Author: Chris Brown

Out with the old (but on a good note)

/ Chris Brown / 10 Comments

This past March was the warmest on record here in Missouri and that made for some nice opportunities to get out and photograph. That said, my enthusiasm for macro photography has been somewhat tempered since my camera body is getting old and showing some signs that it might be on its last leg. The mere fact that I am still using a camera from 2004 may be your first indication that I am something less than a macro photography perfectionist and this is a reflection of the equipment that I first used when I began shooting macro. I started with Canon manual equipment in the mid-1990’s because I thought this would be the best way to learn photography. My stint with a used, and malfunctioning, Canon AE-1 was thankfully short. It was stolen as I returned from a photography trip to the Chiricahua Mountains, but I still lament that the thief made off with the spent rolls of film from the trip! The experience with the AE-1 pushed me towards higher quality, more professional equipment that would stand up to field conditions better. Next up was the Canon F1 and then the wonderfully solid Canon F1N followed later with the game-changing addition of a power winder. The latter was great since insects typically didn’t wait around for me to manually wind the film, refocus, and shoot. The real challenge though was getting the lighting right. At fist I often times had the camera on a tripod which resulted in too many missed shots, restricted what I could shoot, and it didn’t meet what I later realized was my overall goal of macro photography. What I wanted was to have the ability to take satisfactory macro images while not loading myself down with equipment that would detract from also being able to conduct research or simply observe/enjoy nature without trying to capture it on film. I still have a graveyard of old flashes, brackets, and bracket parts that I employed in various combinations to get suitable lighting though it is now clear that I was never able to get the perfect balance. That changed in 2001 when Canon introduced the new MT-24EX macro twin flash and I bought a 1V body. After testing the new system a minimal amount, I realized that macro photography was now made easy relative to what I had wrestled with over the years prior. I had the complete package—no bulky brackets, no hand holding flashes, more certainty of exposure, and quick field set-up. The twin flash allowed me to fire off just the minimal amount of light to obtain my desired depth of field and the flash had sufficient battery power at the lower flash output settings to essentially shoot consecutively without having to wait for the flash to power-up.

Well, at least I thought I had the perfect setup until Ted MacRae took up macro photography and soon demonstrated that options for continuous improvement exist even for this system.

In 2004 I sadly shelved the 1V body and went digital. I briefly used the Canon 10D, which seemed inadequate for various reasons, but then jumped on the newly released Canon 1D Mark II during that same year. It was more than I wanted to spend but there weren’t many options and the benefits were too much to pass up. Most notably, I was sick of buying film, scanning slides, and most of all my hand ached from cataloguing so many slides, i.e., writing a unique code on each slide prior to archiving it in plastic. The time savings alone made the 1D Mark II price palatable and I hoped that investing in a top notch, newly released body would help it remain relevant for a while. I never looked back.

That brings me to that warm day this past March when I settled in to photograph a toad bug, Gelastocoris oculatus (Heteroptera: Gelastocoridae), along the margin of an intermittent creek in Perry Co., Missouri.  As I mentioned above I felt like I was limping along with my dated 1D Mark II but I couldn’t pass up the opportunity to again photograph an individual of G. oculatus that so superbly blended in with its substrate (Figures 1 and 2).

Figure 1. Gelastocoris oculatus, 3.13.2012, Perry Co., MO

Figure 2. Gelastocoris oculatus, 3.13.2012, Perry Co., MO

As I have mentioned before I like to take multiple shots of a subject to help tell a story (yes, including the obligatory head-on close up that Ted always mentions). One important shot in the series can be a photograph from a distance to: 1) better see the subject in its surroundings which can give more insight into its natural history; 2) offer a more artistic view, or, in this case; 3) to show the effectiveness of its cryptic coloration. The actual close-up is great for detail but only gives the viewer an idea that the subject is similarly colored to its background but only a more distant shot really conveys how well the subject melts into the substrate. In this case, Figure 3 was the next progression towards that shot but I was stopped short that day partly due to my middle son falling in the creek and partly due to the apparent malfunctioning of the camera. As you can see, I wasn’t far enough away from the subject to capture what attracted me to the bug in the first place—how well it mimicked its background. In that sense the picture is disappointing because I didn’t finish the story. But on the other hand, the malfunctioning of the camera combined with its age, made it clear that it was now time for a new camera body. So I put on my best frustrated/disappointed face and presented my case to my wife, Jess. It was an easy sell since Jess is… well… at least 95% supportive of my photography. I’ll discuss the new body and the first images soon.

Figure 3. Gelastocoris oculatus, 3.13.2012, Perry Co., MO

Below are more of the variable faces of G. oculatus that I have come across over the years (Figs. 4 – 8). Gelastocoris oculatus is one of two species of Gelastocoris that we have in North America (Arnett 2000). Gelastocoris oculatus can be found continent-wide however G. rotundatus ranges only in the southwest. I love the origin of the family name which the online Merriam-Webster dictionary mentions is from the Greek “gelastos”+ “koris” which translates to “laughable bug”, no doubt due to its odd appearance. Both species are predators that live along the margins of water. Their predaceous nature is made clear by the appearance of their powerful forlegs clearly specialized for catching and securing prey. As you can see, I do not have a picture of their forlegs so I’ve got a great reason to again get down on their level with the new camera.

Figure 4. Gelastocoris oculatus, 5.23.2010, Perry Co., MO

REFERENCE:

Arnett, R.H. 2000. American Insects: A Handbook for the Insects of America North of Mexico. Boca Raton, Florida: CRC Press.

Copyright © Christopher R. Brown 2012

Of Bots and Warbles

/ Chris Brown / 14 Comments

As an undergraduate at Truman State University during the mid-90’s I was part of a small mammal research group led by Dr. Scott Ellis.  My focus was on flying squirrels, but others in the group studied mice.  There were always opportunities to help my colleagues trap mice, and that is where I first encountered bot flies (Oestridae: Cuterebra spp.).  It was common for the live trapped mice to be infected with bot fly larvae, or bots, developing just under the skin of the host.  You might expect a fly parasite of a mouse to be relatively small but that is not the case with bot flies.  The bots cause a grotesquely large growth (or warble), and Cramer and Cameron (2006) report that a single bot can weigh as much as 5% of the host body weight.  That’s like a 150 lb guy having a 7.5 lb growth!  One unfortunate mouse that comes to mind had a warble on its head which caused its eye to bulge out.  I hate to make light of that poor mouse’s condition, but I distinctly recall that the bulging eye made it look as if it was continually surprised.  That said, Cuterebra fontinella infections are not thought to have a negative impact on white-footed mice, and in fact some studies have found that infected mice actually live longer than their non-infected neighbors (Cramer and Cameron 2006).  This relatively benign relationship between host and parasite is also the case in general with other species of Cuterebra, which is attributed to the long evolutionary history shared between the parasite and a single or very few closely related hosts (Catts 1982).  Negative impact or not, I was glad that I didn’t have to worry about bot flies infecting me, at least while I was in temperate Missouri.  Of course I had heard plenty of stories of humans being parasitized in the tropics by the human-attacking Dermatobia hominis, and they didn’t sound like very pleasant experiences.  My favorite story involved the person that had a bot in their ear that just about drove them crazy because they could hear the bot any time it changed positions.  Actually the Slansky article discusses the more negative interaction between D. hominis and its host, and this has been attributed to the less specialized relationship between the parasite and any one host because D. hominis has a broad range of hosts. 

Dermatobia hominis actually employ another insect to deliver its eggs to the host!  They lay eggs on mosquitoes or other blood-feeding Diptera for subsequent transfer to the host.  This makes a lot of sense from my point of view as a potential host—the adults are huge (bumble bee size), and I sure would be wary of one approaching me.  But mosquitoes, now there’s an idea—they are very adept at finding their hosts and are inconspicuous enough that they just might be able to get in close enough to allow the body heat of the host to stimulate the hatching and deposition of a bot.

There are other species of Cuterebra, and each is host specific to some degree.  Cuterebra abdominalis (Fig. 1) and Cuterebra buccata are both specific to lagomorphs (rabbits).  No doubt male tree squirrels and chipmunks get a little nervous every time they hear the species name of their bot fly—“emasculator”.  The species name originated from the observation that the warbles were often located near the genitalia of the squirrels, which prompted the idea, given the impressive size of the warble, that there must be an impact on the reproductive ability of the afflicted squirrels.  Luckily for the squirrels, research has demonstrated that the species name is a misnomer (Catts 1982).

Figure 1. Cuterebra abdominalis, a rabbit bot fly

I knew nothing of the adult Cuterebra at the time I saw the parasitized mice, but that changed when Ted MacRae netted an adult rabbit bot fly, Cuterebra buccata, while we were looking for tiger beetles in northeastern Missouri.  In May of 2006, my wife Jess and I came across an adult C. abdominalis on the edge of a glade at Shaw Nature Reserve near St. Louis, and it is this photo that I discuss more below (Fig. 1).  The only other encounter was from southeastern Missouri in April of 2009 when Ted again found a rabbit bot fly, and this individual had only recently emerged from its puparium (Figs. 2 and 3– See Ted MacRae’s previous post from 2009 on this exact same fly).  All told, that’s only three encounters with adult bot flies from countless hours spent in the field, so my experience is that adult bot flies are rarely encountered.

Figure 2. Newly emerged rabbit bot fly, Cuterebra buccata

Figure 3. Newly emerged C. buccata with shed puparium



The image in Figure 1 represents well the type of photographic opportunity that I look for because it readily leads into various side stories.  Here are some examples: 

1) Amazing natural history—you just can’t make this stuff up.  The Catts review article cited discusses numerous other aspects of bot fly natural history in addition to the discussion above.  For example:

  1. Cuterebra spp. are thought to oviposit in the host habitat where the eggs await close passage of a host.  As with the D. hominis, the body heat of the host stimulates the eggs to hatch. The first instar larvae enter the host through an existing orifice or wound and then travel through the host to find a suitable subcutaneous location to create a warble.  Here, the larva molts to the second instar and continues to draw nourishment from the host.  Cuterebra larvae feed on fluids of the host as opposed to feeding on actual tissue, which would be more damaging to the host.
  2. The larvae spend roughly one month in the host.  Upon completion of the third instar, the larva exits the host, digs into the soil, and pupates.  Bot flies overwinter as pupae.
  3. Adults do not feed and are relatively short-lived.  Their attention is focused on the serious business of reproduction. 

2) Mimicry.  As you can see from the image, C. abdominalis very much resembles a bumble bee.  This image is great for presentations because it captures the attention of grade school kids.  I include this image at the end of a series of slides containing images of bees and wasps alongside the flies that mimic them.  Kids become very engaged and have a lot of fun trying to guess which images represent the models and which represent the mimics.  By the end of the series the kids have become pretty savvy about picking out the imposters but I present this image last and C. abdominalis is so bizarre that it always stumps the audience.  The kids become even more captivated by the discussion of how bot flies make a living.

3) Insect photography technique.  It’s thrilling to find new insects, but the experience can quickly turn disappointing if the insect flies off never to be seen again just as you begin to approach it for a photograph. That would have been the case with my encounter with C. abdominalis if I didn’t have a companion with me in the field.  I was lucky to have my wife, Jess, with me on this hike.  She kept an eye on the fly as I moved in for pictures.  Once or twice it flew at my approach, and Jess was able to keep track of it so I could try again.  Ted and I have also acted as spotters for one another, and this has made the difference between getting the pic or not.

4) Great location.  We encountered C. abdominalis on the edge of the scenic glade that slopes away from the Trail House at Shaw Nature Reserve in Franklin County, Missouri.  It’s always fun to revisit certain places and get to know them and the photographic opportunities they provide.  The Nature Reserve is one such place for me.  It offers countless opportunities for insect photography close to St. Louis due to a wide variety of habitats including prairie, glade, forest, wetland, and riparian areas. 

REFERENCES:

Catts E. 1982. Biology of New World bot flies: Cuterebridae. Annual Review of Entomology 27:313–338.

Cramer J. and G. Cameron. 2006. Effects of bot fly (Cuterebra fontinella) parasitism on a population of white-footed mice (Peromyscus leucopus). Journal of Mammalogy 86:1103–1111.

Slansky, F. 2007. Insect/mammal associations: Effects of cuterebrid bot fly parasites on their hosts. Annual Review of Entomology 52:17–36.

Copyright © Christopher R. Brown 2012

A Modest Model for Mimicry

/ Chris Brown / 19 Comments

Spring is still a long way off but it’s times like these that I draw on past experiences so I can continue to be thrilled by insect natural history even during the coldest of months.  In this case I am thinking back seven years ago to my first encounter with a warty leaf beetle.  These beetles are certainly unremarkable for their size or coloration but the “set-up” shot below attempts to illustrate what is amazing about warty leaf beetles.  Can you pick out the single individual warty leaf beetle (Exema sp.) among caterpillar frass (aka caterpillar poop)? 

Figure 1. Set-up shot with Exema sp. and caterpillar frass

If you had trouble finding the beetle in the above image then check out the next image and you’ll see the beetle has “sprouted” a head, legs, and antennae.

Figure 2. Set-up shot with Exema sp. and caterpillar frass

I don’t know what caught my eye the first time I encountered a warty leaf beetle on the foliage of a small shingle oak while exploring a woodland edge in Perry Co., MO.  It probably helped that it was one of the larger species of the genus Neochlamisus but it still only measured about 3-4 mm.  One thing I do remember about the encounter, though, is that there was something about it that made me do a double take.  My first thought was exactly what the beetle might have hoped, that it was caterpillar frass.  But this frass had legs (Figs. 3 and 4)!  I was at first incredulous but soon became enthralled as I beheld something that I had never noted while flipping through field guides.  I had once again stumbled across something that I would never have imagined—a beetle that mimics caterpillar poop!

Figure 3. Neochlamisus sp. on shingle oak

Figure 4. Neochlamisus from the perspective of a short distance away

The beetles in the tribe Chlamasini were apparently not at the table the day decisions were made on what model they would mimic.  These guys at best mimic small bits of debris but are dead ringers for the frass of lepidopteran larvae (i.e., caterpillars).  Then as if to add insult to injury, we dubbed the tribe the warty leaf beetles!  The Chlamasini may humbly mimic excreta but what they lack in a flashy model they make up for with absolutely superb mimicry.  The Chlamasini are remarkably similar to the frass of lepidopteran larvae in size, shape, texture, and color but the aspect that really completes the mimicry is that, upon disturbance, the head is retracted and the legs and antennae are neatly folded into precisely matched grooves leaving no indication that this was once a beetle (Figs. 5 and 6).  Even the finer details of coloration were not overlooked as some warty leaf beetle species are variably colored, including an almost metallic sheen in some places that closely resembles the coloration of some caterpillar frass.  In fact the mimicry of warty leaf beetles is so convincing that I recently dropped a piece of suspect frass in a vial in hopes that it might sprout legs and represent a new species of warty leaf beetle for me.

Figure 5. Exema sp. with appendages extended

Figure 6. Exema sp. with appendages retracted

If the disturbance is sufficient to cause the beetle to completely retract these appendages, they will likely roll off the leaf and fall out of harms way.  Though these beetles can be relatively common, occurring even in my suburban St. Louis yard, the small size [Exema is only 2-3 mm (Figs. 7 and 8) while Neochlamisus is slightly larger at 3-4 mm] and resemblance to something unremarkable ensures that these beetles often times go unnoticed.  When I have happened to notice these beetles I found Neochlamisus associated with shingle oak, Quercus imbricaria, and Exema associated with Asteraceae, including gray-headed coneflower, Ratibida pinnata, and sweet coneflower, Rudbeckia subtomentosa.

Figure 7. Exema sp. on sweet coneflower, Rudbeckia subtomentosa

Figure 8. Exema sp. ready for flight

The Chlamasini are in the subfamily Cryptocephalinae within the leaf beetle family (Chrysomelidae).  The Chlamisini can be found worldwide but are most diverse in the Neotropics.   We have 6 genera in North America, two of which are shown here.  Interestingly, the excreta theme doesn’t stop at frass-mimicry.  Like other members of Crytocephalinae, warty leaf beetle larvae are “case-bearing”; that is they are housed in a case which in this instance is made out of… you guessed it, their own feces (Fig. 9).  You would think that most moms would frown on such a practices but mothers in the Cryptocephalinae actually instigate the practice when they equip each egg laid with a cap of feces that serves as starting material for the case and likely also serves to dissuade would be predators.

Figure 9. Chlamasini larva, likely that of Exema sp. on sweet coneflower, Rudbeckia subtomentosa

My experiences with Neoclamisus seven years ago captures perfectly why I am so drawn to explore for insects— there is always something new to find and every once in a while something comes out of the wood work that is beyond what I could have imagined.

REFERENCE:

Lourdes Chamorro-Lacayo, M. & A. Konstantinov. 2009. Synopsis of warty leaf beetle genera of the world (Coleoptera, Chrysomelidae, Cryptocephalinae, Chlamisini). ZooKeys 8:63–88.

Copyright © Chris Brown 2012