Lepidoptera

Kristensen, Niels P., Scoble, Malcolm J. & Karsholt, Ole, 2007, Lepidoptera phylogeny and systematics: the state of inventorying moth and butterfly diversity, Zootaxa 1668, pp. 699-747: 731-734

publication ID

http://doi.org/ 10.5281/zenodo.274044

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lsid:zoobank.org:pub:DD4CF392-6AFE-4182-9BB7-6057FC3F64B7

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http://treatment.plazi.org/id/039C87C3-FFED-DC07-FF3E-E5E7FC7AFC62

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Plazi

scientific name

Lepidoptera
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Lepidoptera  systematics: current and future research priorities

It will require very considerable resource investments on the part of the systematic lepidopterists' community to cope with the predicted doubling-to-quadrupling of the recognized species numbers. Not only will the descriptive/analytical phase itself be demanding, so will also the initial phases, viz., specialist collecting in all parts of the world (evidently prioritizing species-rich ecosystems vulnerable to, or even acutely endangered by, accelerating human activities) and the intermediate phase of specimen processing that can render the procured material accessible to practising taxonomists. Exactly because of the easily damageable scale vestiture which is the hallmark of Lepidoptera  , a suite of otherwise useful automated entomological collecting devices (such as Malaise and interception traps) are of limited usefulness for these insects; also, time-consuming preparation procedures already during the field work are near-mandatory for truly satisfactory results, a least in the case of the smaller micro-moths. Moreover, as already mentioned, this vestiture obscures many of the traits that are useful for assigning specimens to family-group taxon, and it thereby impedes non-specialist sorting of museum accessions to the level at which most taxonomists are working.

It is difficult to estimate the number of entomologists presently engaged in research on Lepidoptera  systematics. Most professional workers who make contributions in this field have demanding commitments of other kinds as well (teaching, curatorial, managerial) as have, of course, the amateur taxonomists. The figure for full-time research equivalents of the contemporary Lepidoptera  systematics workforce is, therefore, very much lower than the number of authors of publications on the subject. The specialist coverage of lepidopteran subgroups is somewhat uneven, and the exceedingly low number of taxonomists working on the most speciesrich families, such as Pyralidae  , Crambidae  , Geometridae  and Noctuidae  (Holarctic faunas excepted), is a particular problem. Lepidopterists make no exception to the gloomy picture of the age-structure in the taxonomists' community as a whole, as underscored in the afore-mentioned Gaston & May survey: to our knowledge there are at present disturbingly few Ph.D. students in Lepidoptera  systematics worldwide.

With so much ground still to be covered, and so few workers to cover it, contemporary systematists working on the largest insect orders should pay considerable attention to the criteria on which research priorities should be set. To those systematists who are employed by primarily non-taxonomically orientated institutions (and they constitute a considerable proportion of the grand total), priorities naturally come in the form of taxa which contain economically important species, or which prove to be convenient target taxa for sampling and monitoring in biodiversity assessment/nature management contexts. Moreover, of course, workers in such institutions are usually supposed to deal with geographically restricted faunas.

But what are the guidelines for the few systematists in those universities or major  research museums, where licentia academica is still supposed to prevail? Arguably phylogeny-based generic/genus group classifications of higher taxa (family/subfamily level) should be among the highest contemporary priorities. Good examples of such classifications of a global scope of genus-rich taxa are Kitching's (1987) treatment of Noctuidae-Plusiinae and Miller's (1991) of Notodontidae  . A number of studies of this kind have been restricted to regional faunas; examples are the treatments of Holarctic sesiids ( Naumann 1971 / 1977) and Australian tineids ( Robinson & Nielsen 1993), oecophorids ( Common 1994, 1997, 2000) and olethreutine tortricids ( Horak 2006). In spite of their limitations such regionally based phylogenies may prove useful platforms for developing global classifications. Similarly, purely descriptive, but comprehensive and well-illustrated generic accounts, whether global (e.g., that of Pitkin et al. 2007 on Geometrinae-Pseudoterpini) or regional (e.g., that of Pitkin 2002 on Neotropical Geometridae-Ennominae) are invaluable stepping stones on the way towards the desirable phylogeny-based classifications.

Classificatory 'skeletons' of the said kinds are essential for providing appropriate frameworks for specieslevel revisionary taxonomy. Opinions are divided about priority setting in the latter approach, but few biologists will contest that describing all species and classifying them in accordance with their position on "the one true tree of life" is the ultimate goal of systematics. Genuine progress will depend on a balanced partition of resource investments in bottom up projects in the form of species-level revisions, and top down projects in the form of generic/genus group classifications of higher taxa (family/subfamily level). In this respect contemporary systematic lepidopterology is no different from contemporary systematization of other groups of organisms. What is special about systematization of Lepidoptera  as well as the other 'megadiverse' insect orders is the sheer magnitude of the task. Development of the afore-mentioned classificatory 'skeletons' of the largest family-group taxa will be undertakings which will require time investment (material gathering, preparations and descriptive/pictorial documentation of morphological characters, gene sequencing, phylogenetic analyses, etc) beyond the capacity of individual researchers, and they will be practicable only to research teams with access to major  institutions with truly comprehensive collections. If, therefore, we are to have the much needed globa l classificatory 'skeletons' for e.g., the 'catocaline' or 'hadenine' noctuids, ennomine or larentiine geometrids, phycitine or pyraustine pyraloids etc., etc., then we shall need initiatives to this effect being supported at the managerial level in major  research museums, or perhaps more realistically in consortia thereof. Such initiatives would expectedly come in the form of funded projects with X principal investigators, Y postdocs, Z research students, A technicians and B operation money. Projects of this kind have so far not been commonplace in systematic entomology, but they are what progress in several other scientific disciplines is currently dependent on.

There is, currently, considerable interest in the role of the internet in taxonomy, although the diversity of approaches suggests an area in a state of rapid evolution and exploration. The semi-structured and formalised nature of taxonomic content lends itself to being transposed into database format, rendering it potentially far more accessible and flexible. But the landscape of taxonomic cyberspace is complex. Taxonomic data on the web fall into a few main categories. Ever more descriptive taxonomy is becoming available online as pdf files through electronic journals or journals, like this one, that are largely electronic. Although digital, the medium here remains, like paper, a fixed one. Fixed medium has the benefit of being archivable and helps protect nomenclatural stability. Contributions can also be quality controlled by the traditional review process. But like paper publications, those in pdf format lack the capacity to be updated other than by further and separate publication of results. By contrast, web-pages posted as HTML are capable of being updated, but the ease by which they can be created and posted on the internet means that quality is both highly variable and typically not indicated to readers. Many such websites for Lepidoptera  are accessible on the web. An experiment to provide comprehensive web-based taxonomic revisions in a more controlled environment is the aim of the CATE project (www.cate-project.org), which is being developed currently. One of the two taxa used to trial and demonstrate the CATE method and principles is the Sphingidae  (ca 1400 species). Revisions created through the CATE system (see Godfray et al., in press; Scoble et al., in press) are updatable: anyone with access to the web can submit a proposal to a CATE website. Proposals may range from simple geographical records to descriptions of new taxa. However, peer-review and editorial procedures are built into the workflow so that quality control can be maintained. Less structured, but highly updatable, mechanisms for taxonomy are ‘scratchpads’ (V. Smith, pers. comm.; www.editwebrevisions.info/scratchpadSiteList). These are based on a content management system and are intended to encourage web-based collaboration between taxonomists. The most recent large scale and highly ambitious international project called the Encyclopedia of Life (see www.eol.org) is aimed at building a web-page for each of the ca 1.8 million species. Aggregation (‘mashup’) technology will be used to source taxonomic information from across the web with the intention of encouraging taxonomists to structure and edit the resulting content.

The future of taxonomy looks increasingly as if the internet will eventually predominate as the platform for providing access to information about biodiversity, including all kinds of relevant taxonomic and other data. Software is ever more able to provide users with the data they require in a customised form, such as global or regional checklists, maps of species distributions based on point data, and descriptions of species. The main challenges in this endeavour are generating collaboration among a scattered and variable community, developing the capacity to atomise data to structure underlying databases, and quality control. There is an increasing expectation that information of all kinds should be available on the web. The taxonomic impediment shows little sign of being resolved by more conventional means and the best chance of integrating the effort of all Lepidoptera  taxonomists, be they professional or not, is likely to be through collaboration in cyberspace. It will take a new generation of taxonomists and technology (that of the semantic web particularly) for this vision to be realised, but it is more likely to bear fruit than a more dirigist approach, which has largely failed to produce an organised and structured way of doing taxonomy. Information and Communication Technologies (ICTs) do not merely provide a more accessible and flexible medium for posting data. Rather they provide a highly accessible (virtual) environment for community involvement by anyone with an internet connection. ICTs profoundly change the collaborative and managerial landscape for improving taxonomic coverage. Optimizing the outcome of this innovation will require a judicious balance between initiatives coming through bottom up engagement by practising taxonomists (of whatever status) and from top down priority setting by management within the systematists' community.

Two final points concerning taxonomic research strategy should be mentioned as particularly pertinent to lepidopterology because of its sizeable amateur contingent. The role non-professionals play and continue to play in Lepidoptera  taxonomy cannot be overstated. Duckworth, Genoways and Rose (1993) estimated that there were around 2.5 billion specimens (of all taxa) in natural history collections across the world. (L. Speers in Scoble 2003 suggested a range of 1.5 to 3 billion.) Being such a popular group, the Lepidoptera  component of this huge estimate is surely significant. Amateurs have contributed to this collective resource in two ways. First, they have supplied institutions with specimens to such an extent that many great holdings would be bereft without the material contributions they have made over more than two and a half centuries. And amateurs follow the tradition and continue to gift material. Second, many specimens continue to be held in private collections to this day—some such holdings competing in terms of importance with collections in state-owned collections. Furthermore, most amateur lepidopterists are not just collectors, but also knowledge creators through their records and publications—publications that are often written in collaboration with professional workers. Amateurs form, then, a significant component of our collective taxonomic knowledge base. Given the popularity of Lepidoptera  , their contributions are conspicuously high when we look across all taxa.

Two concerns deserve attention. One is that institutions need to be prepared to cope with substantial amounts of material when they are gifted or bequeathed. Storage space and curatorial effort to deal with large amounts of material need careful planning. Such planning includes the capacity to finance the requirements. A second problem arises when provision has not been made for a private collection when the owner dies. Beneficiaries may not share the same concern for such a collection or may fail to understand its scientific value. It is by no means unknown for collections to be broken up and sold on the open market to maximise their financial returns. The issue of stewardship is a responsibility for the lepidopterist community at large—amateur, professional and institutional.

As noted above, the rate of description of new taxa by professional taxonomists broadly has decreased as the result of adoption of stricter working standards and the emphasis on revisionary taxonomy. However, new species continue to be described without peer-review and without being placed in a revisionary context. It is a major  challenge to professional lepidopterists in leading institutions, which are comparatively well-resourced, to establish close links with the communities of amateur lepidopterists, and less privileged professionals, to optimize the utilization of the considerable labour potential in these communities. If we are to understand and describe, to effect, the diversity of the Lepidoptera  , all lepidopterists need to unite in a common effort. Given the number of enthusiasts, these goals are likely to be within our reach.