Sarp Kaya

Altitudinal size clines, species richness and population density: case studies in Orthoptera

Abstract We examined size clines for various external body structures in two grasshopper species (Chorthippus vagans and Oedipoda miniata) and one katydid species (Poecilimon birandi), along an altitudinal gradient ranging from sea level to 1,980 m in southwest Anatolia (Turkey). In O. miniata and P. birandi all measured structures (body, tegmina, pronotum, and hind femur) were smallest at the highest altitude for both sexes. Hence, in these species, different structures covaried in the same direction, with increasing altitude. In contrast, there was no clear relationship between altitude and size in C. vagans, and different structures covaried in different directions in males and females (i.e., some structures became larger at higher elevations, whereas others became smaller, and this differed with sex). For some other C. vagans traits, there was no significant intraspecies variation. Hence, O. miniata and P. birandi followed the converse Bergmanns Rule, whereas there was no consistent pattern for C. vagans. For C. vagans, small body size was not associated with either local population density (measured as relative abundance) or local species richness, suggesting that neither intra- nor interspecific competition determined body size for this species. For O. miniata, the smallest individuals were found at the site with the highest grasshopper diversity, suggesting that interspecific competition could have influenced O. miniata body sizes at this altitude. However, the largest O. miniata individuals generally occurred at the sites with the highest relative abundance of O miniata. Hence, in this species, body sizes were generally larger at sites with high population densities — consistent with sites that were most favorable and so able to support high densities of O miniata also producing the largest individuals of this species. Observational data on P. birandi similarly suggested that, for this katydid, there is little relationship between local diversity/abundance and altitudinal size-clines.

Phylogeography of Anterastes serbicus Species Group (Orthoptera, Tettigoniidae): Phylogroups Correlate with Mountain Belts, but not with the Morphospecies

Abstract Ten species of the genus Anterastes Brunner von Wattenwyl (Orthoptera, Tettigoniidae) show insular distribution in mountain meadows of Anatolia and the Balkans. Current understanding of the taxonomy and species relationships within the genus is based on morphological characters. However, the extent to which morphological characters are phylogenetically informative, when used to define taxonomic groups or to elucidate detailed evolutionary relationships within Anterastes, is in need of further examination. Moreover, because little is known about the historical biogeography and diversification factors in members of this genus, additional datasets are necessary to test the robustness of species, relationship hypotheses and associated biogeographic patterns, Here we specifically examined, using 16S rDNA sequences, the evolutionary relationships and species boundaries of three closely related species of Anterastes (i.e., the A. serbicus group, comprising A. serbicus, A. burri and A. antitauricus). Additionally A. tolunayi, a species not in the A. serbicus group, but morphologically very similar to members of the group, was included in the molecular analysis to locate the species of the A. serbicus complex within a phylogenetic frame. Hence, the phylogenetic relationships and taxonomic interpretation of the species complex appear more intricate than previously hypothesized, The current molecular data do not allow us to identify A. serbicus, A. burri and A. antitauricus as distinct phylogenetic species, but rather suggest that these morphospecies are themselves a complex of cryptic taxa. Despite the incongruencies among the phylogenetic trees and nonmonophyly of each the three morphospecies, the median joining network resulted in haplotype grouping consisting of four clusters that are definable by geography. Thus, based on the congruency between geography and gene clusters, and the molecular clock estimate, it can be interpreted that 1) a strong correlation between the radiation of the group and the topography of their ranges may exist, 2) the radiation of the group dates back to Late Pliocene or Early Pleistocene and 3) there is a break between the Anatolian and the European lineages, in respect to range change of cold-preferring forms, dating back prior to the last four glacial periods.

Mountainous genus Anterastes (Orthoptera, Tettigoniidae): autochthonous survival across several glacial ages via vertical range shifts

Although the high‐latitude range margins in Europe and North America are intensively studied, attention is gradually turned towards the taxa/populations inhabiting glacial refugia. Here, we evaluate the genealogical history of the cold‐adapted Anatolio‐Balkan genus Anterastes especially to test the possible effects of intrarefugial vertical range shifts during climatic oscillations of the Quaternary. Using concatenated data from sequences of COI+16S and ITS1–5.8S–ITS2, intrageneric relationships and the time of speciation events were estimated. Thirteen different demographic analyses were performed using a data set produced from sequences of 16S. Different phylogenetic analyses recovered similar lineages with high resolution. The molecular chronogram estimated speciation events in a period ranging from 5.60 to 1.22 Myr. Demographic analyses applied to 13 populations and five lineages suggested constant population size. Genetic diversity is significantly reduced in a few populations, while not in others. Fixation indices suggested extremely diverged populations. In the light of these data, the following main conclusions were raised: (i) although glacial refugia are the biodiversity hotspots, species level radiation of the cold‐adapted lineages is mainly prior to the Mid‐Pleistocene transition; (ii) heterogeneous topography provides refugial habitats and allows populations to survive through vertical range shifts during climatic fluctuations; (iii) prolonged isolation of refugial populations do not always result in reduced intrapopulation diversity, but in high level of genetic differentiation; (iv) the cold‐adapted lineages with low dispersal ability might have not colonised the area out of Anatolian refugium during interglacial periods; and (v) populations of invertebrates may have restricted ranges, but this does not mean that they have small effective population size.

Estimating effects of global warming from past range changes for cold demanding refugial taxa: A case study on South-west Anatolian species Poecilimon birandi

Although changes in biodiversity and in ecosystems are surely caused by a range of interacting drivers, such as natural or human-induced factors, one of the important drivers having major impacts on climate and biodiversity and leading to range changes and fragmentation is global warming. Defining past range changes/fragmentations during interglacial periods may provide tools to understand possible impacts of global warming on present biodiversity. To test this assumption we studied a marker gene in the bush-cricket Poecilimon birandi, a species confined to South-west Anatolia that demands a cold climate. Haplotypes of P. birandi constituted three main phylogroups,West, East and Demre. All haplotypes are unique to the respective phylogroup. An AMOVA suggested considerable divergence at all hierarchical levels. Though there is a strong isolation between phylogroups, the East and West groups harbour considerable haplotype diversity. Most of the demographic analyses suggest stable historical populations for the West and East phylogroups, but a coalescent-based demographic analysis indicates a bottleneck for the West phylogroup. The main conclusions are; (i) P. birandi contains considerable phylogenetic signal in 16S rDNA, (ii) there were at least three contemporaneous radiations, which might have originated from isolated refugial populations during Pleistocene, (iii) within a refugium, range changes induced by climatic shifts may be only vertical through an altitudinal gradient, (iv) significant genetic structure can arise in a small heterogeneous area, if the species requires particular habitats and has weak dispersal ability, (v) climatic shifts may cause fragmentation or extinction of populations, but can also lead to divergence of populations suffering from fragmentation, and (vi) altitudinal heterogeneity plays a buffering role, allowing for survival of the refugial biodiversity.

Budding speciation via peripheral isolation: the Psorodonotus venosus (Orthoptera, Tettigoniidae) species group example

The peripatric or budding species model has remained theoretical until recently. The habitat preference and range pattern of the mountainous Psorodonotus venosus species group, distributed in Anatolia and Caucasus, offered potential to test the predictions of the model. The study aimed to confirm the parameters and to provide evidence for peripatric speciation in a terrestrial group. Fourteen populations representing the total range of the group were studied. Sequences of two mitochondrial fragments including four loci (12S rDNA+tDNAval+16S rDNA and COI) and a nuclear fragment including three loci (ITS1+5.8S rDNA+ITS2) were obtained and used in phylogenetic, time estimation, population genetics and demographic analyses. Additionally, phenotypical data were provided for the group. Phylogenetic analyses supported the monophyly of the PVG and suggested similar intralineage relationships, but did not support the monophyly of each of the species in the group. The molecular chronograms indicated radiation of the group throughout the Pleistocene. Demographic analyses suggested constant population sizes for the populations in the centre of the range but a significant departure from constancy in four peripheral populations. Genetic diversity is significantly reduced in peripheral populations, but not in others. We arrived to following conclusions. The data suggest that P. venosus is the ancestral species and P. rugulosus, P. tendurek and P. hakkari are bud species, as their haplotypes are nested within P. venosus. As expected under the budding speciation model, (i) in contrast to ancestral species, genetic diversity is reduced, and there are signs of departure from constant population size in bud species; (ii) bud species have isolated and restricted ranges, while the ancestral species does not, (iii) the relative ages of ancestral and bud species are the most reliable data to confirm the model, and chronograms of PVG well support this prediction, and (iv) the divergence events in the group co‐occurred with major climatic transformations of the Pleistocene.

Contribution to the taxonomy of Poecilimon bosphoricus species group (Orthoptera: Phaneropteridae): two new species from its core range

The Poecilimon bosphoricus species group, representing the most diverse lineage of the bushcricket genus Poecilimon, has been studied in the Basin of Marmara Sea. Two new species, P. warchalowskae sp. n. and P. canakkale sp. n., are described morphologically and acoustically in comparison to their related taxa of the P. bosphoricus species group. Song type and morphology of the new species suggests that they are related to P. turcicus, P. turciae and P. athos and each of these five species can be distinguished by their specific male cerci. The diagnoses are supplemented with comparative figures of morphology and song. Additionally, a short account is given on the synonymy of P. anatolicus with P. sureyanus.