|
The associated image keys can be accessed here (constantly being updated): The picture catalog itself can be accessed via the link Full catalog link in left upper corner. |
Nanophyinae of the Western Palearctic - Part A:
Presentation and Image key
of the Corimaliini
by Peter E. Stüben1 & Karel Schön2
Suggested citation: Stüben, P.E. & Schön, K. (1.1.2024):
Nanophyinae of the Western Palearctic - Part A: Presentation and Image key of the Corimaliini. - Le Charançon. Catalogues & Keys No. 7, Curculio-Institute, Mönchengladbach, Germany.
ISSN 1864-0699. [accessed: dd-mm-yyyy]
The current image key to the Corimaliini can be viewed here: https://nanophyinae.curci.de/pdf_key/corimaliini-key.pdf
A. Corimaliini
01-JAN-2024
Introduction
Whether Nanophyidae sit next to the Brentidae or as their subfamily, the Nanophyinae, opinions differ until today. One third of the approximately 320 known species - between 0.75 and 5 millimeters in size - in 33 genera occur in the Western Palearctic (i.a. Alonso-Zarazaga 2014). The larvae of the Nanophyinae live inside their respective host plants, mining the tissues of stems or flower buds, or as gall-formers. The subfamily is subdivided into the tribes of Corimaliini and Nanophyini. While the latter has a highly segmented antennal club, with the antennomeres clearly separated from each other in a "comb-like" manner, the club of the Corimaliini form a compact oval unit, separated from each other only by sutures. This may suffice at this point for the morphological separation of the tribes, but shall concern us in more detail in a second part B of the catalog to the Nanophyini in the second (right) column.
The ca. 50 species of the Corimaliini, on which we want to concentrate here first, are divided into 4 genera: the species of the genus Allomalia, Corimalia, Hypophyes, and Titanomalia (Alonso-Zarazaga, 1989). What is still missing is the molecular and in this respect systematic-phylogenetic confirmation of this division and the generic assignment of the species. The species, which are mostly light yellow to yellow-brown in color, occur in the Mediterranean region, the Sahara, Namibia, the Near East, and Central Asia. They live on numerous Tamarix plants (Tamaricaceae: Myricaria, Reaumuria, and Tamarix) and develop as 'ovarian gall-makers' in the flowers (Gerling et al. 1976, Kovalev 1995), where they prevent seed formation and have therefore already been recommended as biological control of the unwanted spread of Tamarix plants in the United States and Australia (Sobhian et al.1998). The pseudo-galls eventually fall to the ground and the larvae inside can hop and retreat together with the gall into a sheltered microhabitat for further development.
During the flowering period, the adults can be collected in large numbers - often hundreds - with the beating sheet at midday under the strongest sunlight. In doing so, haste is required with the pooter as the tiny Corimaliini, in most cases only 1 to 2.5 mm in size, can hardly be distinguished from the light background of the beating sheet. They take flight very quickly and return to their Tamarix flowers, following attractants. With their light yellow to yellow-reddish brown vestiture, they resemble withered tamarisk blossoms, and with their spherical shape, they imitate the fruit of their host trees (Formánek 1916). It is therefore not easy to detect them on the beating sheet amongst the flowers and fruits - as long as they do not move.
In any case, if possible it is advisable to collect several dozen specimens and to prepare them by removing the male genitals. Because in most cases they will belong to two, three or even four species, which only reveal themselves to be members of different genera and species groups under the microscope. In this context, the extremely variable elytra pattern, the spots, blemishes, and bands, play only a subordinate role in many species. Most species can only be distinguished or identified by the shape of the aedeagus - but then very easily*. In order not to cause major damage when dissecting these tiny specimens, we recommend opening or removing the last 5 abdominal sternites immediately behind the metacoxae. In the illustrated key to the Corimaliini attached here, highest priority is also given to the often species-specific shape of the aedeagus and the tegmen (the latter are always to be pulled away towards the apex of the aedeagus).
The picture key presented here for the first time is to be understood as an introduction to the determination of the (eventually all) western Palearctic Corimaliini: https://nanophyini.curci.de/pdf_key/corimaliini-key.pdf. It will be constantly supplemented and revised in the coming months and years. All attempts to obtain type material of some very rare species, e.g. in the Museum of St. Petersburg (Russia) or in the Muséum national d'Histoire naturelle in Paris (MNHN), have failed in recent years due to the lack of staff or an unwillingness to support morphological taxonomy; a development that has been observed in many European museums for a decade and is a cause of great concern among taxonomists working in morphology. Well-intentioned photographs of the habitus only really help in a few cases so this has been taken by many entomologists as an opportunity to pay much more attention to molecular species identification. In this way, the misery and helplessness of today's taxonomists is already becoming tomorrow's virtue for many younger colleagues, which we already take into account in this catalog with DNA barcoding (mtCOI).
Identification keys as we know them from the past have long since become obsolete in many cases in view of Chat GPT and (self-)learning AI algorithms for image acquisition. This will also be true for most (larger) weevils in the foreseeable future (Stüben et al. 2019, epilogue). However, in order for algorithms to be used for image pattern recognition big data and a very large pool of images must be available. For the time being, this cannot be assumed to be the case for the Nanophyinae, especially the tiny Corimaliini. Images of each species (Habitus & Aedeagus*) as well as dichotomously constructed differential images for species identification will therefore be with us for some time in the case of nano-insects. On the other hand, there is no question that both paths of development, the visual and molecular perspective, will pave the way for largely automated species identification in the medium term and, like barcoding (or whole genome sequencing), this opens up a great opportunity for all of us: to leave behind the years of familiarization with the identification of species - which can hardly be conveyed to the younger generation - and to devote ourselves as scientists and entomologists to our real tasks again: biology, ecology; ethology and phylogeny of species - and this applies especially to the Corimaliini!
The current image key to the Corimaliini can be viewed here:
https://nanophyinae.curci.de/pdf_key/corimaliini-key.pdf
Peter E. Stüben & Karel Schön
01-JAN-2024
1Dr. Peter E. Stüben, Curculio Institute, Hauweg 62, 41066 Mönchengladbach, Germany.
E-Mail: p.stueben@t-online.de
2Ing. Karel Schön, Valdštejnská 2108, 436 01 Litvínov, Czech Republic.
E-Mail: karelschon@outlook.cz
(Both are members of the CURCULIO Institute)
Coming soon: New insights and phylogenetic studies on the Western Palaearctic Corimaliini...
References
- Alonso-Zarazaga, M.A. (1989): Revision of the supraspecific taxa in the Palaearctic Apionidae Schoenherr, 1823. 1. Introduction and subfamily Nanophyinae Seidlitz, 1891 (Coleoptera, Curculionoidea). - Fragmenta Entomologica, Roma 21 (2): 205-262.
- Alonso-Zarazaga, M.A. (2014): 3.6.4 Nanophyinae Gistel 1848. In: Richard A. B. Leschen & Rolf G. Beutel (Hrsg.): Handbook of Zoology. Arthropoda: Insecta. Coleoptera, Beetles, Vol. 3. Morphology and Systematics (Phytophaga). Walter De Gruyter, Berlin/Boston 2014, S. 416–423
- Formánek, R. (1916): Die Rüßlergattung Nanophyes und ihre Arten. – Wiener Entomologische Zeitung 35: 65 - 79.
- Gerling, D, Kugler, J. & Lupo, A. (1976): The galls of insects and mites that occur on Tamarix spp. in Israel and the Sinai. - Bollettino del Laboratorio di Entomologia Agraria Filippo Silvestri (Portici) 33: 53-79.
- Kovalev, O. V. (1995): Co-Evolution of the Tamarisks (Tamaricaceae) and Pest Arthropods (Insecta; Arachnida: Acarina), with Special Reference to Biological Control Prospects. vii + 109 pp. Pensoft, Sofia-Moscow- St. Petersburg.
- Sobhian, R. Fornasari, L., Rodier, J. S. & Agret, S. (1998): Field Evaluation of Natural Enemies of Tamarix spp. in Southern France. – Biological Control 12, 164–170.
Acknowledgement
We would like to thank Adrian Fowles (Wales) for his linguistic review of the texts and numerous suggestions.
Nanophyinae of the Western Palearctic - Part B:
Presentation and Image key
of the Nanophyini
by Peter E. Stüben1
Suggested citation: Stüben, P.E. (1.1.2024):
Nanophyinae of the Western Palearctic - Part B: Presentation and Image key of the Nanophyini. - Le Charançon. Catalogues & Keys No. 7, Curculio-Institute, Mönchengladbach, Germany.
ISSN 1864-0699. [accessed: dd-mm-yyyy]
The current image key to the Nanophyini can be viewed here: https://nanophyinae.curci.de/pdf_key/nanophyini-key.pdf
B. Nanophyini
01-JAN-2024
Introduction
In recent years, Karel Schön (Czech Republic) has already presented a key (Czech / English) for the 13 Central European species (Schön 2016). A further 12 West Palearctic species or subspecies – probably including two new species that will be described soon – are to be taken into account here.
However, the breakdown of the total of 25 extremely variable taxa is anything but a piece of cake. It makes little sense, as Dieckmann (1963) has already commented, to list and describe color characteristics and elytral patterns in all their intraspecific variants in this key. Apart from morphological characteristics, this will not contribute in any way to species identification for the most highly variable species. On the other hand, this is also true for Dieckmann's favoured, highly stylized, drawings of the rostrum (Dieckmann 1963) with or (almost) without a median keel, which - unlike his illuminating outline drawings of the habitus - allow only at best an approximate assignment of specimens under the microscope to species. Therefore, with few exceptions, the description of the keel-like elevations on the upper side of the rostrum (allegedly absent, present only up to the antennal insertions, or even continued up to the tip) has been almost completely omitted in view of the variability seen in just a single population of a species. An exception in this regard is the morphological differentiation of species into the genera Pericartiellus and Dieckmanniellus by Alonso-Zarazaga (1989), which is also difficult to understand - species, which, however, live on different host plant families (Crassulaceae and Lythraceae).
Similar to the Corimaliini, on the other hand, the almost unvarying aedeagi and tegmen allow an unambiguous and quick species assignment in many cases. But, again, it was Dieckmann who rightly pointed out the ‘measuring acrobatics‘ of some of his predecessors. Many Nanophyini species were, at the first (but ‚understated‘) glance, just 0.7 to 1.0 mm in size, without taking the trouble to measure them exactly. Even today, one still finds ratios of elytra lengths to elytra widths in the identification literature, which are simply not correct and mostly 'clearly exaggerated' numerical values that havepassed on unquestioningly from researcher generation to researcher generation. (As the pictures in this key make clear, there are in this respect e.g. no big differences in the elytral lengths of N. brevis brevis - supposedly as long as wide - and N. globiformis - supposedly 1.5x (!) longer than wide). All these specifications must be readjusted based on focus stacking images.
While these concerns illuminate rather marginal, didactic aspects, the splitting of the 33 West Palaearctic Nanophyini species into no less than 7 genera, which is 'morphologically' hardly comprehensible, should finally be critically questioned and not passed on to the next generation of entomologists without comment in recourse to old traditions (Alonso-Zarazaga 1989). Here today, molecular research is undoubtedly the means of first choice (because an ecological systematics oriented to only a few host plant families, especially Lythraceae and Crassulaceae, rather speaks against such genus splitting)! Even if it turn out surprisingly that there really are 7 clearly separated clades in the molecular Bayesian Nanophyini tree, there is still justified hope that reason will prevail here: with so few species why don't we leave it at "informal groups" or - if it has to be - at subgenera? What is the real value of the current trend towards more and more taxa of higher orders and, above all, what is the increase in knowledge? - We will therefore turn to these questions and possible 'molecular' answers in a future step, using the example of the Corimaliini and Nanophyini in the next few years
The type material for some very rare species could not be viewed or borrowed. This is especially true for the Pic collection in the Muséum national d'Histoire naturelle (Paris), which has been "inaccessible" for taxonomists for several years.
Comment from the author
Allow me one critical comment at this point: It is more than a scandal that, in view of the loss of species in our latitudes and the last remaining species experts and taxonomists, the museum in Paris really has nothing better to do than to discontinue the loan of types (and instead recommend a trip to Paris for frail entomologists). However, it would be even more disastrous if, in return, German museums were to take this as a reason to stop their work in order to save money: making the material available to science that was archived there for all of us for centuries. It doesn't take much imagination to suspect the gravediggers of classical morphological taxonomy here. However, it takes even less imagination to oppose the triumph of those molecular biologists who have long since begun to see molecular barcoding as the perfect substitute for types. Their slogan: "Go ahead and make yourselves superfluous!"
Therefore, the key to the Western Palaearctic Nanophyini is still in an incomplete state. The Western Palearctic species unknown to me to date include:
- Dieckmanniellus nigritarsis (Aubé, 1862), Nanophyes,
E: France, Italy (Sardegna, Sicilia) - Nanomimus yvonnae (A. Hoffmann, 1932), Nanophyes,
E: France [probably the older name of a younger synonym: Nanomimus smreczynski (Dieckmann, 1963); see commentary there!] - Nanophyes aegyptiacus Pic, 1900
N: EG - Nanophyes longipilis Pic, 1919
E: "Caucasus - Nanophyes pallidipes Pic, 1897
E: "Caucasus" - Pericartiellus luteonotatus (Pic, 1919), Nanophyes
E: "Caucasus" - Pericartiellus palaestinus (Pic, 1900) Nanophyes
A: Israel
The current image key to the Nanophyini can be viewed here:
https://nanophyinae.curci.de/pdf_key/nanophyini-key.pdf
Peter E. Stüben
01-JAN-2024
1Dr. Peter E. Stüben, Curculio Institute, Hauweg 62, 41066 Mönchengladbach, Germany.
E-Mail: p.stueben@t-online.de
(Peter Stüben is a member of the CURCULIO Institute)
Coming soon: New findings and phylogenetic studies on the Western Palaearctic Nanophyini...
References
Alonso-Zarazaga, M.A. (2014): Nanophyinae Gistel, 1848, pp. 416-423. – In: Leschen, R.A.B. & Beutel, R.G. (eds.): Handbook of Zoology, Arthropoda: Insecta: Coleoptera, Beetles, Vol. 3. Morphology and systematics (Phytophaga), Berlin, Boston, 469 pp.
Alonso-Zarazaga, M.A. (1989): Revision of the supraspecific taxa in the Palaearctic Apionidae Schoenherr, 1823. 1. Introduction and subfamily Nanophyinae Seidlitz, 1891 (Coleoptera, Curculionoidea). - Fragmenta Entomologica, Roma 21 (2): 205 - 262.
Dieckmann, L. (1963): Die mitteleuropäischen Arten der Gattung Nanophyes Schönh. nebst einer neuen Art aus Bulgarien. (Coleoptera, Curculionidae). – Reichenbachia 23: 169 - 194.
Formánek, R. (1916): Die Rüßlergattung Nanophyes und ihre Arten. – Wiener Entomologische Zeitung 35: 65 - 79.
Hoffmann, A. (1958): Coléoptères Curculionides, 3. Teil. - Faune de France, 62: 1233-1258.
Schön, K. (2016): Icones insectorum Europae centralis. Coleoptera: Brentidae: Nanophyinae. – Folia Heyrovskyana, Series B 28: 1 - 21.
Sprick, P. & Schmidl, J. (2005): Checkliste der Rüsselkäfer Bayerns. – Beiträge zur bayerischen Entomofaunistik 7: 77-95.
Stüben, P.E. (2023): Schlüssel der westpaläarktischen Nanophyini (Coleoptera: Curculionoidea: Nanophyinae). – Weevil News 111.
