Friday, 8 June 2018

Natalicola pallida (Westwood, 1837) - or, The Pale Inflated Stinker

During my first year at university, there was a professor by the name of Brian Case; every time I walked past his office door (as he sadly passed away before my second year, I never had the opportunity to take any of his lectures), all I saw on the name-plaque was brain-case. Similarly, every time I see Westwood's name appended to a species, my mind auto-corrects it, and I suddenly relive Evan Rachel Wood destroying a perfectly unassuming glass of wine with a fair-sized chunk of Anthony Hopkins' (presumably simulated) brain - and, in order to get back to where I was, I have to fight to stop wondering whether he was drinking Chianti.

If you haven't seen the first season of Westworld, that may be a (rather major) spoiler, so sorry for that. Equally, if you would rather receive pictures of insects without tangential pop-culture discussion, sorry for that, too. 

Back on topic, and today's insect is a Tessarotomid shield bug. The shield bugs, by the way, comprise the Pentatomoidea, a globally important group of predators, innocuous herbivores, hugely destructive pests (Nezara and friends) and seasonal delicacies (C.M. Dzerefos writes quite regularly about a Tessaratomid treat) that I have, until now, entirely neglected.

Before I blether too much, here it (he, unless I'm mistaken) is: 


Chongwe Distr., Lusaka, Zambia; 03 June 2018, taken with Olympus E-450 and 3 KOOD magnifiers. 
Beyond being popular as foodstuff in some African tribes, the Tessaratomids are mostly known for... well, not much. As with the rest of the Pentatomorpha (a group which includes the previously featured Anoplocnemis and Pephricus), they can, if sufficiently annoyed, blast you with foul-smelling-but-mostly-harmless liquid; being a fair bit bigger than most of their relatives (I did attempt a scale photo, but he objected and I had no desire to be sprayed in the face), they are sometimes called Giant Stink Bugs (imaginitive) or, for their rather wide abdomens, they are sometimes called Inflated Shield Bugs

Although I was aware of their existence, having never come across one before the little green gentleman above showed up in my garden, I had come to unconsciously think of them as one of those bizarre groups of interesting looking insects that the South Africans see, but aren't really present in Zambia, so as you might imagine, I could not immediately say exactly who I was looking at. Fortunately, help was at hand.

In his unavoidably fantastic 2009 database of African Pentatomoidea (if, like me, you are on limited internet, do consider signing onto someone else's before you click that link, as it takes you directly to the .pdf), Robertson lists a paltry 41 species (one of which with two subspecies) of this superfamily from Zambia, which is - considering that even the UK, which as a temperate island should be doubly depauperate, has at least 36 species in the superfamily - more than a bit low. That's not actually surprising - as a nation, Zambia has been more than a little neglected: while our 908 species of butterfly probably more-or-less covers our total, and I've yet to knowingly encounter a species not on that list, our stinkbugs have been tragically overlooked by generations of Hemipterologists**.

Beyond the inevitable undescribed endemics (this is Africa, after all), a more reasonable estimate of our total Pentatomoids is probably in the region of 251 - which is to say, there are 251 species (of which 14 have a second subspecies in the same situation, and 3 have a third for 268 total forms) of shield bug that have either been previously recorded in Zambia, or are recorded in such a combination of countries that they most likely also occur in a significant part of Zambia, based on Robertson's database. A further 18 species and 2 subspecies occur in multiple countries on either side of Zambia, but are either patchily distributed in well-trafficked countries (i.e., one or more recorded countries may not be native range, but inadvertent introductions through shipping, etc) or despite their "per-country" range seeming to suggest that they should occur in Zambia, have a distribution which could correspond with habitat types not present in Zambia (e.g. species recorded in a continuous band of coastal nations and no landlocked countries).

I don't really need to go on about all that, though - in fact, if I hadn't only finished going through said database this morning, I could probably have gotten straight to the point that Robertson's list has a solitary species in Zambia, Natalicola delegorguei Spinola, 1850 (link is to Stål's type of synonym Gonielytrum curculiventre) - not the same species as the Encosternum delegorguei Spinola, 1850 that Dzerefos writes about - and six species probably in Zambia. After casting about the web for a possible way to work out precisely who I was looking at without having to either drive into town or, of all things, ask someone else, I came to the conclusion that just to access the papers which might help me identify it, I'd have to shell out over a hundred dollars in either direct-access fees or subscriptions, and was entirely ready to give up.

Even with this face staring at me, I was ready to give up and let the little guy
fester away in my hard drive until that imaginary day when I'm going to be
obscenely rich enough to afford thousands of subscriptions, back-issues
and the postage to Lusaka... 

But then something magical happened. Retreating from journals who think it's fair to charge 25 USD a pop for papers that came out fifty years ago without even letting me see the abstract, I stumbled across Philippe Magnien's Illustrated Catalog of Tessaratomidae, and after a brief getting-to-know-you period, I realised that while his "publications" page did not (unlike some of the other hemiptera databases on the same domain) provide access to much (or any, to be honest) of the listed literature, he had thoughtfully included images of specimens under all but one of the relevant species entries.

As it turns out, Natalicola pallida is structurally quite different from all other contenders; while Piezosternum calidum (Fabricius, 1787), Aplosterna virescens Westwood, 1837 , Selenymenum piriforme Montandon, 1894, Stevisonius acutus Jeannel, 1914, Elizabetha courteauxi Schouteden, 1917,  and even Tessaratoma absimilis Distant, 1893 (more on that in a moment) - not to mention Dzerefos' Encosternum delegorguei Spinola, 1850, which Magnien lists as occurring in Gambia as well as Southern Africa, which could possibly suggest a wider range including Zambia - have rather sloping, unpronounced shoulders similar to those seen on Stål's re-described Natalicola delegorguei type, Natalicola pallida has very broad, protruding shoulder pads that threaten to entirely swallow the head and bury the whole insect in a forgotten time when Ridley Scott wasn't making sequels*.

This is easier to see from above:

Natalicola pallida - same individual, still from Chongwe, but from a better angle
 to see the form of the pronotum. 

So that's that.

More or less.

The less, really, comes down to a few disagreements between Robertson's Database and Magnien's catalog: first, the name itself; Robertson consistently uses Natalicola pallidus and Magnien uses Natalicola pallida; these cannot both be correct, but pallida agrees with the gender of Natalicola (i.e., they both end in "a"), so I've tried to use that; conversely, I am inclined to use Robertson's Aplosterna Westwood, 1837 over Magnien's Haplosterna Westwood, 1837; I treat Robertson as more accurate here because they credit Haplosterna to Stål, which explains why wherever Haplosterna virescens is seen, it is followed by a bracketed (Westwood, 1837) - indicating that the binomial is not the one that Westwood described it under. Magnien brackets Westwood for the binomial, but still credits Haplosterna to Westwood, which - unless Westwood used Haplosterna for a different species earlier in the same paper, but described virescens under Aplosterna (not impossible) - doesn't make sense. Next, which may come down the the 9 years between Robertson's work and Magnien's, Robertson records Tessarotoma absimilis from Tanzania only, while  Magnien records this species from the entire East Coast, as well as Zambia, which is evidenced in a picture of a specimen from "Kafue City, Kafue River, Lusaka Zambie".

I should be very clear, here. I have quite regularly been to and through a place called Kafue, close to the Kafue River, and while it gets dangerously closer to being a far-flung shanty/suburb of Lusaka City every year, it is by no means itself a city. That is not to say that I'm questioning the record itself, I just feel that it's important to note that for anyone who heads to Kafue expecting to find a city, don't.

A final note should be made that while the link to Natalicola delegorguei Spinola, 1850 takes you to the Swedish Museum of Natural History's image of Stål's type, with the name credited to Spinola, 1852, I've use Robertson's Spinola, 1850 as this appears to be correct






*while I profess to having enjoyed Blade Runner 2029 and, yes, Prometheus (Alien: Covenant, however much potential it may have had, is unforgiveable by virtue of it's killing off Shaw to distance itself from fanboy-hate for Prometheus, and its stupid "Gotcha" ending undermining the otherwise touching Walter/Daniels relationship and setting it up for an Alien 3 level of "well, none of that film mattered" sequel) this is actually a nod to the '80s and shoulder pads. Yes, I know that he made other films between those originals and their sequels. 

**which should be a word, because Hemipterology is, and while the general preference is for Hemipterist, I've never met anyone who described themself as a Bioist, Zooist or Entomists; terms like Lepidopterist, Orthopterist and Hemipterist imply fanciers or enthusiasts (which, in fairness, is true for a lot of Lepidopterists), along the lines of Philatelists and Racists, rather than studiers-of. 

Tuesday, 29 May 2018

The Unequal Conehead, Conocephalus (Conocephalus) inequalis Uvarov, 1928

Conocephalus Thunberg, 1815 is a massive, successful genus, with well over one hundred species across all continents except Antarctica, and the Orthoptera Species File (OSF) recording forty species within Africa. Throughout their range, they - like many members of the subfamily Conocephalinae Krauss, 1902 - are primarily associated with grassland areas, where they can be an abundant and conspicuous feature of the invertebrate community. In southern Africa, where such fat-and-protein rich insects are an important food resource for humans, they are not so valued as the larger Pseudorhynchus Serville, 1838 and Ruspolia Schulthess, 1898, but are commonly more abundant than either.

Neither I nor the folks at the OSF have found any records of this genus from Zambia, but they are definitely here; the pan-African Conocephalus (Conocephalus) conocephalus, first described by the taxonomic powerhouse that was Carolus Linnaeus in his Systema Naturae (1767), is common across the country, and then there is this little guy: 

Chongwe Distr., Zambia, April 2018

Within the African Conocephalinae, the tribes Agraeciini Redtenbacher, 1891 and Copiphorini Karny, 1912 are largely comprised of more robust insects. Additionally, the majority of the Copiphorini have an extended - sometimes markedly - forward point of the head, distinctly beyond the bases of the antennae, and the Agraeciini are almost exclusively recorded from Tanzania and Kenya, with a single species in Gabon and Cameroon.

This leaves for our consideration the tribe Conocephalini Burmeister, 1838; excluding three species of Thyridorhoptrum Rehn & Hebard, 1915, which seem to be limited to areas North of the equator, the Conocephalini in Africa essentially comprises the previously mentioned Conocephalus and the subtribe Karniellina Hemp & Heller, 2010. While the Karniellina do certainly enter Zambia, being recorded from Muchinga, Northern and Eastern provinces so far (more on that another day, hopefully), males in this group have somewhat shorter elytra (the hardened forewings) and an enlarged pronotum (the conspicuous upper part of the thorax), which in all except one genus (Karniella Rehn, 1914; rather distinctive little beasties from Rwanda and the D.R.C.) are twice the length of the wings - which is not the case here. 

So we turn to Conocephalus itself, and shrink in horror. Even if we make the (dangerous) assumption that all species in this genus in Africa have been described, within the continent, this genus is a mess. Our first port of call is to head to the magnificent, wonderful and previously mentioned Orthoptera Species File, which - short of visiting every museum in every country the Southern African Development Community (SADC), and all those in every country that ever sent entomologists or entomologically-inclined missionaries, colonists or mine operators to them - is the most reliable way of finding out which species are where. 

Excluding species that are in Africa geographically, but don't penetrate (oo-er) south of the Sahara; and, to make our initial workload easier, ignoring species that the OSF only has records from West Africa for (for now - as distribution data is fairly patchy still, this can be unreliable at times), we're looking at twenty-five described species to compare. We can immediately exclude the seven bizarre, elongate species of subgenus Megalotheca, which, although they probably are present in Zambia, look more like a piece of grass dreaming of being a katydid than anything else. Knowing we may have to revisit them later, we're going to put the six species for which the OSF's illustrations show long-winged type specimens to one side - tentatively, though, because to add to the chaos, some species of Conocephalus are known to vary seasonally between long-winged and short-winged forms. This still leaves us with twelve species: seven not illustrated at all, and five with short-winged type specimens illustrated. 

One of the five illustated species is Conocephalus (Conocephalus) inaequalis, and the photographs of the type show that, despite being 90 years old, the type still shows much of the colouring of our little chap. This isn't all that meaningful in itself, but when Uvarov described this species in 1928, he also wrote about five of the other species we want to examine or eliminate, so this seems like a promising rabbit-hole to wriggle down into. 

Before we go any further, anyone of a particularly sensitive disposition should probably look away. This is because, in order to describe why I'm moderately confident that we landed through (mostly) luck on the right insect, I have to show you a picture of the business end of a male katydid, and I don't mean the end it eats with.




On the left, you can see the somewhat obscured terminalia of the individual shown near the beginning of all this preamble; he was not overly co-operative, and with it being cold and dark when we met, I didn't check on the quality of my pictures until after I'd gone back inside.  You can, however, just about make out two spines coming off the inside of his cerci (the arm-like structures at each side), although due to the angle and his poorly-placed hindleg, this takes some peering.





Fortunately, back in 2013, I managed to get a picture of a somewhat more co-operative male which shows this a little more clearly; notice the long, black-tipped spine pointing inwards from just behind the blunt tip of the cercus (no, not the type with dancing bears and trapeze artists), and a second one just a little further back from the tip, about half as long.





Well, as it turns out, Uvarov devoted some time to providing illustrations and descriptions of this end of those five little katydids, and both Conocephalus (Anisoptera) rhodesianus (Peringuey, 1916) and C. (A.) bechuanensis (Peringuey, 1916) are quite, quite different: rhodesianus, described from Zimbabwe (then Southern Rhodesia) has single-spined cerci, which bechuanensis has a tiny second spine that doesn't protrude inward, but rather nestles on top of the large terminal spine.

This is progress; all ten of our remaining suspects are within the subgenus Conocephalus. Exciting times (I speak from a highly caffeinated position, so I recognise that others may be less excited by this).

But wait, there's more. Conocephalus peringueyi, which outside of this paper has only ever been mentioned by the OSF itself, is entirely different, without any long, inwardly projecting spines; and on the subject of C.  inaequalis, Uvarov describes it as:

"similar to C. caudalis, differing from it in the structure of the male genitalia, and in the development of the elytra. The latter are longer than the pronotum, reaching to the middle of the abdomen, with the apex parabolic; they are greenish in front of the radial veins with are green, and brownish behind them, with brown spots along the middle... Cercus similar to that in C. caudalis, but its inner teeth are very unequal in size, the one nearer the base being much shorter and obtuse"


Elytra longer than the pronotum - check; they don't reach the mid-point on the abdomen, but the abdomen of your average grasshopper is of quite variable size depending how well fed, out of breath or dead they are, and the pronotum-to-elytrum proportion is consistent with Uvarov's measurements (elytra 1.5 times length of pronotum) - so check; tips of elytra a smooth, u-shaped curve - check; colour characters - check, except that I can't see any clearly marked brown spots; but brown spots on brownish don't sound too visible at the best of times; and cerci - very much check.

Generally a pretty convincing description; the species Uvarov has grouped C. inequalis with, he's also ruled out for us; if we head to Walker's description of Conocephalus  caudalis (Walker, 1869), we can also incidentally take C. tenellus and C. punctipennis out of the running, since both of them have hind wings longer than the fore wings, and if our little conehead has hindwings at all, they're not even long enough to see; his description of C. caudalis turns out to be a dud; he describes only the female, does so briefly, and apparently doesn't bother to illustrate her; the male was only described some time later by Redtenbacher (1891); his illustration (under synonym Xiphidium natalense) confirms what Uvarov implied: the teeth of the male's cerci are equal in size in C. caudalis; from his descriptions, C. africanus (from Gabon) is another long-winged species, so that's ruled out, while his description of C. guineensis (also from Gabon) covers only the female, which is short-winged, doesn't really give us any reason beyond geography to suspect that we're not looking at that species. Not losing hope, we turn to the last two species: Conocephalus brincki and Conocephalus basutoanus, both described Chopard in 1955.

You know how people who'd read all the books George R.R. Martin had written in the series before Game of Thrones aired used to prematurely distrust certain characters who, it turned out, were absolute monsters? I react that way to Chopard. He seems to have spent his life going out of his way to publish papers in journals I do not have access to (even when UNZA Library isn't closed for Cholera); while the type for C. basutoanus (from Lesotho) is illustrated on OSF, and shows that the male has quite different cerci, the type for C. brincki is not illustrated, and so I cannot comment on it. Geographically, it shouldn't be a problem - the single record is from high mountain heath in the cape - but leaving it here, as "probably inequalis, but could be guineensis or brincki at a stretch" feels like an anticlimax. If only there was some authority that had written about the unusual features of inequalis after all these species had been described...

Oh, wait.

Heller et al did exactly that in 2014, regarding a strange little conehead from the Eastern Congo, describing the male as being similar in the structure of the cerci to inequalis, noting that "this type of cercus does not belong to the common ones in the genus (not figured e.g. in the only available multi-species study of the genus by Pitkin (1980) on species of the Pacific area)".

Is it disingenuous that I knew this before I took you on this long and twisted journey? I actually read it after Uvarov's description, but as Heller et al note the absence of stable identification characters for the rest of the African Conocephalus (which I am tempted to interpret as nobody knows where Chopard's descriptions are), I then went through the rest of these species in an effort to reach a slightly greater degree of certainty.

Did I get it? Somewhat. The species was described from an unknown location in South Africa, probably in the Transvaal, and seemingly also eastern D.R.C., and people with more access to resources and far better qualified than I could go no further than I have to identify a seemingly identical specimen; if inequalis-like animals were present in northern S.A. and eastern D.R.C. but nowhere in between, it would seem impossible for this to be a single species; it may be a little naive, but despite sharing Heller et al's concerns, I find myself feeling that stumbling on this little conehead in Zambia adds just a little bit of confidence to their identification.

And it could have been worse: trying to identify male coneheads in Africa may be nigh-on impossible, but the females are even harder; this female, by association with the male above, I'm assuming to also be Conocephalus (Conocephalus) inequalis.












References:

Characteristics of the Karniellina in: Hemp, C., Heller, K.-G., Kehl, S., Warchalowska-Sliwa, E., Wägele, J.W. & Hemp., A (2010). The Phlesirtes complex (Orthoptera, Tettigoniidae, Conocephalinae, Conocephalini) reviewed: integrating morphological, molecular chromosomal and bioacoustic data. Systematic Entomology 35, pp. 554-580

Descriptions of Conocephalus inequalis, C. peringueyi, C. bechuanensis and C. rhodesiensis in: Uvarov, B.P. (1928). Notes on the Types of Orthoptera described by Dr. L. Péringuey. Annals of the South African Museum 25 pp. 341-357

Descriptions of Conocephalus tenellus, Conocephalus caudalis and Conocephalus punctipennis in: Walker, F. (1869). Catalogue of the Specimens of Dermaptera Saltatoria in the Collection of the British Museum part II, pp. 225-423

Descriptions of Conocephalus africanus, Conocephalus guineensis and male of caudalis in: Redtenbacher, J. (1891) Monographie der Conocephaliden. Verhandlungen der Kaiserlich-Königlichen Zoologisch-Botanischen Gesellschaft in Wien 41 pp. 315-562

and finally:

Support for throwing my hands up in the air and saying b***er it, it's inaequalis in: Heller, K.G., Hemp, C., Liu, C. & Volleth, M. (2014). Taxonomic, bioacoustic and faunistic data on a collection of Tettigonioidea from Eastern Congo (Insecta: Orthoptera). Zootaxa 3785 (3), pp. 343-376.







Thursday, 3 August 2017

Spiny little farmers: the ant genus Polyrhachis in Zambia.

Of the many – very many – ants in Zambia, Polyrhachis are not only among the most conspicuous, but some of the most recogniseable – and, to my unending joy, there exist two open access, freely-downloadable keys to the genus within Africa, and – possibly because Polyrhachis are blessed with a great number of readily visible external features – these are (relatively) easy to read and easy to work through.



Polyrhachis schistacea is the most conspicuous and common Polyrhachis
in much of Zambia, and indeed much of sub-Saharan Africa


The first Polyrhachis to be encountered is almost always Polyrhachis schistacea, a very distinctive, ground-nesting species that is found almost everywhere. Although it probably absent from deep forest, it thrives even in dense, canopied woodland, and occasionally into wetter, riverine forest.

Between Bolton (1973)’s and Rigato (2016)’s reviews of the genus, five species are recorded from Zambia; a sixth species, P. schistacea, is also present throughout the country, and records from Zambia may have escaped mention simply because it is abundant almost everywhere.
With almost 500 species described globally, Polyrhachis is made more manageably by division into a number of subgenera – although all 61 species in sub-saharan Africa fall together into Polyrhachis (Myrma) – and species groups. Of the six species groups recorded from sub-saharan Africa, 2 are known to be present in Zambia, and a third occurs in a number of neighbouring countries and almost certainly extends into Zambia.

Polyrhachis epinotalis is a typical member of the militaris
species group, of which at least six species occur in Zambia.
Kundabwika, N. Province, Zambia. 








Polyrhachis weissi is the sole member of the
revoili species-group recorded from Zambia.
Chongwe, Lusaka Prov., Zambia. 


Although their (rather more speciose) cousins in the genus Camponotus often have not only major and minor workers – often requiring separate keys – but sometimes also several grades between, Polyrhachis ants have only a single worker caste. Camponotus are also rather smooth-bodied, generic-looking ants, whose visible distinctions can be easy to miss; while the various Polyrhachis can have spines and ridges almost anywhere, making them a much easier group to work with.
                















Key to Species known or likely to occur within Zambia 
(brutalised into existence from the keys produced by Bolton (1973) and Rigato (2016)'s derived key)

For those who aren't familiar with the weird and wonderful (?) jargon of ant anatomy, just beyond this list, you will find a picture of Polyrhachis epinotalis with all the body features used in the key. labelled. 


     
     1.    > Pronotum without a distinct margin, sides and dorsum joined by a smooth, uninterrupted curve (revoili group)(S., W., and Central Africa, including Zambia)………..........….Polyrhachis weissi
>          >>Pronotum at least with a partial margin, seen as a raised or projecting flange, ridge, or an acute angle separating dorsum from sides………………………………………….…......………...to 2

     2.    >Metanotal groove indistinct, represented at most by a line scoring across the dorsum of alitrunk, which may or may not interrupt the sculpturation; never impressed, and sometimes undetectable (viscosa group)……………………………………………………………………......………to 3
>    >>With broad, impressed and distinct metanotal groove, in profile this may be seen as a V or U shaped trench separating mesonotum from propodeum (militaris group)…………….….….to 6
 
     3.    >Gaster finely longitudinally striate (South Africa, Malawi)..…....……….Polyrhachis arnoldi
     >>Gaster finely reticulate-punctate……………………………………….………………….to 4
    
     4.       >Antennal scape broadened into a hood at tip, concealing base of following (first funicular) segment from above; the covered section of the first funicular segment is strongly flattened. Eyes generally flat, occasionally convex (widespread throughout Sub-Saharan Africa, from South Africa to Sudan and Ghana)…………………………………….……..........…………Polyrhachis viscosa
     >>Antennae not like this; eyes convex……………………………………………………...to 5
 
     5.       >Ridge between spines of propodeum is raised medially into a distinct tooth or tubercle; the spines themselves curving distinctly upwards (East and Southern Africa) ..Polyrhachis wilmsi
     >>Ridge between spines of propodeum at most arched medially; the spines directed behind and to the side, curved only very slightly upwards (East and Southern Africa, and Angola)……................……………..…………………………………………………….……………Polyrhachis spinicola

      6.       >Petiole with 2 spines………………………………………….........…………………….to 7
     >>Petiole with 4 spines; the second pair may be reduced to small teeth………………...….to 8. 
     >>> Petiole with 6 spines or teeth, the smallest of which often reduced to blunt tubercles behind the lateral spines; eyes placed behind the mid-length of side of head..............Polyrhachis decemdentata
     
     7.     >Spines of petiole more-or-less parallel, strongly hooked backwards at the tips. Clypeus with carina, gaster (usually) with golden pubescence (West and Central Africa, south to D.R.C. and Angola)…………………………….…………………………….........………Polyrhachis laboriosa
     >>Spines of petiole diverging, curved backwards along their length but never hooked apically. Clypeus without carina; gaster usually with grey pubescence, never golden….Polyrhachis wellmani

     8.       >Pronotum entirely without erect hairs dorsally (East and Southern Africa, from Kenya to Natal)………………………………………………………………………………..Polyrhachis schlueteri
>>Pronotum with erect hairs dorsally……………………………………………………….to 9

     9.       >Dorsal surface of thorax without erect hairs except on the pronotum. Sides of head below eyes without erect hairs. Gaster polished, shining, only with very fine reticulation; pubescence short, diluted……………………………………………………………...………….Polyrhachis gagates
     >>Dorsal surface of thorax with erect hairs on all segments; side of head below eyes with erect hairs. Gaster generally dull, with fine reticulate-punctulate sculpturing, or sculpturing hidden by pubescence………………………………………………………………………………….to 10

     10.   >Pubescence sparse, not hiding sculpturation of alitrunk or gaster, usually greyish. Relatively narrow, slender species………………………………………..…………..Polyrhachis schistacea
     >>Pubescence abundant everywhere, at least partially hiding sculpturation of dorsal alitrunk and gaster; generally golden…………………………………………………….……………..to 11

     11.   >Head in full-face view rectangular; sides weakly convex, posterior corners always with distinct, more-or-less obtuse angles. Each eye with a blunt emargination behind, separating dorsum from sides. Propodeal spines short, tooth-like, curving upwards and much shorter than the depth of the propodeal declivity……………………………………..................…………Polyrhachis militaris
     >>Head in full-face view oval, either without or with very faint corners behind; no margination of head behind eyes, sides and upperparts of head smoothly confluent. Propodeal spines long, upturned; as long as or almost as long as the depth of the declivity………………………………………………………………………Polyrhachis epinotalis


Main body parts labelled for reference; unless your eyes are much better than mine, you will have to expand it to read the labels (sorry).
Polyrhachis epinotalis, Kundabwika, Zambia. 


Bolton (1973) includes an overview of the habitats and habits of these species, as known at the time:
  • weissi constructs silk-and-debris nests under or between leaves in trees; it occupies a wide range of habitats from forest and veldt to savannah. 
  • arnoldi has been recorded nesting in tree hollows, protecting the nest with a matrix of silk and dirt. 
  • viscosa nests in sandy soil, usually in exposed sites; ants are primarily found foraging on the ground, but may also climb. It is largely restricted to savannahs and arid zones, but is also found coastally in Ghana. 
  • wilmsi nests in stem galls (in trees, I assume?)
  • spinicola has been recorded from acacia and citrus trees; its nesting habits are not clear. 
  • decemdentata makes its nests in rotten and termite-mined tree branches. 
  • laboriosa is restricted to forested environments, where it builds a nest of twigs and leaf fragments, bound with silk and fungal hyphae, adhered to the undersides of leaves or built in the fork of tree branches; they aggressively defend the nest, spraying acid under their abdomens. Individuals disturbed are far less aggressive, usually simply dropping off their branches. 
  • Boston speculates that wellmani most likely has the same habits as the (very similar) schistacea, of which it may be a synonym. 
  • schlueteri is apparently restricted to hot, moist sites. 
  • gagates is a ground-nesting species, typically found in drier, open habitats such as savannah and semi-desert, only occasionally in scrub forest. The nests have been recorded at the bases of grasses, and under rocks; the entrance may be marked by a wide crater of dirt, or with a wall of woven material which extends into the entrance. 
  • schistacea is primarily a species of savannah and scrub forest, absent from rainforest; it nests in open ground or under stones or – rarely – decaying wood. They may construct a cup-like wall of grass-blades around the nest; they are also noted as a tender of hemipteran bugs. 
  • militaris is noted as an arboreal species of forests, especially rainforest; constructing a nest inside hollows of trunks and branches. Bolton does not separate epinotalis and militaris, so it is assumed here that epinotalis lives much the same life. 

Polyrhachis decemdentata in deep spray forest beside Lumangwe Falls,
Northern Province, Zambia. October 2017.

When this post first went up, back in 2017, I had only been up to the Kalungwishi valley once. Returning in October, I happened upon a small number of a small colony of very uncooperative ants in dense spray forest abutting the magnificent Lumangwe Falls. Between the low light and my sluggish reactions, this is the best picture I managed to get, but these should be Polyrhachis decemdentata, which Rigato lists as occurring in West and Central Africa, to the western parts of Kenya and Tanzania; northeastern Zambia represents a very slight southerly expansion of that range. 




And in case you were wondering why I described them as "farmers" specifically: well, herders might be a better description. Like most ants, some Polyrhachis are fond of sweet things, and, as Homopteran bugs tend to ooze sugar water from their rear ends, they 'milk', protect and sometimes even propogate such insects; Polyrhachis schistacea in particular can reliably be found wherever nymphs of various leafhoppers are seen, such as in the picture below:


Polyrhachis schistacea tending Membracid plant-hoppers in Mpongwe, Copperbelt, Zambia




References: 

1.       Bolton, B.  (1973). The ant genus Polyrhachis F. Smith in the Ethiopian Region (Hymenoptera: Formicidae). Bulletin of the British Museum (Natural History) Entomology 28 (5) pp. 283-369
2         2.       Rigato, F. (2016). The ant genus Polyrhachis F. Smith in sub-Saharan Africa, with
d                descriptions of ten new species. (Hymenoptera: Formicidae). Zootaxa 4088 (1) pp. 1-50



Tuesday, 6 December 2016

The Grasshopper without a name (Thericleidae)

The other day, on a group I follow on a popular social-networking site that shall not be named here, someone decided to complain about people answering queries with Latin names; while his initial complaint was mildly annoying, a later comment claimed that those using Latin names were snobbish and just trying to show off their own knowledge.

This is sufficiently absurd within the confines of the group itself, which covered snakes: snakes in the region do, for the most part, have unique common names; but many have multiple common names, which are not universal across their ranges, while the binomal names are universal; that's the entire point. The argument that they are elitist isn't new; the late, great ornithologist Levaillant was a firm believer that colloquial names were all you needed - but he was working with birds.

With insects, it is extremely unusual to find a species which has its very own common name. Sometimes, this applies to the entire family; take for example, this:

Thamithericles croceosignatus (Bolivar, 1914). Photographed in Chongwe District, Lusaka, Zambia; December 2013.

Not only does this colourful little creature not have a unique common name, its family doesn't; most often, they are referred to as Bush-hoppers, a name which also applies to a number of related families, and also some insects in completely separate orders.

The best that I can do (and will occasionally do for complainants on social-media) is find the English meaning of the name; but for that, see the (long-)previous post on a member of this family, Pseudothericles jallae (Griffini, 1897).

Fair warning: this post is about to turn into a tangled complaint about all sorts of things people and the media say; or things I think they say. 



You might - and people do - wonder why we should care about animals that have spent their entire histories so irrelevant to us that they don't even warrant names in Gosh-darned English.

First off, that's racist.

Look at this picture while you think about what you've done to deserve that. 



Harpethericles leechi, Descamps 1977, in New Kasama, South-East of Lusaka City. 






































Have you ever noticed that every single species of grasshopper in the UK has its very own common name? No? Well, they do. This might - in part - be down to how desperately few grasshoppers the UK has (13 members of suborder Caelifera - short-horned grasshoppers - native); but it also has a lot to do with occurring in Europe.

The Thericleidae - the family which we are currently looking at - do not occur in Europe, but are almost entirely limited to Africa.

This is not to say that Africa does not have a long tradition of naming; elderly villagers can have dozens of names for different creatures that the average European would dismiss at a glance as 'spiders', but many of these names have either disappeared or are disappearing - two well-spoken ladies recently racked their brains trying to find the word for butterfly for me after they dismissed the word 'gulugufe' as meaning something entirely different in Zambian Chewa and Nyanja as it means in Malawian Chewa; and despite both speaking several languages fluently, neither could produce a single word (In much the same way as 'Dumbledore' originally meant bumblebees (and occasionally stag beetles and cockchafers) in the UK, and became a term for a village idiot, 'gulugufe' seems to be primarily used in some areas to indicate a fool with no direction in life)

I am tempted, sometimes, to blame this loss of names indirectly on colonialism; even after independence, Zambia's first president, Kenneth Kaunda, resisted suggestion that local languages should be taught in Zambias schools for decades; believing that an entirely English-speaking population would be better equipped to thrive in a global economy. 

On the other hand, much of Sub-Saharan Africa only began writing down their language after the Europeans arrived; and with relatively small populations subject to the ravages of tribal conflict and the intra-African slave trade long before Ghana decided that gold was less profitable than slavery and launched the trans-Atlantic slave trade, keeping names for specific insects that are only occasionally encountered was probably not a priority in most areas.


Pseudothericles jallae jallae (Griffini, 1897) in
Lusaka South, February 2015. 




If this looks like an argument that they still shouldn't be a priority, that's because you're forgetting that tribal warfare and both the trans-Atlantic and intra-African slave-trades have mostly dried up. 

These days, more serious concerns are economic turbulence, voter dissatisfaction and - my personal favourite - environmental decline.

Aha, I hear you say; you have posted three images so far and not a one of them has wings! These creatures must be limited range endemics with narrow environmental tolerances!

How very insightful of you! Well, you've pre-empted my lengthy argument about how their limited ranges and particular taste where it comes to their living conditions mean that they exist on evolution's knife edge, depending on environmental consistency just to carry on existing.




Lophothericles euchore (Bolivar, 1914)
in Chongwe District, Lusaka, Zambia, February 2016.




And you can probably guess that I'm always happy to see them out and about, because they mean that the local environment is - over the broader area - stable. Needless to say, I don't really see them in the large farming blocks.

I do see some in the suburbs (especially Lophothericles euchore (Bolivar, 1914), left)










It also helps that - thanks to a truly fantastic monograph by Descamps (1977; sadly not available online but can be bought from NHBS for a painful price) - they are fairly identifiable.

But enough of this 'everything must be useful' nonsense. Personally, I think they're pretty awesome little creatures. For example, check out the 12 millimetre porcupine that is Uvaroviobia luanensis (Uvarov, 1953). 


Uvaroviobia luanensis (Uvarov, 1953), Chief Nyalugwe's area, Eastern Province, Zambia. 

You may notice the (Uvarov,1953) that follows its name? That's the author who described it, and the year it was described (and it's in brackets because Uvarov did not commit a terrible crime of nomenclatural impropriety and name a genus after himself; that change came later). In this particular case, the year it was described is also the only record of the species that I can find; recorded from the Luano valley - some distance from where I found it, but environmentally very similar - in 1953. 


You're looking at the male (above) by the way. The females look like this (below): 

Female Uvaroviobia luanensis (Uvarov, 1953)  on unnamed tributary of the Luangwa, Eastern Province, Zambia































Another U. luanensis...
Narrow-range endemic, so same area, too.





It's sexually dimorphic. Well, somewhat polymorphic; Females can sometimes also look like this (right): 

Lophothericles burri Descamps, 1977.
Female
In Chief Nyalugwe's area, Eastern Province










Lophothericles burri Descamps, 1977.
Male
In Chief Nyalugwe's area, Eastern Province


Uvarovobia's presence in a second valley system some distance from the site of its original description shows that it is much more widespread than previously thought, and may even extend in to Mozambique. This is even more likely for the larger, more typical Lophothericles burri Descamps, 1977, which co-occured in the same valley, barely a whistle away from the Mozambique border, and is more widely recorded within Zambia.
















They do get more widespread; Stenothericles porcellus (Miller, 1936), the prime suspect for a slightly troubling species from Chongwe (Lusaka), is recorded by Descamps from Malawi and Zimbabwe; curiously, he does not record it in Zambia at all. Of the two species of the genus that Descamps does record in Zambia, Stenothericles rossi Descamps, 1977 and S. zambiae Descamps, 1977, his illustrations of their cephalic (head) and thoracic (um... thorax) structures is quite different from both Stenothericles porcellus and my Chongwe Stenothericles; which might, then, be filling in a gap in an otherwise wide but disjunct distribution.



Stenothericles cf porcellus (Miller, 1936)
in Chongwe District, Lusaka, Zambia, December '13


For those of you who can't bring themselves to fork out for Descamps' Monograph - and I'm not judging you, I know that it can be hard to justify spending money on animals that you will likely never see, even if you are on the right continent - the best free resource on these and any other common-name-less Tsokonombwe (Chewa - Grasshopper) that you happen to be interested in is probably the Orthoptera Species File.