predator avoidance

BitB Best of 2009

/ Ted C. MacRae / 22 Comments

In my first post of 2009, I looked back at the photographs I had posted during 2008 and picked some of my personal favorites. I hesitated then to call myself a photographer (and still do), but I at least now have suitable equipment to aid in my progress toward that eventual goal. I have learned much over the past six months in my first attempt at serious insect macrophotography (prioritizing in situ field photographs of unmanipulated subjects as a matter of personal choice).  Through this, I’ve come to realize the following skills to be the most important for success:  

  1. Composition
  2. Understanding lighting
  3. Knowing how to use a flash
  4. Knowledge of the subject

I’ll give myself a “A” in the last of these, but in the other areas I still have much to learn. With this caveat, and for the last post of 2009, I offer the following twelve photographs as my final choices for the 2nd Annual “Best of BitB”:  

Best beetle

Cylindera celeripes (swift tiger beetle), Woodward Co., Oklahoma

From Revisiting the Swift Tiger Beetle – Part 1 (June 30).  A decent enough photograph, especially considering that I’d had my camera for about a month when I took it.  However, the discovery of robust populations of this formerly rare and enigmatic species throughout northwestern Oklahoma (and later also in northwestern Missouri) was the most significant find of the 2009 field season, and this photograph is the best capture of that moment.

Best fly

Stylogaster neglecta, a species of thickheaded fly

From Overlooked, needle-bellied, thick-headed fly (Aug 14).  One of my first good “black background” shots.  The white tip of the abdomen compliments the white flower stamens against the background.

Best “true” bug

Beameria venosa, a prairie obligate cicada

From North America’s smallest cicada (Aug 4).  So many different shades of green with white frosting on the bug’s body.  I tried taking this shot in portrait and it just didn’t work—I liked this landscape shot much better.

Best predator

Promachus hinei (Hines giant robber fly) & Ceratina sp. (small carpenter bee) prey

From Prey bee mine (Sept 14).  Robber flies are immensely photogenic, especially those in the genus Promachus due to their prominent “beards.”

Best camoflauge

Dicerca obscura on bark of dead persimmon

From The “obscure” Dicerca (June 19).  Sparkling and gaudy as specimens in a cabinet, the coloration of many jewel beetles actually helps them blend almost perfectly with the bark of their preferred tree hosts.

Best immature insect

Tetracha floridana (Florida metallic tiger beetle) 3rd-instar larva

From Anatomy of a Tiger Beetle Larva (Oct 22).  “Otherwordly” is invariably the first word that comes to mind when someone sees a tiger beetle larva for the first time.  I was lucky enough to get this one in profile with a nice view of its abdominal hump and its curious hooks.

Best arachnid

Centruroides vittatus (striped bark scorpion)

From A face only a mother could love (Oct 6).  Despite some minor depth-of-field problems with this photograph, I’m fascinated by its “smile.”

Best reptile

Eastern collared lizard (Crotaphytus collaris collaris) adult male

From North America’s most beautiful lizard (July 10).  A simply spectacular lizard—all I had to do was frame it well and get the flash right.

Best wildflower

Spiranthes magnicamporum (Great Plains ladies

From Great Plains Ladies’-tresses (Dec 7).  Few flowers are as photogenic as orchids, even native terrestrials with minute flowers such as this one.  I like the frosty texture of the lip and the starkness of the white flower on the black background.

Best natural history moment

Thermoregulatory behavior by Ellipsoptera hirtilabris (moustached tiger beetle)

From Tiger Beetles Agree—It’s Hot in Florida! (Dec 18). I chose this photo for the classic “stilting” and “sun-facing” thermoregulatory behaviors exhibited by this tiger beetle on a blistering hot day in Florida.

Best closeup

Megaphasma denticrus (giant walkingstick)

From North America’s longest insect (Aug 21).  I haven’t tried a whole lot of super close-up photographs yet.  I liked the combination of blue and brown colors on the black background.

Best Landscape

Sand Harbor Overlook, Lake Tahoe, Nevada

From Sand Harbor Overlook, Nevada (March 23).   My choice for “best landscape” again comes from Lake Tahoe.  This is not a great photo technically—I was still using a point-and-shoot and had to deal with foreground sun.  However, none of the other photos I took during my March visit to the area captivate me like this one.  I like the mix of colors with the silhouetted appearance of the trees on the point.

Copyright © Ted C. MacRae 2009

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Monday Moth: White-tipped Black Moth

/ Ted C. MacRae / 25 Comments
Melanchroia_chephise_IMG_1241_1200x800_enh

Photo details: Canon 100mm macro lens on Canon 50D (manual mode), ISO-100, 1/250 sec, f/22, MT-24EX flash w/ Sto-Fen diffusers.

When is a ctenuchid moth not a ctenuchid moth?  When it’s a White-tipped Black Moth (Melanchroia chephise) in the family Geometridae!

I may be a beetle guy, but I also consider myself a competent general entomologist.  What is a competent general entomologist?  Someone who can identify any insect to order at first glance and a majority of them to family – regardless of one’s own taxa of expertise.  Thus, when I encountered this mating pair of moths on the outside wall of my sister-in-law’s condominium in Seminole, Florida, I “recognized” them as something in what I learned as the family Ctenuchidae (later subsumed within the Arctiidae, first as a subfamily and now as several disparate tribes).  They had all the hallmarks of ctenuchids—black and red coloration, narrowish wings with light colored patches, and about the size of the wasps that they presumably mimic.  Upon my return to St. Louis, I sat down to identify the moths—confident that their distinctive appearance would lead to the quick ID that never materialized after scanning through all of the ctenuchine pages at BugGuide.  Frustrated, I resorted to posting the photo on the site’s ID Request, never questioning my ctenuchine placement.  Precisely 4 minutes later, the moths were identified by John Maxwell as Melanchroia chephise and moved to their proper place—among the 50 other adult photographs of this species that can be found on the site!  I might as well have failed to identify a monarch butterfly!

Melanchroia chephise is apparently common in the American tropics, reaching its northern distributional limit along the coastal plains of Florida and Texas but straying further north in certain years.  Larvae feed on several plants in the family Euphorbiaceae, primarily Breynia and Phyllanthus species.  The adult coloration strikes me as obviously aposematic (warning coloration), but I could find no specific references to this.  However, considering that euphorbiaceous plants are famous for their diverse arsenal of latex and irritant toxins (e.g., diterpene esters, alkaloids, glycosides, ricin-type protein toxins, etc.), it seems reasonable to presume that Melanchroia larvae have evolved mechanisms for sequestering one or more of these compounds.  NABA South Texas states that adults of this species are probably mimics of the Red-bordered Pixie (Melanis pixe), an aposematic metalmark butterfly also of Neotropical distribution that reaches south Texas (but not Florida).  Personally, I don’t really see the resemblance (but then, nor am I an avian predator).  I suppose it’s possible that a species such as this can employ different defense strategies in different parts of its range, relying on Batesian mimicry in areas where suitable models occur and aposematism in areas where they don’t, but I have to admit that I’m now straying well outside the coleopteran-centric bounds of my expertise.

Copyright © Ted C. MacRae 2009

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North America’s smallest rattlesnake

/ Ted C. MacRae / 24 Comments

Despite tramping through the brush with great frequency during most of my life, I haven’t really seen that many noteworthy reptiles.  I don’t know whether its because I’ve failed to actually encounter them or whether my singleminded obsession with insects above all other things natural has instead prevented me from seeing what was right in front of me.  Regardless of the reason, all that has seemed to change during the past two seasons (strangely coincident with my decision to start carrying a camera), and I now seem to be enjoying a bit of a reptile bonanza.  Last summer I featured a super-aggressive prairie rattlesnake from a trip to the Black Hills of South Dakota and an uncooperative dusty hognosed snake from Missouri’s critically imperiled sand prairies (both first-time sightings for me).  The reptilian treats continued this year – I saw my first juvenile Osage copperhead in May to go along with the several adults that I’ve encountered, and shortly afterwards during a June trip to northwestern Oklahoma I was treated to a gorgeous male eastern collard lizard, two Texas horned lizards, and a much more cooperative western hognosed snake (the last two being first-time sightings for me).  There was another herp that I saw during that Oklahoma trip, but I did not feature it here because I had stupidly declined to strap the camera bag to my back during a quick look at a roadside habitat.  That sighting was another first-timer for me – a western pygmy rattlesnake (Sistrurus miliaris streckeri).  I’m no herp expert, so wasn’t sure what it was at the time, but I later learned that its small size and distinctive markings were quite diagnostic.

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Western pygmy rattlesnake – Sistrurus miliarius streckeri

Amazingly, I encountered this same species again just a few weeks later during a visit to the White River Hills of extreme southwestern Missouri.  It was during the second of two trips to the region to search for the stunningly beautiful bumelia longhorned beetle, Plinthocoelium suaveolens plicatum (family Cerambycidae), and the weather during that day – continuous drizzle and low, threatening clouds – had not been at all conducive for finding such a sun loving beetle.  After searching an area where I knew the beetles occurred, without success, daughter Madison and I resigned that the drizzle was here to stay and decided to pass the rest of the day with some hiking at one of Missouri’s most spectacularly wild and beautiful places, Hercules Glades Wilderness.  A splendid mix of post oak savannahs and limestone glades intersperses through the oak/hickory forests in these rugged hills, creating some of Missouri’s most scenic vistas.  Near the end of the hike at the edge of one of these glades on the high point of Coy Bald, I saw this little individual coiled up underneath an eastern red-cedar (Juniperus virginiana) tree.  Unlike the terrifyingly aggressive prairie rattlesnakes I encountered in South Dakota last fall, this snake seem to be relying upon its cryptic coloration to avoid detection, rattling only after I had approached quite closely… or maybe it was only then I could actually hear the rattle, which was barely audible and sounded much like the buzz of a small katydid.

Pygmy rattlesnakes are the smallest rattlesnakes in North America, growing to around 15-25 inches long – this individual looked to be about 18-20 inches in length.  They are one of only two U.S. species in the primitive rattlesnake genus Sistrurus – the other being the larger wet prairie inhabiting massasauga (S. catenatus).  All other rattlesnakes (28 species, 13 in the U.S.) belong to the genus Crotalus (Smith et al. 2001).  Western pygmy rattlesnakes are not really a western U.S. species, but rather the westernmost subspecies of this southeastern U.S. species (with subspecies miliarius and streckeri occupying the northeastern and southeastern portions, respectively, of its range).  In Missouri, it is not nearly as common as the timber rattlesnake (Crotalus horridus), occurring only in the extreme southern Ozarks along the border with Arkansas and up into the St. Francois Mountains of the eastern Ozarks (Johnson 1997).  Although no known human deaths have ever been caused by this species, known locally as the “ground rattler,” it is nevertheless poisonous and worthy of respect.  I must admit to having been lulled a little bit by its calmness – much like the juvenile copperhead I photographed in May – and found myself tempted to approach ever closer for photographs.  The photograph below represents the closest that I was able to get before it began “striking” at me – whether these were bluff strikes intended to frighten or actual attempts to bite I do not know.  Suffice it to say that I “got the message” and ended my attempts to get even closer.  Daughter Madison watched in nervous amazement as all this was going on, and afterwards I tried to impress upon her young, virgin mind what a rare and wonderful experience we’d just had.  Perhaps I succeeded, as this was the first story she told to her head-shaking mother upon our return home the following evening!

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Photo details: Canon 100mm macro lens on Canon EOS 50D, ISO 100, 1/250 sec, f/9-10, MT-24EX flash 1/2 power through diffuser caps.

REFERENCES:

Johnson, T. R. 1997. The Amphibians and Reptiles of Missouri. Missouri Department of Conservation, Jefferson City, 368 pp.

Smith, H. M., E. D. Brodie, D. M. Dennis and S. Barlowe. 2001. Reptiles of North America: A Guide to Field Identification. Golden Field Guide from St. Martin’s Press, New York, 240 pp.

Copyright © Ted C. MacRae 2009

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North America’s longest insect

/ Ted C. MacRae / 26 Comments

This past June might be the most successful month entomologically that I’ve ever had.  The excitement of discovering a robust population of Cylindera celeripes (swift tiger beetle) (previously considered one of North America’s rarest tiger beetles) in northwestern Oklahoma lasted only two weeks before being eclipsed by our long-awaited success at finding this same species also in Missouri.  Icing on the cake was provided by finding Ellipsoptera macra (sandy stream tiger beetle) – the last tiger beetle species we had yet to encounter in Missouri, and significant new records for the tiny prairie cicada, Beameria venosa, and the impressive robber fly, Ospriocerus abdominalis, in Missouri’s critically imperiled loess hilltop prairies.  With that rapid-succession-success, my thoughts immediately turned to another of Missouri’s unique natural communities – the dolomite glades of the White River Hills in the extreme southwestern part of the state.  In fact, I had already been yearning to return to the White River Hills, having last visited some years ago and recalling – from the perspective now as an insect photographer – the many photogenic insect species that I’ve encountered there.  Chief among them is Plinthocoelium suaveolens (bumelia borer), a spectacularly beautiful longhorned beetle of neotropical affinity that must be seen to be believed and which I had observed here several years ago in fair numbers as they perched on the lower trunks of their presumed larval host, Sideroxylon (= Bumelia) lanuginosa of the family Sapotaceae.  I had even mentioned to my colleague Chris Brown, as we began the first day of our planned multi-weekend search for C. celeripes and C. macra in northwestern Missouri, that my dream scenario was that we would find both celeripes and macra on that first weekend, negating the need for additional survey the following weekends, in which case we could shoot down to the White River Hills to look for Plinthocoelium.  Who knew how prescient that comment would be!

Megaphasma denticrus - giant walkingstick

Megaphasma denticrus - giant walkingstick

I won’t keep you in suspense – I succeeded in finding and photographing Plinthocoelium, although (happily) there is more to the story than just that.  I’ll share that experience here soon, but first I want to discuss another insect I saw on the first of my two July visits to the White River Hills – Megaphasma denticrus¹ (giant walkingstick).  As implied by its common name, this walkingstick is enormous – females (typically larger than males) can reach lengths of 150+ mm (that’s 6 inches, folks!), making it officially the longest insect species in all of North America.  IMG_0909_1200x800The female I feature here was solidly in that range, and with her front legs held outstretched in front of her (as pictured above), total length exceeded 8 inches.  Of course, this pales in comparison to a related species from Borneo, individuals of which have been documented measuring more than 18 inches in length!  The giant walkingstick is distributed primarily in the south-central U.S. – especially Texas, although records do exist from as far north and east as Iowa, Wisconsin, and Indiana (Arment 2005). I have encountered this species a few times before – always in the White River Hills, but Arment (2005) also records the species from several other counties in the Ozark Highlands across southern Missouri and Arkansas.  In addition to its great size, both sexes of this species can be distinguished from other walkingsticks by the rows of numerous teeth on the underside of the middle (meso-) femur (easily seen in the enlarged view of Photo 2 above) and by the very long antennae (longer than the front femur).  Color is variable – other individuals I have seen are tan with bright red dorsal stripes on the thoracic segments.

¹ Formerly classified with grasshoppers and their kin in the order Orthoptera, walkingsticks are now placed their own order, Phasmatodea, the name being derived from the Greek phasma (apparition, ghost) in reference to their cryptic appearance and behavior (the alternative spellings Phasmodea and Phasmida are improper formations from the Greek root – see Grimaldi and Engel 2005).  The genus name, Megaphasma, thus means “giant walkingstick.”  The specific epithet, denticrus, is derived from the Latin den (tooth) and crus (leg), presumably a reference to the toothed underside of the mesofemur. Many authors, including even some taxonomists (e.g., Beamer 1932), have mispelled the name as “dentricus” – nonsensical in Latin – with some even using both spellings in the same paper (e.g., Maginnis et al. 2008)!

Of course, an outstanding feature of this species, and all walkingsticks in general, is its uncanny resemblance to sticks and twigs.  This cryptic appearance is further augmented behaviorally by the habit of “swaying” back and forth to simulate movement in a gentle breeze.  I must confess that I did not even notice this large female individual – less than two feet away on a low branch – until she started moving about.  Once spotted, a walkingstick of this size would seem to be a tasty – and defenseless – morsel for some avian predator; however, they have another defensive tactic up their sleeve – autotomy (i.e., the ability to shed appendages in response to predatory attack). IMG_0913_1200x800While it may seem that their long, delicate-looking legs are simply “pulled off” by the predator, fortuitously allowing the walkingstick to clamber to safety, leg shed is actually controlled by the central nervous system in response to external stimuli (e.g., grabbing of the leg).  Breakage occurs at predetermined abcission points, which are rapidly sealed after shedding to prevent excessive loss of body fluids.  I experienced this first hand – lacking any container large enough to hold the enormous female, I gently placed her into my net and gingerly carried her back to the truck, only to find a hind leg already shed by the time I got back.  I decided the effort to glue one (or more) legs in place to acheive a well-curated specimen exceeded my interest in starting a collection of this particular group of insects, so I let her go.  Presumably she crawled away to safety, though sadly no longer the ‘perfect’ specimen that I first encountered.

Photo details:
Photo 1 (full insect): Canon 100mm macro lens on Canon EOS 50D (auto mode), ISO 200, 1/320 sec, f/5.6, natural light.
Photos 2 (midrange) and 3 (closeup): same except (manual mode), ISO 100, 1/60 (Photo 2) or 1/250 (Photo 3) sec, f/10 (Photo 2) or f/20 (Photo 3), MT-24EX flash 1/4 power w/ diffuser caps.

REFERENCES:

Arment, C. 2005. Stick Insects of the Continental United States and Canada: Species and Early Studies. Coachwhip Publications, Landisville, Pennsylvania, 202 pp.

Beamer, R. H. 1932. The giant walking-stick (Megaphasma dentricus (Stal.)) found in Kansas. Journal of the Kansas Entomological Society 5(1):28.

Grimaldi, D. and M. S. Engel. 2005. Evolution of the Insects. Cambridge University Press, New York, xv + 755 pp.

Maginnis, T. L., Cool, C. L. and J. L. Muniz. 2008. Some observations on the mating behavior of the giant walkingstick, Megaphasma dentricus (Orthoptera: Phasmidae). Texas Journal of Science 60(1):57-62.

Copyright © Ted C. MacRae 2009

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Ospriocerus abdominalis

/ Ted C. MacRae / 18 Comments
Photo details: Canon 100mm macro lens on Canon EOS 50D, ISO 100, 1/250 sec, f/14, MT-24EX flash 1/4 power w/ diffuser caps.

Photo details: Canon 100mm macro lens on Canon EOS 50D, ISO 100, 1/250 sec, f/14, MT-24EX flash 1/4 power w/ diffuser caps.

My dipteran digression continues with this photograph of the robber fly, Ospriocerus abdominalis (Diptera: Asilidae).  More than just a pretty picture, this represents yet another apparently new state record that I and my colleague Chris Brown discovered a few weeks ago during our 2-day survey of Missouri’s critically imperiled hilltop prairies in the extreme northwest corner of the state.  Like the previously discussed Cylindera celeripes (swift tiger beetle) and Beameria venosa (a prairie-obligate species of cicada), O. abdominalis has not previously been recorded further east than Nebraska, Kansas, Oklahoma and Texas. This large fly is a grassland denizen that ranges over western North America and into Mexico (Cannings 1998, as Ospriocerus aeacus). It is somewhat suggestive of a mydas fly, although its short antennae immediately identify it as a robber fly (mydas flies have elongate clubbed antennae).  It also reminds me of the magnificent western robber fly Wyliea mydas by its mimetic, wasp-like coloration – presumably modeled after spider wasps of the genus Pepsis and Hemipepsis (Hymenoptera: Pompilidae) – but is distinguished by its black body and wings with red dorsal coloration on the abdomen (W. mydas has the abdomen wholly black and the wings red).  While not quite as handsome as W. mydas, it is impressive nonetheless.

The dry hilltop prairie remnants in which O. abdominalis, B. venosa, and C. celeripes were found are associated with the Loess Hills, a unique landform along the western edge of Iowa that reaches its southern terminus in extreme northwest Missouri.  Due to their extreme rarity and vulnerability to woody encroachment and anthropogenic degradation, these remnant habitats are considered one of Missouri’s most critically imperiled natural communities. Only about 50 acres of original habitat remain, and of this only half is in public conservation ownership.  Many of the plants and animals found in these habitats represent hypsithermal relicts that migrated eastward during a dry and warm period after the last ice age and were then “left behind” in pockets of relictual habitat as a return to cooler, wetter conditions forced the main populations back to the west.  More than a dozen plants and two vertebrates occurring in these prairies are listed as species of conservation concern.  As is typically the case, the flora and vertebrate fauna of these remnant habitats have been fairly well characterized, while precious little attention has been given to the vastly more diverse invertebrate fauna.  As we begin to study the insects of these habitats more carefully, we are almost sure to find a great many species that are more typically found further to the west and that live nowhere else in Missouri.  Their continued presence in the state will be wholly dependent upon the critically imperiled habitats in which they live, making conservation and restoration of the remaining loess hilltop prairie remnants in Missouri all the more important.

My thanks to Eric Fisher and Herschel Raney for confirming the identity of O. abdominalis.

REFERENCES:

Cannings, R. A. 1998. Robber Flies (Insecta: Diptera: Asilidae), in Smith, I. M., and G. G. E. Scudder, eds. Assessment of species diversity in the Montane Cordillera Ecozone. Burlington: Ecological Monitoring and Assessment Network.

Copyright © Ted C. MacRae 2009

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North America’s smallest cicada

/ Ted C. MacRae / 17 Comments
Photo details: Canon 100mm macro lens on Canon EOS 50D, ISO 100, 1/250 sec, f/18, MT-24EX flash 1/2 power w/ diffuser caps.

Photo details: Canon 100mm macro lens on Canon EOS 50D, ISO 100, 1/250 sec, f/18, MT-24EX flash 1/2 power w/ diffuser caps.

While searching the hilltop prairies for Cylindera celeripes (swift tiger beetle) at McCormack Loess Mounds Natural Area in northwestern Missouri, I ran across a species of cicada that I’d not yet encountered in the state – Beameria venosa.  Cicadas as a rule are quite large insects, but with a body measuring only 16 mm (well under an inch) in length, B. venosa is one of – if not the – smallest species of this group in all of North America.  Had it not been for its distinctly cicada-esque call I might have thought it was some sort of fulgoroid planthopper (albeit a rather large one).  But a cicada it is, and a beautiful one at that despite its small size.

Beameria venosa is a prairie obligate species occurring from Nebraska and Colorado south to Texas and New Mexico.  To my knowledge, it has not been formally recorded from Missouri, although it is certainly already known from the state (it is listed in the 2009 issue of Missouri Species and Communities of Conservation Concern Checklist as “vulnerable” due to the restricted occurrence in Missouri of the prairie habitats in which it lives).  Froeschner (1952) listed 14 species of cicadas from Missouri but did not include this species even among those of possible occurrence in the state.  In my younger days, I managed not only to find all 14 of those species, but also a fifteenth species – the magnificent Tibicen superbus – in the southwestern corner of the state (formally recorded from the state some years later by Sanborn and Phillips 2004).  The occurrence of B. venosa in Missouri now brings to 16 the number of cicada species known from Missouri.

Despite its small size, the calling song of B. venosa is quite audible.  In fact, it was only due to its call that I noticed and began looking for this individual.  This brings up an interesting point regarding conspicuous insect songs and their role in enhancing predation risk.  Many predators are known to orient to the calls of cicadas (Soper et al. 1976), which in turn exhibit a variety of predator avoidance behaviors such as high perching, hiding, fleeing, and perhaps even mass emergence in the periodical cicadas.  Beameria venosa appears to avoid predators by producing its continuous train of sound pulses at a very high frequency.  Although audible to humans, the high frequency call apparently is not audible to birds and lizards – their chief predators (Sanborn et al. 2009).  In the open, treeless prairies where B. venosa lives, high frequency calling appears to provide the selective advantage for predator avoidance that fleeing, hiding, and high perching cannot.

REFERENCES:

Froeschner, R. C.  1952. A synopsis of the Cicadidae of Missouri. Journal of the New York Entomological Society 60:1–14.

Sanborn, A. F., J. E. Heath and M. S. Heath.  2009.  Long-range sound distribution and the calling song of the cicada Beameria venosa (Uhler) (Hemiptera: Cicadidae).  The Southwestern Naturalist 54(1):24-30.

Sanborn, A. F. and P. K. Phillips.  2004.  Neotype and allotype description of Tibicen superbus (Hemiptera: Cicadomorpha: Cicadidae) with description of its biogeography and calling song.  Annals of the Entomological Society of America 97(4):647-652.

Soper, R. S., G. E. Shewell and D. Tyrrell. 1976. Colcondamyia auditrix nov. sp. (Diptera; Sarcophagidae), a parasite which is attracted by the mating song of its host, Okanagana rimosa (Homoptera: Cicadidae).  The Canadian Entomologist 108:61-68.

Copyright © Ted C. MacRae 2009

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Western hognose snake

/ Ted C. MacRae / 29 Comments

Another herp interlude…

IMG_0655_1200x800
Photo details: Canon 100mm macro lens on Canon EOS 50D, ISO 100, 1/250 sec, f/14, MT-24EX flash 1/4 power w/ diffuser caps.

During my visit to Salt Plains National Wildlife Refuge in northwestern Oklahoma this past June, tiger beetles were not the only wildlife subjects I encountered.  Near the edge of one of the alkaline flats along Sandpiper Trail was this hognose snake.  This is the second hognose snake that I’ve encountered in as many years, the first being a member of a rare, disjunct population of the dusty hognose snake (Heterodon nasicus gloydi) in one of southeastern Missouri’s critically imperiled sand prairie habitats.  There are two species of hognose snake in Oklahoma – eastern (H. platirhinos) and western (H. nasicus).  I presume this individual to be the western due to its strongly upturned rostral (snout), which is only moderately upturned in the eastern species, and black-checkered ventral coloration.  Surprisingly, in checking the Salt Plains reptile species list for confirmation on its identity, I noted that no confirmed sightings of either the eastern or western hognose snake have been recorded at the refuge.  I have since done my good deed to reptile science by submitting this and another photograph I took of the individual to the refuge biologist.  Ted MacRae – entomologist and discoverer of new reptile records!  Western hognose snakes are further classified into three subspecies, two of which – dusty and nominotypical – occur in Oklahoma (the third occurs in Mexico). However, the distinctions between the two U.S. subspecies are subtle¹ and not apparent in this photograph, preventing further classification.

¹ Some authors consider the dusty and western hognose snakes to be separate species, while others have regarded their differences too subtle to warrant even subspecific distinction.

Hognose snakes are famous for their well-choreographed sequence of defensive displays. Their first act is to rear up cobra-like and strike out with their mouth open while hissing (unfortunately, neither of the hognoses I’ve encountered entertained me in this manner).  If the threat continues, they then turn over and writh violently in mock agony before finally rolling over on their backs and playing dead (thanatosis).  Last year’s hognose snake didn’t do this either, insisting instead on continually trying to burrow into the loose sand.  As can be seen from the photograph above, however, playing dead is exactly what this individual did.  With the mouth agape and the tongue protruding, it’s a convincing display of lifelessness.  Amusingly though, whenever the snake was righted it immediately turned over on its back again – not such a good imitation of being dead!  Presumably the snakes predators are as bad at noticing that detail as are the snakes themselves.  As I continued to pester this individual, trying to get him to stick out his tongue further for a better photograph, he eventually started ejecting blood from the lacrymal glands and emitting musk from the cloaca – what better to emphasize a death display than blood and an offensive smell!

Western hognose snakes are classified as a species of ”least concern” on the IUCN Red List of Threatened Species and aren’t listed as a species of concern on the Oklahoma Natural Heritage Inventory database.  Nevertheless, as with many other reptiles and amphibians, populations are declining throughout much of their former range.  This is likely due to the combined effects of urbanization, reduction of habitat, predation by feral dogs and cats, and overcollection for sale to the pet trade.

Copyright © Ted C. MacRae 2009

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North America’s most bizarre lizard

/ Ted C. MacRae / 32 Comments

Hmm, something funny going on here.  This is a bug blog – specifically a beetle blog, yet it’s a post about a lizard that generates a flurry of comments.  I don’t know if lightning will strike twice so quickly, but I did have this second ‘lizard’ post already lined up in the queue.

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The day after seeing a couple of male eastern collared lizards at Four Canyon Preserve in northwestern Oklahoma, I got my second saurian treat with this horned lizard (genus Phrynosoma).  There are actually some dozen species of horned lizards in North America, but the majority are found further west in the U.S. and down into Mexico and Central America.  Of the two that occur in Oklahoma, this particular individual can be identified as a Texas horned lizard (P. cornutum) by the two occipital (back of the head) spines, presence of lateral abdominal finge scales, and dorsal white stripe.  Oklahoma’s other horned lizard (round-tailed horned lizard, P. modestum) is restricted to the northwestern corner of the panhandle and differs from the Texas horned lizard by having four occipital spines, lacking lateral abdominal fringe scales, and more solid pale coloration.

IMG_0392_1200x800Again, my claim of “most bizarre” might be open to debate, as there are certainly many bizarre lizards in North America.  The gila monster once more comes to mind, but I think grotesque is a better descriptor for that animal, and the fan-shaped toe pads of geckos might also get them some votes.  Nevertheless, do a Google search on the phrase “bizarre North American lizard” and the results will be overwhelmingly dominated by references to horned lizards.  It’s no surprise – their squat body form is more suggestive of toads than lizards¹, for which they are commonly called “horned toads” or “horny toads,” and their covering of “horns” (actually modified scales) gives them an otherworldly, almost dinosaurian appearance.  Who among my generation wasn’t terrorized by the sight of these lizards, cheaply magnified, as they threatened the scientists that encountered them in the 60’s sci-fi classic The Lost World?

¹ Even the genus name, derived from the Greek words phrynos (toad) and soma (body), alludes to its toad-like appearance.

IMG_0397_1200x800In reality, these lizards are anything but terrifying.  Instead they employ multiple strategies to avoid being eaten themselves. These adaptations were all on display as I initially passed this individual without even noticing it lying motionless in the middle of the road. Once I had passed I noted movement out of the corner of my eye and turned to see it scurrying towards the vegetation along the side of the road. It’s mottled coloration, blending well with its background, and spine-broken silhouette made it almost invisible. Feeling threatened by my too-close approach, it made a rapid burst for cover, but I cut it off at the pass and blocked its erratic scampers towards the roadside to keep it out in the open so I could take some photographs. Once cornered in the open, it resorted to a third strategy – puffing of the body to make it appear larger. Had I been a true predator, it would’ve had two more strategies up its sleeve that it could have employed as a last resort – bleeding from the eyes (which apparently has a foul taste and will cause a predator to drop the lizard from its mouth) along with the mechanical defense of its hard, spiny scales. Since I didn’t actually try to eat this little guy, I didn’t have a chance to experience these final lines of defense.

The photos here actually represent two individuals – the middle picture is a second lizard that suddenly appeared while I was photographing the first.  The second individual was somewhat smaller than the first and not as boldy marked (note the lack of a distinct dark stripe behind the eye).  Whether these were male and female is difficult to say – horned lizards lack outward sexual characters allow them to be easily distinguished in the field (females do tend to grow a little bit larger). While not threatened or endangered, Texas horned lizards, like many other horned lizard species, have experienced dramatic reductions in its range. Oklahoma has a year-round closed season for both species that makes it illegal to kill or capture horned lizards without written permission. I would see a few more of these fascinating little lizards during my three days at Four Canyon Preserve, suggesting that, at least in this part of the state, horned lizards are doing just fine.

Photo details: Canon 100mm macro lens on Canon EOS 50D, ISO 100, 1/250 sec, f/11-13, MT-24EX flash 1/4 power through diffuser caps.

Copyright © Ted C. MacRae 2009

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