conservation

Cicindela galapagoensis

A tiger beetle is hardly the first organism that comes to mind when the Galapagos Islands are mentioned. However, the Islands are home to a single endemic member of this subfamily, Cicindela galapagoensis.

Cicindela galapagoensis was first collected by then Stanford student F. X. Williams while he was serving as an entomologist on the California Academy of Sciences 1905-1906 expedition to the Galapagos. It was over ten years until this species was formally described, though this distinction went to German entomologist Walther Horn. In Coleoptera of the Galapagos Islands E.C. Van Dyke curtly mentions: “A tiger beetle collected by Williams was described by Dr. Walther Horn … as Cicindela galapagoensis. It had been submitted to him for his opinion.”

This species is represented by two color forms: a dark and a pale form. As one might suspect, this variation has led to some taxonomic confusion. The dark form of C. galapagoensis was described under the name Cicindela vonhageni in 1938, by American Museum of Natural History curator A.J. Mutchler, from 7 specimens collected by W. von Hagen. Additionally, a subspecies, C. galapagoensis discolorata, was described in 1967 from a single specimen collected on Genovesa Island. However, in 1976, Hans Reichardt synonymized vonhageni and galapagoensis discolorata with galapagoensis after finding evidence for only a single species based on the presence of intermediate forms in a large series of specimens.

Cicindela galapagoensis has been collected from seven major islands¹ where it inhabits sand beaches, mud flats, and salt tidal marshes. The adults have been collected at night with no reported observations of activity in the daytime. The larvae have been described and are found in similar habitats to the adults.

While C. galapagoensis is the sole endemic species of tiger beetle in the archipelago, a mainland species, Cicindela trifasciata was apparently introduced onto Santa Cruz Island and subsequently spread to several sites on during an extreme El Niño event in 1982-1983.  Since the apparent introduction, the trifasciata populations have grown to vastly out number the endemic speceis on the order of hundreds to one. As expected, the number of galapagoensis observed in recent studies has dramatically dropped at the sites where the two species co-occur, almost certainly due to fierce competition for prey and potentially larval habitat.

In addition, Cassola et al. noted that C. galapagoensis was not observed on Genovesa Island and, most distressingly, reported that the species primary habitat on the island, a small sand beach, had been incorporated into the tourist trail. The resultant trampling likely wiped out any larvae and rendered the habitat unsuitable, resulting in the extinction of this population.

Back in January, I have the privilege to spend ten days in the Galapagos. Though I did not see any tiger beetles, one of our stops was the beach at Genovesa, on Darwin Bay. We went ashore just after the equatorial sun rose and I was struck by the traces of human activity. Old graffiti was conspicuously emblazoned on the cliffs and footprints were almost everywhere across the small beach. As we proceeded down the beach the impact of foot traffic became even more apparent.

But, as a whole, Cicindela galapagoensis is not in danger. The Santa Cruz and Genovesa populations are not the rule and most of the species habitat is free from introduced competitors and the menace of human foot traffic. Adequate surveys are needed to assess the extent of tricfasciata colonization and the overall health of C. galapagoensis populations in order to develop management strategies. Ultimately, with careful management, this enigmatic species can continue to thrive.

Notes:

¹ Fernandina, Floreana, Genovesa, Isabela, Marchena, San Cristóbal, and Santa Cruz (Peck 2006)

References:

Cassola, F., Roque-Albelo, L., and Desender, K. 2000. Is the Galápagos endemic tiger beetle threatened with extinction? Noticias de Galápagos no. 61: 23–25.

Horn, W. 1915. Coleoptera, Fam. Carabidae, Subfam. Cicindelinae. In P. Wytsman, ed., Genera Insectorum, 82C: 209-487, pl. 16-23.

Mutchler, A.J. 1938. Coleoptera from the Galápagos Islands. American Museum Novitates 981: 1-19.

Van Dyke, E.e. 1953. The Coleoptera of the Galápagos Islands. Occasional Papers of the California Academy of Sciences 22: 1-181.


Revisiting the recently rediscovered C. floridana

It is an early August morning and I am sitting in the Richmond International Airport, once again waiting for a flight to south Florida. There I will be revisiting the site where Cicindelidia floridana, once believed extinct, was rediscovered in 2007.

Last August I had the privilege of seeing this rare species in the wild and photographing several individuals while assisting Barry Knisley with surveys of the potential habitat.

Ever since that trip to Miami I hoped to make another trip down to see this species so when Ted MacRae, author of the excellent blog Beetles in the Bush, mentioned he was traveling to Florida this summer I jumped at the chance to see this species and to meet Ted in person. Before long the arrangements were set; not only would I be meeting Ted, but also the co-author of the floridana paper and prolific tiger beetle collector David Brzoska.

We would not be meeting until the evening of the day after my flight arrived, so upon my arrival in south Florida, while I had some free time, I visited several sites in search of a number of Floridian tiger beetle species (the results of this tangent will be detailed in future posts).

The next evening Ted and I met up at Dave’s where we spent the bulk of the evening looking at Dave’s unparalleled collection of tiger beetles from all over the world and I finally turned in for the night with visions of Manticora and Pseudoxycheila dancing in my head

We got an early start the next morning and headed out from Naples towards Miami on the approximately 2½-hour drive. By the time we reached the site the temperature was climbing through high eighties, presenting a distinct challenge to photographing this specie let alone any tiger beetle.

C. floridana is found in open sandy patches in pine rocklands, a habitat once common in the Miami area. The saw palmetto obscured any sandy areas so from a distance the habitat seemed unsuitable.

As Ted and I readied our camera gear, Dave ventured out through the saw palmetto and soon called out that he had spotted a beetle. I walked to a nearby sandy patch and quickly noticed the distinctive flash of movement. This first beetle darted away and then took flight as I attempted to maneuver closer.

However, in the next sandy area I spotted another beetle and began to slowly move in. This beetle also turned and took flight. And the next. This frustrating sequence of events repeated several times.

At last, after painstakingly inching forward on my stomach, I finally snapped a beautiful shot of a small male beetle. From a distance the beetle’s color was an oily bronze with subtle green undertones, but up close and lit by my flash this striking green was fully visible.

While I snapped off several shots this cooperative beetle remained still and, pressing my luck I moved in for a closer shot. To my surprise I was able to zoom in and get a closer shot which prominently showed the snow-white pronotal setae.

After this definite success, I managed to snap shots of a few other beetles, but none of these images turned out quite as nice as my first shots.

I then observed the behavior of the beetles in a few of the clearings. With the sun out and the temperature well into the eighties the beetles were actively moving about the sandy areas. I would notice a beetle occasionally “duck” its head as it snatched up one of the many small ants that were also running about. The beetle in question would then stand still and, watching closely, I could make out the swift movement of its mandibles as the hapless ant was reduced to mush.

When not actively looking for prey or a mate, the beetles would often take refuge from the sun in the shade of a grass stem near the edges of the clearing.  I did see several attempted matings while I watched and once particularly determined male did manage to maintain his grip. The pair remained coupled for several long minutes until the female dislodged the male and scurried away.

Time passed all too quickly and before long Ted, Dave, and I began to gather back up to the car and soon headed back down the road to Naples. It had been a extremely successful day for me and Ted as well.

Check out Ted’s excellent post on this trip here or check out the photos from my first trip to see this species here.


The Puritan tiger beetle


this just in…

Much to my delight I recently got my copy of the latest issue of the journal Cicindela in the mail; this issue includes two articles which peaked my interest:

In this issue Ted MacRae and Christopher R. Brown report on the occurrence of Dromochorus pruinina in Missouri. In brief, their findings suggest that D. pruinina has a severely limited range within Missouri, comprised of a small area within Johnson county; Ted addresses the implications of this over on his blog.

In the second article in this issue Jan Scott and John Acorn report a mass death of Cicindela purpurea auduboni and Cicindela decemnotata in September 2010. Scott observed some hundreds of these species dead near a trail atop a ridge in Medicine Hat, Alberta Canada.They note that the beetles appeared fresh; unmarred and still flexible with no outward clues to their demise. At the same time some live adults were observed with no apparent abnormalities in their behavior. While there were no photographs taken or official count made, some specimens were collected and deposited in Scott’s personal collection. The authors additionally report no similar incidents in the literature, thus rendering an explanation for this incident problematic.

Possible explanations proposed include that the deceased beetles may have emerged and had their first period of activity as adults in adverse weather conditions  (lower temperatures and rain ) during the previous two weeks; consequently the conditions may have had some significant role in this incident. The authors also note the possibility of a chemical  toxin as the causal agent; however, they dismiss this as a remote possibility citing the lack of evidence (no direct insecticide or other chemical spraying in the nearby area).

Literature Cited:

MacRae, T. C. and C. R. Brown. 2011. Distribution, seasonal occurrence and conservation status of Dromochorus pruinina (Casey) in Missouri. CICINDELA 43(1):1–13.

Scott, J. and J. Acorn. 2011. A puzzling  mass death of Cicindela purpurea auduboni LeConte. and Cicindela decemnotata Say In Medicine Hat, Alberta, Canada. CICINDELA 43(1):15–17.


Presumed extinct, Floridian tiger beetle rediscovered after 73 years

It is about five in the morning on a warm August day and I am sitting in the Richmond International airport. I am waiting to board a flight to Miami, Florida where I will be meeting up with Dr. Barry Knisley, researcher and authority on tiger beetles.

Florida is home to many species of tiger beetles including several endemic to the state. However, the habitats of a number of species are today threatened by urbanization or the development of land for agricultural use, particularly for Florida’s ubiquitous citrus crops. One of these endemic tiger beetles is the strikingly green-colored  floridana form of the minute species Cicindela scabrosa.

This form was first collected in August of 1934 by Frank N. Young and formally described five years later by O.L. Cartwright as a subspecies of Cicindela abdominalis. Cartwright’s description was composed of two brief sentences in the June 1939 Annals of the Entomological Society of America:

Differs from abdominalis in the shinning green color of head, thorax and elytra, the later with purplish reflections posteriorly at the sides, and in the strong deep punctures and fovea of the elytra. The green color will also separate this variety from the variety scabrosa Schaupp.

Additionally, Cartwright notes that Young collected 21 specimens which were divided between museums and private collections:

Holotype and 20 paratypes collected at Miami, Florida, August 9-12, 1934, by Frank Young. Holotype deposited in the U.S. National Museum, paratypes in the collections of California Academy of Science, Museum of Comparative Zoology at Harvard, and in the private collections of F. N. Young, W. M. Gordon, M. A. Cazier, J. W. Angell and the author.

One of the USNM paratypes

Cicindela scabrosa var floridana is a member of a complex of closely related, small cicindelids. The archetypal species in this complex, which also includes C. highlandensis, is Cicindela abdominalis. There has long been much confusion over the relation between these species; at one point there were no less than three synonymous species names for both Cicindela abdominalis and C. scabrosa. In his 1984 treatment of the Cicindela abdominalis complex, Choate elevated Cicindela scabrosa to a full species and placed Cicindela abdominalis floridana as a synonymy of Cicindela scabrosa, attributing the green color to be a sign of recent emergence.

Years after his discovery of C. scabrosa var floridana, in communication with fellow entomologists, Young reported that he collected the specimens in the area surrounding Barry College. Unfortunately, this area, like so much of the neighboring region, had been heavily developed in the intervening time. Several researchers, including Knisley, surveyed numerous Miami-Dade county parks and area preserves for C. scabrosa var floridana but without success.

Approximate view of the original collection site(s) in 1999. Image courtesy of the U.S. Geological Survey

In their 2006 field guide to the tiger beetles of North America, Pearson, Knisley, and Kazilek noted:

An isolated population [of C. scabrosa] in the Miami area has been considered as a subspecies, C. scabrosa floridana Cartwright, which is smaller … and distinctly green above. This population … may now be extinct, probably because of habitat destruction and urbanization.

And so with no suitable habitat remaining and no beetles seen since 1934, despite extensive surveys, this form was presumed to be extinct.

But in September of 2007, over 70 years after this species had last been observed in the wild, a population of Cicindela scabrosa var floridana was rediscovered on privately-owned land in the greater Miami area. Jeff Slotten, a lepidopterist, happened across this population while surveying for butterflies and, being familiar with this species, was well aware of the significance of his discovery. He contacted Barry and a fellow tiger beetle enthusiast, David Brzoska; they set about surveying potential habitats and soon found another population at a directly adjacent site.

The area upon which much of present-day Miami sits was once covered by pine rocklands. This fire-dependent community, found on limestone outcroppings, is comprised of a sparse canopy dominated by Florida slash pine, Pinus elliotti var. densa, and a varied understory which includes many endemic plant species. This habitat once stretched from the Florida Keys up to the northern edge of Miami-Dade County, but in the 1940’s the invention and ensuing widespread use of the rock plow marked the destruction of the majority of Floridian pine rockland.

Today, only a fraction of the original Miami pine rockland habitat remains; by some estimates as little as 2%. Moreover, most of these remaining areas are quite small and often widely separated by miles of heavy development. In addition, many of these remaining pine rocklands now face a new danger; due to the lack of fire, they are being overrun by both native and non-native vegetation as the habitats are transitioning to hardwood hammocks.

Shortly after my arrival in Miami, Barry and I are on the road, heading to survey a potential habitat. Unfortunately the most promising area, within a neighborhood park, was an overgrown mess of vines and small hardwood trees. This turns out to be the norm; while we visit several potential habitats, they too are all overgrown. It was evident that vegetation had been growing unchecked for years and no attempt at maintaining these habitats had been made.

We next head to the site where C. scabrosa var floridana was first rediscovered. This area, along with several other parcels of land, is bordered on one side by a highway while a large development wraps around the other sides. Despite this encroachment there remains a sizable area of pine rockland which, thanks to controlled burns, is in exceptional condition.

An open patch of sand, ideal habitat for C. scabrosa var floridana; notice the charred remnants of a tree on the ground.

Barry and I weave through the clumps of saw palmetto toward a sandy exposure and we pause at the edge. Before long there is a hint of movement and a small tiger beetle darts from the base of a blade of grass towards the center of the sandy patch.

There’s a beetle here…

Its coloration is unique; it is dark, not black, but rather a deep iridescent bronzy-green hue. We inspect several other patches and see a fair number of beetles; the temperature is over 90 degrees and the beetles are very active. Most are moving in and out of the sparse patches of shade or sporadically about the sandy areas, occasionally darting after an ant.

Barry watches a patch of habitat for floridana

Trying to photograph one is particularly difficult; not only are the beetles fast and small, but there are also jagged chunks of limestone sticking out of the sandy ground making it difficult to move about. On my hands and knees, I slowly approach a beetle but it flies off. Again I approach a beetle; it also takes flight. At last I come across a more cooperative beetle and manage a couple quick shots before it also darts away.

A male C. scabrosa var floridana

A weathered chunk of limestone sticks out of the sand

The next day Barry and I set out to survey another promising site; this one borders the area where C. scabrosa var floridana was rediscovered. We do notice some suitable habitat, but most of the ground is covered with a layer of pine needles from the dense canopy. For over an hour there is no trace of the beetles; at last we find a more open area near the edge of the trees.As we walk through the low vegetation, first Barry and then I see a flash of movement, as if a tiger beetle were taking flight. However, neither of us get a good look and only when we spot a stationary beetle are we sure of what we saw. After this exciting find we drive to the second site where floridana was rediscovered. This property sits next to the first site and has also been maintained by controlled burning.

But, on the portion of this property bordering the development, there is a considerable amount of encroaching vegetation which threatens to choke out any exposed sandy areas. The last time it was burned was clearly several years prior to our survey and, as one might suspect, we found no beetles in this area. Moving on, Barry and I find a larger patch of habitat and soon catch sight of more beetles. Here the ground is quite rocky and the saw palmettos are tightly packed, so I am unable to get a decent chance to photograph the beetles in their habitat. I settle instead for a few shots of some beetles which Barry nets as we continue the survey.

Slowly moving in towards a beetle

Barry carefully holds a female during the survey

This form is small, with a body length under 1cm.

As it comes closer to mid-afternoon we wrap up the survey and I begin to prepare for my return; though very short, this trip has been particularly productive. My flight leaves Miami International as the sun sets, my goal reached – I have the pictures I hoped for.

Over the past couple of years, Barry has worked along with Brzoska and Slotten in examining several differences between this form and the closely related members of the C. abdominalis complex. Based on morphological, seasonal, and distributional differences, C. scabrosa var floridana has been elevated to a full species, Cicindela floridana, in a soon to be published paper.

A side-by-side comparison of the four species of the C. abdominalis complex (L-R): C. floridana, C. scabrosa, C. abdominalis, C. highlandensis.

A captive C. floridana showing the vivid green color, reduced maculations, and bright red abdomen.

While the populations appear to be stable, this species requires more research and management; particularly, the remaining habitats must be sufficiently maintained. Controlled burns should be regularly conducted, as they are the first and most critical steps toward control of the encroaching vegetation. With proper care and protection this species, can come to thrive again.

Acknowledgments:

Special thanks to Barry Knisley for facilitating my trip to Florida and providing the specimens for the captive and comparative photograph. Also thanks to Art Evans for assistance in accessing the USNM collection.

References:

Cartwright, O.L. 1939. Eleven new American Coleoptera (Scarabidae, Cicindelidae). Annals of the Entomological Society of America 32:353-364.

Choate, P.M. 1984. A new species of Cicindela Linnaeus (Coleoptera: Cicindelidae) from Florida, and elevation of C. abdominalis scabrosa Schaupp to species level. Entomological News 95: 73-82.

Pearson, D.L., Knisley, C.B., Kazilek, C.J. 2006. A field guide to the tiger beetles of the United States and Canada. Oxford University Press, New York 8 + 227pp.

U.S. Fish and Wildlife Service. Multi-Species Recovery Plan for South Florida: Pine Rocklands. www.fws.gov/southeast/vbpdfs/commun/pr.pdf


revisiting Cicindela albissima

This spring the day after final exams ended I was off to southern Utah to begin work on a summer research project on the Coral Pink Sand Dunes tiger beetle, Cicindela albissima. This was my third trip out to the dunes and as ever I was eager to see these small but spectacular insects. As I have mentioned before on the blog this species is only found within the Coral Pinks Sand Dunes state park, mainly withing a small conservation area (outlined below).

In the coming months I’ll write more on the research itself , but for now a few photos (and a video) of the beetles. Below is an image of an adult female – there are occasionally individuals which have an isolated dark stripe near the rear edge of the elytra.

A third instar larva sits at the mouth of its burrow awaiting an unfortunate passerby

My stay was originally was to be just under two weeks but as my departure date drew closer and there was no sign of rain (a key trigger for the emergence of 1st instar larvae) I chose to prolong my stay by another week. The day after my planned departure a front blew in and brought the first rain to the dunes in over a month. In the early hours of the next day I made the short trek out to the dunes and the 1st instar larvae were all over – just what I had hoped for.

A 1st  instar larvae, removed from its burrow, crawls about in search of a place to dig a burrow

A scarred female C. albissima chews an unfortunete ladybeetle into an unrecognizable ball of mush

Similarly this beetle was vigorously shredding a mystery insect


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