Bol. Mus. Nac. Hist. Nat. Parag. Vol. 14 (1-2), Setiembre 2002, pp. 19 - 24

RETURN TO THE SUBSPECIES CONCEPT IN THE GENUS ZETA (HY- MENOPTERA: ; EUMENINAE )

JAMES M. CARPENTER Division of Invertebrate Zoology, American Museum of Natural History, Central Park West at 79th Street, New York, NY 10024, U. S. A. e-mail: [email protected]

Abstract.- The subspecies recognized in the eumenine wasp genus Zeta are confirmed as synonyms.

Resumen.- Las subespecies reconocidas en el género de avispa eumenina Zeta son inveteradas como sinónimos.

In 1987, I published a study of the subspe- Ma che dire allora delle 16 sottospecie cies of two species of the neotropical potter dell’‘Eumenes flavopictus (Blanch.)’ wasp genus Zeta. At that time, the four recog- riconosciute e descritte del Van der Vecht nized species in Zeta, were divided into 15 sub- (1959, Zool. Verh. Leiden, 41:1-71); o delle species, with most of the subspecies proposed 15 sottospecie del Polistes rothney Cam., pure studiate dal Van der Vecht (1978, by Giordani Soika (1975). I documented that Bijdr. Dierk., 38/97-109); o delle 17 the color characteristics by which most of the sottospecie di Polistes stigma (F.) del subspecies were distinguished: (1) showed dis- Petersen (1987, Ent. Scand., 10:227-259); crepancies between actual specimens and o delle 9 ‘color forms’ dell’Eumenes Giordani Soika’s (1975) key, (2) were transi- lepeleterii Sauss.» del Bequaert; od anche tional. Distributional overlap was also noted. le 10 «color varieties» dell’Eumenes I concluded that these subspecies were not re- maxillosus (DG), pure del Bequaert (1918, ally distinct, and sank most of them. I also Bull. Am. Mus. nat. Hist., 39: 276-278, e opined that “Recognition of subspecies is in 60: 279-281). È però opportuno ricordare my view a poor way of dealing with color varia- che molte delle «color varieties» del Bequaert sono oggi considerate buone tion in vespids anyway” (Carpenter, 1987: specie. E non è impossibile che qualche 257). sottospecie dell’argillaceum si riveli, ad un Giordani Soika (1990: 166-170) took issue più attento studio, anch’essa valida specie. with this conclusion, in an appendix to a pub- Posso già dire che lo studio dell’apparato lication dealing with some other neotropical copulatore di alcune ha già messo in eumenine genera. Below I quote the full ap- evidenza significative differenze, pendix: specialmente nei lobi basali dell’edeago e negli apodemi, come risulta dall’esempio “In una recente pubblicazione (1987, delle figg. 8991: le differenze tra le PSICHE [sic], 94:253-259) il Carpenter sottospecie incarum ed apurimacense enuncia ‘A review of the subspecies con- dell’argillaceum non sono minori di quelle cept in the eumenine genus Zeta’, basata dalla specie mendozanum (Schr.). sullo studio tassonomico di alcune specie Il Carpenter ritiene fonte di difficoltà di questo piccolo genere neotropicale. Il un ‘couplet’ della mia Tabella per le Carpenter si mostra altamente meravigliato sottospecie dell’argillaceum, che definisce dal fatto che alla specie argillaceum (L.) ‘vague’, e così traduce; vengono attribuite 10 sottospecie: ‘Giordani ‘Ferrugineous, or brown-ferrugineous Soika recognizes only four species in Zeta, and black, without yellow markings. In but these are divided into no fewer that 15 some exemples (transitional to hubrichi) subspecies, 10 of which are in argillaceus!’. part of the posterior margin of the pronotum 20 BOL. MUS. NAC. HIST. NAT. PARAG. VOL. 14 (1-2)

and apex of tergum 1 may be yellow’. avvenne, e gli sperimentatori, del tutto ‘Yellow markings fairly extensive both stupiti, conclusero per la non trasmissibilità on thorax and abdomen’. ereditaria dei caratteri acquisiti, e ne fecero A dire il vero, questo ‘couplet’ mi una pubblicazione. sembra assai più chiaro di molti di cui Oggi noi potremmo ritornare al concetto abbonda la letteratura: mi limito a citare - linneano: ‘Species tot sunt quot diversas come esempio - parte della Tabella per la formas ab initio produxit Infinitum Ens; determinazione delle specie di quae deinde formae secondum generationis Stenodynerus (=Nannodynerus Bl.) nella inditas leges produxere plures, at sibi sem- fondamentale Monografia del Bliithgen, per simi les, ut species nunc nobis non sint pubblicata dall’Accademia delle Scienze di plures, quam quae fuere ab initio’. (C. Berlino (Die Faltenwespen Mitteleuropas, Linnaei, Genera Plantarum, Ed. V, 1754, 1961, Abh. Deutsch. Ak. Wiss. Berlin, Kl. p. III). Chem. Geol. Biol., Jh. 1961, 2: 109-110). Ma è oggi difficile accettarlo, e ‘Flügenschuppen zitronen-, hell- oder dobbiamo ammettere la speciazione, e la weisslinchgelb, mit nicht pigmentiertem, razzazione che ne è l’inevitabile fase durchsichtig gelblichem Mittelfleck, und intermedia. E se diamo un nome alle specie linearem solchen Saum, am Innerrand dobbiamo, per chiarezza, precisione, ed geschwàrzt; ausnahmsweise sind sie anche per semplicità, dare un nome anche braunschwarz, mit oder ohne schmale gelbe alle sottospecie. Ovviamente quando le Randbinde, aber nie gerötet’. caratteristiche delle sottospecie sono ‘Flügelschuppen rot oder orange oder nettamente al di fuori dei limiti di hellgelb, mit durchsichtiger roter variabilità della forma nominale o delle iiberlagerung’. altre sottospecie, e sono geneticamente Il nuovo concetto di sottospecie del Car- stabilizzate, sì da ripresentarsi eguali nelle penter è imperniato sul non riconoscimento successive generazioni. della validità delle sottospecie, che A conferma del punto di vista del Car- sarebbero ‘artificial taxa’. Questo concetto penter interviene Mud D’aub (1988, è ripreso dal Carpenter in SPHECOS (1988, SPHECOS, n° 17:12): ‘The use of subspe- n° 17:12), ove approva l’eliminazione delle cies is akin to putting stamps into albums sottospecie proposta dall’Archer ‘especially that have rectangles for each issue’. Non è to the extent that subspecific taxa are elimi- forse tanto pertinente il confronto con nated’. E rafforza questo principio insetti che, certamente, non hanno caselle ricordando le ricerche di McLean (in realtà predisposte; comunque siamo nel più pieno precedute da molte altre di vari AA., concetto linneano «Species tot sunt...’, ove specialmente su Lepidotteri) che hanno 1'«Infinitum Ens» è l’uomo, che stampa gli ‘even shown experimentally that such ‘sub- immutabili francobolli. species’ in Polistes can be produced by Riservandomi di discutere più manipulation of humidity!». ampiamente la questione in un lavoro di In realtà, il fatto che variando alcuni prossima pubblicazione, confermo la fattori ambientali si inducono variazioni di validità delle sottospecie da me segnalate colore in molti insetti, è del tutto ininfluente nella mia nota del 1975 sul genere Zeta nei casi in esame, in quanto tali variazioni Sauss.” sono limitate alla generazione che li ha subiti, e scompaiono completamente già which I translate (after correcting a few ty- alla prima generazione successiva. Ciò mi pographical errors) as: ricorda le ricerche, riportate dai vecchi testi universitari di Zoologia, di alcuni “In a recent publication (1987, Psyche, ‘scienziati’ che, avendo tagliata la coda ad 94:253-259) Carpenter enunciates ‘A re- alcuni topi, si attendevano che la loro prole view of the subspecies concept in the nascesse priva di coda. Questo non eumenine genus Zeta’, based on taxonomic SETIEMBRE 2002 RETURN TO THE SUBSPECIES CONCEPT IN THE GENUS ZETA 21

study of some species of this small literature abounds: I confine to quote - as neotropical genus. Carpenter marvels example - part of the key for the determi- highly at the fact that to the species nation of the species of Stenodynerus argillaceum (L.) 10 subspecies are attrib- (=Nannodynerus BI.) in the fundamental uted: ‘Giordani Soika recognizes only four monograph of Blüthgen, published by the species in Zeta, but these are divided into Academy of Sciences in Berlin (Die no fewer that 15 subspecies, 10 of which Faltenwespen Mitteleuropas, 1961, Abh. are in argillaceus!’. Deutsch. Ak. Wiss. Berlin, Kl. Chem. Geol. But is what one to say then of the 16 Biol., Jh. 1961, 2: 109-110). subspecies of ‘Eumenes flavopictus ‘Tegulae lemon -, brightly - or whitish- (Blanch.)’ recognized and described by van yellow, with not pigmented, lucidly sallow der Vecht (1959, Zool. Verh. Leiden, 41:1- middle-stain, and linear such margin, at the 71); or of the 15 subspecies of Polistes inner-edge blackened; as an exception, they rothney Cam., also studied by van der Vecht are brown-black, with or without narrow (1978, Bijdr. Dierk., 38/97-109); or of the yellow edge-bands, but never reddened‘. 17 subspecies of Polistes stigma (F.) of ‘Tegulae red or orange or light-yellow, Petersen (1987, Ent. Scand., 10:227-259); with transparent red superimposition ‘ or of the 9 ‘color forms’ of ‘Eumenes The new concept of subspecies of Car- lepeleterii Sauss.’ of Bequaert; or also 10 penter has hinged on not recognizing the ‘color varieties’ of Eumenes maxillosus validity of the subspecies, that are ‘artifi- (DG), also of the Bequaert (1918, Bull. Am. cial taxa’. This concept is taken from Car- Mus. nat. Hist., 39: 276-278 and 60: 279- penter in SPHECOS (1988, no. 17:12), who 281). It is opportune to remember how- approves the elimination of the subspecies ever how a lot of the ‘color varieties’ of proposed by the Archer ‘especially to the Bequaert are considered good species to- extent that subspecific taxa are eliminated’. day. And it is not impossible that some And reinforces this principle citing the re- subspecies of argillaceum will be revealed, search of McLean (really preceded by a lot to a more careful study, also valid species. of other varied authors, especially on Lepi- I can already say that the study of some doptera) who have ‘even shown experimen- copulatory apparatus of some has already tally that such ‘subspecies‘ in Polistes can put in evidence meaningful differences, be produced by manipulation of humidity!’. especially in the basal lobes of the aedeagus Really, the fact that varying some envi- and in the apodemes, as results from the ronmental factors induces variations of example of the figs. 89-91: the differences color in many , it is entirely influ- between the subspecies incarum and ential in the cases in examination, in how apurimacense of argillaceum are not much such variations are limited to the smaller than those from the species generation that has suffered them, and they mendozanum (Schr.). already completely disappear in the first Carpenter thinks a source of difficulty following generation. This recalls to me a couplet of my key for the subspecies of the research, reported by the old university argillaceum, that he terms ‘vague‘, and so texts of zoology, of some ‘scientists‘ that, translates; having cut the tail of some mice, were ex- ‘Ferrugineous, or brown-ferrugineous pecting that their issue would be born de- and black, without yellow markings. In prived of tail. This didn’t happen, and the some examples (transitional to hubrichi) experimenters, entirely surprised, con- part of the posterior margin of the pronotum cluded for no hereditary transmissibility of and apex of tergum 1 may be yellow.’ the acquired characters, and they made a ‘Yellow markings fairly extensive both publication of it. on thorax and abdomen.’ Today we could return to the Linnaean To say the truth, this ‘couplet‘ seems concept: ‘There are as many species as me a great deal clearer than many of which those diverse forms which the Infinite Be- 22 BOL. MUS. NAC. HIST. NAT. PARAG. VOL. 14 (1-2)

ing has produced from the beginning; sub- paring both to the species mendozanum. The sequently these forms produced more in figures he provides show differences among accordance with the inherent laws of gen- these three taxa. How exactly are they mean- eration, but always similar to themselves, ingful? The differences are quite minor, but with the result that we do not now have that is not the point: if they are all really dif- more species than have existed from the beginning’. (C. Linnaeus, Genera ferent, that would be grounds for recognizing Plantarum, Ed. V, 1754, p. III). three species, not treating two as subspecies. But it is difficult to accept it today, and Of course, to support such recognition, one we have to admit speciation, and the would have to show that the differences are in racination that is the inevitable intermedi- fact diagnostic: that they are fixed in each spe- ary phase of it. And if we give a name to cies, and that one is not seeing instead intraspe- the species we ought, for clarity, precision, cific variation without taxonomic significance. and also for simplicity, to also give a name That latter in fact appears to be the case. to the subspecies. Obviously when the char- Giordani Soika has not shown that the genita- acteristics of the subspecies are clearly out lia are diagnostic in this case; but even if he of the limits of variability of the nominal form or the other subspecies, and they have had done so, it would not be grounds for re- stabilized genetically, is affirmed by equal taining subspecies, for to do so would simply reappearance in the following generations. be inconsistent. To confirmation of the point of view of Giordani Soika is correct in concluding that the Carpenter Mud D’aub intervenes (1988, I consider subspecies to be artificial taxa: they SPHECOS, no. 17:12): ‘The use of sub- have no place in a phylogenetic system, in species is akin to putting stamps into al- which diagnosable taxa should be treated as bums that have rectangles for each issue’. species. That is, phylogenetic species (Nelson It is not so much perhaps pertinent the com- and Platnick, 1981; Nixon and Wheeler, 1990), parison with insects that, certainly they a concept which is compatible with cladistic don’t have predisposed boxes; however we are in the fuller Linnaean concept ‘Species theory, and being character-based, of greatest tot sunt...’, where ‘Infinitum Ens’ is man, utility in classification, which is concerned with who stamps the unchangeable postage conveying information (Farris, 1979). How- stamps. ever, as I have previously observed (Carpen- Reserving to discuss more broadly the ter, 1996: 2): “But this means that taxa cur- matter in a work of next publication, I con- rently recognized as subspecies are either spe- firm the validity of the subspecies recog- cies or synonyms, and moreover there must be nized by myself in my note of 1975 on the a mixture. Without careful study on a case by genus Zeta Sauss.” case basis, the proper status of subspecific taxa cannot be determined.” Therefore, in catalogs Borsato and Ratti (1999), in their list of and checklists (Carpenter, 1996, 2001; Car- taxa, followed Giordani Soika (1990) in treat- penter and Kojima, 1997; Kojima and Carpen- ing the subspecies of Zeta as valid. Therefore, ter, 1997), I have not proceeded with whole- I now retort. sale changes in status of subspecific taxa. I There are many confusions exhibited in have only made such changes where I have Giordani Soika’s quotation, as I shall detail, documented that the subspecies represent ar- but first I will deal with the one substantive bitrary partitioning of continuous variation, claim, regarding “meaningful differences” in such as the case of Zeta, as well as some of the male genitalia. Giordani Soika states that Giordani Soika’s subspecies in other the differences between two subspecies of neotropical genera (Carpenter and van der argillaceum are not smaller than those com- Vecht, 1991). SETIEMBRE 2002 RETURN TO THE SUBSPECIES CONCEPT IN THE GENUS ZETA 23

Thus, when Giordani Soika cites other ex- capacity for characters to recur in more than amples of species divided into subspecies in one geographical area, yielding polytopic races; the quotation, my response is those are merely (3) the common occurrence of the micro-geo- taxa whose proper status remains to be deter- graphical race; (4) the necessary arbitrariness mined: either valid species or synonyms. And of any degree of population divergence chosen where he complains that the couplet I criticized as the lowest formal racial level” (Wilson and as vague is better than other published cou- Brown, 1953: 100). They concluded: “The plets, that is merely a criticism of the other application of this logic to our present knowl- published couplets. That sort of citation are edge of geographical variation cannot fail to no more than an appeal to authoritarianism: stir a feeling that the trinomial has outlived its the point of my criticism remains. And he also usefulness in taxonomy” (Wilson and Brown, fails to mention that, while I termed the cited 1953: 108). Thus, even to adherents of the couplet “vague,” I did so in the context of say- biological species concept and allopatric spe- ing: “This vague couplet fails for numerous ciation (which obviously may entail divergence specimens in the MCZ” (Carpenter, 1987: 255). prior to speciation) the subspecies has no place. That is the real issue: the subspecies in Zeta Far from being desirable for purposes of “clar- cannot in general actually be distinguished by ity, precision, and also for simplicity” subspe- the characters used to describe them. cies are superfluous. Giordani Soika’s cita- Giordani Soika likewise misses the point of tion of Linnaeus is thus ironic: it is his taxo- my citation of experimental manipulations that nomic approach that is outmoded. produced “subspecies” in other vespids In conclusion, Giordani Soika has produced (MacLean et al., 1978): it calls the color char- no argument for retention of his subspecies, acters into question as diagnostic indicators. which confirms that they should be considered If fluctuations in humidity show plasticity in synonyms, as detailed in Carpenter (1987). coloration, and distributional overlap occurs in subspecies described solely on color differ- ACKNOWLEDGMENTS ences, which moreover intergrade, it is ecologi- I thank Bolívar R. Garcete-Barrett for in- cal variation that is being given a formal Latin viting me to publish in the Boletín del Museo name, not genetically fixed differences. These Nacional de Historia Natural del Paraguay, and are hardly species “in statu nascendi,” which Junichi Kojima for comments on the manu- is Giordani Soika’s stated rationale for formally script. naming subspecies, and so their naming serves no useful purpose. LITERATURE Finally, regarding postage stamps, if the Borsato, W. and E. Ratti. 1999. Antonio subspecies are arbitrary, then it is obviously Giordani Soika (1913-1997): la produ- Giordani Soika who has made postage stamps. zione scientifica. Mem. Soc. Entomol. And this conclusion follows even from a non- Ital. 77 : 43 – 103. cladistic viewpoint. Criticisms of the descrip- Carpenter, J. M. 1987. A review of the tion of subspecies are long-standing in the sys- subspecies concept in the eumenine tematics literature. Wilson and Brown (1953) genus Zeta (: Vespidae). outlined a general argument against use of sub- Psyche 94 : 253 – 259. species, discussing at length the problems pre- Carpenter, J. M. 1996. Distributional check- sented by four features of geographical varia- list of the species of the genus Polistes tion, which are as follows: “(1) the tendency (Hymenoptera: Vespidae; Polistinae, for genetically independent characters to show Polistini). Am. Mus. Novitat. 3188 : 1 independent geographical variation; (2) the – 39. 24 BOL. MUS. NAC. HIST. NAT. PARAG. VOL. 14 (1-2)

Carpenter, J. M. and J. Kojima. 1997 (1996). ai generi Sauss., Checklist of the subfamily Santamenes n. gen., G. Stenogastrinae (Hymenoptera: S., Pseudacaromenes G. S., Vespidae). J. New York Entomol. Soc. Stenosigma G. S. e Gamma Zav. 104 : 21 – 36. (Hymenoptera). Boll. Mus. Civ. Stor. Carpenter, J. M. 2001. Checklist of species of Nat. Venezia 39 : 71 – 172. the subfamily Masarinae (Hymenoptera: Kojima, J. and J. M. Carpenter. 1997. Catalog Vespidae). Am. Mus. Novitat. 3325 : 1 of species in the polistine tribe – 39. Ropalidiini (Hymenoptera: Vespidae). Carpenter, J. M. and J. van der Vecht. 1991. A Am. Mus. Novitat. 3199 : 1 – 96. study of the Vespidae described by Wil- MacLean, B. K., L. Chandler and D. B. liam J. Fox (Insecta: Hymenoptera), with MacLean. 1978. Phenotypic expression assessment of taxonomic implications. in the paper wasp Polistes fuscatus (Hy- Ann. Carnegie Mus. Nat. Hist. 60 : 211 menoptera: Vespidae). Great Lakes Ent. – 241. 11 : 105 – 116. Farris, J. S. 1979. The information content of Nelson, G. and N. I. Platnick 1981. Systemat- the phylogenetic system. Syst. Zool. 28 ics and Biogeography: Cladistics and : 483 – 519. Vicariance. Columbia Univ. Press, New Giordani Soika, A. 1975. Sul genere Zeta York. (Sauss.). Boll. Mus. Civ. Stor. Nat. Ve- Wilson, E. O. and W. L. Brown, Jr. 1953. The nezia 27 : 111 – 135 subspecies concept. Syst. Zool. 2 : 97 – Giordani Soika, A. 1990 (1988). Revisione 111. degli Eumenidi neotropicali appartenenti