…Happy 2nd blogoversary to me! I just now realized it, so happily you’ll be spared the tedious introspection.
Today also marks 150 years since the publication of Charles Darwin’s On the Origin of Species. Sharing the day with my hero (see sidebar quote)—yea!
Megacephala megacephala 3rd-instar larva. Photo © Artur M. Serrano.
In my recent summary of the latest issue of the journal Cicindela, I included a scan of the cover of that issue and its stunning image of the 3rd-instar larva of Megacephala megacephala¹ from Africa. This otherwordly-looking, four-eyed beast was photographed with jaws agape at the entrance to its burrow in Guinea Bissau by Dr. Artur M. Serrano (University of Lisbon, Portugal). I was grateful for his permission to post a scan of this spectacular image; however, he did even better and sent me high-resolution images of not only the larva (above) but the adult (below) as well. This species is one of 13 assigned to the genus—presently restricted to Africa (though not always, see discussion below), where they are usually found in savanna-type habitats and are active during the crepuscular and nocturnal periods (Werner 2000).
¹ An example of a tautonym, i.e. a scientific binomen in which the genus and species names are identical. Familiar tautonymic binomina include the gorilla (Gorilla gorilla), green iguana (Iguana iguana), and European toad (Bufo bufo). Tautonyms are expressly prohibited in plant nomenclature (see Article 23.4 of the International Code of Botanical Nomenclature) but are permitted and, in fact, quite common in zoological nomenclature; Wikipedia lists 51 mammals, 82 birds, 15 reptiles & amphibians, 54 fish, and 33 invertebrates (though not Megacephala megacephla!).
Megacephala megacephala adult. Photo © Artur M. Serrano.
For those of you who see a strong resemblance by this species to another tiger beetle I featured recently, Tetracha floridana (Florida Metallic Tiger Beetle), this is not merely a coincidence. Megacephala and Tetracha are quite closely related, and in fact the two genera, along with a handful of other closely related genera, are at the center of one of the longest-standing disputes in tiger beetle taxonomy (Huber 1994). The genus Megacephala was established by Latreille (1802) for the species pictured here (originally described as Cicindela megacephala Olivier). As additional taxa were found in Africa, Australia and the Western Hemisphere and assigned to Megacephala, several workers attempted to divide the genus into multiple genera (with New World taxa being assigned to Tetracha and a few other mostly South American genera); however, there was little agreement on how these genera should be defined and on what characters they should be based. The debate was effectively swept under the rug in the early 20th Century when Walter Horn, one of the most influential cicindelophiles of all time, accepted a monotypic Aniara based on the strange South American species A. sepulcralis but reunited the world’s remaining taxa within the single genus Megacephala in his world catalogue (Horn 1910). Horn’s use of Megacephala as a catch-all genus was followed by subsequent workers for almost a full century until Huber (1994) once again proposed restricting Megacephala to certain of the African species and resurrecting the genus Tetracha for the bulk of the New World fauna. He also urged additional analyses to resolve the status of the remaining generic names and their composition, which subsequently saw increasing use as subgenera of Megacephala² and later as genera.
² Thus, as type-species for the genus, the species featured here became known as Megacephala (Megacephala) megacephala (Werner 2000)—a triple tautonym that translates to the “Big-headed, Big-Headed, Big-Headed” tiger beetle! Perhaps it’s best that I’m not an African tiger beetle specialist; I probably would have been unable to resist the temptation to resurrect M. senegalensis and assign it as a subspecies of M. megacephala, just so I could refer to the nominate form as Megacephala (Megacephala) megacephala megacephala!
The reversal of Horn’s concepts now appears to be complete, with all seven former subgenera of Megacephala formally being accorded full generic status (Naviaux 2007). This classification is strongly supported by molecular analysis of nuclear 18S and mitochondrial 16S and cytochrome oxidase gene sequences (Zerm et al. 2007), with the resulting dendrogram indicating three monophyletic clades corresponding to the African/Palearctic (Megacephala and Grammognatha, respectively), Western Hemisphere (Aniara, Metriocheila, Phaeoxantha and Tetracha) and Australian (Australicapitona and Pseudotetracha) genera³. The African/Palearctic clade was found to occupy a basal position in the tree, while the Western Hemisphere and Australian clades were more derived. These data support the hypothesis that the early evolution of the megacephalines took place during the break-up of the ancient Gondwana megacontinent, which began about 167 million years ago (middle Jurassic period) and sequentially disconnected Africa from South America and Australia.
³ One striking deviation from the current classification, however, was the support for nesting the single Aniara species within Tetracha, a placement that renders Tetracha paraphyletic and, thus, requires either its division into multiple genera or the sinking of Aniara as a distinct genus. The support for this placement was quite strong and mirrored the results of a broader molecular phylogenetic study of tiger beetles based on full-length 18s RNA data (Galian et al. 2002). The authors concede that this puzzling placement is not corroborated by numerous morphological, ecological and ethological characters that distinguish Aniara from all known Tetracha species.
REFERENCES
Galián J., J. E. Hogan and A. P. Vogler. 2002. The origin of multiple sex chromosomes in tiger beetles. Molecular Biology and Evolution 19:1792–1796.
Horn, W. 1910. Coleoptera Adephaga, Fam. Carabidae, Subfam. Cicindelinae. In P. Wytsman (editor). Genera Insectorum. Fascicle 82a. Desmet-Vereneuil, Brussels, Belgium, pp. 105–208.
Huber, R. L. 1994. A new species of Tetracha from the west coast of Venezuela, with comments on genus-level nomenclature (Coleoptera: Cicindelidae). Cicindela 26(3/4):49–75.
Latreille, P. A. 1802. Histoire Naturelle, Générale et Particulière des Crustacés et des Insectes. Paris: F. Dufart 3 xii 13 + 467 pp.
Naviaux R. 2007. Tetracha (Coleoptera, Cicindelidae, Megacephalina): Revision du genre et descriptions de nouveaus taxons. Mémoires de la Société entomologique de France 7:1–197.
Werner, K. 2000. The Tiger Beetles of Africa (Coleoptera: Cicindelidae). Volume 1. Taita Publishers, Hradec Kralove, Czech Republic, 191 pp., 745 figures.
Zerm, M., J. Wiesner, J. Ledezma, D. Brzoska, U. Drechsel, A. C. Cicchino, J. P. Rodríguez, L. Martinsen, J. Adis and L. Bachmann. 2007. Molecular phylogeny of Megacephalina Horn 1910 tiger beetles (Coleoptera: Cicindelidae). Studies on Neotropical Fauna and Environment 42(3):211–219.
Copyright © Ted C. MacRae 2009
Vodpod videos no longer available.
I don’t think I’ve seen a more egregious example of insect-ID-fail than this one!
It may, in fact, be a moth 🙂
Copyright © Ted C. MacRae 2009
The Florida scrub lizard (Sceloporus woodi) is restricted to isolated sand scrub habitats in peninsular Florida.
Tiger beetles were not the only rare endemic species that I encountered during my visit to the Lake Wales Ridge in central Florida last August. I didn’t know what this small lizard was as I watched it bolt from the trail and scamper for cover during my approach; however, having already found two endemic tiger beetles, I had a feeling that this lizard might also be a good one. The photo shown here is admittedly not one of my best, but it was the only one I managed to get before the lizard ducked into the brush for good. Horribly overexposed, I did what I could with it in Photoshop to make it halfway presentable, but there is no question that its subject represents a Florida scrub lizard, Sceloporus woodi¹. This small, diurnal, ground-dwelling lizard belongs to the family Phrynosomatidae (same family as the Texas horned lizard that I featured in this post) and is restricted to Florida’s rare sand scrub and sandhill habitats. Like the recently featured Highlands Tiger Beetle, this species is threatened by the isolated, disjunct nature of its required habitat—a threat made worse by the ever increasing pressures of agricultural conversion and urban development.
¹ Sceloporus is derived from the Greek word scelos meaning “leg” and the Latin word porus meaning “hole”, referring to the pronounced femoral pores found in this genus of lizards. The species epithet honors Nelson R. Wood, a taxidermist at the U.S. National Museum who collected the type specimen in 1912.
Distribution of the Florida scrub lizard (from Branch et al. 2003).
The Florida scrub lizard is related to and closely resembles the much more common and widely distributed southern fence lizard (Sceloporus undatus), which co-occurs with the scrub lizard in northern Florida. Fence lizards, however, lack the dark brown lateral stripe that is clearly visible in the above photo, a feature seen in juveniles and adults of both sexes of the scrub lizard. Juvenile and adult female scrub lizards also exhibit a dorsal zigzag pattern; however, this fades in males as they reach adulthood and develop the characteristic bright blue belly patches that are seen in both this species and in the fence lizard (Branch and Hokit 2000). Since light blue patches are just visible on the belly and throat of the individual in the photograph, I haven’t been able to determine whether it represents a mature female or a still-juvenile male—any help from a knowledgeable reader would be greatly appreciated. Unlike the fence lizard, the scrub lizard displays a high degree of habitat specificity, occurring as disjunct populations in strict association with the major sand scrub ridges of Florida. The healthiest populations are found on the Mt. Dora Ridge in northern peninsular Florida, on which significant remnants of scrub habitat are preserved in the Ocala National Forest. Populations also occur on the Lake Wales Ridge of central Florida and the Atlantic Coastal Ridge, but the status of these populations is less secure. Populations also once occurred along the southwestern coast on the Gulf Coast Ridge, but these populations are now believed extirpated as a result of urban development (Jackson 1973, Enge et al. 1986). While the Florida scrub lizard is not listed as a threatened or endangered species at the state or federal level, its high specificity to an increasingly isolated and fragmented habitat and its apparently low dispersal capabilities are clear causes for concern over its long-term prospects. As remnant habitats continue to shrink and become more isolated, the threat of localized extinction becomes an increasing concern for the lizard populations that they support.
Scrub lizard habitat is threatened by development, fragmentation and increased vegetation.
The precarious status of scrub lizards and their occurrence in several disjunct, isolated populations makes them interesting subjects for genetic studies. Mitochondrial DNA analyses suggest that scrub lizard populations exhibit a high degree of phylogeographical structure, with populations diverging significantly not only between major scrub ridges, but also within them (Branch et al. 2003). The findings support the notion of long-term isolation of scrub lizard populations on the major scrub ridges and confirm their low dispersal rates among adjacent scrub habitats within ridges (as little as a few hundred yards of “hostile” habitat may be sufficient to prevent movement to adjacent habitats). More significantly, the results support the concept of two distinct morphotypes on the Mt. Dora and Lake Wales Ridges and also raise the possibility that Atlantic Coastal Ridge populations represent a distinct evolutionary entity as well. These findings are consistent with the hypothesis that scrub lizards evolved in central Florida, where they were isolated when surrounding lands were inundated by rising sea levels during the late Pliocene and subsequent interglacial periods during the Pleistocene. During periods of low sea level they dispersed to the younger Atlantic and Gulf Coastal Ridges, where they were isolated from parent populations when more mesic conditions returned during the Holocene (12 kya to present). The genetic distinctiveness of these different ridge populations may justify qualifying each of them for protection as “significant evolutionary units” under the U.S. Endangered Species Act, since it raises concerns about the use of translocations, a common strategy for establishing new populations in restored habitat or augmenting existing populations, as a conservation strategy for the species as a whole. Since lizards located on different ridges are more divergent than lizards from populations located on the same ridge, movement of lizards between ridges could compromise the integrity of the genetic differences that have accumulated over millions of years and result in loss of genetic diversity. As a result, augmenting populations on the Lake Wales and Atlantic Coast Ridges with lizards from robust populations on the Mt. Dora Ridge may not be desirable. Instead, it may be necessary to protect individual scrub lizard populations on each of the major scrub ridges in order to preserve as much of their genetic diversity as possible.
REFERENCES:
Branch, L. C. and D. G. Hokit. 2000. Florida scrub lizard (Sceloporus woodi). University of Florida, IFAS Extension Service Publication #WEC 139, 3 pp.
Branch, L. C., A.-M. Clark, P. E. Moler and B. W. Bowen. 2003. Fragmented landscapes, habitat specificity, and conservation genetics of three lizards in Florida scrub. Conservation Genetics 4:199
Enge, K. M., M. M. Bentzien, and H. F. Percival. 1986. Florida scrub lizard status survey. Technical Report No. 26, U.S. Fish and Wildlife Service, Jacksonville, Florida, U.S.A.
Jackson, J. F. 1973. Distribution and population phenetics of the Florida scrub lizard, Sceloporus woodi. Copeia 1973:746–761.
Copyright © Ted C. MacRae 2009
Dry sand scrubland on Lakes Wales Ridge in central Florida—home to Cicindela highlandensis and Ellipsoptera hirtilabris
In my previous post, I featured the rare Cicindela highlandensis (Highlands Tiger Beetle), restricted entirely to sand scrubland and pine woodland habitats along the Lake Wales Ridge in central Florida (Choate 2003). However, that would not be the only Florida endemic tiger beetle that I would encounter during my early August visit. Another of the several tiger beetle species that I’d hoped to see would also be found that day, although in much lower numbers. Ellipsoptera hirtilabris (Moustached Tiger Beetle) is so named¹ because of the dense covering of prostrate hairs on its labrum that distinguish it from the closely related E. gratiosa (Whitish Tiger Beetle). Both of these species exhibit striking white maculations that cover almost the entire elytral surface and dense white pubescence covering the head, thorax, underside and legs. They are the only species of the genus occurring in Florida, but their ranges do not overlap (Pearson et al. 2006)—E. gratiosa occurs in the coastal pine barrens of Virginia, the Carolinas, southern Georgia and the Florida panhandle, while E. hirtilabris is restricted to peninsular Florida in pine woodlands, sand hills and other habitats with open white sand. Although the latter is considered a Florida endemic, it has been found just outside of Florida in extreme southeastern Georgia on St. Simon’s Island (Choate 2003). In addition to the pubescence of the labrum and their allopatric distributions, the two species may further be distinguished by the slightly less expanded markings and more diffuse edges where they contact the central bronze area in E. hirtilabris and the slightly larger size of E. gratiosa. Like C. highlandensis and C. abdominalis, it seems likely that E. hirtilabris and E. gratiosa evolved from a common ancestor, diverging in isolation from each other during the pre-Pleistocene separation of peninsular Florida from the North American mainland.
¹ The species epithet is derived from the Latin words hirtum meaning “hairy” and labrum meaning “lip”.
Ellipsoptera hirtilabris in the alert position
I found E. hirtilabris to be exceedingly difficult to see and photograph. Unlike C. highlandensis, which resemble bits of debris laying on the surface of the white sands where it lives, the largely white E. hirtilabris blend into the white sand itself and are almost impossible to see until they move. The small bronze-colored patches along the elytral suture augment their cryptic capabilities by resembling small bits of debris, which is especially evident in the photo below. Both Pearson et al. (2006) and Erwin and Pearson (2008) state that adults of this species freeze in position when approached, which may be the reason why I saw so few individuals. Once I did see them, they were extremely wary and difficult to photograph no matter how cautiously I approached. The photos shown here represent the only two individuals that I succeeded in photographing, and in neither case did I succeed in getting a frontal perspective to show the pubescent labrum (stifling heat and oppressive humidity during the photo session did not help matters, either).
The white coloration with small brown markings helps adults blend in perfectly in their white sand habitats
Photo details:
Photo 1: Canon 100mm macro lens on Canon 50D (landscape mode) ISO-100, 1/250 sec, f/16, natural light.
Photos 2 & 3: Manual mode, f/25, MT-24EX flash w/ Sto-Fen diffusers @ 1/8 ratio.
REFERENCES:
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.
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.
Copyright © Ted C. MacRae 2009
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.
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, 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 - 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
Photo details: Canon 100mm macro lens on Canon 50D (manual mode), ISO-100, 1/250 sec, f/22, MT-24EX flash w/ Sto-Fen diffusers.
When is a ctenuchid moth not a ctenuchid moth? When it’s a White-tipped Black Moth (Melanchroia chephise) in the family Geometridae!
I may be a beetle guy, but I also consider myself a competent general entomologist. What is a competent general entomologist? Someone who can identify any insect to order at first glance and a majority of them to family – regardless of one’s own taxa of expertise. Thus, when I encountered this mating pair of moths on the outside wall of my sister-in-law’s condominium in Seminole, Florida, I “recognized” them as something in what I learned as the family Ctenuchidae (later subsumed within the Arctiidae, first as a subfamily and now as several disparate tribes). They had all the hallmarks of ctenuchids—black and red coloration, narrowish wings with light colored patches, and about the size of the wasps that they presumably mimic. Upon my return to St. Louis, I sat down to identify the moths—confident that their distinctive appearance would lead to the quick ID that never materialized after scanning through all of the ctenuchine pages at BugGuide. Frustrated, I resorted to posting the photo on the site’s ID Request, never questioning my ctenuchine placement. Precisely 4 minutes later, the moths were identified by John Maxwell as Melanchroia chephise and moved to their proper place—among the 50 other adult photographs of this species that can be found on the site! I might as well have failed to identify a monarch butterfly!
Melanchroia chephise is apparently common in the American tropics, reaching its northern distributional limit along the coastal plains of Florida and Texas but straying further north in certain years. Larvae feed on several plants in the family Euphorbiaceae, primarily Breynia and Phyllanthus species. The adult coloration strikes me as obviously aposematic (warning coloration), but I could find no specific references to this. However, considering that euphorbiaceous plants are famous for their diverse arsenal of latex and irritant toxins (e.g., diterpene esters, alkaloids, glycosides, ricin-type protein toxins, etc.), it seems reasonable to presume that Melanchroia larvae have evolved mechanisms for sequestering one or more of these compounds. NABA South Texas states that adults of this species are probably mimics of the Red-bordered Pixie (Melanis pixe), an aposematic metalmark butterfly also of Neotropical distribution that reaches south Texas (but not Florida). Personally, I don’t really see the resemblance (but then, nor am I an avian predator). I suppose it’s possible that a species such as this can employ different defense strategies in different parts of its range, relying on Batesian mimicry in areas where suitable models occur and aposematism in areas where they don’t, but I have to admit that I’m now straying well outside the coleopteran-centric bounds of my expertise.
Copyright © Ted C. MacRae 2009
The latest issue of the journal Cicindela arrived in my mailbox today, and as usual some interesting papers are included. For those of you unfamiliar with it, Cicindela is “a quarterly journal devoted to the Cicindelidae,” publishing papers dealing with any aspect of the study of tiger beetles. Founded in 1968 by North American tiger beetle experts Ronald L. Huber, Robert C. Graves, and Harold L. Willis, it was dubbed in those early issues as “…an experiment—an inquiry into the merits (and shortcomings?) of extreme specialization…”. Richard Freitag succeeded Willis in 1975, and that trio has edited and produced this “experiment”—now in its 41st year—ever since! Issues are available for a very nominal $10 per year ($13 outside of the U.S.). My sincere thanks to Artur Serrano (University of Lisbon) for permitting me to post his stunning photograph of the third-instar larva of Megacephala megacephala, photographed in Guinea-Bessau, Africa and gracing the cover of this latest issue.
Tetracha virginica in Wisconsin
Despite the common occurrence of this species across the southern two-thirds of the eastern U.S., its northern and western limits of distribution are still poorly known. Grimek discusses records of this species in Wisconsin during the 45-year period between 1962 to 2007, noting that all of the captures were from sandy areas near rivers in, with the exception of a single specimen, the “Driftless Area” covering the southwestern quadrant of the state. (The Driftless Area, also called the Paleozoic Plateau, is an area that escaped glaciation during the last glacial period). The capture of a specimen very near the Mississippi River suggests the species may also be found in Minnesota, where its occurrence has not yet been documented.
Grimek, H. 2009. Distribution of Tetracha virginica (Linnaeus) in Wisconsin. Cicindela 41(3):57-61
Brasiella cuyabaensis in Bolivia
Brasiella is a large genus (47 species) of small to very small, mostly Neotropical tiger beetles, of which B. argentata is among the most common and widespread. While examining specimens of this species that he had collected in Bolivia, Italian coleopterist Fabio Cassola found a second species among the material. At first thought to potentially represent a new species, its identity was ultimately revealed after examination of the unique male type specimen of B. cuyabaensis from Brazil. This specimen is very similar to B. argentata except for its genitalia (longer and narrower than in B. argentata), and Cassola has confirmed this in his material as well. The previously unknown females were especially problematic; however, Cassola found their longer, more convex labrum (upper lip) to be a useful diagnostic character. Cassola collected B. cuyabaensis some 700 km west of the type locality and speculates that additional specimens of the species may exist in entomological collections, incorrectly placed under B. argentata.
Cassola, F. 2009. Studies of tiger beetles. CLXXV. Occurrence in Bolivia of Brasiella cuyabaensis (Mandl, 1970) (Coleoptera: Cicindelidae). Cicindela 41(3):63-67.
DNA degrades rapidly in pinned tiger beetles
DNA molecular analyses are increasingly being used to elucidate relationships among tiger beetles, both at the species level and at higher levels of classification. However, such research is often hampered by the limited availability of sufficient fresh material representing less common taxa. Pinned museum specimens offer a potential source of DNA for such uncommon taxa; however, successful extraction of useable DNA from pinned specimens has been limited. Kritsky and Duennes, using a standardized DNA extraction method, determined that DNA extracted from pinned tiger beetles rapidly degrades during the first 25 years after collection before stabilizing at ~10% of the original DNA. The authors found that frozen specimens yeilded more DNA than specimens killed in ethanol, perhaps due to degradation of DNA by water in the ethanol, and noted that choice of killing method and use of fumigants during storage can also contribute to loss of DNA. More research is needed to determine optimal conditions for protecting museum specimens while preserving their DNA for future research.
Kritsky, G. and M. Duennes. 2009. The rate of DNA degradation in pinned tiger beetles. Cicindela 41(3):69-73.
Mississippi tiger beetles scavenge dead fish
An established breeding population of Cicindela pamphila [= Habroscelimorpha pamphila] was observed during 2006–2008 in a Mississippi coastal salt marsh. This species was previously considered a rare straggler into Mississippi, occurring primarily along the Texas Gulf Coast south into Mexico. The Mississippi population was observed co-occurring with C. hamata [= Ellipsoptera hamata], C. severa [= Habroscelimorpha severa], and C. togata [= Eunota togata]. On one occasion, individuals of C. hamata and C. severa were observed feeding on a fresh mullet (Mugil sp.) carcass resulting from a raptor kill, adding these two tiger beetle species to the list for which scavenging on dead vertebrates has now been confirmed. Despite the co-occurrence of four species of tiger beetles within this area, the author noted no apparent resource partioning and speculates that carrion resulting from predation by birds, racoons, etc. may provide a valuable resource for scavenging tiger beetles that reduces competition for food.
Grammer, G. L. 2009. A breeding population record of Cicindela pamphila in Mississippi and observations on the scavenging behavior of C. severa and C. hamata. Cicindela 41(3):75-80.
Copyright © Ted C. MacRae 2009
Beetles In The Bush 