COBISS: 1.01 HISTORICAL BIOGEOGRAPHy OF SUBTERRANEAN BEETLES – “PLATO’S CAVE” OR SCIENTIFIC EVIDENCE? ZGODOVINSKA BIOGEOGRAFIJA PODZEMELJSKIH HROŠČEV – »PLATONOVA JAMA« ALI ZNANSTVENI DOKAZ? Oana Teodora MOLDOVAN1 & Géza RAJKA1 Abstract UDC 595.76:551.44 591.542 Oana Teodora Moldovan & Géza Rajka: Historical bioge-ography of subterranean beetles – “Plato’s cave” or scientifc evidence? Te last two decades were particularly prolifc in historical bio-geography because of new information introduced from other sciences, such as paleogeography, by the development of quantitative methods and by molecular phylogeny. Subterranean beetles represent an excellent object of study for historical bio-geography because they are the group with the best representa-tion in the subterranean domain. In addition, species have re-duced mobility, display diferent degrees of adaptations to life in caves and many specialists work on this group. Tree processes have shaped the present distribution of the tribe Leptodirini (Coleoptera Cholevinae) in the world: dispersal, vicariance, and extinction. Terefore, three successive stages can be estab-lished in the space-time evolution of Leptodirini: (1) disper-sal from a center of origin in the present area(s); (2) dispersal, extinction and vicariance among the present area(s); and (3) colonization and speciation in the subterranean domain. Te Romanian Leptodirini, especially those from western Carpath-ians is examined with respect to these processes. Teir pattern of distribution in diferent massifs and at diferent altitudes is discussed, with possible explanations from a historical biogeo-graphic point of view. Key words: Historical biogeography, cave beetles, Leptodirini, Romania. Izvleček UDK 595.76:551.44 591.542 Oana Teodora Moldovan & Géza Rajka: Zgodovinska biogeo-grafja podzemeljskih hroščev – jama »Platonova« ali znanstveni dokaz? Zadnji dve desetletji sta bili za historično biogeografjo še posebej bogati, predvsem zaradi številnih novih informacij in dognanj paleogeografje, razvoja kvantitativnih metod ter molekularne flogenije. Podzemeljski hrošči so odličen model za proučevanje historične biogeografje, saj spadajo v tisto skupino organizmov, ki je v podzemlju najpogosteje zastopana. Hrošči iz podzemlja imajo zmanjšano mobilnost, razvili so številne načine prilagoditev na življenje v tem habitatu. S to skupino organizmov se ukvarjajo številni raziskovalci po svetu. Na trenutno razširjenost vrst rodu Leptodirini (Coleoptera Cholevinae) so vplivali trije procesi: disperzija, vikarianca in izumiranje. V prostorsko-časovnem razvoju Leptodirinov se lahko pojavijo tri zaporedne faze: (1) razširjanje iz izvornega mesta na sedanje/a poročje/a, (2) razširjanje, izumrtje in vi-karianca med sedanjimi območji, ter (3) kolonizacija in spe-ciacija v podzemeljskih habitatih. S tega vidika smo proučevali Leptodirine iz Romunije, s poudarkom na vrstah iz zahodnih Karpatov. V prispevku je opisan vzorec razširjenosti hroščev v različnih gorskih predelih ter na različnih nadmorskih višinah. V razpravo smo z vidika historične biogeografje vključili tudi verjetno interpretacijo. Ključne besede: zgodovinska biogeografja, speleobiologija, Leptodirini, Romunija. 1 Institutul de Speologie “Emil Racovitza”, Cluj Department, Clinicilor 5, P.O.Box 58, 400006 Cluj-Napoca, Romania; e-mail: oanamol@hasdeu.ubbcluj.ro Received/Prejeto: 04.12.2006 TIME in KARST, POSTOJNA 2007, 77–86 OANA TEODORA MOLDOVAN & GéZA RAJKA INTRODUCTION Te Greek philosopher, Plato (428-348 BC), in his book, Te Republic, tells about Socrates teaching lessons of wisdom. One of these is about human beings kept in a cave with one source of artifcial light coming from behind. Te idea of the allegory is that we might have a wrong perception about what is reality, or, that most people live in a world of ignorance because they rely only on their narrow experiences and rely on their own truths. Another possible interpretation of Plato’s allegory is that we might be wrong if we consider concepts and perceived objects on the same level. Historical biogeog-raphy is a science based on concepts and suppositions and there is no direct evidence available in the attempt to build credible scenarios about past and present animal distributions. However, development of this science on circumstantial evidence ensures better understanding of the objects under study. Biogeography studies geographic distribution of organisms. Tis simple defnition describes an extreme-ly complex science. Geology, geography and various branches of biology defne a discipline that is continu-ously developing. Te Swiss botanist de Candolle (1820) was the frst to speak about ecological and historical bio-geography as separate branches of biogeography. Tey difer mainly in what concerns spatial and temporal scales. Historical biogeography reports on evolutionary processes over millions of years, mostly on a global scale (Crisci 2001). Pleistocene glaciations are sometimes col-lectively considered a separate or intermediary branch between historical and ecological biogeography. Te last two decades were particularly prolifc in papers on historical biogeography due largely to new information introduced from other sciences, such as paleogeography, by the development of quantitative methods (Morrone & Crisci 1995) and by the development of molecular phy-logeny. Morrone & Crisci (1995) and Crisci (2001) defne the biogeographic processes that modify the spatial distribution of taxa and recognize nine basic approaches to historical biogeography: (1) Identifcation of the centers of origin, or the existence of “Eden” where diferent lineages of all living beings moved from by dispersal to the present areas; (2) Panbiogeography, which plots the distribution of diferent taxa on maps, connecting their distribution areas together with lines; (3) Phylogenetic biogeography and (4) Cladistic biogeography, both as-suming correspondence between taxonomic relation-ships and area relationships; (5) Parsimony analysis of endemicity that classifes areas by their shared taxa; (6) Event-based methods; (7) Phylogeography; (8) Ancestral areas; and (9) Experimental biogeography. Te evolution of subterranean animals is a pro-cess that can be presumed but not directly proven. Te origin, migration and colonization of the subterranean realm can be explained by a multitude of arguments and indirect evidences which support or falsify the proposed hypotheses. Te role of historical biogeography is to ex-plain the way subterranean animals gain their present distribution, using available data from biology and other sciences. Trough this process, we can gain a new insight into the mechanisms of colonization that have afected some of the extreme areas or habitats which exist in the subterranean domain. Chronologically, the history of a taxonomic group (like the beetles), or of a phyletic lin-eage must begin with its origin. To understand present distribution patterns and why some areas were colonized and others were not, we must frst establish temporal and spatial reference points. SUBTERRANEAN COLEOPTERA ExAMPLES IN HISTORICAL BIOGEOGRAPHy Tere are several reasons why subterranean beetles rep-resent an excellent object of study for historical biogeog-raphy: 1. Tey are the best represented group in the subter-ranean karst environment or domain, with many species inhabiting caves and the mesovoid shallow substratum (also called MSS, see Juberthie et al. 1980); 2. Most species are terrestrial and therefore have re-duced mobility; and while they are not limited to limestone/karst areas, most taxa inhabit caves; 3. A group whose representatives that display dif-ferent degrees of adaptations to life in caves. Some of 78 TIME in KARST – 2007 the lines have endogean and hypogean species, of which the last is more or less adapted to subterranean environment. 4. Tey are a well known group, with many spe-cialists studying various aspects of their biology, in-cluding taxonomy, adaptations, behavior and molecu-lar phylogeny. Two families encompass most of the world’s subter-ranean beetles, the Trechinae (predator Carabidae) and the Cholevinae (detritivorous and saprophagous Leiodi-dae). Our example is from one of the best represented subterranean tribe of Cholevinae, the Leptodirini (for- HISTORICAL BIOGEOGRAPHy OF SUBTERRANEAN BEETLES – “PLATO’S CAVE” OR SCIENTIFIC EVIDENCE? mer Bathysciini). According to ecological biogeography, Leptodirini are presently distributed in caves, MSS, and other dark and humid habitats, such as litter and moss, mostly in the Palearctic region. For historical biogeography the life of the tribe Lep-todirini begins in the Paleozoic. Te present distribution of Leptodirini can only be explained through wegener’s theory of continent drif and the dispersal, vicariance and extinction processes. Dispersal was the main concept in biogeography before wegener and it explains the area of a population by the mechanisms of migration and crossing over geographical barriers. Extinction means the death of local populations, species or even supraspecifc taxa, and its role in biogeography has not always been recog-nized. Vicariance represents the splitting of an ancestral population into several subpopulations, which will later evolve into species through isolation. Tese three pro-cesses have shaped the present distribution of Leptodiri-ni, and three successive stages can be established in the space-time evolution of this group: I. Dispersal from a center of origin in the present area(s); II. Dispersal, vicariance, and extinction among the present area(s); III. Colonization and speciation in the subterranean domain. Fig. 1: historical biogeography of ancestors of Leptodirini, which migrated from Gondwana (a) together with continental microplates (b), up to Eurasia (c), from there dispersed west to the mediterranean region (d) (modifed from Giachino et al. 1998): areas covered by Leptodirini are represented by grey ellipses. I. According to Giachino & Vailati (1998) the ances-tral family of Oricatopidae inhabited the southern part of the Gondwana supercontinent (Fig. 1). Descending from this family, ancestors of Leptodirini and other tribes migrated at the end of Paleozoic to the what is now the south of Eurasia on the microplates that broke of from Gondwana. Tus, Eurasia was colonized by the ances-tors of Leptodirini 120–150 Ma ago. More recently, 50-65 Ma ago, the group dispersed from northeast, through the central south of Asia, up to eastern Eurasia and then toward the west, along the Mediterranean basin. Epigean individuals successively migrated at the surface, and they were probably pre-adapted to low, constant temperatures and high humidity. Jeannel & Leleup (1952) provide ex-cellent examples for preadaptated ancestors of pselaphid beetles, afer studying high altitude (2000-2900 m) bee-tles on Mount Kivu (Congo). At this level, the species are exclusively humic inhabitants, deepened at few centime-ters in humus, where proper conditions, such as constant temperature (10°C) and high humidity, are fulflled. Tey also described a species with similar adaptations to those inhabiting caves, and also found deeper, under the humus. II. Te second phase of evolution of the group prob-ably happened before the Miocene, and possibly in the late Oligocene. Te dispersal of beetles was from Asia, along the Miocene Alpine chain, whose remains are the Cantabric chain, Pyr-enees, Central French Massif, Alps, Dinarides, Balkans, Pindus chain, Peloponnesus chain, and Pontic Alps. Aferwards, some species colo-nized the Apennines, Jura, Carpath-ians, Rodops, Taurus, Caucasus and Mediterranean inlands (Giachino et al. 1998). Due to major geological and geographical transformations of the landscape, extinction and vicari-ance alternated during the next pe-riods. A large and continuous distribution area of epigean and probably endogean ancestors of Leptodirini that migrated from east was then fragmented, even before the coloni-zation of the subterranean domain. New paleogeographic data about the evolution of the Paratethys from Late Eocene to Pliocene has been re-cently published (Steininger & Rögl 1985, Popov et al. 2004), and it ap-pears that paleoconfguration of the Paratethys shaped the distribution of Leptodirini in Europe. TIME in KARST – 2007 79 OANA TEODORA MOLDOVAN & GéZA RAJKA III. Te third stage is represented by colonization and speciation in the subterranean domain. Two sce-narios were proposed for explaining the mechanisms of underground colonization by epigean and endogean rep-resentatives of various groups of fauna (Holsinger 2000, 2005): (1) Te climatic-relict model, in which preadapted or adapted animals were “forced” or constrained by cli-matic fuctuations to fnd refuge in caves. Te best docu-mented are the Pleistocene glacial-interglacial periods. Eventually, surface ancestors of these successful colo-nizers went extinct. Tis model not only fts temperate climate regions, but also any region that has previously sustained drastic climatic changes. (2) Te adaptive-shif model is mostly applied to lava tubes and tropical karst regions. Proposed by How-arth (1981), it explains the active colonization by pre-adapted ancestors and exploitation of new and empty niches to avoid competition. In this model, adaptation to the new environment does not depends on physical isolation from surface ancestors, as is necessaryin the previ-ous model. In our opinion, colonization of the subterranean domain is an active process, as is the case of empty niche colonization anywhere on Earth. Climatic changes have made important contributions in shaping the distribution areas and breaking of gene fow with surface relatives. Climatic changes can also interrupt energetic fow between surface and subterranean environments, leading to extinction of populations on one or both sides. Tis apparently happened in parts of the world directly af-fected by or covered by Pleistocene glaciers. Bellés (1991) enumerates three reasons for cave colonization: 1. Survival, when external stress determines animals to fnd refugee in caves; 2. Opportunism or colonization of an empty space; 3. Convenience or escaping surface competition which uses the same trophic resources. Peck (1980), Vailati (1988) and Juberthie (1988) proposed scenarios for cave colonization by beetles in the family Leiodidae from North America and Europe. Juberthie’s model uses complex data from studies on the ecology, ethology, genetics, tectonics, paleoclimate and geology of species from the Speonomus delarouzeei complex (Leiodidae: Cholevinae: Leptodirini). Tese species inhabit the MSS and caves on Mount Canigou in the French Pyrenees. Te history of this complex begins with the frst glacial period (2.3 Ma), when high altitude species separated from those at low altitude in the Mediterranean climate. Te two species, S. brucki and respectively S. delarouzeei are characterized by dif-ferent mating behavior, by reproductive isolation and by genetic distance. Tere are also diferences in fecundity and egg development speed at diferent temperatures. Tus, depression of temperature during glaciation se-lected cold resistant genotypes at 1000 m altitude, where annual mean temperature in caves is today 8-10°C, while S. delarouzeei remained at low altitude at temperatures of 14°C. During glacial periods, the forest belt displaced several hundred meters downslope on Mount Canigou and was replaced by steppe vegetation. Cracks, voids, MSS and even caves formed during these periods, while flling happened during interglacial periods. At altitudes between 500 and 1000 m two other species, S. emiliae and S. charlottae, inhabit subterranean habitats. S. emil-iae lives in the MSS at 720 m altitude and is presumed to be the ancestor of S. brucki, and probably populated caves and MSS at diferent altitudes. S. emiliae migrated together with the forests during glacial periods through cracks and MSS down to the present altitude. Te isolation of this species and S. brucki, which formed a population at high altitude, happened by inflling of the MSS and related cracks and crevices. Similar mechanism acted in a previous period for separating S. charlottae from an-cestors of S. brucki. By comparing cuticular hydrocarbons (pheromones that act at short distance or by contact) of species of the S. delarouzeei complex, Moldovan (1997) and Moldovan et al. (2003) obtained a diferent composition in the mountain species S. brucki and the Mediterranean species, S. delarouzeei: shorter chains in the frst one and longer in the second. S. emiliae, at an intermediate altitude, displays a mixture of short and long molecules in the cu-ticular hydrocarbon cocktail. Te result can be explained by temperature infuence on cuticular hydrocarbon com-position. A small variation in temperature can change hydrocarbon composition even from the frst generation (Toolson et al. 1990). For subterranean beetles, adaptation to a new climate can rapidly change the pheromone composition, thus representing an important mechanism of isolation that acts prior to mating. Climate changed the distribution of populations on the slope of Canigou Mountain through migrations of ancestral populations. Consequently, composition in cuticular hydrocarbons changed and preceded genetic mutations. Hydrocarbon changes become stable if climate is maintained over long periods of time, eventually causing isolation of popula-tions and genetic mutations. Terefore, speciation of sub-terranean inhabitants can occur without the existence of physical barriers as proposed in Juberthie’s model. 80 TIME in KARST – 2007 HISTORICAL BIOGEOGRAPHy OF SUBTERRANEAN BEETLES – “PLATO’S CAVE” OR SCIENTIFIC EVIDENCE? REFERENCE MARKS IN HISTORICAL BIOGEOGRAPHy OF ROMANIAN LEPTODIRINI with its geographic position in eastern Europe, Romania is very rich in subterranean fauna for a non-Mediterra-nean country. Tis is due to the special features defned as follows (Moldovan et al. 2005): 1. Te geographic position of the country, with cli-matic and fauna infuences from various regions; 2. Te reduced total surface of limestone; karst areas are distributed along the Carpathians and in Dobrogea, covering only 2% of the surface of Romania (Onac & Cocean 1996); 3. Te high number of caves/surface units; even if the covered surface is so small, the speleological potential is high, with almost 12,000 caves discovered prior to 1989 (Goran 1989); 4. Te distribution of caves at low altitude, with 27% of karstic rocks at altitudes below 500 m and 47% up to 1000 m a.s.l. (Bleahu & Rusu 1965); 5. Te patchy distribution of limestone, with small outcrops scattered especially in western and southern regions. From an ecological point of view Romanian karst forms small continental islands between non-karstic rocks, which act as natural barriers to migration of sub-terranean organisms. Each area represents an island to its inhabitants, which in turn leads to isolation and promotes evolution and formation of new species. Te discovery of the MSS has added new insights into the availability of subterranean habitats, but it can explain only short distance migrations between geographically close areas. Fig. 2: Genera of Leptodirini distributed in the Western and Southern Carpathians of Romania. Te above-mentioned features explain the fragmen-tation of the initial distribution area of surface ancestors of cave animals and speciation processes. It also explains the high number of genera and species for a country at 45° northern latitude. Other countries at the same lati-tude are much poorer in species (e.g., Austria - 2 species, Switzerland – 1 species), even though their limestone ar-eas in these countries are larger. Romanian Leptodirini is represented by 8 genera and 6 subgenera with 50 species and 46 subspecies, com-posed of 1 epigean, 10 endogean and 85 strictly caver-nicolous taxa. Concerning the distribution of subterra-nean beetles, the Romanian Carpathians can be divided in three geographical units: western, Southern and East-ern Carpathians. Te last unit has few caves and no rep-resentatives of Leptodirini. More than half of the karst surface of the country belongs to the western unit (the Apuseni Mountains). Tis region also has the highest de-gree of speciation with 63 taxa in the genera drimeotus, Pholeuon and Protopholeuon. Tese species inhabit caves and the MSS. More genera but fewer species are found in the Southern Carpathians: the epigean monospecifc mehadiella, and the 34 taxa of subterranean banatiola, Sophrochaeta, Closania and tismanella (Fig. 2). Te origin of Romanian Leptodirini is strictly linked to dispersal of ancestral lineages that inhabited the Alpine Miocene chain and to a Paratethys evolution. Jean-nel (1924, 1931) and Decu & Negrea (1969) suggested a Dinaric origin for the Romanian Leptodirini, based on morphological similarities, and es-pecially on features of the male geni-talia. Tis theory explains the colo-nization of the Apuseni Mountains through the Bohemian massif, and direct colonization of the Southern Carpathians from the Dinarides. Diferences between the two phy-letic lineages (western drimeotus and Southern Sophrochaeta) justi-fed this hypothesis, which is also supported by new paleogeographic data (Steininger & Rögl 1985, Popov et al. 2004). when these diferent waves of colonization occurred is questionable, because direct Dina-rides-Carpathians connection is ei-ther very old or too recent. Migration of Asian ancestors of Cholevinae was not possible un-til the Upper Oligocene-Early Mio-cene, when a Dinarian-Pelagonian-TIME in KARST – 2007 81 OANA TEODORA MOLDOVAN & GéZA RAJKA Anatolian landmass was formed, and linked to the rest of Europe by the recurring Slovenian corridor. Tis was the frst connection between the Dinarides and Carpathians and lasted until Lower Badenian (16 Ma) when the Central Paratethys was fooded. It provided the possibility of populating the Southern Carpathians by Dinaric lineag-es, which was also at the time of Carpathian system development (Fig. 3). In Upper Ottnangian (17-18 Ma), the basin of the Paratethys was profoundly altered and a con-nection between the Alps and the Carpathians was estab-lished. Te frst Alps-Bohemian Massif-Carpathians con-nection provided conditions for the Apuseni Mountains colonization through the Bohemian massif. In Lower Badenian (15-16 Ma) a major transgression temporarily interrupted the connection between the Carpathians and the Bohemian Massif. Later, in Middle Badenian (14-15 Ma), the connection was defnitively established. A con-nection between the Dinarides and the Carpathians was also established during the Messinian crisis (5-6 Ma) but cannot explain the processes of Southern Carpathian colonization and speciation. Subterranean beetles are less mobile, even if they can migrate over relatively short dis-tances through the non-calcareous MSS. Supposing that epigean and edaphobiont forms migrated and colonized this region, it is improbable to admit that adaptation to deep subterranean habitats and speciation could have oc-curred in such a short period of time. In conclusion, the Dinaric origin of subterranean Romanian beetles can be explained by a frst migration wave of a Dinaride lineage over the Southern Carpath-ians and a later one through the Bohemian massif of a lineage that colonized the Apuseni Mountains. Both lin-eages are morphologically linked to Dinaric species, with some peculiar features in the drimeotus western lineage. An additional migration from the southwest during the Messinian crisis also could have been possible but only for species less adapted to caves. Te next step in the evolution of the Apuseni beetles was subterranean domain colonization. Te processes and mechanisms that could have driven the subterranean colonization were present-ed in the previous section. we also analyzed spatial distribution of species and subspecies of the Drimeotus phyletic lineage to obtain information which can be corroborated with available taxonomic and molecular data. Romanian Leptodirini ofer good material for studying speciation and vicari-ance processes, because it involves insular distribution, which is diferent from the large, continuous limestone surfaces such as those of the Dinarides and the Pyrenees, where speciation has occurred in the absence of geo-graphical barriers. Te Apuseni Mountains are inhabited by three genera (Protopholeuon, Pholeuon and drimeo-tus), belonging to the drimeotus phyletic lineage (Fig. 4). Fig. 3: Evolution of the Paratethys in Upper Ottnangian (a), middle badenian (b) and Lower badenian (c) (Cluj is located in North-Western Romania) (simplifed afer Rögl & Steininger 1984): grey – marine realms, dark grey – evaporitic basins, light grey – important areas with fuvio-terrestrial sedimentation and/or lignite formation, white – continental realms, ? - basins narrowed post-sedimentation by tectonic processes. Te lineage is monophyletic (Bucur 2003) and suggests a common ancestor, probably epigean. Protopholeuon, which is monospecifc, inhabits the Metaliferi Mountains, while the other two genera have larger distribution. Most species of Pholeuon and drimeotus occur in the Pa-durea Craiului and the Bihor mountains. Pholeuon also 82 TIME in KARST – 2007 HISTORICAL BIOGEOGRAPHy OF SUBTERRANEAN BEETLES – “PLATO’S CAVE” OR SCIENTIFIC EVIDENCE? has sub-genera in the Codru-Moma unit, while drimeo-tus is in the Metaliferi and the Trascau Mountains. Each mountain is inhabited by a diferent sub-genus. It is pos-sible that future searches will enlarge the distribution of drimeotus also in Codru-Moma. (Te frst and last speci-men of Drimeotus in the Metaliferi was found as recently as 2001 in a cave well known for Protopholeuon and this was afer several trapping episodes where Protopholeuon/ drimeotus ratio was 150/1.) Fig. 4: distribution of Leptodirini in the Western Carpathians (Apuseni mountains): ´ - drimeotus, n - Pholeuon, u - Protopholeuon, grey areas - karst. Comparing the largest geographical units in the Apuseni, Padurea Craiului and Bihor, the number of spe-cies and subspecies of less adapted drimeotus and the more adapted Pholeuon is diferent between genera and between units. drimeotus (20 species and 12 subspecies) has higher specifc diversity in both units and lower sub-specifc diversity than Pholeuon (6 species and 20 subspe-cies). Tis can be explained by the diference in adaptation and diferent histories of the two genera. Pholeuon, very adapted, is less mobile and very few individuals were found in MSS or under rocks. Preadapted ancestors of Pholeuon colonized deep subterranean environment in the entire area and since then small modifcations have occurred. Lacking competition, infra-generic differentiation of Pholeuon is slow. drimeotus, less adapted and relatively mobile between limestone areas, is under stronger climatic and biologically stronger selective pres-sures, which explains larger distribution areas and higher specifc diversity. Tere are also diferences between the Padurea Craiului and the Bihor drimeotus, with more than two-thirds of the species in the frst mountains. In Padurea Craiului the climate is warmer and less humid, with caves at lower altitude than in Bihor. Terefore, migration and gene fow between populations inhabiting diferent limestone areas or caves are limited and specia-tion is stronger. Te more humid and colder Bihor Mountains allows superfcial migrations and gene in-terchange between geographically close populations. Te altitudinal distribution of Leptodirini was frst discussed by Jeannel (1952), who mentioned the presence of the same genus and even same species at the surface at 1500 m altitude, under the rocks at 1000 m, and strictly cavernicolous at 500 m. A sound analysis of the distribution published by Decu (1980) empha-sizes the lack of correlation between body size and altitude. we found diferent results, given in Table 1. For drimeotus, correlation between altitude and body length or relative length of antennae is negative for Padurea Craiului samples, and positive for Bihor samples. An approach that links geography to morphology is the kriging method, which uses a topographic representation of the data sets. Using the Golden Sofware Surfer 8 we obtained the maps in Fig. 5. As one can see, the vectors defne centers of origin at about 500-700 m altitude. Ancestors of the drimeotus lineage probably inhabited superfcial habitats between 500 and 1000 m altitude. Colonizing caves at lower or higher altitude induced body increase, a process explained by lack of competition and/or de-crease of temperature. Body growth, as a result of cave colonization, is not only known for subterranean beetles. Te t test showed no signifcant diference in body length between populations of Padurea Craiului and Bihor. Te same test on the relative length of antennae gives shorter antennae in Bihor than in the Padurea Craiului samples. Tis can be due to the fact that the higher Bihor Mountains are inhabited by populations less confned to cave, compared to the Padurea Craiului. Pholeuon has the same tendencies as drimeotus, with a negative correla-tion of body length and altitude in Padurea Craiului and TIME in KARST – 2007 83 OANA TEODORA MOLDOVAN & GéZA RAJKA a positive correlation in Bihor, and the antennae length decrease with altitude. tab. 1: Linear regression (y) and coefcient of determination (R2) at drimeotus (13 populations) and Pholeuon (6 populations) from the Padurea Craiului and the bihor mountains (Western Carpathians): bL body length, AL/bL antenna/body lengths ratio. Altitude (m) 0-499 500-999 > 1000 Drimeotus BL y = -0.0003x + 4.4511 R2 = 0.0096 y = 0.0004x + 4.1025 R2 = 0.2337 y = 0.0007x + 3.5404 R2 = 0.3301 AL/BL y = -8E-05x + 0.5969 R2 = 0.1077 y = 3E-05x + 0.5327 R2 = 0.0195 y = 0.0001x + 0.4088 R2 = 0.2449 Pholeuon BL y = -0.0001x + 3.9152 R2 = 0.0239 y = 0.0031x + 2.142 R2 = 0.7849 y = 1E-04x + 4.6179 R2 = 0.0150 AL/BL y = -1E-04x + 0.8619 R2 = 0.2445 y = -0.0002x + 0.9593 R2 = 0.7847 y = -0.0001x + 0.9044 R2 = 0.2529 Mantels test is a regression in which variables are matrices summarizing pairwise similarities among sample locations. Geographic distance was used as a predictor variable, and morphological features of populations belonging to drimeotus and Pholeuon, from the Padurea Craiului Mountains, as dependant distance matrices. For ? = 0.01, the test gives strong correlation for drimeotus samples (Fig. 6) and no correlation for Pholeuon. For the moment, we cannot explain this result, although presumptions can be formulated. Fig. 5: Antennae relative length (a) and altitude (b) variations in geographical coordinates for 15 populations of drimeotus s. str. (red dots) of Padurea Craiului mountains, in 3d and vectorial overlayed representations. Mantel’s test (xLSTAT 2006.5 sofware) was also used to correlate geographic distance with morphologi-cal features, such as body and relative antennae lengths. Fig. 6: histogram representing results of the mantel test on representatives of drimeotus s. str. from Padurea Craiului. 84 TIME in KARST – 2007 HISTORICAL BIOGEOGRAPHy OF SUBTERRANEAN BEETLES – “PLATO’S CAVE” OR SCIENTIFIC EVIDENCE? CONCLUSIONS Plato’s allegory still raises questions in historical bioge-ography of cave beetles, but new scientifc acquisitions will also enhance the chances for a more objective view in explaining the history of one group or another and what shaped their present distribution. we have only presented few results and further research must take into consideration more populations and the surface of the populated area, as in insular stud-ies. In caves, as well as on oceanic islands, the number of endemics can be related to the size of the area. Studies of Barr (1985) and Culver et al. (1973) applied the insular theory of McArthur & wilson to karst areas, which have the characteristics of continental islands separated by non-calcareous “seas”. Tus, the number of subterra-nean species is strongly correlated with the surface of the limestone. Te recent interest in biogeographic studies has re-sulted from conservation necessities, especially in the last decade. For example, the concept of habitat fragmenta-tion became one of the priority themes of conservation researches. Te concept is considered ambiguous, and empirical studies demonstrate a wide variety of direct and indirect efects, even with opposing implications (Haila 2002). Te efects of habitat fragmentation are considered extremely dangerous for species and population preservation, and are ofen mentioned when estab-lishing protection areas for rare and vulnerable species. From a biospeleological point of view, habitat frag-mentation represents one of the main mechanisms that enhanced speciation processes in reduced areas (at least for terrestrial fauna). Tis idea, diferent from the con-servationist concern, can be extremely useful in solving protection problems. Unfortunately, none of the main contributions in conservation biology mentions caves and cave fauna as examples of survival in small, frag-mented areas. 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