Latest

The Cicindela of Linnaeus

Bolton-linnaeus 300px

Carl Linnaeus (or his ennobled name Carl von Linné or the latinate Carolus Linnaeus) laid the foundations for binomial nomenclature, modern taxonomy, and recognized the tiger beetles as a distinct group. As with much of Linnaeus’ writing the description of the genus is in Latin; in the first edition of Systema Naturae he erected the genus Cicindela, noting that unique appearance of the clypeus and the prominent mandibles.

 

From the publication of Systema Naturae and through subsequent editions until his death Linnaeus described eight tiger beetle species. While the species came from Europe, North America, and South Africa Linnaeus placed all eight species in the genus Cicindela. Later workers have dispersed these species across five genera and ajoined numerous subspecies since Linnaeus’ death in 1778.

Europe

Cephalota maura (Linnaeus, 1758)

Cicindela campestris Linnaeus, 1758

Cicindela hybrida Linnaeus, 1758

Cicindela sylvatica Linnaeus, 1758

 Cylindera germanica (Linnaeus, 1758)

North America

Tetracha carolina (Linnaeus 1767)

Tetracha virginica (Linnaeus, 1767)

South Africa

Habrodera capensis (Linnaeus, 1764)

References

Pearson, D. L., Cassola, F., 2005. A quantitative analysis of species descriptions of tiger beetles (Coeloptera: Cicindelidae), from 1758 to 2004, and notes about related developments in biodiversity studies. The Coleopterologists Bulletin, 59(2): 184-193.

Monographie des Cicindélides: Frontispice

frontispiece

I don’t even know what to say!  This work of art is from James Thomson‘s 1857 “Monographie des Cicindélides” You can view the book online at Biodiversity Heritage Library.

Habroscelimorpha dorsalis dorsalis at last!

While I have assisted in a few surveys of Habroscelimorpha dorsalis dorsalis I had not been able to get a decent photo – until now. This past weekend I had the chance to stop and take a few photos of this Federally threatened subspecies at Savage Neck natural area preserve.

This subspecies is noticeably larger than its the other members of the dorsalis complex and, though camouflaged against the sand, is easy enough to spot. However, the beetles were quite flighty and very active making it a real challenge to get a photo. I was finally able to get shots of two males, one with greatly reduced maculations, a common occurrence in this species.

For more information on the dorsalis subspecies see here

why hello there…

This is a third instar larvae of Cicindela albissima – the Coral Pink Sand Dunes Tiger Beetle. I found the larvae to be virtually unapproachable during the day, but at night, with a little patience, I could get right up to their burrows. The head and pronotal coloration of the larvae is quite vivid – one of the most colorful that I’ve seen.

I photographed this individual and many more while I was doing some fieldwork back in 2010. I’ll post a best of from that trip in the coming month, if time permits.

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.

one from the archives…

Back in 2006 I photographed this female Cicindela sexguttata feeding on a caddisfly; the hapless  trichopteran had been attracted to my blacklight placed on a dirt trail along a stream. With the sunrise, I watched as the voracious tiger beetle happened along and was chowing down by the time I snapped this shot.

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.

Follow

Get every new post delivered to your Inbox.