Why are this beetle’s elytra outstretched?

Toposcopus wrightii on dead branch Juniperus virginiana | Major Co., Oklahoma

I’ve puzzled over the beetle in the above photo since I first saw it back in September on Day 2 of this year’s Annual Fall Tiger Beetle Trip. I encountered it on a dead branch of eastern red-cedar (Juniperus virginiana) on top of the main mesa at Gloss Mountain State Park in northwestern Oklahoma. At about 8 mm in length, it immediately struck me as possibly something in the family Ripiphoridae (wedge-shaped beetles). Still, the full-length elytra covering the abdomen made me doubt that identification, so I collected the specimen to get a better look at it when I returned home. Later that same day, while scanning the base of another mesa across the highway from the park at night, I came upon another individual that seemed to represent the same species—this time on a dead branch of fragrant sumac (Rhus aromatica). That individual is seen in the photo below, and two things are immediately apparent: 1) the beetle is a female in the act of oviposition, and 2) it is holding its elytra outstretched in a most curious way.

Another female oviposits on a dead branch of Rhus aromatica.

A quick browse through BugGuide’s ripiphorid images quickly showed a likely match with the genus Toposcopus, and consulting the original description of both the genus and its only included species—T. wrightii (LeConte 1868) showed agreement with the key diagnostic character (eyes divided into two lobes connected by a slender line of smooth, non-faceted corneous membrane). These two females differ from the male by their much less flabellate antennae (presumably the male uses these organs to detect female-emitted pheromones). LeConte described this species from New Mexico, and Rivnay (1929) also saw specimens from Texas and Arizona when he reviewed the North and Central American species of the family. Although the species is listed on Don Arnold’s Checklist of the Coleoptera of Oklahoma, the listing seems to be based only on the presence of specimens in the Oklahoma State University insect collection, while published records of its occurrence in the state are, as far as I can tell, still lacking. This species, thus, seems to be, along with Acmaeodera macra and Chrysobothris octocola (both family Buprestidae), an example of a typically southwestern U.S. species whose distribution extends northeast into the Red Hills Region of northwestern Oklahoma. Considering that Cylindera celeripes (Swift Tiger Beetle) and Amblycheila cylindriformis (Great Plains Giant Tiger Beetle) also have only recently been discovered in this area, it would seem that this part of the state is still undersampled and has the potential to yield additional interesting southwestern U.S. species.

Why is this female holding her elytra outstretched while ovipositing?

Regarding the outstretched elytra, I’ve not seen this type of behavior before with a beetle in the act of oviposition. While several groups of insects in other orders may hold their forewings outstretched as part of threat displays, I’ve not seen a beetle hold its elytra outstretched for any reason at all other than flight and don’t recall seeing such behavior mentioned in the literature either. Thus, I’m at a loss to explain why the beetle is doing this. If you have any ideas I would love to hear them.

One thing that I enjoy immensely about 19th Century taxonomic literature is the rich, often effusive prose that frequently accompanies the descriptive portions of the text. (I also lament that such colorful writings are nearly universally frowned upon my modern editors. Perhaps as taxonomy advances more fully into electronic-only publishing the concerns about space will dissipate and taxonomic authors will no longer be constrained to such sterile, uniform, precisely formatted writings.) The naming of this species provides an especially colorful example of the embellishments permitted to 19th Century authors:

I desire in the name of this beautiful and interesting addition to our fauna, to commemorate the ability of Gen. W. W. Wright, the Chief Engineer and Commander of the Survey in which the species in the present memoir were collected. His attention to the comfort and safety of the party while traveling through a hostile Indian country will not soon be forgotten by any of his companions; while the skill with which the more difficult portions of the route were examined, and the labors of his assistants directed to the most easy methods of surmounting the difficulties, will commend itself to every admirer of correct engineering.

John L. LeConte is widely regarded as the father of North American coleopterology. I don’t think there is anybody from the 19th Century, save perhaps Charles Darwin, that I would have more liked to meet.

REFERENCES: 

LeConte, J. L. 1868. New Coleoptera collected on the survey for the extension of the Union Pacific Railway, E. D. from Kansas to Fort Craig, New Mexico. Transactions of the American Entomological Society 2:49–59.

Rivnay, E. 1929. Revision of the Rhipiphoridae of North and Central America (Coleoptera). Memoirs of the American Entomological Society 6:1–67, 3 plates.

Copyright © Ted C. MacRae 2012

The Third of Florida’s Three Metallic Tiger Beetles

Tetracha virginica (Virginia Metallic Tiger Beetle) | Levy Co., Florida

After three straight posts not about tiger beetles, I’m hoping readers will forgive my return to this fascinating group. The photos in this post represent Tetracha virginica (Virginia Metallic Tiger Beetle), the most widely distributed (at least in the U.S.) of the four species occurring in North America north of Mexico. Even though this species occurs in my home state of Missouri, I’d not found an opportunity to photograph it until August last year at Florida’s “Road to Nowhere“—famous among U.S. cicindelophiles as one of the country’s true tiger beetle “hot spots.” In fact, it was on the very same night at this same place that I photographed the related Tetracha carolina (Carolina Metallic Tiger Beetle) (featured in Not all Florida tiger beetles are rare) and just one day after I photographed the endemic Tetracha floridana (Florida Metallic Tiger Beetle) (featured in Why I Roamed the Marsh at Night). That’s all three species of Tetracha occurring in Florida in just two days (and if I want to photograph the fourth and only remaining U.S. species, Tetracha impressus (Upland Metallic Tiger Beetle), I’ll have to go to Brownsville, Texas and get very lucky!).

The solid green elytra without apical markings distinguish this species from all other Tetracha spp. in the U.S.

Truthfully, I had no plans to post these photos after I took them. Like the other species they were photographed at night, and when I got a better look at the photos on the computer I was disappointed to see the subject was badly covered with large particles of sand. I don’t mind a little bit of debris on insects—it is, after all, a normal part of their appearance. However, too much debris is, for me, an aesthetics killer! “Wait a minute… these don’t look too bad”, you say? Well, thanks to the Clone Stamp Tool in Photoshop Elements, and as a followup to my recent post on this subject, I now have enough confidence to tackle not only small pieces of debris, but also more difficult “debris cases” such as this one with relatively large particles. Here is the same photo as shown above and processed in exactly the same manner, except that no cloning was used to remove the debris:

Aren’t I a dirty boy?!

Obviously, there are limits to what the Clone Stamp Tool can do, and I didn’t try to deal with the sand particles clinging to more difficult to clone body parts such as legs and antennae (although I’m sure that in the right hands even these could be cloned out). Nevertheless, even just cleaning the dorsal surface of the beetle does much to improve its appearance with a relatively minor amount of effort.

And, of course, what would a tiger beetle post be if it did not end with my signature face portrait (notwithstanding a few large sand grains that I wasn’t sure I could clone out effectively)?

Copyright © Ted C. MacRae 2012

Out with the old (but on a good note)

This past March was the warmest on record here in Missouri and that made for some nice opportunities to get out and photograph. That said, my enthusiasm for macro photography has been somewhat tempered since my camera body is getting old and showing some signs that it might be on its last leg. The mere fact that I am still using a camera from 2004 may be your first indication that I am something less than a macro photography perfectionist and this is a reflection of the equipment that I first used when I began shooting macro. I started with Canon manual equipment in the mid-1990’s because I thought this would be the best way to learn photography. My stint with a used, and malfunctioning, Canon AE-1 was thankfully short. It was stolen as I returned from a photography trip to the Chiricahua Mountains, but I still lament that the thief made off with the spent rolls of film from the trip! The experience with the AE-1 pushed me towards higher quality, more professional equipment that would stand up to field conditions better. Next up was the Canon F1 and then the wonderfully solid Canon F1N followed later with the game-changing addition of a power winder. The latter was great since insects typically didn’t wait around for me to manually wind the film, refocus, and shoot. The real challenge though was getting the lighting right. At fist I often times had the camera on a tripod which resulted in too many missed shots, restricted what I could shoot, and it didn’t meet what I later realized was my overall goal of macro photography. What I wanted was to have the ability to take satisfactory macro images while not loading myself down with equipment that would detract from also being able to conduct research or simply observe/enjoy nature without trying to capture it on film. I still have a graveyard of old flashes, brackets, and bracket parts that I employed in various combinations to get suitable lighting though it is now clear that I was never able to get the perfect balance. That changed in 2001 when Canon introduced the new MT-24EX macro twin flash and I bought a 1V body. After testing the new system a minimal amount, I realized that macro photography was now made easy relative to what I had wrestled with over the years prior. I had the complete package—no bulky brackets, no hand holding flashes, more certainty of exposure, and quick field set-up. The twin flash allowed me to fire off just the minimal amount of light to obtain my desired depth of field and the flash had sufficient battery power at the lower flash output settings to essentially shoot consecutively without having to wait for the flash to power-up.

Well, at least I thought I had the perfect setup until Ted MacRae took up macro photography and soon demonstrated that options for continuous improvement exist even for this system.

In 2004 I sadly shelved the 1V body and went digital. I briefly used the Canon 10D, which seemed inadequate for various reasons, but then jumped on the newly released Canon 1D Mark II during that same year. It was more than I wanted to spend but there weren’t many options and the benefits were too much to pass up. Most notably, I was sick of buying film, scanning slides, and most of all my hand ached from cataloguing so many slides, i.e., writing a unique code on each slide prior to archiving it in plastic. The time savings alone made the 1D Mark II price palatable and I hoped that investing in a top notch, newly released body would help it remain relevant for a while. I never looked back.

That brings me to that warm day this past March when I settled in to photograph a toad bug, Gelastocoris oculatus (Heteroptera: Gelastocoridae), along the margin of an intermittent creek in Perry Co., Missouri.  As I mentioned above I felt like I was limping along with my dated 1D Mark II but I couldn’t pass up the opportunity to again photograph an individual of G. oculatus that so superbly blended in with its substrate (Figures 1 and 2).

Figure 1. Gelastocoris oculatus, 3.13.2012, Perry Co., MO

Figure 2. Gelastocoris oculatus, 3.13.2012, Perry Co., MO

As I have mentioned before I like to take multiple shots of a subject to help tell a story (yes, including the obligatory head-on close up that Ted always mentions). One important shot in the series can be a photograph from a distance to: 1) better see the subject in its surroundings which can give more insight into its natural history; 2) offer a more artistic view, or, in this case; 3) to show the effectiveness of its cryptic coloration. The actual close-up is great for detail but only gives the viewer an idea that the subject is similarly colored to its background but only a more distant shot really conveys how well the subject melts into the substrate. In this case, Figure 3 was the next progression towards that shot but I was stopped short that day partly due to my middle son falling in the creek and partly due to the apparent malfunctioning of the camera. As you can see, I wasn’t far enough away from the subject to capture what attracted me to the bug in the first place—how well it mimicked its background. In that sense the picture is disappointing because I didn’t finish the story. But on the other hand, the malfunctioning of the camera combined with its age, made it clear that it was now time for a new camera body. So I put on my best frustrated/disappointed face and presented my case to my wife, Jess. It was an easy sell since Jess is… well… at least 95% supportive of my photography. I’ll discuss the new body and the first images soon.

Figure 3. Gelastocoris oculatus, 3.13.2012, Perry Co., MO

Below are more of the variable faces of G. oculatus that I have come across over the years (Figs. 4 – 8). Gelastocoris oculatus is one of two species of Gelastocoris that we have in North America (Arnett 2000). Gelastocoris oculatus can be found continent-wide however G. rotundatus ranges only in the southwest. I love the origin of the family name which the online Merriam-Webster dictionary mentions is from the Greek “gelastos”+ “koris” which translates to “laughable bug”, no doubt due to its odd appearance. Both species are predators that live along the margins of water. Their predaceous nature is made clear by the appearance of their powerful forlegs clearly specialized for catching and securing prey. As you can see, I do not have a picture of their forlegs so I’ve got a great reason to again get down on their level with the new camera.

Figure 4. Gelastocoris oculatus, 5.23.2010, Perry Co., MO

REFERENCE:

Arnett, R.H. 2000. American Insects: A Handbook for the Insects of America North of Mexico. Boca Raton, Florida: CRC Press.

Copyright © Christopher R. Brown 2012

Traffic Jam Treehoppers

Sometimes photo opportunities come at the unlikeliest of times. A few weeks ago while traveling back to Corrientes, Argentina from neighboring Chaco Province, I came upon traffic at a standstill just a few kilometers from the towering Gral. Belgrano bridge that spans the massive Rio Paraná to link Chaco and Corrientes Provinces. People were already getting out of their cars and walking around, suggesting a wreck closer to (or on) the bridge had completely shut down the highway for the time being. Somebody said they heard it might be another 45 minutes before it could be opened. What to do now? It was the end of my last day after a week of insect collecting/photographing in the area, and the last thing I wanted to do was spend the evening sitting on a divided highway with nowhere to go and nothing remotely interesting to look at…

Enchenopa gracilis (Germar, 1821) | Chaco Province, Argentina

…or so I thought. While scanning the highway right-of-way to see if there might be anything possibly interesting to look at, I spotted a small clump of woody shrubs down the embankment and across the erosion gully before the fenceline. I looked around—everybody was out of their cars with the engines shut off, so I grabbed my camera (not really sure why) and started walking towards the shrubs while looking ahead every now and then for any sign that people were getting back in their cars and moving again. I reached the shrubs and saw they represented something in the mallow family (Malvaceae) due to their small, orange, über-staminate flowers. Immediately I spotted the familiar thorn-like shape of treehoppers in the tribe Membracini, probably a species of Enchenopa or related genus. I had been hoping to see more of these after photographing another species further south in Buenos Aires last year, but I hadn’t seen a single treehopper during the entire week. Fortunately I had my 65mm lens already on the camera, so I quickly snapped a few shots and collected a couple of specimens. Just as quickly as I had done that, I heard somebody yelling to me from the road above that people were getting back into their cars ahead. These few shots and specimens would have to do. (And, disappointingly, after spending the next hour creeping towards the bridge there wasn’t even a wreck to look at!)

As I did with those previous photos, I sent these to Andy Hamilton (Canadian National Collection, Ottawa), who forwarded them on to Dr. Albino Sakakibara (Universidad Federal de Parana, Brazil) and then reported back to me that:

My Brazilian colleagues…have been able to identify your “beautiful photos” as representing Enchenopa gracilis, a species that has been illustrated only once (in 1904), and certainly not by a photograph!

Another individual, this one with no trace of green colorationi and less distinctly marked wings.

The illustration referenced by Andy comes from Kellogg (1905—p. 169, fig. 239), and as he notes at BugGuide the problem with old illustrations is that many of them are either inaccurate or use obsolete names. Enchenopa gracilis does not occur in North America, thus the drawing in Kellogg (1905) probably does not actually represent this species. Nevertheless, a recent dissertation on the insect fauna associated with pigeon pea in Brazil (Azevedo 2006) shows several photographs of adults that agree nicely with these photos. Enchenopa gracilis actually seems to be a bit of a pest on that crop, and it has also been reported in association with a variety of other plants across several different families (Lopes 1995, Alves de Albuquerque et al. 2002). Interestingly, I could not find any species of the family Malvaceae recorded as a host for E. gracilis.

REFERENCES:

Azevedo, R. L. 2006. Entomofauna associada ao feijão guandu [Canjanus cajan (L.) Millspaugh] no recôncavo baiano. Ph.D. dissertation, Centro de Ciências Agrarias e Ambientais, Universidade Federal da Bahia, Cruz das Almas, 54 pp.

Alves de Albuquerque, F., F. C. Pattaro, L. M. Borges, R. S. Lima & A. V. Zabini. 2002. Insetos associados à cultura da aceroleira (Malpighia glabra L.) na região de Maringá, Estado do Paraná. Maringá 24(5):1245-1249.

Kellogg, V. L. 1905. American Insects. Henry Holt & Co., New York, 674 pp.

Lopes, B. C. 1995. Treehoppers (Homoptera, Membracidae) in southeastern Brazil: use of host plants. Revista Brasileira de Zoologia 1213:595-608.

Copyright © Ted C. MacRae 2012

Seeing the unseen

While trying to nab a cicada from the small trees planted on the grounds at our experiment station here in Fontezuela, Argentina, I happened to notice a bit of movement on one of the branches nearest to me (while the cicada flew off with a screech and a clatter). A closer look revealed what looked like a slight protuberance of the branch to be a nymphal planthopper (family Fulgoridae), and at ~15 mm in length a pretty good-sized one at that. I would have never noticed it had it not moved, so good was its camouflage, but I didn’t have the time to spend trying to photograph it right then and there. Instead, I popped it into a vial (you do always carry a vial with you, don’t you?) and continued my fruitless quest for cicadas.

Undet. fulgorid nymph | northwestern Buenos Aires Province, Argentina

Later that evening I placed it on a palm tree in the hotel courtyard (not really the appropriate host, but it was the only real tree available). I took the standard dorsal view photo, and while not as good a color match as the (still undetermined) tree upon which I found it one still gets a sense for how difficult it might have been to see this nymph flattened against the slightly greenish bark.

A lateral profile view makes the bug much more visible.

One thing I’ve learned from much better photographers than myself is to get down and low relative to the subject—even to the point of looking up at it if possible. This provides views that are far more interesting than the typical looking-down-from-above shots. In the case of this nymph, the above and following low-angle shots really brought it to life and emphasize its unusual form.

Even lower. How did I get the nymph to "prop" itself?

Of course, with the nymph on the side of a fairly large tree, one can only get so low. To get even lower, I placed the nymph on a small stick and used hand-holding and bracing techniques to get even lower. I took quite a few shots experimenting with composition, and the shots I ended up liking the best were frontal-oblique from slightly below bug-level with the stick rather sharply angled down and the bug slightly propped up on its front legs. Easier said than done—this nymph was loathe to stop crawling once I moved it to the stick and tended to be negatively geotactic (crawled upwards). As a result, every time I angled the stick downward it would turn around and start crawling the other way, and in any case when it did stop it tended to flatten itself against the branch. Through trial and error, I learned that if I braced my thumb and forefinger against its head/pronotum to stop its progress and held it in place for awhile it would stay put. I also learned that if I slightly blew on its face when it was flattened against the branch that it would prop itself upwards a bit. Thus, for this shot it was a matter of letting it crawl upwards almost to the end of the stick (to eliminate excess stick that poke into the camera with a frontal-oblique angle), bracing it for a moment, inverting the stick downward and pointing slightly towards the camera, and then blowing on its face a bit—simple, huh? The black transverse band on the lower face adds a lot of character to the shot.

The obligatory face-on shot

The face-on shot is a staple for me, but even with this shot the angle is important—angle the back of the stick down too much and you get the all black background (not in itself bad, just not what I wanted for this shot), angle it too high and too much of the back of the bug shows up as blurred clutter in the background). The foreward projecting “nose” of this nymph prevented me from getting both the tip of the nose and the eyes in focus (without using excessively small aperatures), so I opted for the latter (I’ve never seen a good face shot of an insect in which at least the eyes were not in focus).

Unfortunately, family-level identification is as good as it is going to get for this individual. I sent the photos to fulgorid expert Lois O’Brien, who eliminated several options but couldn’t narrow down further among several remaining possible genera (“Our ignorance of nymphs is abysmal…”). Her recommendation was to go back to the tree and try to find adults, and apparently some species tend to live on the same tree for years and years. I’ll be returning to Fontezuela later in April—hopefully the fall season will not have advanced to far by then.

Copyright © Ted C. MacRae 2012

Chicharra que canta, calor adelanta

Dorisiana drewseni - male singing

There is a species of cicada (“chicharra” in Spanish) that strikes me as quite common in the central Humid Pampas region of Argentina. I saw numerous individuals during March of last year at La Reserva Ecologica Costanera Sur (where these photos were taken), and again during the past week I’ve noted them abundantly in the trees around my base station in western Buenos Aires Province. Thanks to cicada expert Barry University’s Allen Sanborn (apparently himself an endangered species), I now know these to be the species Dorisiana drewseni (Stål, 1854), occurring in Argentina, Uruguay and southern Brazil (Aoli et al. 2010).

Dorisiana drewseni, female resting on thistle

As in North America, the song of the cicada is associated with the dog days of summer and their midday heat. “Chicharra que canta, calor adelanta” is a Spanish idiom that loosely translates to “Cicadas singing, heat follows”. March is late summer in Argentina, and the days can still be quite hot even at temperate latitudes (yesterday was 34°C, or 93°F). Despite being half-a-world away from St. Louis, the droning song of the cicada sounds a bit like home in late August. While I was at the Reserva last March I really wanted to photograph a male in the midst of song, but the above photo was the only shot I managed from several males. Singing males are extremely difficult to approach to within even a long-handled net’s reach—much less a camera lens’ focal distance. I think the only reason I was able to photograph the male above was because I approached him from slightly below and behind (though certainly still within the field of vision of those huge, bulging eyes). One shot was all I got, and off he flew, shrieking noisily as he crashed and thrashed through the foliage before reaching open air and completing his escape.

Females, on the other hand, seemed to be much more approachable (perhaps because they, unlike singing males, never do anything to draw attention to themselves). The female in the photo above was calmly sitting on a thistle-like plant at eye-level, never flinching at my approach (albeit cautious) and calmly staying put while I snapped a few photos. One look at her tattered wings, however, suggests that she had already seen better days and perhaps no longer had the strength to attempt to flee (maybe even expectedly awaiting predation at this point in her life).

A second female rests calmly on a tree branch

Not long after taking the photographs of the first female, I saw another female sitting on a tree branch. As I mentioned, females don’t call attention to themselves the way males do, so finding females is a bit more of a crapshoot—I only happened to see this one because she was on a tree branch at eye level with an unobstructed view hanging right next to the path I was following. Obviously much fresher and in better shape than the previous female, she nevertheless allowed me to get as close as I wanted, with the photographs above and below representing the two that I am happiest with.

That's one heck of a cibarial pump!

I haven’t had quite the same luck during the present trip in securing one of these—probably because my lone attempt so far was during the heat of the day on a day that was already warm enough. Come to think of it, I didn’t manage any of the above photographs last year until quite late in the afternoon when temperatures began to drop off a bit. We’ll see what the next few weeks brings—I am still committed to getting the money shot of a male in the midst of his song. Chicharra que canta, Ted adelanta!

REFERENCE:

Aoki, C., F. Santos Lopes & F. Leandro de Souza. 2010. Insecta, Hemiptera, Cicadidae, Quesada gigas (Olivier, 1790), Fidicina mannifera (Fabricius, 1803), Dorisiana viridis (Olivier, 1790) and Dorisiana drewseni (Stål, 1854): First records for the state of Mato Grosso do Sul, Brazil. Check List 6(1):162–163.

Copyright © Ted C. MacRae 2012

Lord of the flies!

I happened upon a rather interesting scene last week in a soybean field in northern Argentina (Chaco Province). This assassin bug (family Reduviidae) had captured and was feeding on an adult stink bug of the species Piezodorus guildinii—an important pest of soybean in Argentina and Brazil (where it is known by the common names “chinche de la alfalfa” and “chinche verde pequeño”, respectively). Assassin bug predation is always interesting enough itself, but what made this scene especially fascinating was the large congregation of flies surrounding and even crawling upon the predator and its prey. I had not witnessed something like this before, but it seemed clear to me that the flies were engaging in kleptoparasitism—i.e, stealing food. I’ve gotten into the habit of keeping a full set of extension tubes mounted on the camera with my 100mm macro lens—this not only provides the most useful (for me) range of magnification but also serves as a convenient and easy-to-use field microscope. Through the viewfinder I could see that there were at least two markedly different types of flies involved—more abundant, small, brown flies that I presumed (incorrectly, as it turns out) to be some type of drosophilid (vinegar fly), and a few larger, black flies that were completely unfamiliar to me. The flies were apparently feeding on fluids from the stink bug prey but also crawled all over the assassin bug as it fed. The assassin bug seem unencumbered in its feeding by the presence of the flies, but periodically it would slowly wipe its forelegs over its head to dislodge flies that had settled onto it. Just as quickly as they flew away, however, they crawled back.

The assassin bug, on the other hand, I recognized as very likely a species of Apiomerus—a large, exclusively New World genus known in North America as “bee killers” for their habit of sitting on flowers and ambushing visiting bees for prey. The prey selection behaviors of these insects, however, are more generalist than the name implies, as can be seen by these photographs. To verify my generic ID and possibly obtain a species ID, I sent some of these photos to Dimitri Forero at the Heteropteran Systematics Lab at University of California-Riverside. Dimitri is revising portions of Apiomerus (e.g., Berniker et al. 2011) and working on a general phylogenetic hypotheses for the genus. In the past he has been quite helpful in fielding questions from me about these bugs, and within a few hours Dimitri replied to inform me that the assassin bug was, indeed, a member of the genus Apiomerus, likely representing the common, widespread species A. lanipes (ranging from Panama to Argentina), based on its coloration, locality, and relative size. Update 12 March, 3:07 pm—After seeing the last photo in this post (which I did not send to him initially), Dimitri wrote to say the ventral abdominal pattern was not characteristic of A. lanipes. He asked about its size, to which I replied that it was about the same length but maybe a little less robust than A. crassipes (eastern North America). He later added, “I now think that this is A. flavipennis Herrich-Schaeffer, 1848. It is very similar to A. lanipes, but a lot smaller (lanipes is really robust), and with the abdomen with black and white patches, whereas in lanipes the abdomen is always black. I checked some series of specimens that I have here and, I am pretty sure now of the ID. I have material from Argentina as well. In some specimens that coloration of the corium varies, but the original description says it is yellow with a “hairy” pronotum, which fits very nicely your photos.” Apiomerus flavipennis is known from Argentina and Southern Brazil only.

Quite unexpectedly, Dimitri also noted that at least some of the flies could belong to the family Milichiidae. He first became aware of these flies after seeing a photograph of Apiomerus showing something similar and suggested Milichiidae online as a possible source for more information. This remarkably informative  website by milichiid expert Irina Blake, who dubs species in the family as “freeloader flies”, is a model for how websites dealing with obscure insect taxa should be organized and populated (and features on the home page a great photo of ant-mugging flies taken by our favorite myrmecophile). At any rate, I forwarded my photos to Irina and within minutes received her response that the bigger black flies most probably represent the cosmopolitan Milichiella lacteipennis and the smaller flies a species of the family Chloropidae (of “dog pecker gnat” fame) in the subfamily Oscinellinae, noting that she has seen similar (or the same?) chloropids in other photos as well engaging in kleptoparasitism.

Not long after receiving the first reply from Dimitri, I got another message from him with a link to a very interesting paper by Eisner and colleagues (1991), who recorded freeloader flies in Florida preferentially attracted to stink bugs and leaf-footed bugs (family Coreidae) being preyed upon by the orb-weaving spider Nephila clavipes. Olfactory stimuli were already suspected to be involved in attraction of milichiids and also chloropids (Sivinski 1985); however, Eisner et al. (1991) experimentally demonstrated that milichiid attraction was tied to specific components of defensive sprays in several pentatomid and coreid species (including P. guildenii, the prey species in this series of photographs). The defensive sprays of the bugs were generally ineffective at preventing predation by the spiders (and apparently this is the case for A. lanipes and other reduviids as well), thus serving as a signal to milichiids and chloropids not only of the presence of a food source but perhaps also assisting search for mates in a density dependent fashion (Sivinsky 1985). Milichiid attraction to hymenopteran prey, richly endowed with integumental glands themselves, has also been documented; the Eisner study raises the question whether these types of prey are also detected from chemical cues.

REFERENCES:

Berniker, L., S. Szerlip, D. Forero and C. Weirauch. 2011. Revision of the crassipes and pictipes species groups of Apiomerus Hahn (Hemiptera: Reduviidae: Harpactorinae). Zootaxa 2949:1–113.

Eisner, T., M. Eisner & M. Deyrup. 1991. Chemical attraction of kleptoparasitic flies to heteropteran insects caught by orb-weaving spiders. Proceedings of the National Academy of Sciences of the United States of America 88:8194–8197.

Sivinski, J. 1985. Mating by kleptoparasitic flies (Diptera: Chloropidae) on a spider host. Florida Entomologist 68(1):216–222.

Copyright © Ted C. MacRae 2012

To the land of Gauchos

Today I leave for an extended stay in Argentina. Many have asked me if my trip is for work or fun, and my standard response has been, “It’s for work, and it will be fun!” For the next eight weeks, I’ll be helping out with field trials and speaking to farmers (while sampling a few Malbecs as well). Of course I would rather it be an 8-week collecting trip, but I consider myself fortunate even to have an opportunity such as this. I’ll pick up a few insects along the way, but what I really hope to bring back in large quantity is photographs.

It’s a little difficult to predict how reliable and consistent I’ll have internet access or the time to take advantage of it, so postings over the next few weeks may be a little less regular than what has become my usual custom. The trip is also heavily front-loaded with work activities as I get my bearings and spend time getting to know my new colleagues, so I’m not sure when I might have new photos to show here. Not to worry, I have plenty of material that I haven’t yet shown. Until then, I leave you with this photograph I took last November at  in Buenos Aires. These tiny bugs seem to be early-instar leaf-footed bug (family Coreidae) nymphs, their bright red and black coloration and aggregating behavior indicating ample chemical protection against predation.

Early-instar coreid nymphs | Buenos Aires, Argentina

Copyright © Ted C. MacRae 2012