Zygogramma Desmogramma leaf beetles in Argentina


The east end of  in Buenos Aires offers a quiet contrast to the more populated central and western areas. Few people leave the levee-trail system that surrounds the famous wetlands and pampas grass stands in those latter areas; however, those that do find in the east a mosaic of pastures and young woodlands that offer a greater diversity of sights and invite a more leisurely pace. November is spring in Buenos Aires, and as such there were a number of plants beginning to bloom in the Reserve. One plant I found blooming in abundance in one small part of the east area was a member of the family Malvaceae that I take to be Abutilon pauciflorum, a few of which were being devoured by these leaf beetles (family Chrysomelidae).


These beetles are clearly members of the subtribe Doryphorina within the nominate subfamily, looking very similar to the North American species Zygogramma suturalis (ragweed leaf beetle) or the vittate species of Calligrapha (subgenus Bidensomela), e.g. Calligrapha bidenticola. Both of these genera are represented in Argentina, and at first I was inclined to believe the beetles belonged to the latter genus since its Central and South American members are associated almost exclusively with malvaceous plants (North American species of Calligrapha have adapted to plants in several other families). However, a view of the tarsus in the last photo suggests that the claws are joined at the base, a character that immediately separates members of the genus Zygogramma from the genus Calligrapha (species of Doryphora also have fused tarsal claws but exhibit a completely different gestalt). Eight species of Zygogramma have been recorded from Argentina, but I wasn’t able to find photographs of any that look reasonably similar to the individuals in these photos.  The identification will have to remain, frustratingly, non-specific.

Update 12/6/11: I just received an email from Shawn Clark (Brigham Young University, Provo, Utah) saying that he suspects the beetles belong to the genus Desmogramma. This genus is distinguished from both Zygogramma and Calligrapha by having the prosternum sharply angled upward anterior to fore coxae or mesosternum with a distinct horn directed anteriorly (Flowers 2004) and the claws widely separated and unarmed. Unfortunately, neither character is visible in these photos. Three species of Desmogramma are recorded from Argentina, and the coloration of these individuals resembles that described by Stål (1862) for D. striatipennis (D. semifulva and D. nigripes have the 3rd, 5th and 9th elytral interstices light).


These photographs represent continued efforts with the so-called ‘blue sky background’ technique that I’ve been trying to perfect as an alternative to the black background one typically gets in insect macrophotography with full-flash illumination of the subject. All of these photos were taken at ISO 640 using an MP-E 65mm lens at f/13 with 1/160 sec (1st photo) or 1/125 sec (2nd and 3rd photos) exposure and F.E.C. -1. These are similar settings to those used in my previous and not as satisfactory attempt, but this time the results were much better. Not only is the color of the sky spot-on blue, but these photos have much better detail than the previous. In this case, I believe “locking'” the subject relative to the lens to prevent motion blur was the key—I used my left hand to hold the leaf with the beetle towards the bluest area of the sky, rested the camera lens on my left wrist, used my fingers to fine tune the leaf position as I looked through the viewfinder, and held my breath!

REFERENCE:

Flowers, R. W. 2004. The genera of Chrysomelinae (Coleoptera: Chrysomelidae) in Costa Rica. Revista de Biología Tropical 52(1):77–83.

Stål, C. 1862. Monographie des Chrysomélides l’Amérique. C. A. Leffler, Upsal, 365 pp.

Copyright © Ted C. MacRae 2011

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About Ted C. MacRae

Ted C. MacRae is a research entomologist by vocation and beetle taxonomist by avocation. Areas of expertise in the latter include worldwide jewel beetles (Buprestidae) and North American longhorned beetles (Cerambycidae). More recent work has focused on North American tiger beetles (Cicindelidae) and their distribution, ecology, and conservation.
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10 Responses to Zygogramma Desmogramma leaf beetles in Argentina

  1. Sam Heads says:

    Lovely images Ted. Incidentally, what sort of diffusers are you using with your MT-24EX? I recently purchased this flash unit and I’m having all sorts of trouble with the light being too intense. I use it with both the MP-E 65 and the Canon 100 mm macro lenses. First of all the light is very intense and secondly I think the flash heads are way too close to the subject. I’ve ordered (but not yet received) two Kaiser flash shoes to lift them further away from the bracket which I think might help, but I would appreciate any advice you can offer on this.

    This also reminds me that I have an Argentinian tiger beetle for you that I should put in the mail.

    • Thanks Sam. Yes, the light from the MT-24EX is very harsh (but I disagree with those who have abandoned it for single point units such as the 480EX and 580EX). Diffusion is the key – I use Sto-Fens + Gary Fong Puffers with the 65mm and a homemade diffuser for the 100mm. I’m not completely happy with either one, but the 100mm diffuser is about as good as I’ve seen with that longer lens. I think Alex’s tissue paper hood gives better results with the 65mm – I’ve used it myself at times but find the Sto-Fen + Puffer combo easier to deal with in the field. Kaiser shoes are not good for the 65mm – you actually want the flash heads as close to the subject as possible to maximize apparent light size (and then using diffusers to eliminate the harshness of the lighting). I do use Kaiser shoes with the 100mm so that I can extend the flash heads a little further in front of the lens (thus increasing apparent light size).

      I’d love to see the Argentine tiger beetle!

      • Sam Heads says:

        Thanks for the useful pointers Ted — much appreciated. I use the 100 mm a lot for grasshoppers, so I think the Kaiser shoes might come in handy there. I ordered the Sto-Fens from B&H earlier and will get an order to Gary Fong for some Puffers.

        I’ll get the Argentine beetle in the mail to you today.

  2. Great shots! Also reminds me that I need to get extension tubes or a bellows so I can turn my Nikon macro lens into something approaching the MP-E lens…

    • Thanks DFW. Just remember tubes will get you maximum mag of a little under 2X (compared to 5X with the MP-E). More importantly the working distance will still be much larger than with the MP-E, so the quality of lighting will not be as good since the flash heads will be further away from the subject. Tubes are better than nothing, but the capabilities won’t be anywhere close to those of the MP-E.

      That said, I’m a big fan of tubes with a longer macro lens for certain situations, as explained in my post, “Use of extension tubes for better lighting“.

      • My flashes sit right on the front of the lens, so they’ll be the same distance from the subject as always even with extension tubes. Or I can just take them off and position them anywhere I want. Yea for the Nikon wireless flash system! I’m not too worried about the lighting issues, but I do need to do something about the mag. I don’t expect it to be as great as the MP-E lens with the extension tubes, but there’s a limit to the size of things I can photograph with my current setup that I find annoying. If I can improve it, even by 2x, by doing something simple like adding tubes, then it seems worth it.

        • Not sure about Nikon, but with my 100mm lens the working distance w/ tubes is ~25mm less than at the same mag w/o tubes. My flash heads are lens-mounted also, so this does improve quality of lighting (though still not as good as with the 65mm lens). I use Kaiser shoes with the 100mm lens as well – this gets the flash heads another 25mm or so closer to the subject.

          Currently I’m looking at a bracket system that will get the flash heads off the lens altogether and allow me to position them as close to the subject as I want. That would allow me to use the Sto-Fen+Puffer diffusers (which do great at short distance but not so great at longer distance) for all shots regardless of which lens I’m using, and since the flash heads are no longer lens-mounted I can switch between lenses without even touching the flash heads. Added bulk may one drawback.

          One can go crazy trying to come up with the perfect solution!

  3. TGIQ says:

    I am often frustrated by my inability to ID a critter from photos alone up here in a northern temperate system; I can only imagine how much harder it is in the southern hemisphere!!! The blue sky technique you’re using is really coming along and I can’t wait to see/hear about the results as you continue to hone it!

    • As a general rule North America is better known than South America. However, I can imagine insects in the far north, especially certain groups, being much more difficult to identify than those found in a bustling Neotropical metropolis.

      Hey, I cut my taxonomic teeth back in the days when literature to identify species was available only in a university library or by typing a letter to the author (hopefully still living) and waiting several weeks to see if you got a response (and if they still had reprints of the paper available)!

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