Fun at Salinas Grandes

/ Ted C. MacRae / 3 Comments

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My colleagues and I greatly enjoyed our visit to the Salinas Grandes salt flats in Catamarca Province, but there was a moment of tension between Federico and Agustín. You see, Federico is only 12″ tall, so we have to keep a close eye on him to make sure he doesn’t get himself into any trouble. Apparently he had wandered off too far for Agustín’s comfort, leading to a bit of a scolding. Despite his small size, however, Federico took it all in stride and stayed close for the remainder of our visit.

Copyright © Ted C. MacRae 2013

Greetings from Argentina

/ Ted C. MacRae / 2 Comments

Perhaps some have noticed that things have been relatively quiet of late here at Beetles in the Bush. I have been hard at work in South America for the past couple of weeks, first in Brazil and now in Argentina. Posting should return to normal when I return to the U.S. next week; however, in the meantime I thought it might be a good idea to show just how hard I have been working:

Salinas Grandes, Provincia de Catamarca, Argentina

Salinas Grandes, Provincia de Catamarca, Argentina

Copyright © Ted C. MacRae 2013

Baffling beetles

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Even though I pride myself as a fairly competent coleopterist, I occasionally run into beetles that—despite my best efforts—I just cannot identify them beyond the family level. I don’t feel too bad about that, as the group’s 350,000 to 400,000 described species represent more than a third of all described life forms! Still, with the amount of information now available online combined with traditional print literature, it’s frustrating when I photograph species that seem quite distinctive but fail to show up in any search result. Here are a couple of South American beetles that I’ve pondered over for a year or more now. If you have any thoughts on their identity I would appreciate hearing from you.

Tenebrionidae? | Campinas, São Paulo, Brazil.

Tenebrionidae? | Campinas, São Paulo, Brazil.

This first beetle was encountered January 2011 on the trunk of a tree in the city of Campinas, southeastern Brazil (São Paulo State). I only got this one shot of it before it dropped and disappeared, and except for the bright green color of the head and pronotum it reminds me of some of the long-jointed beetles—formerly the family Lagriidae but now a subfamily of Tenebrionidae (darkling beetles).

Elateridae | Rt 16 nr. Rio Nego, Chaco Province, Argentina

Elateridae | Rt 16 nr. Rio Negro, Chaco Province, Argentina

This is without question a species of click beetle (family Elateridae), but despite its rather distinctive coloration I’ve not found any images that resemble it. I found these beetles fairly commonly on flowers of Solidago chilensis in April 2012 at several localities along Rt 16 in northern Argentina (Chaco Province).

Copyright © Ted C. MacRae 2013

Brazilian Bike Adventure

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Atlantic Forest

Atlantic Forest in Serra do Mar.

Yesterday I joined my Brazilian colleagues on a bicycling tour from the outskirts of São Paulo to the beaches of the Atlantic Coast. To say that the tour was an ‘adventure’ is an understatement—it was epic! For those not familiar with São Paulo, its 20 million inhabitants make it not only the largest city in Brazil, but also one of the five largest cities in the world. Yet, despite the explosive growth it has seen during the past century, it remains isolated from the Atlantic Coast of southeastern Brazil by the Serra do Mar, a 40-kilometer wide swath of rugged, mountainous terrain and part of the Great Escarpment that runs along much of the eastern coast of Brazil. It is here where some of the last tracts of Atlantic Forest, the second largest forest ecotype in South America after the Amazon, remain. Atlantic Forest once stretched along much of Brazil’s Atlantic coast, turning inland in its southern reaches to Paraguay and the northern tip of Argentina. However, much of the forest, especially in populous southeastern Brazil, has fallen victim to the axe. Only the ruggedness of the Serra do Mar has allowed the Atlantic Forest to survive in such close proximity to one of the world’s most populous cities. Understandably, travel between São Paulo and the coast has been difficult. In former years, vehicles had to snake their way through the mountains along a treacherous 2-lane highway with steep grades and hairpin turns. That highway has since been circumvented by an elevated, double, 4-lane highway of alternating spans and tunnels, and the old highway, now closed to vehicles, is instead used by maintenance crews for the new highway and cyclists who yearn to experience the Atlantic Forest up close and personal.

Our van dropped us off in the outskirts of São Paulo, from where we rode along the main highway a short bit before accessing the old highway. Dropping into the Atlantic Forest was like being magically transported into virgin wilderness. The pavement was so encroached by the forest, steep and slippery in places, that it was hard to imagine it ever served as a link between Brazil’s largest city and its largest port. Heavy rains the previous night made the forest moist and gave it an earthy aroma, and moisture-laden air hung heavy with fog and intermittent drizzle. For a time it seemed we would have an uninterrupted, 40-km downhill freeride; however, just a few kilometers into the ride we encountered the first of what would be many landslides blocking the route. I can honestly say that I’ve never portaged a bike through as rough and tumble a pile of trees, rocks, and mud as I did on this day. Still, perhaps encouraged by the fresh bike tracks that lay before us, we soldiered on. After picking our way through a half-dozen such landslides we came upon a work crew who said there were another 30–40 landslides further down along the route. We were at a tunnel that connected with the main highway, so we decided to play it safe and take the main highway the rest of the way down. That, too, was an adventure, made feasible only by the fact that traffic was crawling at a snail’s pace due to the popularity of the Atlantic beaches with the citizenry of São Paulo. It was enjoyable to swish past the cars as they idled their engines, but we had to navigate about seven kilometers worth of shoulderless tunnels. That would have been impossible in normal traffic, but the congestion made finding room to squeeze by large trucks and buses the biggest problem (and I guess breathing exhaust!). Eventually we made it down into Santos, the largest port city in Brazil, and after picking our way through the center of the city, took a ferry to the beach city of Guarujá. Rain, landslides and traffic had thrown everything they had at us, but we persevered the 53-km trek and watched the sun break through while enjoying our just rewards in a beachside restaurant.

Following are a few more of my favorite photos from the day, and you can see all of them in my Facebook album Brazilian Bike Adventure.

Descending into the forest.

Descending into the forest.

Magical vistas such as this were around every turn of the road.

Magical vistas such as this awaited us around every turn of the road.

Manacá da Serra (Tibouchina mutabilis) was abundant in the forest.

Manacá da Serra (Tibouchina mutabilis) flowered in abundance in the forest.

Elevated roadways bypass the beauty of the forest below them.

Why did the ‘hellgramite’ (order Megaloptera, family Corydalidae) cross the road? (Thanks to dragonflywoman for the ID.)

The first of many landslides that blocked our path.

The first of many landslides that blocked our path.

The new elevated highway snakes through the Serra do Mar. This portion was closed due to landslides.

The new elevated highway snakes through the Serra do Mar. This portion was closed due to landslides.

Outside of the cicada killer, this digger wasp (family Crabronidae) on the beach at Guarujá is the largest that I have ever seen.

A large digger wasp (family Crabronidae) greets us on the beach at Guarujá.

My Brazilian colleagues and I enjoy some well-deserved refreshments after our 53-km trek!

My Brazilian colleagues and I enjoy some well-deserved refreshments after our 53-km trek!

I may have looked like a nerd still in my cycling clothes, but the wave experience was unforgettable.

I may have looked like a nerd still in my cycling clothes, but the wave experience was unforgettable.

Copyright © Ted C. MacRae 2013

T.G.I.Flyday: Argentine robber

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I’m back in South America for the next 2+ weeks, and though it will be another week before I actually make it into Argentina, I am celebrating my return to that lovely country with photos of Argentinian insects taken during last year’s extended visit but that I haven’t had a chance to share before now. Earlier this week I featured Camponotus sericeiventris (though I prefer the literal translation, “silky-bellied humpbacked ant“)—easily among the most handsome ants that I’ve ever seen and which I encountered in the remnant quebracho forests at Chaco National Park in northern Argentina. Today’s feature is an equally handsome robber fly (order Diptera, family Asilidae), also seen at the park and which landed on a dead log just long enough to allow one good lateral profile shot of the beast in all its hairy splendidness! (Probably it zipped off to impale an Odontocheila tiger beetle in the back of the neck!)

Triorla sp. | Chaco National Park, Argentina

Triorla sp. | Chaco National Park, Argentina

I sent this photo to a few fly guys looking for a more authoritative opinion about its identity, mentioning its resemblance to some of our North American species of Efferia. Herschel Raney agreed that it belonged to at least that group, while Eric Fisher suggested a species in the genus Triorla (an early segregate of Efferia that is now widely regarded as a valid genus). The most recent checklist of robber flies from Argentina (Artigas & Hengst 1999) lists three species in the Efferia group (all in the genus Nerax); however, both Herschel and Eric confirmed my suspicion that Argentina, and especially the north, is not well studied for Asilidae. Eric further suggested that there could be as many as several times the number listed, mainly undescribed but also described from adjacent countries and occurring in Argentina but not yet recorded from there. Also, I had presumed this individual to represent a female since it lacked the distinctly swollen genital capsule (e.g. see this post, presumably another Efferia-group species), but Herschel thought the terminal structure was odd and did not look female.

REFERENCE:

Artigas, J. N. & M. B. Hengst. 1999. Clave ilustrada para los géneros de asílidos argentinos (Diptera: Asilidae). Revista Chilena de Historia Natural 72:107—150.

Copyright © Ted C. MacRae 2013

The “silky-bellied humpbacked” ant

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Last year during my extended work stay in Argentina, I was able to slip away from my duties during the first week of April and spend some time in the city of Corrientes in the northeastern part of the country. The city is one of my favorites in Argentina, but what I love most about it is its convenience as a base camp for exploring some of the habitats in the Grand Chaco ecoregion of northern Argentina. One day I had a chance to visit Chaco National Park about 100 km northwest of the city, site of some of the last remnants of the great quebracho forests that once covered much of northern Argentina. The forest preserved at Chaco NP takes its name from the quebracho colorado chaqueño (Schinopsis balansae) trees that dominate it, standing in defiant contrast to the vast, hot sea of cotton fields and mesquite fence-rows that surrounds it. While hiking a trail through the heart of the forest, I looked down to see a most impressive ant crawling across the forest floor:

Camponotus sericeiventris

Camponotus sericeiventris | Chaco National Park, Argentina

Because of its black color and the striking, silky sheen of the abdomen, I was immediately reminded of the Camponotus mus ants that I had photographed a year earlier further south in Buenos Aires. However, this fellow (er, fella…) was considerably larger than that species, and looking at the photographs later I was also struck by the acute spines at the humeral angles of the pronotum (in C. mus the humeral angles were obtuse) and the flattened legs. All of this combined to make it one of the most handsome ants that I had ever seen! I posted the above photo on my Facebook page asking for ID help, and James Trager quickly responded that the ant represents Camponotus sericeiventris, which translates roughly to “silky-bellied humpbacked” ant. Now there’s a common name I can get behind.

Camponotus sericeiventris

Of course, it turns out that I could have easily determined the species on my own using the characters I had already noted—primarily the acute spines. Googling “camponotus acute spines” retrieves as its first result a paper by Wheeler (1931) that discusses this ant and a newly discovered (at the time) cerambycid beetle, Eplophorus velutinus [now Euderces velutinus] mimicking the ant (Fisher 1931). As soon as I read Wheeler’s first paragraph I knew I had the right species:

Camponotus (Myrmepomis) sericeiventris, owing to its size, wide distribution and dense covering of silver or golden pubescence, is one of the handsomest and most conspicuous ants of the American tropics.

Apparently this ant is a popular choice of models for mimics in a number of insect groups. Lenko (1964) reported another cerambycid beetle, Pertyia sericea, as a mimic of C. sericieventris (the similarity of species epithets being no coincidence), and friend and colleague Henry Hespenheide has not only described a zygopine weevil, Copturus paschalis, from Costa Rica as a mimic of this ant (Hespenheide 1984) but also postulated mimicry by Apilocera cleriformis [now Euderces cleriformis] and three other species of Cerambycidae collected by him in central Panama. Henry further noted mimics in the families Cleridae and Mutillidae and the fact that all of the beetle mimics of this arboreally foraging ant are themselves woodborers or predators of woodborers as larvae.

It is interesting that Fisher (1931), in his description of E. velutinus, made no mention of the mimicry, while Wheeler (1931) in his paper about C. sericeiventris discussed this in great detail. He further noted the diversity of cerambycids here in our North American fauna that mimic ants. These include species in the genera Clytoleptus, Euderces, Cyrtophorus, Tilloclytus and—most strikingly—Cyrtinus pygmaeus, our smallest species of Cerambycidae which occurs on dead wood among small ants such as Lasius americanus, and Michthisoma heterodoxum which resembles small Camponotus pennsylvanicus workers. I’ve not yet encountered M. heterodoxum, which seems restricted to the southeastern Coastal Plain, but I have beaten C. pygmaeus from dead branches and can personally attest to the effectiveness of their mimicry—some slight something about the way they moved made me question my immediate assumption that they were ants and caused me to take a closer look at them before I shook them off the beating sheet. I wonder how many times before that I collected this species without realizing it!

REFERENCE:

Fisher, W. S. 1931. A new ant-like cerambycid beetle from Honduras. Psyche 38:99–101.

Hespenheide, H. A. 1984. New Neotropical species of putative ant-mimicking weevils (Coleoptera: Curculionidae: Zygopinae). The Coleopterists Bulletin 38(4):313–321.

Lenko, K. 1964. Sobre o mimetismo do cerambicideo Pertyia sericea (Perty, 1830) com Camponotus sericeiventris (Guerin, 1830). Papéis Avulsos de Zoologia (São Paulo) 16:89–93.

Wheeler, W. M. 1931. The ant Camponotus (Myrmepomis) sericeiventris Guérin and its mimic. Psyche 38:86–98.

Copyright © Ted C. MacRae 2013

Featured Guest Photo: A Spectacular Case of Mimicry

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On occasion I receive photos from readers that are so remarkable I simply must share them (with the owner’s permission, of course). Recently I received a note from Len de Beer in Maputo, Mozambique, who was looking for help identifying a tiger beetle he had photographed on the beaches of the Maputo elephant reserve. My knowledge of Afrotropical tiger beetles is rudimentary, so I had to tap the expertise of fellow cicindelophile Dave Brzoska for the ID (many thanks, Dave), but in the ensuing correspondence Len sent me the following photograph that he took of another tiger beetle species while living in Madagascar:

The mimic: Peridexia hilaris

The mimic: Peridexia hilaris | Anzojorobe, Madagascar (photo © Len de Beer) 

A spectacular species to be sure, but the story behind its appearance is even more remarkable. This tiger beetle is one of two species in the Madagascan-endemic genus Peridexia, both of which exhibit color patterns that are a near-perfect match for that of the local pompilid wasp, Pogonius venustipennis (see photo below). According to Pearson & Vogler (2001), not only do these tiger beetles share the wasp’s bright yellow and black color pattern, but they also run in constant small circles (rather than the distinct, straight-line sprints that are more typical of tiger beetles) and fly readily when frightened, only to land again on the forest floor. These running and flying behaviors more closely resemble the foraging movements of the wasp than the movements of a typical tiger beetle, resulting in mimicry so effective that even tiger beetle collectors have been fooled and stung on the fingers when they attempted to collect their first Peridexia!

The model: Pogonius venustipennis

The model: Pogonius venustipennis (photo © Len de Beer)

Camouflage is the most widely observed predator avoidance mechanism in tiger beetles, with numerous species known whose color patterns closely resemble or otherwise allow them to blend in with the color and texture of the soils found in their preferred habitats. Nevertheless, mimicry is common enough (although anecdotal evidence still far outweighs true experimental evidence). Pearson & Volgler (2001) list examples of tiger beetles resembling mutillid wasps (commonly called “velvet ants”) from North and South America, as well as India, and also mention a South American tiger beetle species, Ctenostoma regium, that is the same size and shape as Paraponera clavata (or “bullet ant”), a large solitary species that is purported to pack the most painful of all insect stings (that this is true, I am inclined to agree). Tiger beetles can also serve as models—there is a katydid in Borneo whose immatures bear a remarkable resemblance to arboreal species of tiger beetles in the genus Tricondyla (Pearson & Vogler 2001, Plates 26 and 27). It has also been suggested that mimicry in tiger beetles might not be restricted to Batesian associations (unprotected mimic and harmful model) but may also include Müllerian associations (both model and mimic are distasteful or harmful).

My sincere thanks to Len de Beer for allowing me to post his photographs of this remarkable tiger beetle and the wasp it mimics.

REFERENCE:

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

Copyright © Ted C. MacRae 2013 (text)