Евразиатский энтомол. журнал 15. Прил. 1: 43–47 © EUROASIAN ENTOMOLOGICAL JOURNAL, 2016 On some approaches for estimating local species richness of parasitoid Hymenoptera Î íåêîòîðûõ ïîäõîäàõ ê îöåíêå ëîêàëüíîãî âèäîâîãî áîãàòñòâà ïàðàçèòè÷åñêèõ ïåðåïîí÷àòîêðûëûõ (Hymenoptera) V.E. Gokhman Â.Å. Ãîõìàí Botanical Garden, Moscow State University, Moscow 119234 Russia. E-mail: [email protected]. Ботанический сад Московского государственного университета, Москва 119234 Россия. Key words: hymenopterous parasitoids, local species richness, taxonomic revision, molecular characters, DNA barcoding, chromosomes, karyotypes, faunistic survey. Ключевые слова: паразитические перепончатокрылые, локальное видовое богатство, таксономическая ревизия, молекулярно-генетические признаки, ДНК-баркодинг, хромосомы, кариотипы, фаунистический обзор. Abstract. Main approaches for estimating local species spite an increasing advent of the so-called modern meth- richness of parasitoid Hymenoptera, i.e. methods of classical ods in systematics, i.e. molecular, chromosomal and taxonomy, certain modern techniques as well as surveys of analogous approaches [Heraty, 2003; Gokhman, 2009]. regional faunas are discussed and compared. Additions of As far as newly described species are concerned, newly recorded species to local inventories due to faunistic additions of these taxa can result from taxonomic stud- studies usually exceed those resulting from taxonomic revi- sions either fully based on morphological characters or also ies, including generic revisions and descriptions of sep- using chromosomal, molecular and/or similar ones. Neverthe- arate species. In turn, these works are either entirely less, the use of DNA barcoding and other modern techniques based on morphology or can include data obtained by will undoubtedly revolutionize both local and global studies modern techniques. On the other hand, extensive re- of parasitoid faunas. search using contemporary methods in systematics (e.g. DNA barcoding) as well as detailed surveys of regional Резюме. В работе обсуждаются и сравниваются ос- faunas also can substantially increase the number of новные подходы к оценке локального видового богатства recorded species [Quicke, 2015]. In the present paper, I паразитических перепончатокрылых: методы классичес- am going to review and compare these sources of local кой таксономии, различные современные методики, а так- species estimates in more detail. же обзоры региональных фаун. Пополнение локальных This paper is dedicated to the 70th anniversary of an списков вновь зарегистрированными видами за счет фау- outstanding Russian entomologist, Professor Arkadiy нистических исследований обычно превышает таковое, S. Lelej, who has made an enormous contribution to the являющееся результатом таксономических ревизий, ко- taxonomic and faunistic study of the order Hy- торые целиком основаны на морфологических особеннос- тях, а также используют наряду с этим хромосомные, menoptera in many territories including the Russian Far молекулярно-генетические и/или им подобные признаки. East [Lelej, 2012]. Тем не менее, использование ДНК-баркодинга и других современных методов, несомненно, революционизирует Methods of classical taxonomy как локальные, так и глобальные исследования фаун па- разитоидов. Taxonomic treatments can change the existing spe- cies estimates in a number of ways. For example, my Introduction restricted experience of worldwide taxonomic revisions of a few relatively small parasitoid genera shows that Parasitic wasps are one of the most diverse, taxo- most of these studies can only moderately increase, if nomically complicated and economically important at all, the number of known species [Gokhman, 1994; groups of insects, which currently includes far more Baur et al., 2014]. However, a revision of another moder- than 70 thousand described species [Rasnitsyn, 1980; ate-sized genus, Trachyarus Thomson (Ichneu- Aguiar et al., 2013]. However, various estimates of local monidae), has approximately doubled the number of its species richness of parasitoid Hymenoptera can strongly species in the Palaearctic region [Gokhman, 2007]. Nev- differ in terms of the number of recorded species both in ertheless, many of them were mostly or entirely restrict- the temperate zone and in the tropics [Rodriguez et al., ed to less studied territories, such as the mountain 2013; Tselikh, 2014]. Moreover, these estimates are of- ranges of Central Europe or the Russian Far East, from ten based on external morphology [Quicke, 1997] de- which many other parasitoid species were described 44 V.E. Gokhman during the last few decades (see e.g. [Kostjukov, 1995; [König et al., 2015]. In this case, karyotypic information Belokobylskij, Tobias, 2007]). In addition, Elzinga et al. therefore provided the first direct morphological sup- [2011] showed that molecular data obtained from indi- port of the presence of cryptic species. It is also worth viduals of several Trachyarus species did not confirm noting that even crossing experiments are not always morphology-based species borderlines, although no able to reveal the true nature of the taxa under analysis, formal taxonomic change was made since that publica- because, for example, members of some populations tion. The data presented in this chapter, together with that belong to different species of the L. distinguendus many analogous studies, therefore suggest that gener- complex can produce hybrid offspring under certain ic revisions and descriptions of separate species usual- circumstances. Nevertheless, hybrid individuals will be ly lead to a relatively slow increase in the amount of immediately recognized due to their intermediate chro- local species records. mosome number and specific karyotype structure. At first glance, this continuous accumulation of Both above-mentioned complexes of cryptic species, species numbers due to taxonomic treatments must be i.e. A. calandrae and A. quinarius as well as L. dis- the predominating source of addition to local species tinguendus s.l., were supposed to have relatively broad lists, because, at least in theory, only these studies can host ranges. However, a detailed investigation has shown adequately and reliably describe the existing biodiver- that each of these complexes contained different species, sity. However, in reality we usually observe the reverse which preferred to attack either beetles of the family pattern (at least in the better-studied temperate zone), Dryophthoridae and a few similar taxa, or members of the i.e. a strong increase in the number of previously de- family Anobiidae [Baur et al., 2014; König et al., 2015]. scribed species due to faunistic research [Quicke, 2015], Recently, a rapidly increasing amount of analogous pa- as opposed to any recent taxonomic study. This can be pers mainly based on the results of molecular research explained by the fact that revision of a poorly studied [Zhang et al., 2011; Chesters et al., 2012; Derocles et al., but potentially speciose taxon is usually very difficult, 2016] also demonstrates that many examined parasitoid time-consuming and subject to obvious flaws, and there- species with wide host ranges are in fact complexes of fore studies of that kind are relatively rare (but see e.g. cryptic species. These results suggest that situations of [Kostjukov, 1995]). this kind can be far more widespread than it was sup- posed before. This is especially true for endoparasitoids Studies using modern techniques and/or tropical groups which generally tend to have narrower host ranges [Quicke, 2015]. Specifically, DNA Since «host races» or «strains» are widespread in barcoding along with information on bionomics of differ- parasitoid Hymenoptera [Clarke, Walter, 1995], it is par- ent populations of apparently the same polyphagous ticularly important to know whether these «races» rep- morphospecies, Apanteles leucostigmus (Ashmead, resent either subpopulations of the same species or 1900) (Braconidae), from a particular area of Costa Rica different, although often cryptic, species. To distin- showed that their studied individuals actually belonged guish between these possibilities, environmentally in- to at least 36 putatively undescribed monophagous or dependent characters (e.g. DNA and/or karyotype struc- strictly oligophagous species [Smith et al., 2008]. Fur- ture) must be studied. For example, a few years ago thermore, another molecular and bionomic study [Kenyon [Baur et al., 2014] we were able to describe a cosmopol- et al., 2015] demonstrated that each of the three examined itan synanthropic species, Anisopteromalus quinarius morphospecies of the genus Horismenus Walker (Eu- Gokhman et Baur, 2014 (Pteromalidae), which was ini- lophidae) in the southern USA and Mexico also har- tially differentiated on the basis of karyotypic study boured at least one cryptic species. from a presumably well-known and also cosmopolitan An approach based on extensive molecular research A. calandrae (Howard, 1881) with a similar biology. and subsequent morphological description of taxa re- Moreover, as soon as the presence of the two separate vealed during that study (the main components of the species was established, many interspecific differences so-called turbo-taxonomy [Riedel et al., 2013]; also see in morphology, DNA structure, life-history strategies below) therefore can substantially increase the number etc. immediately began to come to light (reviewed in of described species, especially in tropical regions, which [Baur et al., 2014]). Furthermore, an