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

Brazil Bugs #15 – Formiga-membracídeos mutualismo

Of the several insect groups that I most wanted to see and photograph during my trip to Brazil a few weeks ago, treehoppers were near the top of the list.  To say that treehoppers are diverse in the Neotropics is certainly an understatement – South America boasts an extraordinary number of bizarre and beautiful forms that still, to this day, leave evolutionary biologists scratching their heads.  The development of this amazing diversity is a relatively recent phenomenon (thinking geological scale here), as there are no known membracid fossils prior to Oligo-Miocene Dominican and Mexican amber – well after the early Cretaceous breakup of Gondwanaland split the globe into the “Old” and “New” Worlds.  With its origins apparently in South America, numerous groups continued to spring forth – each with more ridiculous pronotal modifications than the last and giving rise to the dazzling diversity of forms we see today.  Even North America got in the evolutionary act, benefiting from northern dispersal from South America’s richly developing fauna via temporary land bridges or island stepping stones that have existed at various times during the current era and giving rise to the almost exclusively Nearctic tribe Smiliini (whose species are largely associated with the continent’s eastern hardwood forests).  Only the subfamily Centrotinae, with its relatively unadorned pronotum, managed to successfully disperse to the Old World, where it remains the sole representative taxon in that hemisphere.  With a few notable exceptions, treehoppers have virtually no economic importance whatsoever, yet they enjoy relatively active study by taxonomists, evolutionists, and ecologists alike – due almost completely to the bizarreness of their forms and unique mutualistic/subsocial behaviors.

I did manage to find a few species of treehoppers during the trip (a very primitive species being featured in Answer to ID Challenge #4 – Aetalion reticulatum), and of those that I did find the nymphs in this ant-tended aggregation on a small tree in the rural outskirts of Campinas (São Paulo State) were perhaps the most striking in coloration and form.  Most were jet black, although a few exhibited fair amounts of reddish coloration, and all exhibited sharply defined white bands of wax and long erect processes on the pronotum, mesonotum, and abdomen.  I’ve seen a fair number of treehopper nymphs, but I did not recognize these as something I had seen before, and given the incomplete state of immature taxomony I feared an identification might not be possible.  Still (and I know this is probably beginning to sound like a broken record), I gave it the old college try.

I usually like to start simple and get more creative if the results aren’t satisfactory, so I went to my old friend Flickr and simply typed “Membracidae” as my search term.  Predictably, pages and pages of results appeared, and I began scanning through them to see if any contained nymphs at all resembling what I had.  After just a few pages, I encountered this photo with very similar-looking nymphs, and although no identification beyond family was indicated for the photo, I recognized the lone adult sitting with the nymphs as a member of the tribe Aconophorini – a diverse group distinguished from other treehoppers by their long, forward-projecting pronotal horn.  Luck was with me, because I happen to have a copy of the relatively recent revision of this tribe by Dietrich and Deitz (1991).  Scanning through the work, I learned that the tribe is comprised of 51 species assigned to three genera: Guayaquila (22 spp.), Calloconophora (16 spp.), and Aconophora (13 spp.).  The latter two genera can immediately be dismissed, as ant-interactions have not been recorded for any of the species in those two genera – clearly the individuals that I photographed were being tended by ants.  Further, the long, laterally directed apical processes of the pronotal horn, two pairs of abdominal spines, and other features also agree with the characters given for nymphs of the genus Guayaquila.  In looking at the species included in the genus, a drawing of a nymph that looked strikingly similar to mine was found in the species treatment for G. gracilicornis.  While that species is recorded only from Central America and northern South America, it was noted that nymphs of this species closely resemble those of the much more widely distributed G. xiphias, differing by their generally paler coloration.  My individuals are anything but pale, and reading through the description of the late-instar nymph of the latter species found every character in agreement.  A quick search of the species in Google Images was all that was needed to confirm the ID (at least to my satisfaction). 

In a study of aggregations of G. xiphias on the shrub Didymopanax vinosum (Araliaceae) in southeastern Brazil, Del-Claro and Oliveira (1999) found an astounding 21 species of associated ant species – a far greater diversity than that reported for any other ant-treehopper system.  The most frequently encountered ant species were Ectatomma edentatum, Camponotus rufipes, C. crassus, and C. renggeri, and after perusing the images of these four species at AntWeb I’m inclined to believe that the ants in these photos represent Camponotus crassus (although I am less confident of this ID than the treehoppers – corrections welcome!).  The authors noted turnover of ant species throughout the day in a significant portion of the treehopper aggregations that they observed, which they suggest probably reflects distinct humidity and temperature tolerances among the different ant species and that might serve to reduce interspecific competition among ants at treehopper aggregations.  Since treehopper predation and parasitism in the absence of ant mutualists can be severe, the development of multispecies associations by G. xiphias results in nearly “round-the-clock” protection that can greatly enhance their survival.

Update 3/3/11, 9:45 a.m.:  My thanks to Chris Dietrich at the Illinois Natural History Survey, who provided me in an email exchange some clarifying comments on the origins and subsequent dispersal of the family.  The first paragraph has been slightly modified to reflect those comments.

REFERENCES:

Del-Claro, K. and P. S. Oliveira. 1999. Ant-Homoptera interactions in a Neotropicai savanna: The honeydew-producing treehopper, Guayaquila xiphias (Membracidae), and its associated ant fauna on Didymopanax vinosum (Araliaceae). Biotropica 31(1):135–144.

Dietrich, C. H. and L. L. Deitz.  1991.  Revision of the Neotropical treehopper tribe Aconophorini (Homoptera: Membracidae).  North Carolina Agricultural Research Service Technical Bulletin 293, 134 pp.

Copyright © Ted C. MacRae 2011

Brazil Bugs #1

ID Challenge #3 update: I knew this would be a hard one, and so far nobody has figured this one out (only one commenter got the right order!).  I’ve released the comments gotten so far so you can see where things stand, and maybe with the additional information (and my pointing out an important clue) it will be enough for one of you to arrive at a full ID.  Further comments are still being moderated until I decide to close the challenge.  Right now the points are there for the taking!


This past Monday I embarked on an extended business trip to Brazil.  “Wow, Brazil!” – you say, and while getting to travel to an exotic tropical locality on my company’s dime definitely rocks, I do have to justify the trip by actually working.  Add that to the time involved with planes, automobiles, and hotel transfers, and there is precious little time for more esoteric activities such as photographing insects.  It is Brazil, however, and summer at that, so whatever time does become available over the next ten days, I’ll be on it!  I’m stationed in Campinas, about 2 hours north of São Paulo, and this evening I had my first opportunity to break out the camera and do a little exploring around the hotel grounds during the waning hours of daylight. I’m not normally one to take short walks just looking for any random insect to photograph, but hey – it’s Brazil!  I also don’t normally like to post photographs of insects without knowing much about them – especially their identity. But hey, it’s Brazil!  I think I’ll be lucky to figure out most things to family, although I might be able to drill down a little further on occasion.  With that prelude, I hope you’ll indulge me these random postings over the next 10 days or so, primarily photographs but perhaps accompanied by a little bit of text.

Coreidae?

At first I thought this was a member of the hemipteran family Pyrrhocoridae (red bugs), as some North American species have similar coloration; however, members of that family apparently lack ocelli, which this insect clearly possesses. This would seem to indicate instead some species of Lygaeidae (seed bugs), but the forewing membrane with numerous veins arising from a transverse basal vein and presence of what appears to be a distinct metathoracic scent gland opening suggest instead some “unleaf-footed” species of leaf-footed bug (Coreidae). Whatever its identity, I would imagine it is quite distasteful, based on what clearly seems to be aposematic coloration and the fact that there were numbers of these bugs hanging out quite conspicuously on these flowers.

Same species?

This individual was differently colored than the others, but otherwise it seemed structurally and behaviorally identical.  Is it merely a highly melanized individual?  Maybe a case of sexual dimorphism, and I only saw this one individual of one of the sexes?  Maybe it truly is a different species – it is Brazil, afterall!

Pseudoplusia includens?

Daylight began to slip away much too soon, and I was about to pack it up when  I noticed some blurs at the flowers.  I realized that moths had begun to visit the flowers in the obscurity of dusk and became determined to photograph one, despite the fact that they never actually landed on the flowers but hovered in front of them instead.  It was quite difficult to even get them framed in the viewfinder, and on those few occasions when I managed to do this it was all but impossible to spend any time trying to focus – I used the lamp on the flash unit to help me see the moth, then just framed and quickly took the shot.  This one actually turned out not too bad – a little bit of blur in the wings but otherwise acceptable enough to let me tentatively identify it as Pseudoplusia includens (soybean looper).  Brazil is well on its way to becoming the world’s largest producer of soybean, and the caterpillars of these moths are enjoying the bounty!

Family Crambidae, possibly Herpetogramma phaeopteralis (ID by Chris Grinter)

I saw one last moth before the final traces of daylight disappeared – I don’t have any idea about its identity, but it’s a pretty picture nonetheless.  It has the generic look of the large family Noctuidae, so that’s what I’m gonna go with until somebody tells me differently.  Edit 1/20/11 – Somebody just told me differently!  According to Chris Grinter, this is a species of Crambidae, possibly Herpetogramma phaeopteralis (tropical sod webworm).  Thanks, Chris!

I don’t know the name of the plant whose flowers these insects were visiting, but the hotel staff has promised to ask their gardener in the morning and let me know – now that’s service!

Copyright © Ted C. MacRae 2011

Assassin ate

IMG_1146_1200x800

I came upon this interesting scene last month while hiking through Allen David Broussard Catfish Creek Preserve State Park, which preserves some of the highest quality remnants of sand scrub habitat on the Lake Wales Ridge of central Florida. The spider seems to be Peucetia viridans (green lynx spider), widespread across the southern U.S. and distinguished by its bright transparent green color with red spots and black spines (Emerton 1961). These largest of North American lynx spiders hunt diurnally on low shrubs with an agility excelled only by the jumping spiders (Salticidae) and aggressively attack their insect prey. In this case, the prey is one of the so-called “bee assassins” of the genus Apiomerus (Hemiptera: Reduviidae). The common and generic names of these insects both derive from their habit of preying upon bees, not only on flowers but also by ambushing them at nest entrances, although other insects are preyed upon as well. Ironically, this particular assassin himself got ate.

An interesting situation was uncovered while I tried to determine which species of Apiomerus was represented by the prey. By virtue of its pale ventrals with the front and hind margins black, it keys to A. spissipes in a literature-based key to Florida Reduviidae (Bierle et al. 2002) – one of two species considered widely distributed across the eastern U.S. In reality, however, it appears that this individual represents another species named almost 30 years ago but which remains officially undescribed. As explained in this BugGuide post by Daniel Swanson, the genus was revised by Berkeley grad student Sigurd Leopold Szerlip in partial fulfillment of the requirements for a Ph.D., who proposed a number of taxonomic acts including the description of 19 new species. Among these were eastern U.S. populations to which the name A. spissipes had been applied, with those in Florida being described as the new species “A. floridensis“. However, dissertations do not meet the criteria of publication according to Article 8 of the International Code of Zoological Nomenclature (ICZN 1999), and none of the dissertation was formally published. Thus, “A. floridensis” remains an invalid, unpublished name.  This is a most unfortunate situation, as Swanson considers the dissertation to be well done.  It is not only names, but important information about life histories and detailed genitalic studies that remain unavailable to the scientific community as well.  What are the nomenclatural impacts of this work remaining unpublished?  Is this as much a failure by the advising professor as by Szerlip himself?  What ethical considerations would need to be addressed in order for it to be published in absentia, or is this even possible?

Photo details: Canon 100mm macro lens on Canon EOS 50D (manual mode), ISO-100, 1/250 sec, f/13, MT-24EX flash 1/2 power through diffuser caps.

REFERENCES:

Bierle, S., E. Dunn, S. Frederick, S. Garrett, J. Harbison, D. Hoel, B. Ley and S. Weihman. 2002. A literature-based key to Reduviidae (Heteroptera) of Florida (assassin bugs, and thread-legged bugs). Unpublished manuscript, University of Florida, Department of Entomology and Nematolgy, Insect Classification ENY 4161/6166, 18 pp.

Emerton, J. H. 1961. The Common Spiders of the United States. Dover Publications, Inc., N.Y., xx + 227 pp.

International Commission on Zoological Nomenclature [ICZN]. 1999. International Code of Zoological Nomenclature, 4th Edition. The International Trust for Zoological Nomenclature, c/o Natural History Museum, London. xxix + 306 pp.

Szerlip, S. L. 1980. Biosystematic revision of the genus Apiomerus (Hemiptera: Reduviidae) in North and Central America. Unpublished Ph.D. thesis, University of California, Berkley, CA.

Copyright © Ted C. MacRae 2009

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Magodo – giant twig wilter

petascelis-remipes

In previous posts, I have highlighted some of the insects I observed on a trip to South Africa in November-December 1999.  All of the photos I have shown to this point were taken at Borakalalo National Park in North West Province or at the Geelhoutbos farm of Susan Strauss below the Waterberg Range in the formerly Northern, now Limpopo Province.  Both of these locations are deep inside the bushveld, providing ample opportunity to observe an incredible diversity of insect life.  This is not to say that insects, even spectacular ones, cannot be found in more urban areas.  During the weekend between those two mini-expeditions, I stayed with my friend and colleague, Chuck Bellamy, at his home in Pretoria, a beautiful city with lovely architecture, elegant gardens… and some very impressive bugs!  The bug in this photo was found on a tree in a shrubby enclave, and at well over 35 mm in length it is easily the largest leaf-footed bug (order Hemiptera, family Coreidae) that I have ever seen.  Its chunky build, velvety black coloration with thin yellow lines along the sides and down the center of the thorax, and greatly enlarged hind femora quickly led me to a provisional identification of a male Petascelis remipes, or giant twig wilter.  This ID was confirmed by my friend and colleague Harry Brailovsky, an entomologist at UNAM (Universidad Nacional Autónoma de México) and world expert on Coreidae (and who, incidentally, just recently published a review of this Afrotropical genus – Brailovsky 2008).

According to Picker et al. (2002), these insects are found on plants in the genus Combretum.  Like most species in the family, they have scent (“stink”) glands that provide defensive capabilities. Adults are gregarious and bold, walking towards intruders with antennae vibrating when disturbed, and they are apparently capable of squirting their defensive secretions for some distance.  The nymphs are black as well but futher advertise their noxiousness with warning coloration of red spots on a whitish background. Interestingly, and despite their powerful chemical defenses, this species is considered a delicacy in parts of Mozambique where it is known as Magodo.  In a post called Insects for Dinner (in a blog with the eerily similar title, Beating about the Bush), Bart Wursten of Gorongosa National Park in Mozambique describes how local folk burn small patches of the grassland in which these insects are found to smoke them out and catch them.  The Magodo hunters kill the bugs by breaking off the head and removing the scent glands, which releases a very strong almond-like smell.  In doing this, the locals are able to catch considerable quantities of the bugs, which they eat with supper.

Lest you believe such practices are an anomaly, van Huis (2003) has compiled a list of about 250 insect species used as food in sub-Saharan Africa.  Lepidoptera, Orthoptera and Coleoptera represented the bulk (78%) of species eaten, with Isoptera, Hemiptera, Hymenoptera, Diptera and Odonota making up the rest.  Several examples of toxic insects and the traditional methods used to remove the poisons were given.  It was noted that whether or not insects are eaten depends not only on taste and nutritional value, but also on customs and ethnic preferences or prohibitions.  I’m not one to shy away from the thought of eating insects – after all, shrimp are just bugs that live in water, and insects rank far lower in ‘slime factor’ than many other invertebrates (e.g., oysters) that enjoy great popularity in our culture.  I’ve eaten roasted beet armyworm (Spodoptera exigua) pupae and munched on chocolate covered ants, but that’s kid stuff – the armyworms tasted like the soy sauce in which they were roasted, and the ants tasted like, well… chocolate.  I did once eat a softshelled crab (alive!), and I actually hope to one day taste the enormous grub of the giant metallic ceiba borer, Euchroma gigantea, eaten by indigenous cultures in Central and South America.   Still, I think I’d need a lot of faith in my chef’s scent gland removal prowess before I started scarfing Magodo down like popcorn.

What insects have you eaten?

REFERENCES:

Brailovsky, H.  2008. Notes on the genus Petascelis Signoret and description of one new species (Hemiptera: Heteroptera: Coreidae: Coreinae: Petascelini).  Zootaxa 1749:18–26.

Picker, M., C. Griffiths and A. Weaving. 2002. Field Guide to Insects of South Africa. Struik Publishers, Cape Town, 444 pp.

van Huis, A. 2003. Insects as food in sub-Saharan Africa. Insect Science and Its Application 23(3):163-185.

Copyright © Ted C. MacRae 2009

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Millipede assassin bug

Ectrichodia crux

I continue the hemipteran theme begun in the last post with this photograph I took in South Africa below the Waterberg Range in Northern (now Limpopo) Province. I recognized them as members of the family Reduviidae (assassin bugs), and since to my knowledge species in this family are exclusively predaceous (except for the so-called “kissing bugs” of the mostly Neotropical subfamily Triatominae, large distinctive bugs that feed exclusively on vertebrate blood), I found what I took to be a case of scavenging on a dead millipede to be rather curious.  It had rained the previous evening, resulting in a burst of millipede (and insect) activity that night, and this scene was rather commonly encountered the following morning. Of course, appearances can be deceiving, and it turns out that I actually was witnessing predation – and a most unusual case at that.  The individuals in this photo represent Ectrichodia crux (millipede assassin bug), a common species in many parts of southern Africa.  Although nearly 500 species of assassin bugs are known from the region (Reavell 2000), E. crux is easily recognizable due to its large size (adults measure up to 22 mm in length), stout form, and coloration – shiny black, with a distinctive black cross incised on its dull yellow thorax and with yellow abdominal margins (Picker et al. 2002). The nymphs as well are distinctive – bright red with black wing pads. Clearly, these insects are advertising something.

Ectrichodia crux belongs to the subfamily Ectrichodiinae, noted for their aposematic coloration – often red or yellow and black or metallic blue, and as specialist predators of Diplopoda (Heteropteran Systematics Lab @ UCR).  Species in this subfamily are most commonly found in leaf litter, hiding during the day under stones or amongst debris and leaving their shelters at night in search of millipedes (Scholtz and Holm 1985). They are ambush predators that slowly approach their prey before quickly grabbing the millipede and piercing the body with their proboscis, or “beak.”  Saliva containing paralytic toxins and cytolytic enzymes is injected into the body of the millipede to subdue the prey and initiate digestion of the body contents, which are then imbibed by the gregariously feeding assassin bugs.

Millipedes employ powerful chemical defenses – primarily benzoquinones and sometimes hydrogen cyanide gas as well, which are discharged from specialized glands along the millipede’s body – to protect themselves from predation.  Thus, specialized predation of millipedes is a niche that has been exploited by relatively few predators, and little is known about the mechanisms used for circumventing these defenses. The recently reported millipede specialist, Deltochilum valgum (order Coleoptera, family Scarabaeidae), has been observed killing its prey by violently decapitating and disarticulating it before feeding on the body contents (Larsen et al. 2009, summary here); however, the exact manner by which the beetle avoids or withstands the millipede’s chemical discharges remains unknown.  For ambush predators such as Ectrichodia crux and other ectrichodiines, a strategy similar to that described for another millipede specialist predator, larvae of the phengodid beetle, Phengodes laticollis (order Coleoptera, family Phengodidae), might be employed. This species subdues its millipede prey by piercing thinner regions of the millipede’s integument (e.g., intersegmental membranes on the ventral surface) with its hollow sickle-shaped mandibles and apparently injecting gastric fluids that abruptly paralyze the millipede, thereby preventing it from discharging its gland contents (Eisner et al. 1998).  These undischarged benzoquinones remain confined to the glands and are prevented from diffusing into the body cavity by the glands’ impervious cuticular lining, thus allowing the phengodid larva to safely imbibe the liquified systemic contents of the immobilized millipede.

REFERENCES:

Eisner, T., M. Eisner, A. B. Attygalle, M. Deyrup and J. Meinwald. 1998. Rendering the inedible edible: Circumvention of a millipede’s chemical defense by a predaceous beetle larva (Phengodidae).  Proceedings of the National Academy of Sciences USA 95(3):1108–1113.

Larsen, T. H., A. Lopera, A. Forsyth and F. Génier. 2009. From coprophagy to predation: a dung beetle that kills millipedes. Biology Letters DOI:10.1098/rsbl.2008.0654.

Picker, M., C. Griffiths and A. Weaving. 2002. Field Guide to Insects of South Africa. Struik Publishers, Cape Town, 444 pp.

Reavell, P. E. 2000. The assassinbugs (Hemiptera: Reduviidae) of South Africa. http://oldwww.ru.ac.za/academic/departments/zooento/Martin/reduviidae.html#ectrichodiinae.

Scholtz, C. H. and E. Holm (eds.). 1985. Insects of Southern Africa. Butterworths, Durbin, South Africa, 502 pp.

Copyright © Ted C. MacRae 2009

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