A Horridus Birthday

For many years now, I’ve celebrated my birthday each year with the “season-opener-birthday-bug-collecting-trip.”  This happens regardless of what day of the week it falls (although two years ago I did get roped into a business trip – I made up for it by stumbling into a quick but thoroughly enjoyable tour of Pipestone National Monument before my flight back home).  Last year I made sure I got the day off and had a nice, festive (tiger beetle) birthday.  For this past April 23rd, a Friday, I celebrated my 29th birthday (for the 2-dozenth time!) by grabbing long-time field companion Rich and shooting down to Sam A. Baker State Park in the Ozark Highlands of southeastern Missouri.  My goal for the trip was to find the very uncommon Cladrastis kentukea (American yellowwood), a small tree that is known to occur in Missouri only in the White River Hills of the extreme southwest and in a few localities in and near Sam Baker State Park.  Actually, it wasn’t the tree so much that I was after, but a small jewel beetle – Agrilus cladrastis – that utilizes this plant exclusively for its larval host. To date, the only Missouri specimens of this species have been collected by the late, great Gayle Nelson on yellowwood in the White River Hills, and I wanted to see if I might be able to find it in southeastern Missouri as well.  April is still too early to encounter active adults, but my plan was to: 1) find examples of the tree, 2) collect dead wood from them, and 3) cut living branches to leave in situ for infestation this season and retrieval the next.  Long story short, I succeeded on all three counts (though I won’t know for a few weeks whether the wood I brought back actually harbors any as yet unemerged adults – finger crossed!).

The area where we expected to find the tree was steep, rocky slopes overlooking Big Creek on the north side of the park.  Rich and I were hiking a trail below the slopes, and I had gotten a little bit ahead of him when I saw a 30″ long snake stretched straight out across the trail.  Recognizing it immediately as one of our venomous species, but not quite sure which one, I blurted out, “Wow, what a gorgeous snake!”  Rich, a better herpetologist than I, shouted from a distance back, “What kind?”  In the few seconds during which this exchange was taking place, it all registered – the dark stripe behind the eye, the bold markings (too dark for a copperhead, too big for a western pygmy rattlesnake, too widely spaced for a massasauga), the black tail (not yellow-green like a juvenile copperhead), and a tiny little one-chambered rattle!  I yelled back, “A young timber rattler!”  Rich got there promptly, and we decided that it must be a yearling based on the time of year, its length, and the size of the rattle.

I have seen a few timber rattlesnakes (Crotalus horridus) in Missouri over the years, but never like this.  My previous sightings have all been fleeting glimpses after hearing them shooting into the underbrush to escape my close approach – me oblivious to their presence until it was too late.  This young snake, by contrast, didn’t flinch as I approached (carefully), set down the backpack, and assembled the camera to begin taking photographs.  As I began taking a few photos of the head area (from a respectful distance – the vision of that terrifyingly aggressive prairie rattlesnake from two years ago still lingers), it became agitated and started moving for cover.  Rich wasn’t too anxious to head it off at the pass, but I wasn’t satisfied with the shots that I’d gotten so far, so I grabbed my net to block it from disappearing into the litter.  That caused it to pause just long enough for me to get back into position and frame a shot… that I couldn’t get off before it started moving again!  We did this a few times until it finally just crawled right into the net – now what?!  I carried the net over to some large rocks on the side of the trail and used them to flip the net and dump out the snake, which immediately headed for cover underneath the rocks.  I figured the photo shoot was over then, but the space under the rocks was not deep, and after a bit of probing for escape routes the snake eventually settled into a money pose and I was able to snap away with glee – what do you think?

Missouri has five venomous snake species, all of which are pit vipers with three being rattlesnakes.  I’ve featured two of these in previous posts – the Osage copperhead and the western pygmy rattlesnake.  Both of these species occur throughout the Ozark Highlands, although the latter is more common in the southwestern part of the state.  The third rattlesnake species in Missouri, eastern massasauga, is rare in wet habitats scattered across northern Missouri, while the cottonmouth (or water moccasin) is limited to stream, river, and swamp habitats in the southern Ozarks and southeastern lowlands.  Many internet references list the western massasauga also as occurring in Missouri, but this subspecies is not included in the most recent Snakes of Missouri (Biggler and Johnson 2004).  Within Missouri, timber rattlesnakes have a statewide distribution, but they have been extirpated by humans from many areas and now occur as small populations in scattered locations across the state.  The same is true in other parts of their range as well, particularly along the western and northern limits.  It is thus a rare and exciting treat to see one of these magnificent animals, although the reasons for its rarity are both sobering and maddening.

REFERENCE:

Briggler, J. and T. R. Johnson.  2004. Snakes of Missouri. Missouri Department of Conservation, Jefferson City, 16 pp.

Copyright © Ted C. MacRae 2010

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Hello World!

These are two of the Cylindera celeripes (swift tiger beetle) larvae that I’m rearing.  Note: nobody has ever reared this species before!  Nobody has ever even seen its larvae (before now, that is).

These larvae hatched from eggs that were laid by adults I brought back from northwestern Oklahoma last summer.  I placed the adults in a small terrarium of native soil – at first just to see if I could keep them alive, and then to see if I could get them to lay eggs.  The adults lived for about 4 weeks, and a short time later larval burrows started appearing in the soil.  I fed them once or twice a week by placing 2nd instar corn rootworm larvae in the open burrows or dumping Lygus nymphs into the terrarium and letting them catch them naturally.  I wasn’t sure this was working, because as the summer progressed I saw fewer and fewer open burrows.  By October, there were no open burrows, and I feared none had survived.  Nevertheless, I placed the terrarium in a cool (10°C, or 50°F) incubator for the winter and pulled it back out in late March.  Within one week ten larvae had reopened their burrows – I believe all but one of them are 3rd instars, which is the last instar before pupation, and since they have awoken they have fed voraciously on 3rd instar fall armyworm larvae, which I dangle above their burrow.  I love watching them snatch the armyworm from my forceps and drag the hapless prey down into their burrow.  I’ve already preserved examples of the three larval instars and will describe it shortly (although truth be told, the 2nd and 3rd instars are from larvae I found in the field – but that is a post for another day).  However, I’m keeping my fingers crossed for the piece de resistance – successfully rearing the species from egg to adult!

Photo Details: Canon MP-E 65mm 1-5X macro lens on Canon 50D, ISO 100, 1/250 sec, f/13-16, MT-24EX flash 1/8 power w/ Sto-Fen diffusers.

Copyright © Ted C. MacRae 2010

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Anatomy of a Tiger Beetle Larva

My first experience looking for tiger beetles in Florida had gone well.  Despite its small size and urban surroundings, the narrow strip of coastal scrub and saltwater marsh along the intracoastal waterway behind my sister-in-law’s condominium boasted a robust population of what I took to be a single tiger beetle species.  The specimens I collected and photographs I took would later reveal that two co-occurring and closely related species were present: Ellipsoptera marginata (Margined Tiger Beetle) and E. hamata lacerata (Gulf Beach Tiger Beetle).  I had spent close to two hours under the August sun observing and photographing the beetles before I decided that I had given the preserve a thorough enough look.

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As I was heading back, I noticed a little bit of high ground alongside a red mangrove thicket and went over to give it a look.  As I approached I saw something I hadn’t yet seen that day – tiger beetle larval burrows.  Larval burrows, especially larger ones such as these were, are unmistakeable – almost perfectly circular (slightly cut out on one edge) and smoothly beveled around the perimeter.  There were a number of burrows clustered on the small bit of high, dry ground, and my first thought was that their inhabitants represented the same (what I thought was a single) species that I had encountered so commonly that day as adults.  I then reasoned, however, that more likely they represented another species whose adults are active later in the season – perhaps one of the so-called “spring/fall” species whose larvae typically reach maturity during the heat of summer.  The size of the burrows (~5mm dia) suggested they were inhabited by 3rd instar larvae (the final instar before pupation), in which case it may be possible to rear a few to adulthood – if I could get at them. I tried fishing (Pearson and Vogler 2001) a few holes with a grass blade but didn’t get any bites, so I decided to watch for awhile and see if any of the larvae, believing the danger of my approach had passed, would reappear at the tops of their burrows.  Waiting for tiger beetle larvae to appear is a crap shoot – maybe they’re active, and maybe they’re not, and crouching in the stifling summer air of a coastal marsh in Florida is not an easy thing to do for very long.  Fortunately my wait was short, as within a few minutes I saw one re-appear at the top its burrow.  I slowly got out my knife and moved to place the tip on the soil about 1″ from the burrow at a 45° angle for an attempted tunnel block (Pearson and Vogler 2001), but it spooked and dropped back down into its burrow before I could get then knife in place.  No matter, I knew it was in there now and that it would likely reappear if I could muster the patience.  I positioned the knife and waited – crouched under the baking Florida sun, until when it did re-appear I plunged the knife into the soil with authority.  It was a good jab – I had blocked its retreat without injuring it, and a quick flip of the knife popped out the soil plug and exposed the startled larva, flipping vigorously in a vain attempt to escape before settling down amidst its unfamiliar, exposed surroundings.

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For those of you who have never seen a tiger beetle larva, they are among the most other-wordly creatures one can imagine.  The large, heavily sclerotized head bears two long, sickle-shaped, upward-pointing mandibles and up to three pair of highly-acute eyes whose arrangement on each side conveys the image of a “face” with congenital birth defects.  The top of the head is flattened to lie flush with the surrounding soil as the larva sits at the top of its burrow, and huge, powerful mandibular muscles fill the cranial cavity.  The remainder of the body – long, narrow, and cylindrical – hangs from the head at a 90° angle down into the burrow and is unremarkably grub-like, save for a curious hump on the dorsal side of the 5th abdominal segment.  Close examination of the hump reveals an intricate pattern of forward-facing hooks and spines that function in anchoring the larva against the side of its burrow to prevent struggling prey from dislodging it.  The life of a tiger beetle larva is a life of waiting – unlike the adults who run down their prey, the larvae sit in their burrows and wait for prey to come to within lunge’s reach.  While the eyes of most grub-like insects detect little more than light and dark, those of tiger beetle larvae are densely packed with photoreceptors that permit detailed focusing and depth perception for detecting whether potential prey has ventured close enough to their burrow (Pearson et al. 2006).  When that happens, they strike with lightning speed, plunge their mandibles into their prey, and drag it down into the depths of their burrow where it is summarily dispatched with a few bites of their powerful mandibles.  Larvae consume they prey in a manner similar to that of adults in that they chew but don’t swallow their prey. Rather, they secrete digestive secretions containing proteolytic enzymes that begin digesting the prey extra-orally as they chew.  The resulting bolus is masticated and its liquid components sucked out until nothing but a dry wad of indigestable chitin remains, which is spat out of the burrow (Pearson and Vogler 2001).

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Looking at this strange insect, it occurred to me that I had not yet attempted macrophotographs of a tiger beetle larva out of its burrow, and this would be a good opportunity to get more practice with my Canon MP-E 65 mm macro lens – a lens with incredible magnification capabilities, but one that is also a bit of a temperamental beast to use hand-held in the field.  The subject was unusually cooperative, perhaps too stunned by its sudden predicament to know what to do, and as I took the photographs I focused in particular on characters of the head and dorsal hump (often useful in identifying tiger beetle larvae, at least to genus).  Time was growing short once I finished taking photographs, so I placed the larva in a vial and returned the following day to extract a chunk of native soil to place in a rearing container, managing to collect two more larvae as well (unfortunately, one became instant “prey” for the other.  Note to self: when placing multiple tiger beetle larvae in a container of soil, seal the artificial burrows into which you place each one!).  I paid little further attention to the photographs, other than to transfer them onto my computer and add metadata upon my return to St. Louis.  I didn’t know what species the larvae represented, but I assumed they were something in the genus Cicindela or one of its several former subgenera.  However, had I studied the photos and considered the locality and habitat, I would have realized that my assumption was incorrect¹.  That realization would come in surprise fashion two months later when the two adults emerged within a few days of each other…

¹ Ten points to whoever can use this information to arrive at an identification before my next post 🙂

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Photo details:
All photos: Canon EOS 50D, manual mode, ISO-100, 1/250 sec, MT-24EX flash w/ diffuser caps.
Photo 1: Canon 100mm macro lens, f/22, 1/4 power flash (photo slightly cropped).
Photos 2-4: Canon MP-E 65mm 1-5X macro lens f/16, 1/8 power flash.

REFERENCES:

Pearson, D. L., C. B. Knisley and C. J. Kazilek. 2006. A Field Guide to the Tiger Beetles of the United States and Canada. Oxford University Press, New York, 227 pp.

Pearson, D. L. and A. P. Vogler.  2001. Tiger Beetles: The Evolution, Ecology, and Diversity of the Cicindelids.  Cornell University Press, Ithaca, New York, 333 pp.

Copyright © Ted C. MacRae 2009.

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Tiger Beetle Rearing

I recently found an interesting website called Tiger Beetle Rearing.  This website by doctoral candidate Rodger Gwiazdowski in the Joseph S. Elkinton lab, University of Massachusetts, Amherst contains a wealth of information and photographs covering equipment, techniques, and methods for rearing tiger beetles from egg to adult, with a primary focus on rearing endangered and threatened species of tiger beetles for conservation and re-release into the wild.  The lab has reared a number of tiger beetle species but is particularly interested in the Puritan tiger beetle (Cicindela puritana), threatened in the northeastern U.S.  After the first year of rearing, 90 2nd and 3rd instar C. puritana larvae were obtained and, as of the last update, were overwintering in individual tubes.  You’ll need to register with the site with a username and password to access the site, but this is accomplished quickly and easily.

Welcome to the Hotel Cicindela!

Welcome to the Hotel Cicindela!

I found this website of great interest as I begin my own efforts at rearing these beetles in the laboratory.  My primary interest is in rearing larvae that I collect in the field to adulthood – adults are much more easily identified than larvae (indeed, the larvae of many species remain undescribed), and rearing field-collected larvae is one way to get around the often limited temporal occurrence that many tiger beetle species exhibit as adults.  My operation isn’t nearly as sophisticated as the one developed in the Elkinton lab, but then I’m just a working stiff trying to do this (and a million other things) on the side. Despite this, I have had my first success, rearing to adulthood a larva I collected during the summer last year (see my post It’s a girl!).  In addition, I currently have a number of larvae collected last fall in Nebraska and South Dakota, which I put in terraria of native soil and kept in a cold incubator during the winter.  I pulled them out earlier this spring, and soon afterwards a number of larvae opened up their burrows and have been feasting on fall armyworm and corn earworm caterpillars every 2-3 days or so.  The larvae were collected from a variety of habitats and soil types, including sand, alkaline seeps, and red clay banks, so I’m hopeful that the ensuing adults will represent a variety of interesting species – perhaps some that I did not encounter in the field during that trip.

Cicindela_scutellaris_rearing_P1020931_2Beyond this, however, I am also interested in trying my hand at cross-breeding experiments – particularly with Missouri’s unique population of Cicindela scutellaris (festive tiger beetle).  I’ll need to wait until fall for this, however, since adults that are active in the field right now are sexually mature and have presumably already mated.  In the fall, a new generation of sexually-immature adults will emerge and feed for a time before burrowing back in for the winter and re-emerging the following spring ready to mate.  I would like to cross individuals from southeastern Missouri – representing an intergrade between the northern subspecies lecontei and the southern subspecies unicolor – with individuals from the northern part of the state that are clearly assignable to subspecies lecontei.  If possible, I would also like to obtain individuals from even further south that are clearly assignable to subspecies unicolor and cross them with both the southern and northern Missouri populations.  These crossing experiments may provide some insight into which of the subspecies the intergrade population is more closely related to, and it will be interesting to see how closely the progeny from the lecontei x unicolor cross resemble individuals from the intergrade population and the range of variation that they exhibit.  I should mention that Matt Brust (Chadron State College, Nebraska) has done a number of these inter-subspecific crosses with C. scutellaris, with some very interesting results among the progeny.

What I can do right now is work on techniques to make sure I can get females to lay eggs and then rear the larvae all the way through to adulthood.  For this, I brought back 9-10 live individuals from two localities of the intergrade population encountered on my recent trip to the southeastern lowlands.  Adults imbibing moisture from polymer gelI put equal numbers of males and females from each locality into separate terraria – each filled with native soil and a hydrophilic polymer gel made of anionic polyacrylamide. The beetles, who normally obtain moisture from their food or by “chewing” moist soil, chew instead on the gel. This eliminates the need to maintain a water dish or cotton batting that must be changed daily in order to prevent the growth of mold and bacteria. A few of the adults in each terrarium died shortly afterwards, possibly a result of stress or dehydration during transport (the photo right shows how eagerly they imbibed moisture from the polymer gel after being placed in the terrarium), but the remainder have lived for four weeks now and have been digging burrows and feeding whenever food is offered.  According to Matt Brust, C. scutellaris does not lay eggs on the surface of the soil (as does C. celeripes), but rather lays them about 1.5 to 2 inches below the surface.  It takes 2-3 weeks before the eggs start hatching, so I am expecting to see larval burrows appearing anytime now.  Matt tells me the key to getting eggs is to feed the adults “big-time” – thus, I have been offering fat, juicy fall armyworm or corn earworm larvae to the adults whenever they are out of their burrows.  Watch this entertaining video of one adult having lunch:

Copyright © Ted C. MacRae 2009

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Bon appétit!

I collected this larva in northwest Nebraska during last year’s Fall Tiger Beetle Trip.  I collected an adult Cicindela lengi (blowout tiger beetle) at the spot – a species that greatly resembles but is much less common than the ubiquitous C. formosa (big sand tiger beetle – see my post Cicindela lengi vs. Cicindela formosa for a comparison of the two species).  Before finally finding that adult, however, I had fished out several larvae from the site in the hopes that they represented that uncommon species (see how I did this in my post Goin’ fishin’).  After collecting the larvae and placing them in a small terrarium with native sandy soil, they burrowed in but then closed up shop – I wasn’t sure whether they had survived or not.  In early December I put the terrarium in a 10°C incubator for the winter and brought it back out earlier this month.  Yesterday, happily, this larva and one other opened up their burrows again, so with any luck I’ll feed them well and they’ll complete their development.  While I do hope they represent C. lengi, other possibilities include C. scutellaris (festive tiger beetle), which would not be exciting, and C. nebraskana (prairie long-lipped tiger beetle), which would be VERY exciting.  One species I do not have to worry about it being is C. formosa, as the larvae of that species make very unique excavations in the sand with the burrow opening directed towards the excavation (I don’t believe I’ve posted photos of that here, yet – I’ll have to do so soon).

In the meantime, here is a closeup of the larva in the video prior to feeding. Those of you who have ever reared or photographed tiger beetle larvae will know just how easily “spooked” these larvae can be – any sudden movement will cause the larva to “drop” into its burrow and sit there for awhile. As a result, it was a real challenge to go through the whole process of taking first the photos and then the video while feeding it without causing it to drop.

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Coming soon – lunchtime for adults!

Copyright © Ted C. MacRae 2009

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It’s a girl!

I’ve been interested in collecting insects since I was 10 years old, and my current collection dates back to spring semester 1978 when, after finally declaring a major, I kicked off my life as an entomologist with Entomology 101. I did my graduate work on the now-defunct Homoptera (I just can’t call them hemipterans), using laboratory rearing to figure out life history details of several species of leafhoppers. Although my allegiance would soon switch to beetles (where it has remained ever since), my interest in rearing insects would persist. It wasn’t long before I began rearing wood boring beetles as a way of studying their distributions and host plant associations. I’ve reared beetles from literally hundreds of batches of wood – buprestids, cerambycids, bostrichids, clerids, ostomids, you name it – if it breeds in wood, I’ve reared it. Not to mention the parasitic hymenopterans and even predaceous asilids associated with them. Rearing has been part of my professional life as well. In the early part of my career in industry, I supervised an insectary that maintained laboratory colonies of nearly two dozen arthropod species to support research. We reared moths, beetles, flies, roaches, aphids – even mites and nematodes. However, despite having reared hundreds of species of insects, I had never reared a tiger beetle – until now!

This little gal – a gorgeous individual representing Cicindela limbalis (common claybank tiger beetle) – was waiting for me when I returned from my recent trip to western Nebraska and South Dakota. I had collected her as a 3rd instar larva from her burrow atop a steep clay bank in western Missouri, where my colleague and I were conducting our survey for Cicindela pruinina (now Dromochorus pruininus). I had entertained the hope that it might prove to be that species, but the abundance of larval burrows within this patch of habitat – where C. pruinina had not been seen – and the fact that they contained mostly 3rd instars suggested it would prove to be one of the spring-fall clay associated species. After fishing her from her burrow, I filled an empty Starbuck’s Frappucinno bottle (there is, apparently, only one place in the Ozarks where availability of good coffee obviates the need to resort to a cold, sugary, “coffee-flavored” drink in the morning) with native clay and dropped her in, where she immediately proceeded to dig a new burrow. She was thoughtful enough to dig her burrow right down along the glass so that I could keep an eye on her over the next several weeks, occasionally dropping in a fat fall armyworm larva and watching it meet its gruesome yet mercifully quick death. A few weeks before my trip, she sealed up her burrow and disappeared from view. Curious (and impatient), I emptied the soil from the bottle and found her down at the bottom, quiescent but apparently healthy. I put the soil back into the bottle and dropped her in, and she immediately dug a new burrow, sealed it up, and disappeared from view once again. My curiosity satisfied, I had an easier time leaving her alone after that, and when I returned from my trip, there she was.

Cicindela limbalis occurs throughout Missouri on eroded or sparsely vegetated clay soils, although it is less common in the southern Ozark Highlands – being largely replaced by Cicindela splendida (splendid tiger beetle). I’ve most often encountered C. limbalis on roadside embankments, along 2-tracks through open forest and woodland, and in glade habitats. This individual shows the greatly reduced elytral maculations that are typical of populations found throughout most of Missouri – only in the extreme northern tier of counties is the full pattern of maculation expressed (as exemplified by this individual from central Nebraska). At one time, this reduced maculation was the basis for recognition as a separate subspecies (C. limbalis transversa); however, no distinct geographical forms are currently recognized for this species (unusual in cicindelid taxonomy). Regardless of her taxonomic identity, I’m enjoying watching my new pet – she now occupies a larger, roomier terrarium filled with native clay, into which she has dug a burrow and spends most of her time sitting at its entrance. As she did when she was a 3rd instar, she enjoys a fat fall armyworm larva for lunch every few days. She will eventually take up permanent residence in a neat row inside a wooden, glass-topped box, but for now I’m going to do everything I can to delay that fate. Of all the many thousands of insects that I’ve reared over the years, she is my favorite.

Goin’ fishin’

For the past two days I’ve been in Sioux County, Nebraska – just east of Wyoming and just south of South Dakota. As I traveled up through the western panhandle to arrive at this spot, I was pleasantly surprised by the varied terrain – not at all the monotonously flat landscape that I expected. The landscape in this so-called Pine Ridge area is even more surprising – an impressive escarpment drops 1,400′ from the high shortgrass prairie down to an eery badlands below. The escarpment itself is forested with Ponderosa pine and is studded with numerous impressive buttes. The photos shown here were taken in Sowbelly Canyon – typical of the landscape along the escarpment – and in the badlands below Monroe Canyon a little further west.

Enough about pines and buttes – my business here is tiger beetles. I met up yesterday with tiger beetle aficionado Matt Brust, who recently took a position here at Chadron State College after finishing his Ph.D. in Lincoln. I’ve been corresponding with Matt for a bit now, and when I told him of my interest in doing a tiger beetle trip through western Nebraska, he was more than willing to show me around and hopefully help me find some of the more unusual species I was looking for. Of course, tops on the priority list was Cicindela nebraskana (prairie long-lipped tiger beetle). This beetle isn’t common anywhere within its range and just sneaks into the northwest corner of Nebraska, where the type locality is located. Until recently, the species was known from very few specimens in Nebraska. Matt did some intensive sampling a few years ago and located a few limited populations in the vicinity of the type locality. Yesterday, he took me to two of these localities, and we succeeded in finding one individual at the first and several at the second. It was at the type locality where I succeeded in getting this field photo. While admittedly harshly-sunlit, it is as far as I know the only field photograph of the species – all others that I’ve seen have been taken in terraria. I’ll fix it up a bit with Photoshop and re-post once I get back home. This species looks similar to the black morph of Cicindela purpurea audubonii, which co-occurs with C. nebraskana in Nebraska, but it lacks the bright white labrum and elytral markings of the former. Also, as I would learn during these past two days, it can be instantly recognized in the field by its shinier appearance and “stubbier” legs. A few days before my arrival, Matt succeeded in finding the species in the next county to the east, an eastern range extension of about 60 miles, and today I located the species at another new locality between the two. It is gratifying to have played a small role in increasing our knowledge about this unusual species.

My success with C. nebraskana has come despite uncooperative weather. A series of frontal systems has moved through the area since my arrival, resulting in several rain events and lots of cool, cloudy weather. Tiger beetles are sun-loving insects, and when it gets too cold or wet the adults dig in and don’t come out until the sun shines through or temps warm enough to trigger them to dig out. Matt had taken me to another locality – a sand embankment – where we might find the beautiful Cicindela lengi (blowout tiger beetle), but it rained prior to our arrival and we saw no activity. I tried finding adult burrows to dig them out, but the rain had obliterated any trace of the diggings, making their burrows impossible to find. We did, however, note an abundance of larval burrows. I went back to the spot today hoping to see some activity, but thick clouds and cool temps made that unlikely. This is when I decided to “go fishing.” Tiger beetle larval burrows are easily recognized by their perfect circular shape and clean “beveling” around the entrance (1st photo). Burrows of 3rd instars (the last larval instar in tiger beetles) are distinctly larger than those of 2nd instars (2nd photo), while those of 1st instars are smaller still (not shown). Larvae sit at the burrow entrance and ambush any suitable prey that comes too close. During cool, cloudy weather, however, they drop to the bottom of their burrow – up to a foot or more deep. A technique useful for extracting inactive larvae from their burrows is called fishing and involves inserting a thin grass stem down to the bottom of the burrow in an attempt to coax the larva into “taking the bait” and biting the end of the grass stem (3rd photo). The grass stem is then pulled up rapidly – much like setting the hook when fishing – in an attempt to pull the larva out of its burrow before it has a chance to let go of the stem. It can take a few tries, but with practice one can more often than not succeed at removing the grotesquely odd, yet beautiful larva (4th photo). Note the huge, heavily sclerotized head with upward facing jaws. The hump in the middle of the back is armed with forward-curved spines that helps the larva avoid being pulled out of the burrow by struggling prey (but they’re not so effective against obsessive cicindelophiles!). As I managed to “fish” larvae I placed them in a plastic container with their native soil. In the 5th photo, four larvae have already begun digging new burrows, and one more 3rd instar (L) along with a 2nd instar (R) has just been placed in the container. I’ll bring this container back with me and continue to feed the larvae live insects in the hopes of rearing them to adulthood. I cannot say with certainty that the larvae I collected represent C. lengi – other species that could potentially occur at this site include C. scutellaris (festive tiger beetle) and C. limbata (sandy tiger beetle). However, the locality is known for the abundant occurrence there of C. lengi, so I’m hopeful that that is what I’ve collected – we’ll know in a few weeks. In the meantime, I’ll have additional opportunities to look for this species, along with C. limbata, as I pass through the Sand Hills region later this week.

Tomorrow morning I head to the Black Hills in South Dakota, where I hope to find not only Cicindela longilabris laurentii (Boreal long-lipped tiger beetle) in the high pine forests, but also intergrades between this species and the closely related C. nebraskana in the more open habitats of the middle latitudes. Look for an update in a couple days or so.

The hunt for Cicindela celeripes

One of the more enigmatic tiger beetle species in North America is Cicindela celeripes LeConte (swift tiger beetle). This small (6-8 mm), flightless species has been recorded from a restricted area of the eastern and southern Great Plains – from eastern Nebraska and westernmost Iowa south through Kansas to western Oklahoma and the Texas panhandle (Hoback and Riggins 2001, Pearson et al. 2006). Unfortunately, populations of this species appear to have suffered severe declines. It apparently is holding strong in the Flint Hills region of Kansas, but many of the records from outside of that area date back more than a century. Reportedly once common on the bluff prairies along the Missouri River, it has not been seen in Nebraska since 1915 and may have been extirpated from that state (Brust et al. 2005). The reasons for this decline undoubtedly involve loss of preferred habitat – upland prairies and grasslands with clay or loess soils and sparse or patchy vegetation. Areas supporting these native habitats have been drastically reduced since European settlement of the region, and suppression of fire – so vital to prairie ecosystems – has led to extensive woody encroachment on the few prairie relicts that do remain. Unlike many other tiger beetle species that have been able to adapt to these anthropogenic changes, this species apparently cannot survive in such altered habitats.

Chris Brown and I have been interested in this species ever since we began surveying the tiger beetles of Missouri. It has not yet been recorded from the state, but we have long suspected that it might occur in extreme northwest Missouri. It is here where the Loess Hill prairies along the Missouri River reach their southern terminus. (Incidentally, the Loess Hills are themselves a globally significant geological landform, possessing natural features rarely found elsewhere on earth. They will be the subject of a future post). We have searched several of what we consider to be the most promising potential sites for this species in Missouri, though without success. Nevertheless, we remain optimistic that the species might eventually be found in Missouri and has simply been overlooked due to the limited temporal occurrence, small size, rapid running capabilities, and tendency of adults to dart rapidly to the bases of grass clumps where they hide (Pearson et al. 2006). Furthermore, even though the species has not been seen recently in adjacent areas of Nebraska where it has been recorded in the past, it has been seen recently in a few Loess Hill prairie remnants just to the north in Iowa.

A few weeks ago, I was fortunate to receive specific locality information for one of the recently located Iowa populations. Armed with site descriptions, Google maps, photographs, and whatever book learnin’ I had gained about this species, my colleague and I made the long drive to southwestern Iowa in hopes of locating the population for ourselves, seeing adults in their native habitat, and using the learnings we would gain about their habitat preferences and field behavior to augment our efforts to eventually locate the species in northwestern Missouri. At mid-July, we were nearing the end of the adult activity period, but adults had been observed at the site the weekend prior, so we felt reasonably confident that adults might still be found. Additionally, fresh off of our recent success at locating the related Cicindela cursitans in Missouri (another small, flightless, fast-running species), we were hopeful that we now possessed the proper “search image” to recognize C. celeripes in the field should we have the good fortune to encounter it.

Walking into the area, I was impressed at the extensiveness of the prairie habitat – much larger than any of Missouri’s Loess Hill prairies. The presence of large, charred red-cedar cadavers on the lower slopes revealed active management for prairie restoration. We later learned from the area manager that the restoration area had been acquired from a neighboring landowner who had used the land for grazing and sold it when it became unproductive. I can only imagine the second thoughts that landowner must have had when subsequent burn regimes and woody growth removal prompted a return to the beautifully lush sea of prairie vegetation that now covered the hills. As we approached the area where we decided the beetles must have been seen, we started searching slowly and deliberately – looking carefully for any movement between the clumps of grass. It didn’t appear to be prime habitat for C. celeripes – the vegetation was just so thick, with only small openings among the plants. We continued to scour the area closely but saw nothing, and my optimism began to wane. Wrong spot? – I don’t think so. Bad search image? – hard to imagine, considering its similarity to C. cursitans. Too late? – could be.

After it became obvious we were searching the same gaps in the vegetation repeatedly, I started walking towards a small cut further down the hillside that I had noticed earlier (just visible in the previous photo). I had thought, “That’s tiger beetle land down there!” My optimism increased when I reached the cut, seeing the remains of an old, overgrown 2-track leading through the cut and on down the hillside. Vegetation was much sparser within and below the cut – it looked perfect. Chris had become distracted taking photographs of something, so I began searching. I’d been in the cut a few minutes when I thought I saw something flash across a bare patch out of the corner of my eye – was that it? It had to be. I carefully inspected around the base of every clump of vegetation at my feet but found nothing. It must have been wishful thinking – just another spider. I continued on down the cut, and within a few more minutes I saw the flash again – this time there was no doubt as to what it was, and I had a lock on it. I started slapping the ground frantically as the little guy darted erratically under, around, and over my hands. In the few seconds while this was happening, I was simultaneously exuberant at having succeeded in finding it, utterly astounded by its speed and evasiveness, and desperately afraid that it was getting away – swift tiger beetle, indeed! Persistence paid off, however, and eventually I had it firmly in my grasp.

We would see a total of seven individuals that day. Most of them were within or immediately below the cut, while another individual was seen much further down the 2-track. Mindful of the population declines this species has experienced, we decided to capture just three individuals (even though by this point in the season mating and oviposition would have been largely complete) in hopes that at least one would survive the trip back to the lab for photographs. Our primary goal – to see the species in its native habitat – had been accomplished. We now turned our attention to attempting in situ field photographs. This would prove to be too difficult a task – each beetle we located immediately ran for cover, and flushing it out only caused it to dart to another clump of vegetation. This scenario repeated with each beetle until eventually it simply vanished. We would have to settle for photographs of our captured specimens in a confined arena – a few of which are shown here. The beetles were photographed on a chunk of native loess taken from the site, and no chilling or other “calming” techniques were used. Spomer et al. (2008, Field Guide to the Tiger Beetles of Nebraska and South Dakota) state that C. celeripes is a delicate species that does not do well in captivity. It has never been reared, and the larva is unknown. Nevertheless, I placed the chunk of native loess in a plastic tupperware container and transplanted into one corner a small clump of bluegrass from my yard. The soil around the grass clump is kept moist, and every few days I have placed various small insects in the container. Of the three individuals that we brought back, two died within two days. The third individual (these photographs), however, has now survived for four weeks! Moreover, it is a female, and during the past two weeks six larval burrows have appeared in the soil (and another egg was seen on the soil surface just yesterday). Indeed, an egg can be seen in the upper right of the first photo. It remains to be seen whether I will be successful at rearing them to adulthood; however, I’m hopeful this can be accomplished using methods described for C. cursitans (Brust et al. 2005).

Do I still think C. celeripes occurs in Missouri? I don’t know – on one hand, the mixed grass Loess Hill prairie habitats in which the beetle lives in Iowa do extend south into Missouri, and the beetle could be inhabiting them but be easily overlooked for the reasons I’ve already mentioned. However, Missouri’s Loess Hill prairie relicts are small, both in number and in size, and highly disjunct. Such features increase the likelihood of localized extinctions and hamper recolonization through dispersal, especially in flightless species that must traverse unsuitable habitat. With its adult activity period winding down, renewed efforts to locate this species in Missouri will have to wait until next season. Hopefully, the knowledge we gained this season will help this become a reality. For now, the hunt continues…

(closing photo by C. Brown)