North America’s longest insect

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

Add to FacebookAdd to NewsvineAdd to DiggAdd to Del.icio.usAdd to StumbleuponAdd to RedditAdd to BlinklistAdd to Ma.gnoliaAdd to TechnoratiAdd to Furl

About these ads

About Ted C. MacRae

Ted C. MacRae is a research entomologist by vocation and beetle taxonomist by avocation. Areas of expertise in the latter include worldwide jewel beetles (Buprestidae) and North American longhorned beetles (Cerambycidae). More recent work has focused on North American tiger beetles (Cicindelidae) and their distribution, ecology, and conservation.
This entry was posted in Diapheromeridae, Phasmida and tagged , , , , , , , , , , , . Bookmark the permalink.

25 Responses to North America’s longest insect

  1. troymullens says:

    Great photos and excellent write-up. Enjoyed this a lot. Well done.

    I have been looking for them this summer with no luck. I know they are plentiful, but my eye has not been attuned properly for walking sticks. I have seen them several times in years past at the Ft. Worth Nature Center, Tarrant County, TX.

    Again, congratulations on the success with the Missouri Tiger Beetles.

    Troy

    If you are ever near Ft. Worth, call me and we will tour the Nature Center. 3500+ acres of fun and varied habitat.

    • Thank you, Troy, for you always kind comments. I suspect it’s still early in the year to see adults – they always seem more numerous later in the season.

      • Nick says:

        Hi there Ted,
        Really nice pictures there!
        I have recently started to collect phasmids in my area (New Jersey) and I am trying to make cultures of phasmids from around the USA. If it is not too much work, do you think it could be possible for you to ship a female (and male?) to new jersey if you incounter Megaphasma denticrus (or other species) on any of your future trips? I can pay you through paypal for any costs. I already have Diapheromera femorata, I am quite sure you have those in Texas too.
        Thank you for your time,
        Nick

        • Hi Nick,

          I’d be happy to help you with getting your cultures started, but please note that interstate movement of live insects that feed on plants is regulated by the USDA Animal and Plant Health Inspection Service (APHIS). You’ll need to complete an application for a permit, which can be found at the APHIS website.

          My next field trip will be the first part of October – if everything is in order by then, I’ll keep you in mind as I look for things.

          • Nick says:

            Hi Ted,
            Thanks for letting me know this! I read through their site and sent them an email. I need to know the level of containment they want before I go through all the trouble of the application process. If they require laboratory like settings which I cannot provide in my apartment, then I will just stick to my local sticks.
            Thanks again,
            Nick

            • APHIS will likely have no problem with Megaphasma since it is native to the US, but your state entomologist, which APHIS will pass the application to for their comment, might be concerned about its non-native status in New Jersey. I suggest going ahead and completing the application, stating something like this for Question 15, “Methods to be used to prevent plant pest escape”:

              Insects will be maintained in screened cages inside a closed room without open windows. Insects and used cage materials will be frozen for 72 hours prior to disposal.

  2. Marvin says:

    Great post, Ted.

    Starting to see more and more adult walking sticks, but there are still many green nymphs. I find getting the entire insect in focus is quite a photographic challenge.

    • Hi Marvin – thanks. Yes, focus on such a long and narrow insect is quite a challenge. Photo 1 turned out alright, but I just missed it a tad in Photo 2 with the fore legs. Not a problem in Photo 3 with the extreme closeup!

  3. MObugs41 says:

    Beautiful specimen indeed, we stayed at a cabin in Ozark, MO and these giant beauties were everywhere. In fact one even started crawling up my husbands leg, of course I remained silent and let him discover this huge insect himself…lol. Let’s just say he was less than thrilled to have one of these things on his person.

  4. Steve says:

    Great story, but I’m certain an adult insect cannot regenerate a leg.

    • Yes, you are quite right, and I feel rather silly for forgetting that fact. At least one molt is required for partial regeneration, and three are required to fully regenerate a lost limb. Alas, the female featured here has no hope of regaining her former perfection :)

  5. Beau says:

    Fascinating descriptions- I’ve always enjoyed walking sticks, yet never quite sure what species they may be. I’ve seen some very large ones here in the Missour River Ozark Border regions- I’ll have to look more closely too.

    • Most of what I’ve seen around here (just slightly south of you) is the northern walkingstick (Diapheromera femorata). There are probably at least a few other species in Missouri, but I’m not sure.

  6. Hi Ted

    Very interesting again and nice shots. What does this creature eat?

    Look forward to the upcoming article and photos of the cerambycid beetle.

    Best regards, Trevor

    • Thanks again, Trevor. Like all walkingsticks, nymphs and adults are nocturnal foliage feeders. Hosts recorded in the literature for this species include grass, oak, grape, and mesquite. Here in the Ozarks, I presume they are feeding primarily on oaks (Quercus spp.), which dominate the forest canopy.

  7. Chris Brown says:

    Great post and pics. You made the right choice to use natural light for the first pic. As I’m sure you’re finding out, something so long can be challenging to get a photo of that properly captures the size and look of the insect but that image nails it.

    BTW, my latest visit to beetlesinthebush was made possible by some free time I’ve come across as Jess and I are in the hospital with our new son, Avery! He came a little early but he’s doing great.

    Best Regards

    • Thanks, Chris. I tried taking several photos of the full insect with the flash and just didn’t like any of them. I finally decided to try natural light and was much happier. Even then, it took a number of shots before I felt like I got the focus and composition right. It was the first time I’d tried to photograph such a long, narrow subject – truly a challenge.

      Wow – congratulations on the birth of Avery! I’ll look forward to seeing some pics. Please give Jess my warmest regards.

      p.s. I was hoping we’d be able to sneak in a fall weekend tiger beetle foray together – looks like that idea is toast (at least for you) :)

  8. That’s amazing! If I happened to walk by this insect in the woods, I probably would have missed it since it blends in so well. Very cool little creature. Nice pictures!

  9. Dave Rentz says:

    hi Ted
    Thanks for a great write-up of this nice stick. I especially appreciate your specific notes on how the photos are taken. Very helpful. Now on to more reading.
    Dave Rentz

  10. Megan says:

    I have to make a website for my Biology class in college and my topic is Megaphasma detricus. We need to get permission for using pictures on our site and I really like yours so I was wondering if I could use them!

  11. Pingback: Giant Walkingstick | Save America Club

Commentaria

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s