tiger beetles

Bee Fly Parasitism of Tetracha virginica

/ Ted C. MacRae / 25 Comments

I expected to gain a better understanding of insect photography principles and techniques at last weekend’s BugShot insect photography workshop at Shaw Nature Reserve in Gray Summit, Missouri.  I even expected that I would walk away from the event with some new friends.  The one thing I did not expect was the discovery of an apparently unreported host/parasitoid relationship amongst my beloved tiger beetles.  Nevertheless, that’s exactly what happened in a patch of barren soil just outside of the Dana Brown Education Center where the event was being held.

Tetracha virginica 3rd instar larva | Shaw Nature Reserve, Franklin Co., Missouri

I had spied the small cluster of tiger beetle burrows the previous day as we left on our first group hike.  The burrows were unmistakably those of Tetracha virginica (Virginia metallic tiger beetle) due to their size (no other tiger beetle in east-central Missouri approaches the size of this species), and in fact some of the larvae were seen sitting at the tops of their burrows.  Tetracha larvae are easily distinguished from other genera of North American tiger beetles (in addition to their size) by their distinctive white-margined pronotum.  I had to catch back up with the group but came back later in the day and took a few photographs of one of the larvae sitting in its burrow.  Some of the other BugShot attendees were there and wanted to take photographs, but the larvae dropped on their less-practiced approach.  No problem, I just “fished” a larva out of its burrow and let them take their photographs.  When they finished, I began taking my own photographs, but I only got off one shot before the larva suddenly made a bee-line for its burrow and dropped in before I could block its escape.  Oh well, I do already have photographs of the larva of this species from other locations.

Tetracha virginica 3rd instar larva | Shaw Nature Reserve, Franklin Co., Missouri

The next day I passed by the burrows again with Crystal and Lee.  I really wanted them to see the larvae, but they were not active.  No problem, I grabbed a long grass stem, chewed on one end, and inserted it to a depth of about 35 cm before it hit bottom.  A little jiggling to get the larva to bite, then a quick jerk back and out came the larva.  I never tire of seeing someone witness this for the first time—the way they jump back half-startled when they see the otherworldly larva flying through the air and landing on the grass.  I grabbed the larva and placed it on the barren clay to let them take photographs.  Crystal went first, and as she looked at the larva through her viewfinder she exclaimed, “there are wormy-things [the technical term, of course] on him.”  Lee and I looked, and sure enough there were two small “wormy-things” attached to the back of the tiger beetle.  I immediately recognized them as bee fly larvae (family Bombyliidae)—specifically Anthrax analis, the only bee fly known to parasitize tiger beetle larvae in the United States.  I was quite excited by this discovery, as I have never seen these before despite fishing untold numbers of tiger beetle larvae from their burrows over the past decade or so.  We all went camera crazy and took our turns photographing larvae and host, after which I popped it into a vial to keep for an attempt at rearing out the bee flies.

Anthrax analis larvae attached to abdomen of Tetracha virginica larva

It now seems that our find represents more than just a personal discovery, as bee flies—to my knowledge—have not yet been reported parasitizing any species of the genus Tetracha.  Of the 70 Anthrax spp. for which hosts have been recorded (Yeates and Greathead 1997), only three are known to parasitize tiger beetles.  Shelford (1913) gave the first account of A. analis (as Spogostylum anale) parasitzing Cicindela scutellaris lecontei, noting that the adult females lay their eggs by flying backward and downward while thrusting the abdomen forward until it touches the sand near the host burrow entrance.  Hamilton (1925) found Cicindelidia obsoleta parasitized by this species, and Bram and Knisley (1982) expanded its known host spectrum to include C. hirticollis, C. tranquebarica, Cicindelidia punctulata, and Ellipsoptera marginata.  Photographs of larvae (presumably of this species) parasitizing undetermined tiger beetle larvae can be seen in Pearson and Vogler (2001) and in this photo by Chris Wirth.  Anthrax gideon has been recorded parasitizing Pseudoxycheila tarsalis in Costa Rica (Palmer 1982) and Oxycheila trisis in Brazil (Arndt and Costa 2001), while a third undetermined Anthrax sp. has been reared from larvae of Pentacomia ventralis, also in Brazil (Arndt and Costa 2001).  Oxycheila and Pseudoxycheila are related to Tetracha at the tribal/subtribal level (depending on which classification you follow), so the finding of A. analis utilizing Tetracha is not unexpected.

Closer view of anteriormost Anthrax analis larva

The beetle larva and its unwelcome tagalongs is now in a container of native soil and has accepted the starter burrow that I made for it. Hopefully at least one of the bee fly larvae will complete its development and emerge as an adult to allow confirmation of its identity.  If this host association does turn out to be unreported, we will follow up with at least a short journal communication.  To that end, any literature citations you are aware of regarding bee fly parasitism of tiger beetles that is not listed below would be most welcome.

Congratulations to Ben Coulter, who wins yet another BitB Challenge with 14 points (this guy is a machine!), and Mr. Phidippus came close with 13 points.  Ben and Phiddy were the only participants that figured out the parasites were bee flies of the genus Anthrax, and Phiddy was the only participant to guess the correct genus for the host.  Ben’s win gives him a now commanding lead with 49 points in the current BitB Challenge Session #4 as we enter the home stretch.  Mr. Phidippus and Roy are still in striking distance with 39 and 28 points, respectively.  Is anybody capable of keeping him from his third title?  We shall see.

REFERENCES:

Arndt, E. and C. Costa.  2001.  Parasitism of Neotropical tiger beetles (Coleoptera: Carabidae: Cicindelinae) by Anthrax (Diptera: Bombyliidae).  Studies on Neotropical Fauna and Environment 36(1):63–66.

Bram, A. L. and C. B. Knisley.  1982.  Studies on the bee fly Anthrax analis (Bombyliidae), parasitic on tiger beetle larvae (Cicindelidae).  Virginia Journal of Science 33:90.

Hamilton, C. C. 1925. Studies on the morphology, taxonomy, and ecology of the larvae of Holarctic tiger beetles (family Cicindelidae).  Proceedings of the U.S. National Museum 65 (Art. 17):1–87.

Palmer, M. K.  1982.  Biology and behavior of two species of Anthrax (Diptera: Bombyliidae), parasitoids of the larvae of tiger beetles (Coleoptera: Cicindelidae).  Annals of the Entomological Society of America 75(1):61–70.

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.

Shelford, V. E.  1913.  The life history of a bee-fly (Spogostylum anale Say) parasite of the larva of a tiger beetle (Cicindela scutellaris Say var. lecontei Hald.).  Annals of the Entomological Society of America 6(2):213–225.

Yeates, D. K. and D. J. Greathead.  1997. The evolutionary pattern of host use in the Bombyliidae (Diptera): a diverse family of parasitoid flies.  Biological Journal of the  Linnaean Society 60:149—185.

Copyright © Ted C. MacRae 2011

Use of extension tubes for better lighting

/ Ted C. MacRae / 17 Comments

The photos in this post of Tetracha floridana (Florida Metallic Tiger Beetle) illustrate a technique that I have begun using recently to improve the lighting in my full-flash insect macrophotographs—use of extension tubes!  I know this sounds strange, and I actually just stumbled onto it myself when I started using extension tubes in combination with my Canon EF 100mm macro lens.  Okay, I can hear it now: “Why not use the Canon MP-E 65 mm macro lens?”  It’s a good question, as at magnifications above 1X there is no finer lens than the 65mm.  However, the tiger beetles that I spend a lot of time photographing are right in that size range where sometimes I need magnifications below 1x (whole body shots of medium to large species), while other times I need magnifications above 1X (small species and closeups—particularly face shots).  Fortunately, the entire spectrum of magnifications (up to 5X) is covered by these two lenses, but there is, unfortunately, no overlap.  This is where the extension tubes come in—when all 68mm are added the 100mm lens effectively changes from a 1.0X–∞ lens to a 0.7–2.0X lens.  This gives a frame width of 11–33 mm, perfect for nearly all North American tiger beetles (most species range from 6-20 mm, excluding legs and antennae). 

In addition to allowing a more appropriate range of magnifications without the need to switch out lenses, this has one other effect—it moves the lens a little closer to the subject.  That in itself is of no particular benefit, but since I use the front-of-the-lens-mounted Canon MT-24EX dual flash, it also moves the flash a little closer to the subject.  It’s not a huge distance, only about 20 mm, but keep in mind that the flash heads extend forward from the front of the lens (especially with the Kaiser shoes that I use with my diffuser), and the front of the diffuser itself lies at about 60 mm in front of the lens face.  Thus, at 1X the the front of the diffuser sits ~80 mm from the subject with the 100mm lens only, but with 68 mm of extension tubes added it sits only 60 mm from the subject.  The closer the light source is to the subject, the greater the apparent light size, and larger apparent light size results in more even lighting with reduced specular effects.

Tetracha floridana | Pinellas Co., Florida (100mm lens only)

100mm lens + 68mm extension tubes

100mm lens only (slightly cropped)

100mm lens + 68mm extension tubes

The primary disadvantage to doing this is loss of ability to focus to infinity.  Frankly, this is functionality I never used with the 100mm lens, preferring instead the 17-85mm wide-angle lens for more general landscape and habitat photos.  The other downside is that placing the lens closer to the subject can result in greater chance of “spooking” the subject and causing it to flee or behave evasively.  Again, however, my experience is that if a subject can be photographed at 1X with the 100mm lens, it can be photographed at 2X with the 100mm lens + extension tubes.

Has anybody else ever tried this, and if so what was your experience?

Copyright © Ted C. MacRae 2011

Gnom, Gnom, Gnom…

/ Ted C. MacRae / 9 Comments

I’ve become a big fan of night-time tiger beetle photography since my early August trip to Florida.  Not only does it open up the world of nocturnal species that might go undetected during the day, it also affords the opportunity to see diurnal species engaged in behaviors that are more difficult to photograph during the day.  This female Gulf Beach Tiger Beetle (Ellipsoptera hamata lacerata) came to my blacklight at a coastal salt marsh near Steinhatchee and promptly began munching on a smaller beetle that had also come to the light.  I didn’t get a good enough look at the prey early on to identify it, and by the time I was able to zoom in big with the camera lens the prey had already been macerated to a crunchy pulp.  It was interesting to watch the tiger beetle grasp and chew the prey with its mandibles while manipulating its position with its maxillary parts.




Copyright © Ted C. MacRae 2011

Why I Roamed the Marsh at Night

/ Ted C. MacRae / 22 Comments

Tetracha floridana (Florida Metallic Tiger Beetle) | Pinellas Co., Florida

For two years I waited.  The narrow strip of coastal scrub and mangrove marsh along the intracoastal waterway behind my sister-in-law’s condominium in Seminole, Florida had been an unexpected surprise during my first visit in August 2009.  Despite its small size and urban surroundings, it proved to be a good spot for tiger beetles, including Ellipsoptera marginata (Margined Tiger Beetle) and the closely related E. hamata lacerata (Gulf Coast Tiger Beetle).  Also living there was a much rarer tiger beetle—the Florida-endemic species Tetracha floridana (Florida Metallic Tiger Beetle), but I did not know this at the time.  In fact, had I not happened upon some larval burrows as I was leaving the preserve and decided to collect a few and rear them to adults, I would still not know they were there.  Only after the two larvae that made it back to St. Louis alive emerged as adults in their rearing container did I realize what I had found.  The reason I had not seen any adults during my visit was simple—they, like all members of the genus to which they belong, are strictly nocturnal!  Nevertheless, I knew I would return sooner or later and have another shot at seeing adults of this species in the wild.

A male, distinguishable by the thick brushy pads on the front tarsi.

And return I did.  My wife and I decided fairly early this year that we wanted to return to Florida for our summer vacation.  She likes the beach and her sister, and the kids like the beach and their aunt.  I don’t like the beach so much (though my sister-in-law is pretty cool), but I love Florida for its diversity of tiger beetle species and their high level of endemism.  During my 2009 trip I managed to find nine species, which, in addition to T. floridana, included also the very rare and potentially threatened Cicindelidia highlandensis (Highlands Tiger Beetle), known only from the Lake Wales Ridge in central Florida, and the (near) endemic Ellipsoptera hirtilabris (Moustached Tiger Beetle).  This year I set my sight on several other endemics—e.g. Cicindelidia floridana (Miami Tiger Beetle)—and near-endemics—e.g. Cicindelidia scabrosa (Scabrous Tiger Beetle).  My searches for these targets would have to wait for a few days, but for T. floridana I had only to wait until nightfall on the day we arrived.  The bleating chorus of tree frogs was my signal, and as the rest of the family retired to their bedrooms I geared up with my collecting fanny pack, camera bag and headlamp and headed out to the marsh.

The species lacks the violaceous reflections found on the elytra of T. carolina.

As I mentioned in my previous post, it was a little unnerving to walk into the marsh surrounded by darkness and greeted by scuttling hordes of sea slaters.  The anticipation of finally seeing T. floridana, however, was more than enough motivation to forge onward while deliberately scanning the ground with my headlamp.  For some amount of time I focused on the more barren areas, which is where I would have expected the adults to occur, but only after I also began scanning some of the sparsely vegetated ground—typically slightly elevated above the moister and more barren areas—did I see the first adult.  Its agile dash into and through the vegetation upon my approach was a little surprising and required more effort than I expected to finally capture it.  Elation!  Finding rare species is always a treat, but it is extra special when you find one where nobody previously knew it existed.  Over the course of the next 1½ hours (as well as the following night and two nights after that) I would see countless adults, giving me comfort that I could collect a reasonable voucher series without causing negative impacts on the population.

A female oviposits in the soil amongst the sparse, salt-tolerant vegetation.

I had hoped to see mating pairs but never did; however, I did find a female in the act of oviposition.  Consistent with the apparent adult preference for sparsely vegetated areas rather than barren ground, the female was nestled amongst the vegetation while she excavated a hole for the egg she would lay.  On the last night that I visited the marsh, I focused my efforts on finding larval burrows, starting in the area where I had seen them two years ago.  I only found a few but succeeded in fishing one 3rd-instar larva out of its burrow.  You see, even though I photographed one two years ago, the larva of this species remains undescribed in the literature.  Since I allowed the two larvae I had collected to complete their development to adulthood, I still lacked preserved specimens that could be used for the basis of a description.  I now had one, but for a formal description it would be better to have at least a few examples.  Remembering that I had seen the female ovipositing amongst vegetation rather than out in the open, I began searching the nearby vegetated areas for burrows.  This approach was met with better success, and from the dozen or so burrows that I was able to find, I succeeded in fishing out two more 3rd-instars.  I already have several preserved larvae of Tetracha virginica (Virginia Metallic Tiger Beetle) and a single T. carolina (Carolina Metallic Tiger Beetle) collected in southeastern Missouri by my good friend Kent Fothergill—this small series of T. floridana now leaves me lacking only the also-undescribed T. impressa (Upland Metallic Tiger Beetle) among the four North American (sensu stricto) species of Tetracha.  I will be anxious to compare the larvae of T. floridana I now have with those of T. carolina and T. virginica in an effort to find species-specific characters.

This male is sporting some very impressive teeth on his mandibles.

Copyright © Ted C. MacRae 2011

The (almost) Florida-endemic Cicindelidia scabrosa

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The recently rediscovered Cicindelidia floridana (Miami Tiger Beetle) may have been the highlight of my 48-hour early August blitz through Florida, but it was by no means the only Florida-endemic that I hoped to find during the trip.  In fact, the day before I saw C. floridana I found the species it was formerly considered a subspecies of, C. scabrosa (Scabrous Tiger Beetle), itself an almost Florida-endemic (its distribution extends just north of the border into extreme southeastern Georgia).  I had word that I might find the species in sand pine scrub habitat along the Gulf Coast around Lower Suwanee National Wildlife Refuge and Cedar Key Scrub State Preserve (Levy Co.).  This area lies very near yet another locality (where I was hoping to find yet another Florida-endemic), further justifying my decision to travel several hours north the day before I was to retrace my route back to the south and then continue on down to Naples to meet up with Dave Brzoska and Chris Wirth for the trip to Miami to see C. floridana.

Cicindelidia scabrosa (Scabrous Tiger Beetle) | Levy Co., Florida

Cicindelidia scabrosa is one of four small, sand-dwelling species with red venters collectively referred to as the abdominalis-species group (Brzoska et al. 2011).  The nominate species, C. abdominalis (Eastern Pinebarrens Tiger Beetle), is the most widespread member of the group, occurring across the Southeastern U.S. Coastal Plain from Maryland and New Jersey to Louisiana (Pearson et al. 2006).  The three remaining species are Florida-endemics (C. floridana and C. highlandensis—Highlands Tiger Beetle) or near endemic (C. scabrosa), presumably evolving during the Pleistocene Epoch (1.8 million to 10,000 years ago) at a time when fluctuating sea levels repeatedly isolated peninsular Florida from the mainland.  I found both C. abdominalis and C. highlandensis during my 2009 trip, so finding C. floridana and C. scabrosa on this trip means that I have now seen all four members of the abdominalis-species group.

Black, sculptured elytra and dense lateral bands of pronotal setae distinguish this species.

There is little doubt about the distinctiveness of C. scabrosa compared to C. abdominalis and C. highlandensis, as neither of the latter two species exhibit the distinctly scabrous elytra or rows of flattened setae on the sides of the pronotum exhibited by C. scabrosa.  The distinction of C. scabrosa from C. floridana, however, is more subtle—C. scabrosa is shiny black and always exhibits a post median marginal spot anterior to the apical lunule, while C. floridana is shiny green and usually lacks the post median marginal spot.  In addition, the legs of C. floridana are somewhat lighter in coloration than those of C. scabrosa.  The difference in coloration is subtle in preserved specimens but obvious in living individuals.  After seeing the C. scabrosa in the field one day and C. floridana the next, my first thought regarding the latter was, “Wow, that’s different!”—a result of the brilliant coppery highlights that are quite evident in living individuals but apparently fade in preserved specimens.

Sand pine scrub, habitat for Cicindelidia scabrosa and Ellipsoptera hirtilabris

The distinction between C. scabrosa and C. floridana is not limited to subtle morphological characters—included also are differences in habitat, distribution, and seasonal occurrence.  Cicindelidia scabrosa occurs broadly across the Florida peninsula in sand pine scrub, a xeromorphic plant community featuring an open canopy of sand pine (Pinus clausa) growing on well-drained, infertile, sandy soils (Brzoska et al. 2011).  The species is absent, however, from much of south Florida where the wet areas of the Everglades limit availability of suitable habitat.  Cicindelidia floridana, on the other hand, is restricted to a small area of Miami-Dade County and parts of the Keys where pine rockland habitat, a savanna-like forest of Florida slash pine (Pinus elliotti var. densa) and scrub understory, can be found growing on limestone outcrops.  The photos in this post were taken on an open 2-track through sand pine scrub near Cedar Key Scrub State Preserve.  Occurring here in asscociation with C. scabrosa was another (almost) Florida-endemic tiger beetle, Ellipsoptera hirtilabris (Moustached Tiger Beetle), which I have also seen in association with C. abdominalis and C. highlandensis (but not C. floridana).

The obligatory face shot!

It is perhaps redundant for me to state that it was extraordinarily hot while I photographed these beetles.  Temperatures were already approaching 90°F when I found the first individuals, and by mid-day when they finally disappeared it was nearly 100°F.  Add to that the mid-summer Florida humidity, and I was about as soaked as I ever get. It’s a photographer’s nightmare—trying to protect expensive gear while scrumming through the sand and sweating profusely, all the while still trying to get the perfect shot!  The beetles were smart enough to call it a day at 12:30 p.m., and I must say I didn’t mind having to get into an air-conditioned car, chug a quart of ice-cold Gatorade, and spend the next several hours not broiling under the hot Florida sun while making the long drive south.

REFERENCES:

Brzoska, D., C. B. Knisley, and J. Slotten.  2011.  Rediscovery of Cicindela scabrosa floridana Cartwright (Coleoptera: Cicindelidae) and its elevation to species level. Insecta Mundi0162:1–7.

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.

Copyright © Ted C. MacRae 2011

Predator or Prey?

/ Ted C. MacRae / 25 Comments

Ellipsoptera hamata lacerata | Dixie Co., Florida

Everyone knows that tiger beetles are predators, but look closely at the underside of the head of this female Ellipsoptera hamata lacerata (Gulf Beach Tiger Beetle), photographed in a coastal marsh in Dixie Co., Florida earlier this month.  See the ant head attached by its mandibles to the base of the tiger beetle’s left maxillary palpus?  Detached ant heads latched onto the palp or antenna of a tiger beetle are a fairly common sight—Pearson and Vogler (2001) show the head of an ant attached to the antenna of Eunota togata (Cloaked Tiger Beetle), and Pearson et al. (2006) show one attached to the antennae of Cicindela formosa (Big Sand Tiger Beetle).  I’ve also photographed Cylindera celeripes (Swift Tiger Beetle) with an ant head attached to its antenna.  Pearson and Vogler (2001) and Pearson et al. (2006) both suggest that the ant heads are the result of predation attempts by groups of ants attempting to overpower and kill the tiger beetle, making the ants the predators and the tiger beetles the prey.

Note ant head attached by its mandibles to the base of the tiger beetle's left maxillary palpus.

Although some ants are well known for their predatory horde behavior, I’m not sure I buy this as an explanation for the common occurrence of ant heads attached to tiger beetles.  Tiger beetles themselves often prey on ants, and while I have seen numerous tiger beetles with ant heads attached to them, I have never seen one actually being overpowered by ants (scavenging an already dead tiger beetle, yes—but not overpowering and killing one).  Moreover, the ant heads are nearly always attached to the base of an antenna or palpus—right next to the tiger beetle’s mouth, and almost never on more distal parts of the antennae or other parts of the body.  If the ants were attempting to prey on the tiger beetle, wouldn’t they also (if not even more commonly) be found attached to the tiger beetle’s legs or soft intersegmental membranes?  And how would the ants have come to be decapitated while in the act of attempting to overpower the beetle?  I suggest it is more likely that the ants were prey, latching onto the nearest part of their killer’s body in a last ditch attempt to avoid their inevitable fate.  The antennal and palpal base are about the only tiger beetle body parts that would be within reach of an ant in a tiger beetle’s toothy grasp.  While the rest of the ant was consumed, the head remained because it was firmly attached to the beetle.

I realize that an identification based only on the detached head of an ant may be difficult, but if one is possible it would be appreciated.  The ant head shown in Pearson and Vogler (2001) was identified as Polyergus sp.

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 2011

Photographing the Newly Rediscovered Cicindelidia floridana

/ Ted C. MacRae / 21 Comments

Cicindelidia floridana | Richmond Heights area, Miami-Dade Co., Florida

When Brzoska et al. (2011) announced the rediscovery of Cicindelidia floridana last April (and also provided convincing evidence for considering it a full species), I could hardly contain my excitement. At a time when increasing numbers of species are being reported in decline or going extinct, the news that this small jewel of a beetle had somehow managed to survive in tiny chunks of remnant habitat (completely surrounded by the sprawling metropolis of Miami) after having not been seen for more than half a century and presumed extinct (Pearson et al. 2006) was cause for celebration.  For me, the timing couldn’t have been better as I was already planning a visit to Florida later in the summer to spend a little time with my family and—of course—search for some of Florida’s several endemic tiger beetle species.  The precise locations where C. floridana have been found have not been publicly disclosed (for obvious reasons), but when I contacted lead author Dave Brzoska and told him of my plans to be in Florida this summer and my interest in seeing the beetles, he graciously offered to take me to the sites himself.  Expedition turned to party when Chris Wirth, author of the cicindelocentric blog Cicindela, made arrangements to fly down from Virginia and join Dave and I on our trip.  This would be Chris’ second visit to see the beetles, having been one of the very lucky first few to see it after its rediscovery while assisting second author Barry Knisley on the initial surveys that were conducted.  For me, it was a cicindelophile’s dream come true—a day in the field with Dave (whom I had not seen in more than 25 years), meeting Chris for the first time, and looking for and (hopefully) photographing one of North America’s rarest tiger beetles.

Pine rockland habitat for Cicindelidia floridana.

Adults beetles frequent sparsely vegetated sandy exposures in the palmetto understory.

After a delightful evening looking at meticulously curated specimens in Dave’s astounding collection, the three of us left early the following morning from his home in Naples to make the 2½-hr drive to Miami.  Temperatures in south Florida during early August can soar as the day progresses, and as they do the beetles—already flighty and difficult to observe—become even more so before eventually taking refuge under debris.  We arrived at the first site right at mid-morning, at which time I was allowed to remove my blindfold (just kidding!).  One of the features that distinguishes this species from C. scabrosa is its habitat—south Florida pine rockland as opposed to the more widespread peninsular sand pine scrub habitat frequented by C. scabrosa.  Pine rockland is a fire-adapted community composed of an open canopy of south Florida slash pine (Pinus elliottii var. densa) and a diverse understory of cabbage palm (Sabal palmetto) and other shrubs.  As I readied my camera gear, Dave told me to look for small exposures in the understory and then watch them for any sign of movement.  The adult beetles, despite their brilliant coloration, are among the smallest tiger beetle species and are exceedingly difficult to detect amongst the vegetation and debris covering the soil.  I could have just let Dave look for the beetle first while I tagged along and then let him “show” them to me, but I wanted to find them for myself, so I struck out on my own and started searching.

Shiny green coloration and reduced elytral maculation distinguish this species from C. scabrosa.

It wasn’t long before I heard Dave and Chris call out that they had seen one, and while the temptation was great to go over to where they were and look at what they had already found, I stayed the course and continued searching on my own.  Finally, I saw one!  It was gorgeous and brilliantly colored—much more copperish in appearance than I had expected (Dave later explained that this is something seen better in the live beetles and not so well in preserved specimens).  Deciding how to approach an unfamiliar tiger beetle for photography is always a crap shoot—until one gets a feel for its behavior and the way it reacts to movement it is difficult to know precisely how to approach it.  I had gone ahead and tempted fate by mounting my 65mm macro lens and its very short working distance, so I would need to draw on the entirely of my experience in photographing tiger beetles to figure out how to get close enough to these beetles to photograph them.  I hadn’t even gotten down on my knees yet before the first adult took flight and disappeared before my eyes.  Knowing what to look for now, I continued searching and found another adult after a short time—with the same result!  Beetle after beetle appeared before me on the sparsely vegetated sand openings and then zipped away well before I had the camera in position.  Finally, by about the 10th beetle that I saw I found one that seemed a little more cooperative (or maybe I had just finally learned how to move in on them).  I carefully, slowly layed down on the ground and got the camera in position as the beetle skitted here and there, obliviously feeding on the occasional ant, then located it in the viewfinder and started firing off shot after shot.  The two photos above represent my favorites from that series and well show not only the elytral sculpturing and flattened pronotal setae that distinguish both this species and C. scabrosa from the other members of the group (C. abdominalis and C. highlandensis), but also the bright greenish coloration, reduced elytral maculation, and lighter leg coloration that Brzoska et al. (2011) used as justification for elevation to a full species distinct from C. scabrosa.

Cicindelidia floridana adults mating.

After failing to get more shots of the next 10 or so adults that I found, I saw a male hop on top of a female and attempt to mate.  I quickly got into position to photograph them, but just as I got them framed they uncoupled and ran their separate ways.  I figured I had probably lost my only chance to photograph a mating pair, but shortly afterwards I encountered another couple that was already engaged.  I saw them before they became disturbed and moved, and as a result I found it relatively (relatively!) easy to get in position and begin photographing without alarming them.  Tiger beetles are often encountered coupled but not actively mating, as the males will often ‘mate guard’ a female for an extended period after mating to prevent other males from mating with her (in many beetles, the last male to mate with a female stands a greater chance of fertizilizing the eggs she lays) (Pearson and Vogler 2001).  This couple, however, was actively engaged as evidenced by the exserted male genitalia firmly penetrating the female genital opening.

Genitalia actively engaged.

I watched the mating pair for a period of time and notice that at times the male held the female more tightly with his front legs, while at other times he held his front legs extended widely out to the sides.  I have seen this same behavior in nearly every tiger beetle species in which I have observed mating pairs and have yet to find or intuit an explanation.  The male has dense, brush-like pads on the undersides of the front tarsi, which presumably are used to aid in grasping the female during mating and may also possibly aid in signaling during courtship.  Perhaps extending the legs to the sides is done at times when the female is not struggling to dislodge the male (itself an interesting subject), allowing them to serve a tactile function to better warn against intruding males.

Sometimes the male held his forelegs against the female...

...while other times the forelegs were extended widely to the sides.

All told we spent about 2½ hours at the site, and I estimate that I saw a total of approximately 30 beetles.  Some may have been the same as those I had seen before, since I tended to focus my searches in three small areas of sandy exposures not too distant from each other.  Chris and Dave each worked separate areas as well, also seeing a good number of beetles and suggesting that the population at this site, despite the limited extent, is quite good.  Puddles of water on the road as we entered the site indicated that the site had received recent rains, which may have been at least partly responsible for the level of adult activity observed. We drove by additional pine rockland remnants in the vicinity before heading back to Naples, some of which are known to contain the beetle and others that still need additional survey to determine the presence of the beetle and its status. With an extent of suitable habitat that is among the smallest of all North American tiger beetles, I suspect that C. floridana will be a good candidate for listing on the Endangered Species List. It will be a second chance for the beetle—and for us to see if we will be able to muster the will to save a species once thought extinct from actually becoming so.

Me with Dave "Dr. Tiger Beetle" Brzoska.

Tiger beetle photographer extraordinaire Chris Wirth.

Congratulations to Ben Coulter, who returns to his winning form and takes this first round in the current BitB Challenge Session (#4) with 14 points. Dave Hubble takes 2nd with 12 points, while Mr. Phidippus and FlaPak tie for the final podium spot with 10 points each.  Nine other participants tested their skills, and if you didn’t play, they’ve all now got the jump on you!

REFERENCES:

Brzoska, D., C. B. Knisley, and J. Slotten.  2011.  Rediscovery of Cicindela scabrosa floridana Cartwright (Coleoptera: Cicindelidae) and its elevation to species level. Insecta Mundi 0162:1–7.

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, N.Y., xiii + 333 pp.

Copyright © Ted C. MacRae 2011

Tiger Beetle Nocturnal Perching

/ Ted C. MacRae / 19 Comments

Ellipsoptera hamata lacerata | "Road to Nowhere" Dixie Co., Florida

During last week’s 48-hour blitz through Florida, I spent one evening blacklighting at the famed “Road to Nowhere” tiger beetle hot spot and encountered this male individual of Ellipsoptera hamata lacerata¹ clinging to the grass near my light.  A quick search of the surrounding area revealed a number of similarly perched individuals, including a mating pair and all representing the same species.

¹ Males (identified by the brushy pads under the foretarsi) of this species are distinguished from the closely related E. marginata, which co-occurs with E. hamata lacerata along the Gulf coast of Florida, by the lack of a distinct tooth on the underside of the right mandible.

Like many species in this and related tiger beetle genera, E. hamata is diurnal but also highly attracted to lights at night. This is thought to be related to nocturnal dispersion behaviors (Pearson and Vogler 2001) intended to avoid higher daytime predation risks. Nocturnal perching on foliage is also common among diurnally-active species in riparian habitats and seems also to be an adaptation for reducing predation. Pearson and Anderson (1985) noted that perched beetles removed from the grass and placed on the ground were often quickly preyed upon by larger nocturnally-active tiger beetles. At “Road to Nowhere” this might include the slightly larger Habroscelimorpha severa which occurred in enormous numbers alongside this species on the mud flats, or the much larger Tetracha virginica which occurred in fair numbers on the adjacent road.

REFERENCES:

Pearson, D. L. and J. J. Anderson.  1985. Perching heights and nocturnal communal roosts of some tiger beetles (Coleoptera: Cicindelidae) in southeastern Peru.  Biotropica 17(2):126–129.

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

Copyright © Ted C. MacRae 2011