macrophotography is proper illumination of the subject right in front of the lens, which may be just millimeters away. This includes trying to avoid casting a shadow on it. There is not one, simple solution to this problem, and the type of lighting to use will depend on the distance from the lens, time of day, angle of the sun, brightness of the background, reflectance of the subject etc.

In order to get a sharp photo of this Clusia grandiflora flower on the dark, shady forest floor in Suriname I filled a small Ziplock bag with soil and leaves, and used it as a beanbag. This 1 second exposure was taken with a Canon EF 14mm on Canon 7D, illuminated with twin flashes Canon MT-24EX.

In order to get a sharp photo of this Clusia grandiflora flower on the dark, shady forest floor in Suriname I filled a small Ziplock bag with soil and leaves, and used it as a beanbag. This 1 second exposure was taken with a Canon EF 14mm on Canon 7D, illuminated with twin flashes Canon MT-24EX.

What works for me in many cases is a single, remote flash in a softbox (Canon 580EXII in a Photoflex LiteDome XS, either wireless or attached with a Camera Shoe Cord). Because of the proximity of the subject to the lens, a flash mounted directly on top of the camera will not work, as it will cause the shadow of the lens to fall right in front of it. If the subject is not moving (e.g., a flower, an insect sitting motionlessly), and the sun is not directly behind my back, I use a collapsible golden or silver reflector to bounce ambient light at the subject. I also use custom made brackets to mount a pair of small, twin flashes (Canon MT-24EX) about 20 cm away from the front of the lens, which are then diffused with wide pieces of thin, white plastic (made of a cheap plastic folder bought at Staples.) I have also had good experience using inexpensive, flexible brackets DMM-901 (I am not sure who makes these, but they can be ordered here.)

Stabilization. The illumination and sharpness of the background is what often makes or breaks a wide-angle macro photograph. Since it would be difficult to rely entirely on flashes to evenly light the background in a shot that encompasses a part of the landscape, most wide-angle macro photos will require long, often 0.1-2 sec exposures. For this reason a large proportion of my wide-angle photography is made from a tripod. I use a Gitzo GT2531EX, which is light, very sturdy, and allows me to position the camera in any way I want – from close to the ground to 177 cm high. But even a higher number of my photos are taken with the camera resting either on a “beanbag” (in most cases simply a Ziplock bag filled with sand or soil) or directly on the ground. Sometimes, when I am trying to get a really low angle for a subject on the ground, I quickly dig a little hole, place a plastic bag at the bottom (to keep the camera dry), and position the camera in it. In this way the lens is exactly at the level of the ground, or even slightly below it.

Wide-angle macrophotography usually requires long exposures, and thus capturing fast-moving animals is difficult. Here, mammalogist Burton Lim is processing bats collected in Suriname, while small stingless bees are gorging on cornmeal that he uses to dry his specimens. I was able to freeze the action and partially expose the background using twin flashes Canon MT-24EX, and Canon EF 14mm mounted on Canon 7D.

Wide-angle macrophotography usually requires long exposures, and thus capturing fast-moving animals is difficult. Here, mammalogist Burton Lim is processing bats collected in Suriname, while small stingless bees are gorging on cornmeal that he uses to dry his specimens. I was able to freeze the action and partially expose the background using twin flashes Canon MT-24EX, and Canon EF 14mm mounted on Canon 7D.

A stag beetle (Cyclommatus eximius) from the highlands of New Britain, Papua New Guinea. Here I used a Canon 16-35mm with an extension tube, mounted on a full-frame camera Canon 1Ds MkII.

A stag beetle (Cyclommatus eximius) from the highlands of New Britain, Papua New Guinea. Here I used a Canon 16-35mm with an extension tube, mounted on a full-frame camera Canon 1Ds MkII.

For wide-angle photography high in the trees or in situations where a regular tripod or a beanbag cannot be used, I rely on a Gorillapod flexible tripod, which can be wrapped around a branch, providing pretty secure stabilization.
One critically important piece of equipment in wide-angle macro is a remote shutter release, which reduces the chances of vibration caused by pressing the shutter. Recently I have started using a Vello ShutterBoss Timer Remote, which is both less expensive and more functional than the original Canon one.

Camera selection. To say that within the last 10 years the quality of digital cameras has grown exponentially is of course a truism. My cell phone’s camera has twice the resolution and much better low light performance than my first, $5,000 digital SLR (Nikon D1x). You can now walk into a Walmart, and for $399 get an SLR capable of taking photos that were virtually impossible 20 years ago. The latest “pro-sumer” bodies are capable of taking shots in near darkness, and the high ISO performance of almost all SLRs is bound to make you wonder why anybody still uses ISO lower than 400. My point is that cameras have become so sophisticated that no matter which one you chose, the images taken with it can be outstanding. Nonetheless, in wide-angle macrophotography the choice of the right SLR body matters. (I should mention that many point-and-shoot cameras can be a great choice for wide-angle macrophotography, but my experience with them is limited.)

Even in extreme wide-angle closeups, flash illumination is not always required. This molting grasshopper in Suriname was photographed using only ambient light with a hand-held Canon 7D camera and Canon 14mm lens.

Even in extreme wide-angle closeups, flash illumination is not always required. This molting grasshopper in Suriname was photographed using only ambient light with a hand-held Canon 7D camera and Canon 14mm lens.

It may seem counterintuitive that, although you will be using wide-angle lenses, the best cameras for wide-angle macro are not those with a full-frame sensor (35mm equivalent), but rather those with a smaller one. Such cameras give the illusion of producing an image that is magnified, usually by a factor of 1.3-1.6, compared to a full-frame sensor, but in fact the image is simply cropped. Why then buy a wide-angle lens if 30-60% of its coverage is going to be cropped by the small sensor? This is because the shorter (wider) the lens the more likely it is to introduce distortion and chromatic aberration at the edges of the frame, and these faults become more pronounced at close focal ranges, and even more so when the lens is mounted on an extension tube. By using a camera with a sensor smaller than full-frame, you are tapping into the “sweet spot” of the lens – the image captured by the sensor uses mostly the central, sharpest and least distorted portion of the lens, while still retaining the wide-angle perspective (albeit with a smaller coverage.) And of course a camera with a smaller (higher crop) sensor will help you magnify the small, central subject of the photo.

Custom flash brackets that I use in most of my wide-angle macrophotography. They are designed to be mounted directly on the front of the lens, and fit lenses with the diameter of 58-82mm.

Custom flash brackets that I use in most of my wide-angle macrophotography. They are designed to be mounted directly on the front of the lens, and fit lenses with the diameter of 58-82mm.

My favorite camera for wide-angle macro is Canon 7D, which has the cropping factor of 1.6; occasionally I also use Canon 1D MkII, with the cropping factor of 1.3. The only time when I use a full-frame body is when I shoot with a Canon 16-35mm with an extension tube – this is because animals larger than 40 mm or so fill up the frame, and block the background if a camera with the sensor smaller than full-frame is used.

I hope that this brief overview of my approach to wide-angle macrophotography was helpful, and will encourage you to try and perfect your own methods. As with any other photographic techniques, practice makes masters, and no amount of theoretical information will ever replace simply going into the field and chasing critters with your lens. And if you have any specific questions, comments, or suggestions, leave them in the comments below or drop me a line.

A cluster of mushrooms (possibly Hygrocybe sp.) in a New England forest. [Canon 1D MkII, Sigma 15mm, ambient light]

A cluster of mushrooms (possibly Hygrocybe sp.) in a New England forest. [Canon 1D MkII, Sigma 15mm, ambient light]