endangered species

Rediscovery of Cicindela scabrosa floridana

/ Ted C. MacRae / 5 Comments

ResearchBlogging.orgIn refreshing contrast to the more usually heard reports of declining and extinct species, a new paper by Dave Brzoska, Barry Knisley, and Jeffrey Slotten (Brzoska et al. 2011) announces the rediscovery of a tiger beetle previously regarded as probably extinct.  Cicindela scabrosa floridana was described from a series of unusually greenish specimens collected in Miami, Florida in 1934; however, no additional specimens turned up in the following 70+ years despite dedicated efforts in the late 1980s and early 1990s by Brzoska, Knisley, and Ron Huber to locate and search areas around the presumed type locality.  This paucity of specimens and occurrence of the type locality in highly urbanized Miami had caused most contemporary tiger beetle researchers to presume that the population had fallen victim to the ceaseless sprawl of urbanization and its attendant habitat destruction.  However, in September of 2007, co-author Jeff Slotten, working with David Fine, rediscovered a population of individuals matching the type series while surveying butterflies in pine rockland habitat in the Richmond Heights area of Miami.  Subsequent surveys of pine rockland habitat in surrounding areas revealed populations of the beetle at three sites – all in the Richmond Heights area. 

Source: Brzoska et al. (2011)

Cicindela scabrosa floridana was originally described by Cartwright (1939) as a variety of the broadly distributed southeastern U.S. species C. abdominalis.  In describing the closely related C. highlandensis (endemic to the Lake Wales Ridge of central Florida), Choate (1984) also elevated the peninsular Florida-endemic C. scabrosa (previously considered a subspecies of C. abdominalis) to full species status and treated floridana as a subspecies of scabrosa, apparently due to the similarity of their elytral sculpturing, occurrence in both of dense flattened setae on the pronotum, and their allopatric distributions.  The new availability of additional specimens of floridana, however, has allowed more detail comparisons of this form with scabrosa.   In addition to the markedly greener elytra, the great majority of floridana lack post-median marginal spots – found consistently in scabrosa, and the apical lunule is generally thinner in floridana than in scabrosa.  Moreover, no floridana were found to exhibit the vestigial middle band that scabrosa often exhibits, and the leg color of floridana also is lighter and more yellow than most scabrosa specimens.  Differences in habitat, distribution and seasonality were also noted – scabrosa occurs in sand pine scrub habitat throughout most of peninsular Florida north of Miami from late spring to mid-summer, while floridana occurs only in pine rockland habitats in southern Florida with adults active well into October.  These consistent differences in morphology, distribution, habitat, and seasonality led Brzoska et al. to elevate floridana to full species status.  According to the most recent classifications of North American and Western Hemisphere tiger beetles (Pearson et al. 2006, Erwin and Pearson 2008), the new name would be Cicindela (Cicindelidia) floridana.  However, Brzoska et al. follow the classification initially proposed by Rivalier (1954) and followed by Weisner (1992) in regarding Cicindelidia as a full genus, resulting in the new combination Cicindelidia floridana.  The character differences identified by Brzoska et al. are illustrated with detailed photographs and presented in a key to allow recognition of the now four species in the abdominalis group.

The rediscovery of a rare species thought to be extinct is always cause for celebration.  However, there is much work still to be done before prospects for the long-term survival of C. floridana can be considered secure.  Many potential scrub and pine rockland sites throughout Miami-Dade, Broward, and Palm Beach Counties were identified and surveyed after the initial discovery of C. floridana in the Richmond Heights area.  Unfortunately, to date the beetle has been found only at three sites in the Richmond Heights area.  This suggests that C. floridana populations are small, highly localized, and greatly restricted in distribution, making the species a likely candidate for listing as endangered by the U. S. Fish and Wildlife Service.   To their credit, the authors have not revealed the precise locations of these sites, which will hopefully reduce the temptation by those with more philatelic tendencies to undercut ongoing studies of the distribution, abundance, biology, and habitat of C. floridana.  These studies will be critical in the development of effective conservation strategies to ensure that this highly vulnerable representative of Florida’s natural heritage does not, once again, become regarded as extinct.

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.

Cartwright, O. L. 1939. Eleven new American Coleoptera (Scarabaeidae, 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.

Erwin, T. L. and D. L. Pearson. 2008. A Treatise on the Western Hemisphere Caraboidea (Coleoptera). Their classification, distributions, and ways of life. Volume II (Carabidae-Nebriiformes 2-Cicindelitae). Pensoft Series Faunistica 84. Pensoft Publishers, Sofia, 400 pp.

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.

Rivalier, E. 1954. Démembrement du genre Cicindela Linne, II. Faune americaine. Revue Francaise d’Entomologie 21:249–268.

Wiesner, J. 1992. Checklist of the Tiger Beetles of the World. Verlag Erna Bauer; Keltern. 364 pp.

Copyright © Ted C. MacRae 2011

Cylindera celeripes – Fig. 1

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One of the plates from our recently submitted manuscript on Cylindera celeripes (swift tiger beetle).¹  For the record, this is my first official attempt at assembling a plate in Photoshop for electronic submission – I sure hope I get quicker at this!

Fig. 1. Cylindera celeripes (LeConte) adults at: a) Hitchcock Nature Center, Pottawattamie Co., Iowa (13.vii.2008); b) Alabaster Caverns State Park, Woodward Co., Oklahoma (10.vi.2009); c) same locality as “b”, note parasite (possibly Hymenoptera: Dryinidae) protruding from abdomen and ant head attached to right antenna; d) Brickyard Hill Natural Area, Atchison Co., Missouri (27.vi.2009). Photos by C.R.Brown (a) and T.C.MacRae (b-d).

¹ “Historical and contemporary occurrence of Cylindera (s. str.) celeripes (LeConte) (Coleoptera: Carabidae: Cicindelitae) and implications for its conservation” – submitted to Journal of Insect Conservation.

Copyright Ted C. MacRae 2011

Is Missouri’s disjunct population of Johnson’s tiger beetle extirpated?

/ Ted C. MacRae / 15 Comments

ResearchBlogging.orgThe December 2010 issue of the journal CICINDELA came out a little over a week ago. Leading off inside is the first in a series of papers that I, along with colleagues Chris Brown and Kent Fothergill, have prepared detailing our work with several species of tiger beetles in Missouri of potential conservation interest. At the start of our surveys, Missouri’s tiger beetle fauna was already fairly well characterized, at least qualitatively, due to the efforts of heavy hitters Ron Huber and Dave Brzoska, who for many years lived in nearby eastern Kansas. Despite their attentions, however, questions lingered regarding the precise distribution and status of several species of restricted geographical occurrence within the state, and our surveys over the past 10 years have sought to resolve these questions and, if necessary, recommend conservation efforts to secure the long-term survival of these species within the state.

One of these species of interest is Habroscelimorpha circumpicta johnsonii (Johnson’s tiger beetle). This subspecies is widely distributed in inland areas of the central and south-central United States, where it is associated exclusively with barren areas surrounding saline seeps. Despite the broad occurrence of the main population, the Missouri population of this subspecies has long been of particular interest for several reasons: 1) its widely disjunct isolation, occurring several hundred miles east of the nearest populations in central Kansas, 2) its strict association with the highly restricted saline seeps of central Missouri (Fig. 1), and 3) the exclusive blue-green coloration of the adults (Fig. 2) that contrasts with the varying proportions of reddish and/or dark morphs, in addition to blue-green morphs, found in other populations. The highly disjunct and isolated occurrence of this population and its unique coloration have been considered by some workers as grounds for separate subspecific status. Another restricted, disjunct population of this species in North Dakota has already been accorded subspecific status – H. circumpicta pembina.

Despite its restricted occurrence in Missouri, a long history of collection records exist for the subspecies. Numerous specimens are housed in the Enns Entomology Museum in Columbia, Missouri, with a majority of these coming from a single location (Boone’s Lick Historic Site) and dating back as early as 1954. In more recent years (1985-1992), Ron Huber and Dave Brzoska found significant numbers of beetles at two additional locations near Boone’s Lick. Despite these numerous records, the subspecies was listed as a “Species of Conservation Concern” by the Missouri Natural Heritage Program with a status of “S2S3” (vulnerable or imperiled) due to the rarity of its required saline seep habitats in Missouri. Unfortunately, this alone did not appear to be sufficient protection for the species, as my own observations beginning in the mid-1990s suggested that populations of the beetle had declined significantly from their historical levels. Concomitant with these apparent declines was the observation that the sites supporting these beetles had themselves suffered severe degradation that reduced their apparent suitability as habitat for the beetle. As a result of these observations, Chris and I initiated comprehensive surveys during the 2001 field season to assess the conservation status of the Missouri population and identify potential new sites. Our first order of business was to petition a status change to “S1” (critically imperiled), and for the next three years we regularly visited the historical sites throughout the presumed adult activity period, noting occurrence of adults and recording their numbers and the circumstances of their habitat associations. Included in these surveys also were two new sites identified using the Missouri Natural Heritage Database.

The results were not good – during the 3-year survey, only a single beetle was observed at the historical location of Boone’s Lick, and none were observed at the two other locations discovered by Ron Huber and Dave Brzoska. More significantly, all three sites had suffered severe degradation due to vegetational encroachment, cattle trampling, or other anthropogenic disturbance. Moreover, of the two potential new sites identified, only one of these (Blue Lick Conservation Area) was found to support a small population of the beetle. Three apparently suitable saline seeps exist at this latter site; however, beetles were observed at only one of them. During the final year of the survey, prolonged flooding occurred at this site (frustratingly, a result of earth-moving operations by site personnel), which was followed in subsequent years by significant vegetational encroachment (Fig. 3). No beetles were observed at this site during the final year of the survey, nor has the species been seen there in multiple visits to the site in the years since.

Is the Missouri disjunct population of Johnson’s tiger beetle extirpated? There is little reason to be optimistic. What is clear is that the beetle is now below detectable limits, and with the loss of suitable habitat at all sites known to have supported the beetle in the past and little chance that new, high-quality sites will be identified, prospects for an unaided comeback are dim. The saline seep habitats at the three historic sites appear to have suffered irreparable degradation and offer little restoration potential to the degree required to support viable beetle populations; however, there are still two saline seeps at Blue Lick that do offer at least a semblance of suitable habitat. It is imperative that these last remaining examples of Missouri’s critically imperiled saline seeps habitats receive the highest priority for protection if the beetle (should it still exist) is to have any chance of surviving in Missouri. Johnson’s tiger beetle is only one of several tiger beetle species whose presence in Missouri appears to be in jeopardy (others being Dromochorus pruinina – loamy ground tiger beetle, and Cylindera celeripes – swift tiger beetle). I end this post with our closing admonition in the paper:

The loss of this beautiful and distinctive beetle from Missouri’s native fauna would represent a significant and tragic loss to this state’s natural heritage. We urge the Missouri Department of Conservation, the Missouri Department of Natural Resources, and other conservation organizations within the state to identify and allocate the resources needed to develop and implement a recovery plan for the species in Missouri.

REFERENCE:

Brown, C. R. and T. C. MacRae. 2011. Assessment of the conservation status of Habroscelimorpha circumpicta johnsonii (Fitch) in Missouri CICINDELA 42(4) (2010):77-90.

Postscript. On a happier note, I am pleased to be joining the editorial staff for CICINDELA. While my role as layout editor is more functional than academic, I am nevertheless thrilled with the chance to “rub shoulders” with the likes of Managing Editor Ron Huber and long-time cicindelid experts Robert Graves and Richard Freitag. I hope my contributions to the journal’s production on the computer end of things will be favorably received by its readership.

Copyright © Ted C. MacRae 2011

Bruneau Sand Dune tiger beetles caught in the act!

/ Ted C. MacRae / 15 Comments

ResearchBlogging.orgThe newest issue of CICINDELA (“A quarterly journal devoted to Cicindelidae”) contains an interesting article by my good friend and fellow tiger beetle enthusiast Kent Fothergill, who presents a fascinating sequence of photos documenting a field encounter with a mating pair of the endangered Bruneau Sand Dune tiger beetle (Cicindela waynei) (Fothergill 2010).  This is one of several tiger beetle species in the C. maritima species group that inhabit sand dunes in central and western North America – others include the Coral Pink Sand Dune tiger beetle (C. albissima), the St. Anthony Sand Dune tiger beetle (C. arenicola), the Colorado dune tiger beetle (C. theatina), and the sandy tiger beetle (C. limbata).  With the exception of the latter, these species show highly restricted distributions in their preferred sand dune habitats, and because their populations are so small they are especially vulnerable to drought and ever-increasing anthropogenic pressures (i.e., invasive plants, motorized vehicular traffic, overzealous collectors).  While the Bruneau Sand Dune tiger beetle has not been accorded status on the Endangered Species List, the Idaho Department of Fish and Game and the Bureau of Land Management have classified it as globally imperiled.

Bruneau Sand Dune tiger beetle, Bruneau Sand Dune State Park, Idaho. Photo © Kent Fothergill 2009.

Kent was observing these beetles in Bruneau Dune State Park in southwestern Idaho – the main habitat for this species – when he encountered several pairs of C. waynei in the process of mating.  Photographs were taken of one mating pair, revealing a fascinating sequence of behaviors that included vigorous but unsuccessful attempts by the female to dislodge the male, eversion and penetration of the female by the male aedeagus, and subsequent mate guarding (see photo above).  It is, in fact, this latter behavior that is most often observed among tiger beetle mating pairs and not actual mating itself, which is only rarely observed.  Kent noted the uniquely modified male mandibles (see photo below) and their possible role in preventing the male from being dislodged during the female’s initial protestations.

Male Bruneau Sand Dune tiger beetles sport impressive choppers! Photo © Kent Fothergill 2009.

This apparently is the first documented report of mating in this species, and its occurrence in May is considerably later in the season than Baker et al. (1997) speculated – significant because protection of 1st instar larvae is a management priority for conservation of this species.  The potential occurrence of 1st instars during a longer period of time is an important consideration for continued management of this species, as the Bruneau Sand Dune population continues to show evidence of decline despite the prohibition of insect collecting, cattle grazing, and off-road vehicles within the park (Bosworth et al. 2010).  Human trampling and pesticide applications to adjacent rangelands are continuing threats that have proven more difficult to manage.

My sincerest thanks to Kent Fothergill for presenting me the opportunity to review his manuscript prior to publication and allowing me to reproduce here two of his spectacular photographs of this gorgeous and rare species.

REFERENCES:

Baker, C. W., J. C. Munger, K. C. Cornwall and S. Staufer.  1997. Bruneau Dunes tiger beetle study 1994 and 1995.  Idaho Bureau of Land Management, Technical Bulletin 97-7, 52 pp.

Bosworth, W. R., S. J. Romin and T. Weekley.  2010. Bruneau Dunes tiger beetle assessment.  Idaho Department of Fish and Game, Boise, Idaho, 36 pp.

Fothergill, K.  2010. Observations on mating behavior of the Bruneau Dune tiger beetle, Cicindela waynei Leffler (Coleoptera: Carabidae: Cicindelinae).  CICINDELA 42(2):33–45, 7 color plates.

Copyright © Ted C. MacRae 2010

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What’s so special about this beetle?

/ Ted C. MacRae / 25 Comments

Regular readers of this blog might recognize this as the swift tiger beetle, Cylindera celeripes. This tiny, flightless beetle was once common in the central Great Plains; however, the species has experienced dramatic declines over the past century due to near complete destruction of its preferred prairie habitats.  By the time I first became interested in this species a few years ago, the Flint Hills of Kansas were its last known stronghold.

But that’s not what’s so special about this beetle.

My colleague Chris Brown and I began looking for this species as part of a survey of Missouri tiger beetles.  Although not previously known from the state, historical records from loess hilltop prairie habitats in southwestern Iowa suggested that it might be found in extreme northwestern Missouri at the southern terminus of the Loess Hills landform.  Earlier searches in this part of the state by us and others had turned up empty; however, it was easy to imagine that the beetles had eluded detection due to their small size, cryptic resemblance to ants, and limited temporal occurrence.  In an effort to understand more specifically its habitat preferences and gain a better search image for the species, we visited one of the historical Iowa localities in 2008 and succeeded in finding the species ourselves for the first time.

But that’s not what’s so special about this beetle.

Armed with this experience, Chris and I conducted another dedicated search for this species in Missouri during 2009, targeting the largest and highest quality loess hilltop prairie remnants remaining in the state.  At last, our efforts were rewarded when we found beetles in several loess hilltop prairie remnants in Atchison and Holt Counties.  Their numbers were not high at any of the sites, but the finds nevertheless represented a new state distribution for a species that has only seen contractions to its known range for many years now.

But that’s not what’s so special about this beetle.

A few weeks before finding the beetle in Missouri, I had an opportunity to visit Alabaster Caverns State Park in northwestern Oklahoma, where BugGuide contributor Charles Lewallen had photographed the species in 2003.  I not only succeeded in finding the species at the original locality but determined also that its population there was quite robust.  Indeed, on the same trip I discovered robust populations at several nearby localities, suggesting that the species occurrs commonly throughout the red clay/gypsum hills of northwestern Oklahoma.  Further observations of the species in northwestern Oklahoma last month seem to confirm this.  The beetle in these photographs comes from Alabaster Caverns, but that’s not what’s so special about it.

What is so special about it is that it’s the first ever reared individual of this species!  For those of you wondering why this is significant, until now the immature stages of this species have remained completely unknown.  A few contemporary students of the group have tried to rear the species, but the adults are delicate and do not travel well – indeed, my own first attempt to rear the species when I found it in Iowa was not successful.  However, when I found the Alabaster Caverns population, I placed ~12 adults in a small terrarium into which I had placed a chunk of native soil and moistened with water.  The adults survived well in this terrarium over several days of travel, and once back in the lab I kept them alive for several weeks by feeding them small caterpillars and fruit flies.  When larval burrows began to appear I fed them periodically with very small caterpillars and rootworm larvae, inserting them into individual burrows and sealing the burrow entrance to prevent their escape.  Additional prey larvae were inserted into burrow entrances as they were reopened, and the soil in the terrarium was moistened whenever its surface became quite dry.  By late October, all of the burrows had become inactive, and I wasn’t sure if the larvae had died or were just overwintering.  Nevertheless, I placed the terrarium in a cool (10°C) incubator, where it remained until this past March when I pulled it out of the incubator and returned it to warmer temperatures.  Within days, larval burrows reappeared, and I knew then that I had a decent chance of rearing the species to adulthood.  In early July, the beetle in these photographs emerged from its burrow – the first ever reared swift tiger beetle!  Several more adults emerged during the following 2-3 weeks.

While this rearing was in progress, I managed to find larvae of this species on a return trip to Alabaster Caverns last October.  Both 2nd- and 3rd-instar larvae were collected and preserved to go along with the preserved 1st-instar larva that I had extracted from the rearing container when larvae first began to appear.  While these preserved specimens are all that I need to complete a manuscript describing the larval instars, having reared the species completely from egg to adult as well will provide a most gratifying conclusion for that manuscript.

Copyright © Ted C. MacRae 2010

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Give the Gift of Green

/ Ted C. MacRae / 6 Comments

The mission of The Nature Conservancy is to preserve the plants, animals and natural communities that represent the diversity of life on Earth by protecting the lands and waters they need to survive.

Blue jay, Oklahoma, USA. Photo © Harvey Payne.

One of my favorite conservation organizations is The Nature Conservancy.  It’s hard to argue with their success—more than 119 million acres of land, 5,000 miles of rivers, and 100 marine projects worldwide have received protection as a result of their efforts.  Even more important than the scale of their success is the manner in which it has been achieved using science and a decidedly non-confrontational focus on partnerships.  I have seen this approach in action in my own state of Missouri at Victoria Glade and at Four Canyon Preserve in Oklahoma, where prescribed burns, managed grazing, and removal of woody vegetation are restoring significant examples of our nation’s unique grasslands to their presettlement glory. 

Yangtze River, China. Photo © Dou Weiyang.

The intial focus of the Conservancy’s conservation efforts was simple: preserve wilderness by buying land. As environmental challenges have increased, the Conservancy has adopted a diversity of tactics to acheive sustainable conservation results.  The Conservancy relies heavily on membership to fund these conservation efforts, with 60% of revenues coming from individuals. A fun and creative way to support the work of the Conservancy during this Holiday Season is through their Green Gift Guide, which offers unique gifts that will go twice as far; pleasing the recipient while at the same time helping the Conservancy in their efforts to protect the world’s most precious habitats for future generations. Following are their Top 5 Green Holiday Gifts:     

  1. Adopt an Acre.  You can choose whether your gift protects unbroken swaths of Appalachians forest, mountain streams in the Rockies, meandering Southern bayous or miles of beautiful sandy beaches where US and Mexico border, or Adopt an Acre abroad in Africa, Australia or Costa Rica.
  2. Plant Trees in the Atlantic Forest. Part of the Conservancy’s Plant a Billion Trees campaign, each tree purchased will be planted in the Atlantic Forest, one of the world’s biggest and most endangered tropical forests.
  3. Adopt a Coral Reef. This unique gift will help protect the coral reefs and beautiful seascapes found in Palau, the Dominican Republic or Papua New Guinea.
  4. Help Save the Northern Jaguar (NEW THIS YEAR). Help to protect the large landscapes that northern jaguars need to flourish. Jaguars roam from as far south as Patagonia all the way to Arizona and New Mexico and your gift will help to provide the dense jungle and scrubland they enjoy.
  5. Give the Gift of Clean Water. Freshwater ecosystems water our crops, light our homes and bring us joy. Help to protect the flow and supply of fresh water and ensuring the well-being of our own species.

For additional eco-friendly holiday gift ideas, visit the Conservancy’s Green Gift Guide.  

Copyright © Ted C. MacRae 2009

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Highlands Tiger Beetle

/ Ted C. MacRae / 11 Comments

When my wife and I made plans to spend a week at her sister’s condominium in Florida this past summer, I began making a list of the tiger beetle species that I wanted to see.  I would be happy to see anything, since I had never before tiger beetled in Florida, but early August was looking to be on the late side for many things.  In addition, since this was a family vacation, I would only have a couple days at most to sneak off on my own and immerse myself in bug hunting.  All this meant that I would have to be very judicious about where I went and what I looked for.  I sought advice from a few other cicindelophiles on species and localities, and by the time we made the 16-hour drive from St. Louis to Seminole (near St. Petersburg) I had settled on two destinations—the Lake Wales Ridge of central Florida to look for Cicindela highlandensis (Highlands Tiger Beetle), and the so-called “Road to Nowhere” near Steinhatchee where as many as 10 species of tiger beetles can be seen when the season is right.  Things started out well when, before even looking for any of these species, I stumbled upon Ellipsoptera marginata (Margined Tiger Beetle), its sibling species E. hamata lacerata (Gulf Beach Tiger Beetle), and some 3rd-instar larvae in their burrows that proved to be the Florida endemic Tetracha floridana (Florida Metallic Tiger Beetle) in the small coastal preserve just outside the back door of my sister-in-law’s condo.

Lake Wales Ridge_IMG_1128_1200x800_enh

Dry sand scrubland on Lakes Wales Ridge in central Florida

The big target of the trip, however, was not so straightforward.  Cicindela highlandensis is one of Florida’s rarest endemic tiger beetles, being restricted entirely to remnant sand scrubland and pine woodland habitats along the Lake Wales Ridge of Polk and Highlands Counties in central Florida (Choate 2003).  The Lake Wales Ridge represents former shorelines deposited when the rest of peninsular Florida was covered by seas.  The quick draining sands have created desert-like open habitats dominated by oaks, pines, and other drought-tolerant species.  Cicindela highlandensis is one of many plants and animals endemic to the Lake Wales Ridge, which has the highest concentration of endangered plants in the continental U.S.  Unfortunately, the natural communities found on the Lake Wales Ridge have suffered severe reductions from their historical occurrence.  An estimated 85% of the scrub and sandhills has been converted to citrus groves and urban developments, and the few remaining tracts face not only continued development pressure, but also the threat of degradation from reductions in the frequency and extent of the wildfires that are essential for their maintenance (Turner et al. 2006).  NatureServe (2009) estimates that C. highlandensis populations have declined by as much as 90%, and only a few of the sites where it is known to occur are large enough to sustain viable populations.  While the species has a global status of G1 (critically imperiled) due to its limited range, restricted habitat, and very small population size, and is a candidate for listing as an endangered species by the U.S. Fish & Wildlife Service (Pearson et al. 2006), it remains—bafflingly—unlisted even as threatened by the State of Florida.  As a result, there is no formal conservation management plan for this species to ensure its survival.  Fortunately, the largest populations of C. highlandensis occur on an assemblage of public and private lands that are under partial to full conservation ownership, and preservation/management activities are taking place at most of these.

Cicindela_highlandensis_IMG_1126_1200x800_enh

Cicindela highlandensis, Highlands Tiger Beetle, in alert position

I had debated whether to look for Cicindela highlandensis at all—not because I wasn’t anxious to see it, but because I lacked confidence that I would be able find it.  A late season search for a rare species had all the hallmarks of a potential wild goose chase.  Nevertheless, I like a good challenge, and I had succeeded in obtaining information about specific locations for the species (a matter of public record; however, I prefer to maintain some discretion in this venue).  Although I began my search with tempered optimism, it didn’t take long for me to acheive my goal.  Similar to my experience with Cylindera celeripes in Oklahoma, I had barely walked ten yards into a gorgeous sand scrub habitat at the first site I had planned to search before I saw an individual.  The dark metallic blue coloration of the species would seem to make it easily seen in its white sand environs; however, in reality it is almost impossible to see until it moves.  Some have suggested that its coloration functions to make the beetle resemble the many small pieces of debris that litter the sand surface—perhaps the bits of charred wood that are common in open, fire-mediated environments.  Its dependence upon natural disturbance factors such as fire was made apparent to me by the distinct preference I noted for adults to congregate along trails kept open by human disturbance, and to a lesser degree in the larger, naturally open scrub areas.  The adults made very short escape flights and were easy to follow but difficult to approach closely enough for photographs due to extreme wariness—their long legs giving some indication of their highly cursorial capabilities.

Cicindela highlandensis

Cicindela highlandensis - note absence of setae on thorax and abdomen

Cicindela highlandensis is closely related to two other species of tiger beetles in Florida—C. abdominalis (Eastern Pinebarrens Tiger Beetle), widely distributed throughout the Atlantic and Gulf Coastal Plain, and C. scabrosa (Scabrous Tiger Beetle), confined to the Florida Peninsula and adjacent southeastern Georgia.  Both of these species are absent from the Lake Wales Ridge and, thus, do not co-occur with C. highlandensis. It is likely that C. highlandensis evolved from isolated populations of the widespread C. abdominalis that diverged during pre-Pleistocene separation of the Lake Wales Ridge from the mainland (Choate 1984).  Despite its resemblance to both C. abdominalis and C. scabrosa, C. highlandensis can be distinguished from both of those species by the complete absence of flattened, white setae on the sides of the prothorax and the abdomen and by the highly reduced or absent elytral maculations (note the very small apical markings on the individuals in these photographs).  All three of these species belong to the subgenus Cicindelidia (American Tiger Beetles) and possess red adominal coloration that is prominent during flight.

Photo details:
Photo 1: Canon 17-85mm zoom lens on Canon 50D (landscape mode), ISO-100, 1/160 sec, f/13, natural light.
Photos 2–3: Canon 100mm macro lens on Canon 50D (manual mode), ISO-100, 1/250 sec, f/14 (photo 2) or f/20 (photo 3), MT-24EX flash w/ Sto-Fen diffusers.

REFERENCES:

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

Choate, P. M., Jr. 2003. A Field Guide and Identification Manual for Florida and Eastern U.S. Tiger Beetles.  University Press of Florida, Gainesville, 224 pp.

NatureServe.  2009.  NatureServe Explorer: An online encyclopedia of life [web application].  Version 7.1.  NatureServe, Arlington, Virginia.  Available at: http://www.natureserve.org/explorer (accessed: November 12, 2009).

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.

Turner, W. R., D. S. Wilcove and H. M. Swain.  2006.  State of the scrub: conservation progress, management responsibilities, and land acquisition priorities for imperiled species of Florida’s Lake Wales Ridge.  Archbold Biological Station, Lake Placid, Florida, iii + 44 pp.

Copyright © Ted C. MacRae 2009

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Saving endangered species with herbicides

/ Ted C. MacRae / 25 Comments

ResearchBlogging.orgThe latest issue of Cicindela (a quarterly journal devoted to tiger beetles), which arrived in my mailbox last week, features an article coauthored by my good friends Kent Fothergill and Kelly Tindall of Portageville, Missouri, along with lead author Stephen Bouffard of Boise, Idaho (Bouffard et al. 2009).  The article reports the results of a vegetative management pilot test for using herbicides to restore habitat for the critically imperiled St. Anthony dune tiger beetle, Cicindela arenicola.  This species is endemic to Idaho, primarily the St. Anthony Dunes area in the southwestern part of the state (Pearson et al. 2006), and like the Coral Pink Sand Dunes tiger beetle (Cicindela albissima, recently covered in this post) it is restricted to sand dune habitats that are threatened by a variety of land-use practices, including motorized vehicle use, livestock trampling, intentional stabilization of dunes by grass seeding, conversion of dune habitats to agriculture, and disposal of public lands by transfer to private ownership (Idaho State Conservation Effort 1996).

Cicindela_arenicola

Cicindela arenicola, copyright © Kent Fothergill 2008

Bouffard et al. conducted their study at Minidoka National Wildlife Refuge in southern Idaho. Cicindela arenicola was recorded on small remnant sand dunes within the refuge during the mid-1990’s but had not been detected in more recent opportunistic searches. The authors noted that the sand dunes appeared to have become overgrown with the invasive annual grass, downy brome (Bromus tectorum). Their study comprised three elements: 1) herbicide treatment on dune habitats to reduce downy brome density; 2) surveys of treated versus untreated plots during the following season to assess the efficacy of the herbicide in reducing downy brome density and any effect it might have on native vegetation, as well as the presence of C. arenicola; and 3) laboratory bioassays to evaluate the acute toxicity of herbicides on a surrogate tiger beetle species, Cicindela repanda (common shore tiger beetle). The laboratory bioassays were necessary, because toxic effects by a herbicide against tiger beetles would negate its potential usefulness for habitat improvement. For the herbicide treatment plots, Imazapic (trade name Plateau®) was selected because of its effectiveness against downy brome, minimal effects on native vegetation, and low toxicity to animals, including insects. Imazapic is labeled for control of downy brome and for use on rangeland. A nonselective herbicide, glyphosate (trade name Touchdown®) was also evaluated in the laboratory bioassay, even though it was not used in the field test, because glyphosate-based herbicides also have low animal toxicity and have been shown to be effective in assisting the establishment of native plant species in prairie restorations.

The authors were successful in observing live adult C. arenicola in both of the test plots where adults of this species were last seen in the mid-1990s. Moreover, larval burrows – putatively representing this species – were also noted in the plots. No adults or larvae were seen in a third plot; however, no previous records of the species exist in the area where that plot was located. They noted the presence of residual downy brome stems from the previous season’s treatment in the sprayed plots but no new growth, while the untreated controls exhibited extensive new downy brome growth. More importantly, no negative impacts on native vegetation – principally rabbitbrush (Chrysothamnus sp.) and Indian ricegrass (Achnatherum hymenoides) – were noted in the sprayed plots. The third plot had only a light downy brome invasion prior to treatment, and no apparent negative effects were observed on the native bunchgrasses, rabbitbrush, and sagebrush (Artemisia tridentata) in this plot after treatment. In the laboratory, neither imazapic nor glyphosate showed evidence of acute toxicity against the surrogate tiger beetle, C. repanda.

While the use of herbicides for conserving endangered species may seem counterintuitive, this study demonstrates a potential use for herbicides in restoring and improving sand dune habitat for a critically imperiled species of tiger beetle. Herbicides that are effective in reducing invasive annual grasses with minimal effects on both native vegetation and tiger beetles could greatly facilitate habitat management for a number of critically imperiled western U.S. sand dune tiger beetles besides C. arenicola, including C. albissima in southwestern Utah, C. waynei (Bruneau tiger beetle) in western Idaho, and C. theatina (Colorado Great Sand Dunes tiger beetle) in southern Colorado. Where vegetational encroachment presents a threat to critical sand dune habitat, broad spectrum or grass selective herbicides may offer an effective and convenient alternative to habitat restoration. Additional research will be needed to determine if repeat applications of herbicides will be necessary to prevent reinvasion, and if so with what frequency, as well as the chronic or behavioral effects of herbicides on both larval and adult forms of the insects targeted for conservation.

I thank Kent Fothergill for allowing me to use his beautiful field photograph of C. arenicola, which also graces the cover of the current issue of Cicindela.

REFERENCES:

Bouffard, S. H., K. V. Tindall and K. Fothergill. 2009. Herbicide treatment to restore St. Anthony tiger beetle habitat: a pilot study. Cicindela 41(1):13-24.

Idaho State Conservation Effort.  1996.  Habitat conservation assessment and conservation strategy for the Idaho Dunes Tiger Beetle.  Report No. 7, Boise, ID.

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 2009

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