Biological Journal of the Linnean Society, 2010, 99, 424–444. With 5 figures Multilocus phylogeography of the flightless darkling beetle Nyctoporis carinata (Coleoptera: Tenebrionidae) in the California Floristic Province: deciphering an evolutionary mosaic MAXI POLIHRONAKIS* and MICHAEL S. CATERINO Department of Invertebrate Zoology, Santa Barbara Museum of Natural History, 2559 Puesta del Sol Road, Santa Barbara, CA 93105, USA Received 16 July 2009; accepted for publication 9 September 2009 bij_1360 424..444 The California Floristic Province (CFP) is considered a global biodiversity hotspot because of its confluence of high species diversity across a wide range of threatened habitats. To understand how biodiversity hotspots such as the CFP maintain and generate diversity, we conducted a phylogeographic analysis of the flightless darkling beetle, Nyctoporis carinata, using multiple genetic markers. Analyses of both nuclear and mitochondrial loci revealed an east–west genetic break through the Transverse Ranges and high genetic diversity and isolation of the southern Sierra Nevada Mountains. Overall, the results obtained suggest that this species has a deep evolutionary history whose current distribution resulted from migration out of a glacial refugium in the southern Sierra Nevada via the Transverse Ranges. This finding is discussed in light of similar genetic patterns found in other taxa to develop a foundation for understanding the biodiversity patterns of this dynamic area. © 2010 The Linnean Society of London, Biological Journal of the Linnean Society, 2010, 99, 424–444. ADDITIONAL KEYWORDS: cytochrome oxidase I (COI/CoxI) – guftagu – southern Sierra Nevada. INTRODUCTION The California Floristic Province (CFP) is simultaneously a region of high biodiversity and one in which development and other land uses severely threaten parts of the native biota. As such, it has been recognized as a globally significant biodiversity hotspot by Conservation International in an effort to raise awareness and establish its needs as a top conservation priority (Conservation International, 2009). The CFP comprises approximately 70% of the state of California and extends north across the state boundary into Oregon and south into the Baja California peninsula. Understanding the range of diversity patterns of species in this region is essential for preservation of its delicate ecological systems. By reconstructing the evolutionary history of species and integrating this information with geographic data, we *Corresponding author. E-mail: [email protected] 424 will develop a better understanding of how these regions accumulate and maintain diversity (Avise, 2000). The dynamic geographic history and high habitat diversity of the CFP are frequently invoked as causes of increased species diversification and have been used to explain phylogenetic patterns across many plant and vertebrate taxa (Calsbeek, Thompson & Richardson, 2003). Recent comparative phylogeographic analyses of the CFP have revealed relatively concordant spatial barriers and high genetic diversity related to the orogeny of the Transverse Ranges, Tehachapi Mountains, and the Sierra Nevada (Calsbeek et al., 2003; Feldman & Spicer, 2006; Rissler et al., 2006; Chatzimanolis & Caterino, 2007a), and have used this information to identify diversification ‘hotspots’ within the larger CFP ‘hotspot’ (Davis et al., 2008). Although these generalized patterns provide a useful comparative framework for phylogeographic investigation of the CFP, fine-scale analyses of patterns within species continue to provide the © 2010 The Linnean Society of London, Biological Journal of the Linnean Society, 2010, 99, 424–444 PHYLOGEOGRAPHY OF N. CARINATA foundation for our understanding of how biodiversity patterns arise in this region because concordance of genetic barriers across broad spatial scales among taxa does not necessarily imply parallel patterns of local adaptation and diversification (Feldman & Spicer, 2006). In the past decade, the Transverse Ranges have received much of the attention of phylogeographers in the CFP (Calsbeek et al., 2003; Lapointe & Rissler, 2005; Chatzimanolis & Caterino, 2007a). Their unusual orientation, extending from the California coastline inland across southern California, and the diversity of habitats that they encompass have been suggested as primary contributors to phylogeographic complexity in this region. Although this intriguing area deserves further attention, empirical studies yielding interesting results from populations in the southern Sierra Nevada and Tehachapi Mountains have also been accumulating (Macey et al., 2001; Segraves & Pellmyr, 2001; Jockusch & Wake, 2002; Matocq, 2002; Feldman & Spicer, 2006; Kuchta & Tan, 2006; Chatzimanolis & Caterino, 2007a, b; Davis et al., 2008; Caterino & Chatzimanolis, 2009). Many of these studies provide evidence for deep divergence between southern Sierra clades and coastal and more southerly populations, leading some studies to recognize the southern Sierras as a glacial refugium (Rich, Thompson & Fernandez, 2008), although evidence for this is equivocal (Kuchta & Tan, 2006). Divergence times estimated for a Sierra Nevada break range from approximately 2 Mya (Feldman & Spicer, 2006) to 9.9 Mya (Segraves & Pellmyr, 2001), further emphasizing that concordant spatial genetic patterns may not imply concurrent chronology (Feldman & Spicer, 2006), especially when long persisting geographical features are subject to climactic fluctuations over an extended period of time. This long and dynamic history coupled with increased habitat complexity resulting from the extremely varied topography of the Sierra Nevada highlight the importance of this area as a centre of genetic diversity and lineage diversification in the CFP. Comparative phylogeography demands a broad perspective, based on many taxa and genetic markers. To date, our understanding of regional patterns in the CFP is based heavily on both vertebrates and mitochondrial DNA. In the present study, we expand both perspectives in a multilocus analysis of the flightless darkling beetle Nyctoporis carinata LeConte (Tenebrionidae) throughout its range in central and southern California. Previous comparative analysis of N. carinata using mitochondrial DNA (mtDNA) (Caterino & Chatzimanolis, 2009) revealed several interesting patterns within recognized evolutionary hotspots of the CFP (Davis et al., 2008). First, althlough many flightless organ- 425 isms exhibit a north–south genetic break attributed to the Transverse Ranges (Maldonado, Vila & Wayne, 2001; Calsbeek et al., 2003; Sgariglia & Burns, 2003; Forister, Fordyce & Shapiro, 2004; Feldman & Spicer, 2006; Chatzimanolis & Caterino, 2007b), the mtDNA gene tree of N. carinata revealed a prominent east–west break in the middle of the Transverse Ranges (as also observed in California mountain king snakes: Rodríguez-Robles et al. 1999; pond turtles: Spinks & Shaffer, 2005; and Sepedophilus rove beetles: Chatzimanolis & Caterino, 2007a). Second, the deepest split in the N. carinata mtDNA gene tree separated the southern Sierra Nevada and Tehachapi populations from the central and southern California populations, corresponding to the Sierran break discussed above. In addition, one of two sampling localities in the Tehachapi Mountains had two highly divergent mtDNA haplotypes (0.11 uncorrected, 0.25 corrected) with one haplotype sharing a more recent common ancestor with populations to the south, and the other being more closely related to populations in the north. These results suggest that high diversity in this region may result from mtDNA contact zone between formerly isolated populations. A detailed multilocus analysis investigating these patterns will add to a growing body of research aiming to understand and document the biodiversity of these important ecological regions. The present study uses two independently evolving sequence markers to evaluate phylogeographic hypotheses using N. carinata. It has become apparent that the validity of phylogeographic hypotheses is increased when biparentally inherited markers from the nuclear genome are used in conjunction with uniparentally inherited mitochondrial markers. Theoretical and empirical studies have documented both stochastic and deterministic factors that limit the ability of mtDNA to accurately represent the history of a species (Irwin, 2002; Zhang & Hewitt, 2003; Godinho, Crespo & Ferrand, 2008). Most significantly, these include asymmetrical migration rates of males and females (Jockusch & Wake, 2002; Miller, Haig & Wagner, 2005; Berghoff et al., 2008; Kerth et al., 2008; Ngamprasertwong et al., 2008), genetic drift, and/or lineage sorting (Maddison, 1997), with all of them potentially resulting in discordance among markers. Multilocus analysis of N. carinata phylogeography provides a robust basis to test several hypotheses and to examine the generality of patterns documented to date. Specifically, we investigate whether both marker types support: (1) the east–west geographic break through the middle of the Transverse Ranges (sensu Chatzimanolis & Caterino, 2007a); (2) the isolated southern Sierra Nevada clade with putative contact to the Transverse Ranges through the © 2010 The Linnean Society of London, Biological Journal of the Linnean Society, 2010, 99, 424–444 426 M. POLIHRONAKIS and M. S. CATERINO as a potential outgroup. The differences between N. vandykei and N. carinata, on the other hand, are very minor, and preliminary mitochondrial analyses did not clearly separate these two species; thus, we considered them as probable synonyms in the present study. All specimens were collected directly into 100% ethanol and stored at -70 °C prior to extraction. Collection localities are grouped into regional ‘populations’ in accordance with previous studies (Fig. 1) (Chatzimanolis & Caterino, 2007a; Caterino & Chatzimanolis, 2009). These areas correspond to geologically discrete subunits of the mountainous areas surrounding the Transverse Ranges, although boundaries between a few, particularly in the western Transverse Ranges, are less pronounced. Most of these, excluding the Santa Lucia Mountains to the north-west, and the Tehachapi, Breckenridge and Sierra Nevada Mountains to the north-east, collectively constitute the Transverse Ranges (Fig. 1). Tehachapi Mountains; (3) designated evolutionary hotspots within the CFP (Davis et al., 2008); and (4) lineages of cryptic species within N. carinata (Caterino & Chatzimanolis, 2009). MATERIAL AND METHODS FIELD COLLECTION Nyctoporis carinata is abundant and widely distributed throughout much of central and southern California, and can be found in detritus material and under rocks and loose debris. Both sexes of N. carinata lack wings and are thus flightless. Specimens were collected throughout the Transverse Ranges, central and southern Sierra Nevada, and the Santa Lucia mountains of the outer coast ranges. Most specimens clearly represent the nominal species N. carinata LeConte. We sampled a small number of specimens from the central and southern Sierra Nevada which correspond to Nyctoporis vandykei Blaisdell, and one specimen from Lake County (north of the San Francisco Bay) representing Nyctoporis aequicollis Eschscholtz. Based on morphology, the latter appears quite distinct, and was initially treated FOCAL GENES Genes from both the mitochondrial and nuclear genome were targeted in this study to compare infor- 3.1 3.2 3 1.1 1 4 2.2 2.1 2 7.1 6.1 5.1 7.2 7.4 7.3 6.2 6.3 6 13.1 13 4.1 5 8.1 7.5 6.4 6.5 9.1 789 10.1 10.2 10.3 10 11.1 11.2 11.3 11 12 12.1 Figure 1. Map of southern California with population designations and specific collecting localities as coded in the Appendix (i.e. 1.1 = locality one from population one; 1.2 = locality two from population one, etc.) (1, northern Santa Lucia Mountains; 2, southern Santa Lucia Mountains; 3, south-western Sierra Nevada; 4, Breckenridge Mountains; 5, Tehachapi Mountains; 6, Santa Ynez Mountains; 7, north-west Transverse Ranges; 8, central Transverse Ranges; 9, Sierra Pelona; 10, San Gabriel Mountains; 11, San Bernardino Mountains; 12, San Jacinto Mountains; 13, Santa Cruz Island). A few numbers cover multiple proximate populations, indistinguishable at this scale. Populations 6–12 comprise the entire Transverse Range region. © 2010 The Linnean Society of London, Biological Journal of the Linnean Society, 2010, 99, 424–444 PHYLOGEOGRAPHY OF N. CARINATA mation from two independently evolving loci. The well-studied mitochondrial protein coding cytochrome oxidase I (COI) gene has been used in a large number of phylogeographic and phylogenetic analyses, especially among insect and arthropod groups (Caterino, Cho & Sperling, 2000). The nuclear marker used was from an intron in the Guftagu (GFT) gene, identified during a screening of Tribolium introns (M. S. Caterino, M. Polihronakis, I. Ouzounov, unpubl. data) provided by V. Krauss (Krauss et al., 2008). In Drosophila, the GFT gene is important during the development of adult morphological structures and is primarily associated with the external sensory organs. The targeted intron is located after the first region of coding sequence relative to both Drosophila and Tribolium annotated genomes. GENERATING DNA SEQUENCE DATA Genomic DNA was extracted from forebodies (head and prothorax) of field collected specimens using DNeasy Tissue extraction kits (Qiagen). Apart from dissection, extractions were minimally destructive, and chitinous parts were mounted as vouchers after extraction. Full collection data, including voucher numbers and corresponding DNA extractions, can be accessed through the California Beetle Project database (http://www.sbnature.org/calbeetles). Amplification of the latter half of COI was performed using previously described polymerase chain reaction (PCR) protocols and reagents (Caterino & Chatzimanolis, 2009) with the primers C-J-2183 and C1-N-3014 (Simon et al., 1994). Amplification of the GFT intron required a nested PCR reaction with an initial amplification using degenerate primers GFT37F (5′-AAA ATG MGN ATH CGN GCN TTT CC-3′) and GFT86R (5′-TCN ACA TAC TTY TCR TCC AT-3′). The nested amplification was done using an internal species specific forward primer located approximately 35 bp downstream of the degenerate forward primer (NycaGFT) with the initial reverse primer. PCR products were purified using Qiaquick PCR Purification kits (Qiagen) or ExoSAP-IT® (USB Corp.). Forward and reverse sequencing reactions and sequence visualization were performed by Macrogen, Inc. (Korea). All DNA sequences were edited in GENEIOUS Pro, version 4.5.4 (Biomatters Ltd) and aligned in SE-AL, version 2.0a11 (http://tree.bio.ed.ac.uk/software/seal/). Both genes were easy to align manually; the COI gene did not have any indels, and the GFT intron had several small indels that were accommodated by inserting gaps. Sequence identity was checked by performing BLAST searches in GenBank (Altschul et al., 1997). To test for patterns of selection at either locus, Tajima’s D (Tajima, 1989) was estimated in ARLE- 427 QUIN, version 3.1 (Excoffier, Laval & Schneider, 2005). Significance was evaluated by comparing the observed test statistic to a distribution generated from 1000 permutations of the original data such that P-values represent the proportion of the distribution that is less than or equal to the observed value. Recombination in the nuclear gene was assessed using the PHI (pairwise homoplasy index) statistic (Bruen, Phillipe & Bryant, 2006) implemented using the software SPLITSTREE, version 4.10 (Huson, 1998; Huson & Bryant, 2006). ANALYSES OF POPULATION STRUCTURE AND SPATIAL AUTOCORRELATION To test for significant genetic breaks across certain geographic barriers, we performed analysis of molecular variance (AMOVA) and spatial autocorrelation analyses. The degree of population divergence and haplotype exclusivity was determined using FST values (which differ from traditional FST values because they incorporate both overall similarity and haplotype frequencies; Excoffier, Smouse & Quattro, 1992), as calculated in ARLEQUIN. Spatial autocorrelation analyses were performed to examine the relationship between genetic and geographic distance at the individual level, and to compare markers for possible differences related to sex-biased dispersal. These analyses provide a finer-scale evaluation of isolation-by-distance (IBD) than matrix correlation tests because it is possible to assess the behavior of the slope of autocorrelation values as the size of distance classes increase. These were performed in GENEALEX, version 6.1 (Peakall & Smouse, 2006), with each marker treated individually as a single population using the even sample size option with 20 distance classes. Significance of the autocorrelation coefficient was assessed using 999 permutations of the data in addition to 1000 bootstrap replicates. Of the seven evolutionary hotspots designated by Davis et al. (2008), our samples cover three of them (Santa Lucia Mountains; north-eastern Transverse Ranges, Tehachapi and Piute Mountains; and San Bernardino and San Jacinto Mountains). To determine whether genetic diversity within N. carinata was consistently higher or more divergent in these areas, we generated a genetic landscape shape for each of the markers using the software ALLELES IN SPACE (AIS) (Miller, 2005). The genetic landscape interpolation method implemented in AIS uses a Delaunay triangulation-based connectivity network from X and Y geographic coordinates and assigns real and interpolated genetic distances to the Z-axis to produce a three dimensional landscape (Miller et al., 2006), which provides a visual representation of © 2010 The Linnean Society of London, Biological Journal of the Linnean Society, 2010, 99, 424–444 428 M. POLIHRONAKIS and M. S. CATERINO genetic diversity patterns across a sample area. Unlike AMOVA, this method requires no a priori group designations. Genetic landscapes were interpolated using raw genetic distances and a 50 ¥ 50 grid with a distance weight value of one. Sensitivity of the analysis to changes in grid size, weighting parameter values, and genetic distance measure were evaluated, but resulted in minimal changes to the resulting landscape plot. We also calculated genetic diversity within populations using uncorrected and corrected distances, as calculated in PAUP* (Swofford, 2002). in GFT, where both haplotypes from this individual were minimally different from those in many populations of N. carinata. Therefore, we consider the species status and relationship of this entity uncertain and do not treat it as an outgroup. For this reason, our trees should be interpreted as unrooted, although ‘midpoint rooting’ (as implemented in PAUP*) is used for presentation. RESULTS SEQUENCE PHYLOGENETIC ANALYSIS AND NETWORK CONSTRUCTION Relationships among individuals or haplotypes were inferred using phylogenetic and network methods to obtain both bifurcating and nonbifurcating perspectives of the gene lineages. Models of molecular evolution for each individual marker were evaluated in MRMODELTEST, version 2.3 (Nylander, 2004). According to the Akaike information criterion, the COI data best fit the HKY + I + G model, and the GFT data best fit the GTR + G model. Gene trees were inferred in MRBAYES, imposing the model specified by AIC, using default priors for all parameters. Branch length priors for each marker were determined through comparison of branch lengths of maximum likelihood trees generated in GARLI, version 0.96 (Zwickl, 2006) to those obtained in the Bayesian analyses. Haplotype networks were built using COMBINE TREES (Cassens, Mardulyn & Milinkovitch, 2005), which implements the union of maximum parsimonious trees approach (UMP), using parsimony trees as input. For the nuclear data set, parsimony trees were generated with gaps coded as a fifth state, using a heuristic search in PAUP* (Swofford, 2002) with tree bisection–reconnection branch swapping and 500 replicates of random sequence addition, saving 200 trees per replicate. Heuristic search options for the mitochondrial data set were modified to accommodate the large number of trees generated (500 replicates of random sequence addition saving a maximum of 20 trees per replicate). Because of the computational demands of the COMBINE TREES software, the first 1000 trees from the parsimony search were analysed in two sets of 500 trees each. Ten networks were constructed for each data set which were then used to generate a ‘best network’ with the fewest number of cycles (Cassens et al., 2005). The best networks for each set of 500 trees were compared to ensure concordance when only subsets of trees from the parsimony search were used. Although mitochondrial DNA showed N. aequicollis to be rather divergent from other samples, tentatively supporting its outgroup status, this was not the case DATA A total of 130 and 109 individuals were sequenced for the COI (826 bp) (Genbank accessions EU37099EU37190 and GU049332-GU049339) and GFT (497 bp) (Genbank accessions GU049270-GU049331) genes, respectively. Of the 109 samples with GFT sequence, 34 had polymorphic sites (Appendix S1). Individuals with one polymorphic site were phased manually and both haplotypes were included in the analysis. Specimens with two or more polymorphic sites were phased using the software PHASE, version 2.1 (Stephens, Smith & Donnely, 2001; Stephens & Scheet, 2005). There were three cases that resulted in ambiguous phase calls and so autapomorphic polymorphic sites for these individuals were coded as missing data. For all three cases, this resulted in just one parsimony informative polymorphic site that was phased manually. Thus, further discussion of sequences from both genes will refer to haplotypes. The mean Tajima’s D-values for COI and GFT estimated across all populations were not significant (P = 0.55 and 0.52, respectively). At the population level, the northern Santa Lucia population had a significant Tajima’s D-value (P = 0.01) for the COI gene, and the north-west Transverse Range population had a significant Tajima’s D-value (P = 0.05) for the GFT gene, potentially indicating past selection or population bottlenecks for these two populations. There was no evidence for recombination in the GFT intron according the PHI test (P = 0.80). The latter half of the COI gene targeted for amplification had 224 variable sites, with 207 of those being parsimony informative. The COI data set had a total of 100 unique haplotypes with no one haplotype dominating more than 10% of the entire sample. Of the 497 bp sequenced of GFT, 53 were variable, with 27 of those being parsimony informative. The GFT data set had a total of 62 unique haplotypes, although the three most common haplotypes dominated 49% of the data set. Interestingly, approximately 20% of the haplotype diversity in the GFT data came from within the south-western Sierra population, whereas this population only accounted for 9% of the haplotype diversity of the COI gene. © 2010 The Linnean Society of London, Biological Journal of the Linnean Society, 2010, 99, 424–444 PHYLOGEOGRAPHY OF N. CARINATA POPULATION STRUCTURE AND AUTOCORRELATION ANALYSIS High differentiation among populations was supported by both markers. All FST values based on the COI data were significant, except for some of the comparisons with the Breckenridge Mountains population where only two individuals were sampled (Table 1, lower diagonal). Pairwise FST values based on the GFT locus were also almost all significant (Table 1, upper diagonal), with exceptions between the Sierra Pelona and central Transverse Range populations, as well as between the southern Santa Lucia and north-west Transverse Range populations. Both of these insignificant values are between geographically adjacent areas, suggesting gene flow between them, although insufficient sampling cannot be ruled out as an explanation. Spatial autocorrelation analyses showed a strong decline in relatedness with increasing distance A) 429 (Fig. 2). A decreasing slope of the spatial autocorrelation graphs is indicative of an IBD trend (i.e. autocorrelation values decrease as distance class size increases), whereas significant r-values indicate higher or lower genetic relatedness than predicted if individuals were randomly distributed (Smouse & Peakall, 1999; Peakall, Ruibal & Lindenmayer, 2003). COI haplotypes showed significant IBD with decreasing r-values from 0–165 km. The increase in r-values at approximately 200 km likely reflects the close relationship of some individuals from the central Transverse range population with individuals from the San Bernardino and San Jacinto populations. Beyond 218 km, autocorrelation values were relatively unchanging and significantly negative. The GFT locus exhibited a very similar pattern, showing a general IBD trend up to approximately 150 km, at which point r-values remained negative with some fluctuation. The similar relationships between genetic and geographic 0.8 0.7 0.6 0.5 0.4 r 0.3 0.2 0.1 0.0 -0.1 -0.2 -0.3 29 49 67 86 98 117 140 150 165 178 205 218 235 255 270 295 317 368 477 Distance (km) B) 0.7 0.6 0.5 0.4 0.3 r 0.2 0.1 0.0 -0.1 -0.2 -0.3 29 51 69 90 107 121 145 159 178 204 217 235 252 270 293 313 346 453 Distance (km) Figure 2. Spatial autocorrelation graphs of COI haplotypes (A) and GFT haplotypes (B). Dotted lines represent the 95% confidence interval with respect to the null hypothesis that individuals are randomly distributed. © 2010 The Linnean Society of London, Biological Journal of the Linnean Society, 2010, 99, 424–444 0.29 – 0.65 0.83 0.71 0.27 0.31 0.75 0.56 0.61 0.63 0.62 0.58 – 0.80 0.75 0.95 0.79 0.56 0.73 0.90 0.75 0.72 0.75 0.63 0.90 Southern Santa Lucias 0.68 0.68 0.69 0.64 0.71 0.72 0.70 0.60 0.39 0.36 – 0.81 0.81 Southwestern Sierra Nevada Bold values are significantly different from zero (P < 0.01). Northern Santa Lucias Southern Santa Lucias Southwestern Sierra Nevada Breckenridge Mountains Tehachapi Mountains Santa Ynez Mountains Northwest Transverse Ranges Central Transverse Ranges Sierra Pelona San Gabriel Mountains San Bernardino Mountains San Jacinto Mountains Northern Channel Islands Northern Santa Lucias 0.94 0.80 0.83 0.80 0.82 0.96 0.81 0.66 0.41 – – – – Breckenridge Mountains 0.75 0.69 0.73 0.69 0.73 0.77 0.73 0.62 – – 0.79 0.53 0.58 Tehachapi Mountains 0.37 0.43 0.39 0.19 0.25 0.44 0.32 – 0.46 – 0.77 0.22 0.32 Santa Ynez Mountains 0.48 0.64 0.63 0.59 0.63 0.71 – 0.27 0.57 – 0.85 0.05 0.30 Northwest Transverse Ranges 0.88 0.72 0.65 0.62 0.60 – 0.68 0.49 0.12 – 0.82 0.80 0.73 Central Transverse Ranges Table 1. Pairwise population FST comparisons for COI (lower diagonal) and GFT (upper diagonal) 0.70 0.56 0.47 – 0.23 0.04 0.66 0.48 0.12 – 0.81 0.75 0.70 Sierra Pelona 0.68 0.57 0.48 0.25 – 0.25 0.53 0.43 0.26 – 0.76 0.46 0.52 San Gabriel Mountains 0.70 0.57 – 0.83 0.63 0.85 0.64 0.16 0.70 – 0.86 0.66 0.66 San Bernardino Mountains 0.71 – 0.11 0.87 0.66 0.89 0.66 0.18 0.74 – 0.87 0.70 0.70 San Jacinto Mountains – 0.75 0.70 0.78 0.51 0.83 0.30 0.31 0.59 – 0.82 0.32 0.43 Northern Channel Islands 430 M. POLIHRONAKIS and M. S. CATERINO © 2010 The Linnean Society of London, Biological Journal of the Linnean Society, 2010, 99, 424–444 PHYLOGEOGRAPHY OF N. CARINATA B) Y (Eas tern edge) A) 431 X (Southern edge) Y (Eas te rn edge) C) X (Souther n edge) Figure 3. Landscape shapes from ALLELES IN SPACE analyses. A, connectivity network based on Delaunay triangulation overlayed onto map of southern California (the vertex of each triangle represents a collecting locality). B, landscape interpolation of COI sequence data. C, landscape interpolation of GFT sequence data. The Z-axis in (B, C) represents the degree of genetic discontinuity between two localities. distance between the two genes suggest that dispersal is not sex-biased. Comparison of the genetic landscape shapes for the two genes provided a visual representation of the genetic diversity patterns observed over the sampling area (Fig. 3). Peaks on each landscape shape represent the degree of genetic discontinuity between two localities as determined by the Delaunay triangulation method (Miller et al., 2006). Thus, when collecting localities are geographically close in proximity (short distances between vertices), high peaks repre- sent areas of high genetic diversity. On the other hand, when localities are further apart (long lines between vertices), high peaks are more appropriately interpreted as genetic barriers. Both markers demonstrated high diversity among the south-western Sierra populations as a result of high genetic divergence among several geographically proximate localities, as well as a barrier across the Central Valley. The landscape based on the COI data (Fig. 3B) also exhibited genetic discontinuity in the Transverse ranges, beginning at the southern tip of the Central © 2010 The Linnean Society of London, Biological Journal of the Linnean Society, 2010, 99, 424–444 432 M. POLIHRONAKIS and M. S. CATERINO Valley separating the Tehachapis, Breckenridge Mountains, and south-western Sierra populations from the eastern and western Transverse Range populations. The plot of the GFT data (Fig. 3C) had a barrier that was not exhibited by the COI data between the southern Sierra Nevada and northern Transverse Ranges. Thus, the areas of high genetic diversity in N. carinata corresponded to the Transverse Ranges and southern Sierra hotspots designated by Davis et al. (2008). However, in contrast to Davis et al. (2008) our samples from the Santa Lucia, San Bernardino, and San Jacinto Mountains did not exhibit increased levels of diversity. PHYLOGENETIC ANALYSIS AND NETWORK RECONSTRUCTION mtDNA Analyses of COI revealed very high levels of divergence among haplotypes, especially among regions. Uncorrected distances were as high as 0.11 uncorrected (0.27 corrected), or 0.07 uncorrected (0.11 corrected) if the nominally distinct populations of N. aequicollis and N. vandykei are excluded. The UMP method of network building resulted in one network but with a large number of unsampled nodes. Thus, because of the high haplotype diversity and non-network-like behavior of the COI gene, these data are presented as a phylogenetic tree only. The COI gene tree showed five main clades, principally: the western Transverse Ranges (most) + Channel Islands + southern Santa Lucias; eastern, central, and small inclusions of western Transverse Ranges and Tehachapis; San Jacinto Mountains (most); northern Santa Lucias; and Sierra Nevada (including the Breckenridge Mountains) + Tehachapis (most) (Fig. 4). The most strongly supported relationship among the major clades linked the eastern and western Transverse Range clades (PP = 1.0). This supported a single lineage covering the bulk of the Transverse Ranges with two exceptions: (1) it did not include the San Jacinto Mountains and (2) it did include the southern part of the Santa Lucia Mountains, which is not considered part of the Transverse Ranges. The break between these two major Transverse Range groups corresponds loosely to the Ventura and Cuyama River drainages in the lower elevations. However, at higher elevations, no such obvious geographic barrier is observed. Most populations were predominantly single lineages. However, almost all had individuals appearing elsewhere in the tree. The only two monophyletic populations were those from the northern Santa Lucia Mountains (the north-western part of our sampling region) and from Santa Cruz Island. Most individuals from the San Jacinto Mountains population (at the south-eastern extreme) fell out in an isolated clade, although two San Jacinto individuals (haplotype N21) were more closely related to a clade of primarily San Bernardino (the neighbouring region to the north) haplotypes. The large clade containing the remaining eastern Transverse Range samples contained San Bernardino, San Gabriel, and Sierra Pelona haplotypes intermingled with minimal site fidelity. Although the San Bernardino haplotypes were the most cohesive of these, two of these individuals were more closely related to haplotypes from elsewhere in this broad region. The eastern Transverse Range clade included haplotypes from the central Transverse Ranges (the Tecuya Trail locality in the San Emigdio Mountains), as well as one haplotype from the Tehachapis. Another interesting element of this larger eastern Transverse Range clade was a subclade of haplotypes from further west in Ojai and the eastern-most Santa Ynez Mountains (the Murrietta Trail locality). Although the area covered by the eastern Transverse Range clade is more or less contiguous, it is the most wide-ranging, with several extensions beyond its core area. The mainly western Transverse Range clade included all individuals from the north-western Transverse Range and Santa Cruz Island populations, as well as all individuals from the southern Santa Lucia Mountains. Most individuals from the Santa Ynez Mountains were also included, with the exception of the Murrietta Trail samples mentioned above. GFT Divergence among GFT alleles was much lower than that seen in mtDNA. Most haplotypes differed by only one or a few changes. For this reason, the phylogenetic tree based on these sequences was largely unresolved. With such low divergence, the likelihood of direct ancestor–descendant relationships among sequences was high, and we therefore based our inferences on the UMP network (Fig. 5). Although genetic variation was generally low, three of the four main groups in this network were recognized by a high frequency of identical haplotypes over broad (mostly) contiguous geographic regions, along with linked derivative haplotypes. The most widespread of these was the western group (orange), including all haplotypes from the northern and southern Santa Lucias, northwestern Transverse Ranges, Santa Ynez Mountains, Santa Cruz Island, the central Tranverse Ranges, and a single individual from the San Gabriel Mountains; the central group (green) included most haplotypes from the Sierra Pelona, San Gabriel Mountains, Tehachapi Mountains, and the northern California representative of N. aequicollis (G58 & G59); the eastern group (blue) included all haplotypes from the San Jacinto Mountains, all but one from the San Bernardino Mountains, one haplotype from the San Gabriel © 2010 The Linnean Society of London, Biological Journal of the Linnean Society, 2010, 99, 424–444 PHYLOGEOGRAPHY OF N. CARINATA 433 Figure 4. A, COI gene tree inferred in MRBAYES (*posterior probability ⱖ 0.80). B, corresponding clade designations on sample map. Arrow from the yellow clade refers to the placement of the Nyctoporis aequicollis specimen from the northernmost Lake County sampling area (not visible on map). Mountains, and a disjunct group of haplotypes from the Ojai Valley and extreme eastern end of the Santa Ynez Mountains. The fourth main group (yellow) represented a diverse clade of related, mostly unique, haplotypes from the southern Sierra Nevada region. Both the COI and GFT gene trees supported an east–west break in the Transverse Ranges in the eastern Santa Ynez Mountains/western Ventura County area. However, the genetic break between the two clades supported by the COI data was positioned slightly west of the break supported by the GFT data set. In addition, the geographic relationships of populations within each clade were somewhat different between genes in that the COI haplotypes from the eastern group were almost all closely related to haplotypes found in the Sierra Pelona and San Gabriel Mountains, whereas GFT haplotypes in these areas were more closely allied with those further east, in the San Bernardino Mountains population. Although the region where these discontinuities are observed more-or-less coincides with the confluence of several major drainages (principally the Ventura and Santa Clara Rivers), it is only approximate, and neither corresponds precisely to the Santa Clara break found by Chatzimanolis & Caterino (2007a) in Sepedophilus beetles, and among other species. The results from an analysis of the COI and GFT markers differed in many other respects. Although both gene trees revealed a few large clades with broad geographic continuity, the exact regions defined by these clades showed little congruence. The GFT network did not reveal a strong relationship between © 2010 The Linnean Society of London, Biological Journal of the Linnean Society, 2010, 99, 424–444 434 M. POLIHRONAKIS and M. S. CATERINO Figure 5. A, GFT union of maximum parsimonious trees approach network; sizes of boxes within coloured clades scaled to haplotype frequency, numbers in parentheses denote the frequency of the haplotype if > 1 (haplotypes in some haplotype boxes have different numbers as a result of missing data but are otherwise identical). B, corresponding clade designations on sample map. Arrow from the green clade refers to the placement of the Nyctoporis aequicollis specimen from the northernmost Lake County sampling area (not visible on map); ‘X’ in population four denotes no nuclear data are available for this region. © 2010 The Linnean Society of London, Biological Journal of the Linnean Society, 2010, 99, 424–444 PHYLOGEOGRAPHY OF N. CARINATA Sierran and Tehachapi populations as seen with COI, instead grouping the Tehachapis strongly with the central portion of the Transverse Ranges, the San Gabriel Mountains, and the Sierra Pelona (haplotype G01 is the most common in all these areas). Sierran populations were more closely related to Tehachapi individuals than to any other group, but were highly divergent relative to the minimal divergence observed throughout the remainder of the network. Most individuals from the San Jacinto and San Bernardino Mountains shared a GFT haplotype, whereas most San Jacinto COI haplotypes were highly divergent. Almost all northern Santa Lucia individuals had a GFT sequence identical to those from the southern Santa Lucias, as well as to most individuals from the north-western Transverse Ranges, and Santa Ynez Mountains, whereas the COI data supported the northern Santa Lucia population as being exclusive and highly divergent. Finally, although the Lake County specimen (corresponding to N. aequicollis) differed by only a single mutation in GFT from the eastern Sierra Pelona group, its COI sequence was highly divergent from all other groups. DISCUSSION Detailed comparative phylogeographic analyses provide a means to study how geography influences the evolutionary history and biodiversity patterns of organisms. Within the CFP, there are many geographic barriers that are hypothesized to have a pervasive effect on species across different taxonomic groups. Although evidence supporting this hypothesis is increasing, much of the data are focused on vertebrates, and, until recently, heavily dependent on single locus analyses of mitochondrial DNA. The present study aimed to evaluate the phylogeographic history of a dynamic part of the CFP through analysis of N. carinata, a flightless darkling beetle with a widespread distribution in central and southern California, using mitochondrial and nuclear genes. THE PHYLOGEOGRAPHIC HISTORY OF N. CARINATA Phylogeographic expectations of N. carinata are guided by two main ecological factors. The first is their flightlessness; we expect populations to be relatively isolated as a result of their inability to traverse unsuitable habitat, and for lineage breaks to correspond well with major geographic or ecological features (although these may have varied considerably over time). Second, we expect similar dispersal abilities of males and females and therefore do not expect population structure to be significantly influenced by sex-biased dispersal (Jockusch & Wake, 2002; Matyukhin & Gongalsky, 2007). 435 The COI sequences of N. carinata were characterized by high divergence, high haplotype diversity, low population connectedness, broad geographic cohesiveness, and a combination of mono- and polyphyletic populations. This pattern signifies an old, broadlydistributed species with historically-isolated populations, some of which have come into secondary contact with subsequent gene flow (Jockusch & Wake, 2002). This was supported by the overall non-monophyly of populations with otherwise high FST values. Interestingly, geographically peripheral populations from the southern Sierra Nevada, the northern Santa Lucia Mountains, and the San Jacinto Mountains were the most isolated and exclusive (with one individual exception in the latter case), whereas more centrally located populations showed higher levels of admixture. This suggests that, if populations had remained completely isolated, they would have had enough time to achieve monophyly. Monophyly of the Santa Cruz Island population can also be cited in this respect because, although founder effects would be likely to explain monophyly for this disjunct population, there was no evidence for a bottleneck based on estimates of Tajima’s D. The GFT data supported a somewhat different scenario. The results obtained based on this marker showed low levels of divergence and low haplotype diversity within and across most populations (with a few common haplotypes shared among, and dominating most populations), but were similar to mitochondrial results in low population connectedness, and showed similar patterns of geographic relationships among populations. This overall pattern is consistent with a series of relatively rapid, stepwise colonizations from one or more ancestral pools of diversity into more peripheral areas, with historical continuity between populations that now appear to be isolated. East–west Transverse Range break The COI gene tree and GFT gene network both supported an east–west genetic break through the Transverse Ranges, although they did not completely overlap. The location of this break based on the COI gene followed the eastern boundary of the north-west Transverse Ranges but turned west to include the southernmost sampling locality from the Santa Ynez Mountains (Fig. 4B). The location of the genetic break based on the GFT network was further east between the central Transverse Ranges and the Sierra Pelona. Although there are no significant geographic barriers that would explain a genetic break in either of these regions, there are two other examples of an east–west break further east in the Transverse Ranges, in Sepedophilus rove beetles (Chatzimanolis & Caterino, 2007a) and California mountain king snakes (Lampropeltis zonata) (Rodríguez-Robles et al. 1999), that © 2010 The Linnean Society of London, Biological Journal of the Linnean Society, 2010, 99, 424–444 436 M. POLIHRONAKIS and M. S. CATERINO approximately correspond with N. carinata. Increased sampling of N. carinata in these regions, in addition to further comparative work including other taxa, would help determine whether these genetic breaks are a result of stochastic processes (Irwin, 2002), or the result of geography. Isolation of southern Sierra Nevada population On the basis of the high diversity of the nuclear gene in the southern Sierras, we propose that this population was ancestral and potentially served as a glacial refugium (Hewitt, 2000; Rich et al., 2008). Furthermore, the genetic data from both the mitochondrial and nuclear markers supported a south and westward dispersal out of this area with an ancient stepping stone colonization through the Transverse Ranges. Potential geographic barriers reducing southward dispersal for flightless N. carinata beetles are the Kaweah and Kern River drainages (Segraves & Pellmyr, 2001; Feldman & Spicer, 2006). These drainages may have served as successive filters to dispersal, resulting in reduced population sizes during colonization as demonstrated by a single derived nuclear haplotype in the Tehachapis (G01), which linked the larger western, central, and eastern groups throughout the rest of the range. Interestingly, all of the main groups in the GFT network, with the exception of the southern Sierra population, were dominated by one main haplotype with several derivative haplotypes that suggest there were subsequent filters to dispersal east and west out of the Tehachapis Mountains and Sierra Pelona region. EVOLUTIONARY HOTSPOTS Our finding of both high genetic divergence and diversity of N. carinata populations from the Sierra and Tehachapi Mountains populations is interesting in light of similar results from an increasing number of other studies focusing on a wide variety of taxa distributed throughout the CFP (Macey et al., 2001; Segraves & Pellmyr, 2001; Jockusch & Wake, 2002; Matocq, 2002; Feldman & Spicer, 2006; Kuchta & Tan, 2006; Chatzimanolis & Caterino, 2007a, b; Davis et al., 2008). In addition to evidence of divergent southern Sierran populations, two of these studies with sufficient taxon sampling also support higher genetic diversity in this region (Kuchta & Tan, 2006; Rich et al., 2008). This contrasts with previous work revealing higher genetic diversity within southern or coastal populations (Law & Crespi, 2002; Matocq, 2002), suggesting that refugia and/or genetic diversity hotspots have existed in multiple areas, although possibly over different time periods. The elevated diversity in the southern Sierran region for both genes clearly supports the contention that this area represents an evolutionary hotspot. Can these data shed light on any of the underlying processes? The maintenance of high diversity in these populations supports the hypothesis that this region once served as a glacial refugium that potentially sourced expansion into coastal and southern populations via the Transverse Ranges. However, this population was paraphyletic in the mtDNA tree with respect to haplotypes from the Tehachapi and Breckenridge Mountains, but monophyletic and quite divergent in the GFT network. Non-monophyly of mtDNA combined with monophyly of the nDNA is considered characteristic of differential introgression patterns between the two genomes (Chan & Levin, 2005; Weisrock et al., 2006; Linnen & Farrell, 2007; Peters et al., 2007; Spinks & Shaffer, 2007; Zhang & Sota, 2007; Gompert et al., 2008), and is suggestive of some interesting evolutionary dynamics in the Tehachapi Mountains. Conflicting relationships inferred by the nuclear and mitochondrial markers in the Tehachapi Mountains are consistent with differential introgression combined with several range fluctuations, which resulted in unique contact zones for each of the two markers. The haplotype relationships of the two markers from the southern Sierra Nevada suggest that migration out of this region comprised multiple events that occurred over an extended period of time. Under this scenario, an initial population expansion southward was followed by subsequent isolation (i.e. population contraction or relatively simple isolation-by-distance) between populations in the south-western Sierra, and those in the Breckenridge and Tehachapi Mountains. The divergence patterns of haplotypes in this region suggest that this isolation lasted long enough for several population-specific mutations to accumulate in both the nuclear and mitochondrial genes. To explain the discrepancy of relationships of the Tehachapi Mountains population between the two markers, we hypothesize secondary contact between these isolated populations with differential introgression of mitochondrial genes from the south-western Sierra populations south into the Breckenridge and Tehachapi Mountains populations. This scenario would explain why individuals from the Tehachapi Mountains had a derived nuclear haplotype and an ancestral mitochondrial haplotype. The data are suggestive of asymmetrical mitochondrial introgression during secondary contact as a result of a lack of derived nuclear or mitochondrial haplotypes in the south-western Sierra population. We also did not sample any individuals with an ancestral nuclear haplotype and a derived mitochondrial haplotype. Finer-scale sampling would help resolve historical connections in this area. © 2010 The Linnean Society of London, Biological Journal of the Linnean Society, 2010, 99, 424–444 PHYLOGEOGRAPHY OF N. CARINATA High genetic diversity of N. carinata from the southern Sierras and Transverse Ranges corresponded to evolutionary hotspots designated by Davis et al. (2008). However, only the southern Sierras received support from both marker types, whereas diversity in the Transverse Ranges was supported by the COI data only. Evidence for other evolutionary hotspots (sensu Davis et al., 2008) within the southern CFP is equivocal; other recognized areas for which our data might be pertinent (i.e. the central coast ranges, the San Bernardino Mountains, and San Jacinto Valley) showed little above baseline levels of diversity in either locus. EVIDENCE FOR CRYPTIC SPECIES? Although some of the suggested morphological characters separating the three species N. carinata, N. vandykei, and N. aequicollis are relatively discernable, high variation in N. carinata precludes their consistent application. Two of the main characters originally cited to distinguish N. vandykei from N. carinata are the former’s comparatively slender, less robust form, and less pronounced frontal carina (ridge) on the head (Blaisdell, 1931). However, both these characters vary considerably within N. carinata, such that some specimens are easily diagnosed, whereas others are not. The uncertainty surrounding the morphological distinctions was not necessarily clarified by the genetic data. In the COI gene tree, ‘N. vandykei’ specimens were paraphyletic with respect to N. carinata specimens from the Tehachapi and Breckenridge Mountains, whereas, in the GFT network, the ‘N. vandykei’ individuals are monophyletic and deeply diverged from the rest of the individuals sampled (discussed above). The uncertainty surrounding N. aequicollis is even greater as a result of its very close ties with populations in the central portion of the Transverse Ranges according to the GFT gene, at the same time as being quite distinct from most other lineages in the COI tree (but grouped with the south-west Sierra and Tehachapi clade with midpoint rooting). Aside from the questionable status of the named species, high divergence among mtDNA haplotypes was also initially suggestive of additional cryptic species within N. carinata. Where populations were monophyletic, average uncorrected distances to neighbouring populations exceeded 0.05 in all cases (Caterino & Chatzimanolis, 2009). The high divergence of the two most northerly and southerly populations (northern Santa Lucias and San Jacinto Mountains, respectively), in particular, suggested that these lineages represented genealogically distinct units as a result of allopatric divergence. However, this hypothesis was not supported by the nuclear data, 437 which revealed that many of the individuals from both of these populations shared identical haplotypes with neighbouring populations. Mitochondrial studies of other arthropod taxa in the CFP have found levels much lower than this to correspond with well differentiated subspecies (e.g. 0.014 in the yucca moth Tegiticula maculata; Segraves & Pellmyr, 2001), and for comparable divergences to correspond to fully distinct species (0.08 in a species complex of the California turret spider, Antrodiaetus riversi; Starrett & Hedin, 2007). In the latter case, nuclear data were fully concordant with the mitochondrial, offering a stark contrast to the situation in N. carinata. GENETIC VARIATION: MITOCHONDRIAL VERSUS NUCLEAR DATA It is often assumed that large-scale population-level processes will result in relatively parallel patterns between marker types, although this is not always the case (Ballard, Chernoff & James, 2002; Bensch et al., 2006; Weisrock et al., 2006). Thus, the most difficult questions for multilocus phylogeography are what differences are expected, what differences exceed expectations, and what are the underlying causes in either case (Hudson & Turelli, 2003; Zink & Barrowclough, 2008). Most of the expected differences between mitochondrial and nuclear markers in the present study likely arise from two factors: differential mutation rates and uneven effective population sizes (Forister et al., 2004). In general, the possibility of recombination in nuclear loci and selection in both marker types should also be considered, although we found no evidence for either of these in our dataset. There are little data on expected mutation rates in nuclear introns relative to mitochondrial proteincoding sequences (Zhang & Hewitt, 2003) but the background rate should be significantly lower, perhaps one-tenth the mtDNA rate (Hare & Palumbi, 2003). The interaction of mutation generation and maintenance via larger Ne is generally expected to yield lower variation in nuclear haplotypes in a population sample (Zink & Barrowclough, 2008), although just how much less will be determined by many additional factors (Hudson & Turelli, 2003). The clearest finding supported by both genes was the generally low population connectedness. Both FST and autocorrelation analyses indicated rapid attenuation of similarity with distance. This indicates that the shared haplotypes or related haplotypes we observed across populations did not result from recent gene flow. This is further supported by COI relationships, where such geographic discordance was most obvious (San Bernardino haplotypes in the San Jacintos; Central Transverse Range haplotypes in the Tehachapis). In no cases were ‘rogue’ haplotypes identical © 2010 The Linnean Society of London, Biological Journal of the Linnean Society, 2010, 99, 424–444 438 M. POLIHRONAKIS and M. S. CATERINO to any in their source areas, indicating that we sampled descendants of the original contact, and that the observed relationships resulted from either ancient migration or the retention of ancestral polymorphism from a more broadly-distributed historical population. In the GFT network, these particular sets of areas shared common haplotypes but did not share any of the more recently derived variants within their respective groups. This supports the latter scenario suggesting these populations were broadly connected in the past. Further work resolving details of the evolutionary history in this group would continue to solidify support for the importance of this region with regard to the unique evolutionary dynamics and species diversity patterns found in the present study. Specifically, we need a more robust outgroup for this species, which may be difficult as a result of the fact that it is the only genus in its tribe worldwide. However, because of the relatively low variation of the nuclear gene in the present study, it may be possible to use species in related tribes of Pimeliinae to root the N. carinata nuclear gene tree. Increased taxon sampling in areas of high diversity, such as the southern Sierra Nevada, and throughout the more peripheral parts of the range would also provide further insight into important evolutionary processes in the species and the region. ACKNOWLEDGEMENTS Our field collections were assisted and facilitated by numerous individuals and agencies. We thank R. Aalbu, S. Chatzimanolis, K. Hopp, P. Jump, S. Mulqueen, S. Russell, P. Russell, A. Short, K. Will, the California Department of Fish and Game, Los Padres National Forest, Angeles National Forest, Sequoia National Forest, San Bernardino National Forest, San Dimas Experimental Forest, Arroyo Hondo Preserve (Land Trust for Santa Barbara County), Camp Cedar Falls, the UC McLaughlin Reserve, UC Sedgwick Reserve, UC Whitaker Forest, the UC James Reserve, and the UC Santa Cruz Island Reserve. We appreciate the assistance of I. Ouzounov and G. Betzholtz in the laboratory, J. Q. Richmond for help with the data interpretation, and V. Krauss for sharing his Tribolium intron data. This work was supported by the Schlinger Foundation, a bequest from G. Ostertag, and National Science Foundation award DEB0447694 to M. Caterino. REFERENCES Altschul SF, Madden TL, Schäffer AA, Zhang J, Miller W, Lipman DJ. 1997. Gapped BLAST and PSI-BLAST: a new generation of protein database search programs. Nucleic Acids Research 25: 3389–3402. Avise JC. 2000. Phylogeography. The history and formation of species. Cambridge, MA: Harvard University Press. Ballard WJ, Chernoff B, James AC. 2002. Divergence of mitochondrial DNA is not corroborated by nuclear DNA, morphology, or behavior in Drosophila simulans. Evolution 56: 527–545. Bensch S, Irwin DE, Irwin JH, Kvist L, Åkesson S. 2006. Conflicting patterns of mitochondrial and nuclear DNA diversity in Phylloscopus warblers. Molecular Ecology 15: 161–171. Berghoff SM, Kronauer JC, Edwards KJ, Franks NR. 2008. Dispersal and population structure of a New World predator, the army ant Eciton burchellii. Journal of Evolutionary Biology 21: 1125–1132. Blaisdell FE. 1931. Studies in the Tenebrionidae, number 3. Pan-Pacific Entomologist 8: 41–46. Bruen TC, Phillipe H, Bryant D. 2006. A simple and robust statistical test for detecting the presence of recombination. Genetics 172: 2665–2681. Calsbeek R, Thompson JN, Richardson JE. 2003. Patterns of molecular evolution and diversification in a biodiversity hotspot: the California Floristic Province. Molecular Ecology 12: 1021–1029. Cassens I, Mardulyn P, Milinkovitch MC. 2005. Evaluating intraspecific ‘network’ construction methods using simulated sequence data: do existing algorithms outperform the global maximum parsimony approach? Systematic Biology 54: 363–372. Caterino MS, Chatzimanolis S. 2009. Conservation genetics of three flightless beetle species in southern California. Conservation Genetics 10: 203–216. Caterino MS, Cho S, Sperling FAH. 2000. The current state of insect molecular systematics: a thriving Tower of Babel. Annual Review of Entomology 45: 1–54. Chan KMA, Levin SA. 2005. Leaky prezygotic isolation and porous genomes: rapid introgression of maternally inherited DNA. Evolution 59: 720–729. Chatzimanolis S, Caterino MS. 2007a. Toward a better understanding of the ‘Transverse Range break’: lineage diversification in southern California. Evolution 61: 2127– 2141. Chatzimanolis S, Caterino MS. 2007b. Limited phylogeographic structure in the flightless ground beetle, Calathus ruficollis, in southern California. Diversity and Distributions 13: 498–509. Conservation International. 2009. Biodiversity Hotspots. Downloaded on 13 July 2009. Available at: http://www. biodiversityhotspots.org/xp/hotspots/california_floristic/ Pages/default.aspx Davis EB, Koo MS, Conroy C, Patton JL, Moritz C. 2008. The California Hotspots Project: identifying regions of rapid diversification of mammals. Molecular Ecology 17: 120–138. Excoffier L, Smouse P, Quattro J. 1992. Analysis of molecular variance inferred from metric distances among DNA haplotypes: application to human mitochondrial DNA restriction data. Genetics 131: 479–491. © 2010 The Linnean Society of London, Biological Journal of the Linnean Society, 2010, 99, 424–444 PHYLOGEOGRAPHY OF N. CARINATA Excoffier L, Laval G, Schneider S. 2005. ARLEQUIN ver. 3.0: an intergrated software package for population genetics data analysis. Evolutionary Bioinformatics Online 1: 47– 50. Feldman CR, Spicer GS. 2006. Comparative phylogeography of woodland reptiles in California: repeated patterns of cladogenesis and population expansion. Molecular Ecology 15: 2201–2222. Forister ML, Fordyce JA, Shapiro AM. 2004. Geological barriers and restricted gene flow in the holarctic skipper Hesperia comma (Hesperiidae). Molecular Ecology 13: 3489– 3499. Godinho R, Crespo EG, Ferrand N. 2008. The limits of mtDNA phylogeography: complex patterns of population history in a highly structured Iberian lizard are only revealed by the use of nuclear markers. Molecular Ecology 17: 4670–4683. Gompert Z, Forister ML, Fordyce JA, Nice CC. 2008. Widespread mito-nuclear discordance with evidence for introgressive hybridization and selective sweeps in Lycaeides. Molecular Ecology 17: 5231–5244. Hare MP, Palumbi SR. 2003. High intron sequence conservation across three mammalian orders suggests functional constraints. Molecular Biology and Evolution 20: 969–978. Hewitt G. 2000. The genetic legacy of the Quaternary ice ages. Nature 405: 907–913. Hudson RR, Turelli M. 2003. Stochasticity overrules the ‘three-times rule’: genetic drift, genetic draft, and coalescence times for nuclear loci versus mitochondrial DNA. Evolution 57: 182–190. Huson DH. 1998. SplitsTree: a program for analyzing and visualizing evolutionary data. Bioinformatics 14: 68–73. Huson DH, Bryant D. 2006. Application of phylogenetic networks in evolutionary studies. Molecular Biology and Evolution 23: 254–267. Software available at http:// www.splitstree.org Irwin DE. 2002. Phylogeographic breaks without geographic barriers to gene flow. Evolution 56: 2383–2394. Jockusch EL, Wake DB. 2002. Falling apart and merging: diversification of slender salamanders (Plethodontidae: Batrachoseps) in the American West. Biological Journal of the Linnean Society 76: 361–391. Kerth G, Petrov B, Conti A, Anastasov D, Weishaar M, Gazaryan S, Jaquiéry J, König B, Perrin N, Bruyndonckx N. 2008. Communally breeding Bechstein’s bats have a stable social system that is independent from the postglacial history and location of the populations. Molecular Ecology 17: 2368–2381. Krauss V, Thümmler C, Georgi F, Lehmann J, Stadler PF, Eisenhardt C. 2008. Near intron positions are reliable phylogenetic markers: an application to holometabolous insects. Molecular Biology Evolution 25: 821–830. Kuchta SR, Tan AM. 2006. Lineage diversification on an evolving landscape: phylogeography of the California newt, Taricha torosa (Caudata: Salamandridae). Biological Journal of the Linnean Society 89: 213–239. Lapointe FJ, Rissler LJ. 2005. Notes and comments – congruence, consensus, and the comparative phylogeogra- 439 phy of codistributed species in California. American Naturalist 166: 290–299. Law JH, Crespi BJ. 2002. The evolution of geographic parthenogenesis in Timema walking-sticks. Molecular Ecology 11: 1471–1489. Linnen CR, Farrell BD. 2007. Mitonuclear discordance is caused by rampant mitochondrial introgression in Neodiprion (Hymenoptera: Diprionidae) sawflies. Evolution 61: 1417–1438. Macey JR, Strasburg JL, Brisson JA, Vredenburg VT, Jennings M, Larson A. 2001. Molecular phylogenetics of western North American frogs of the Rana boylii species group. Molecular Phylogenetics and Evolution 19: 131–143. Maddison WP. 1997. Gene trees in species trees. Systematic Biology 46: 523–536. Maldonado JE, Vila C, Wayne RK. 2001. Tripartite genetic subdivisions in the ornate shrew (Sorex ornatus). Molecular Ecology 10: 127–147. Matocq MD. 2002. Phylogeographical structure and regional history of the dusky-footed woodrat, Neotoma fuscipes. Molecular Ecology 11: 229–242. Matyukhin AV, Gongalsky KB. 2007. The home range size of two darkling beetle species (Coleoptera, Tenebrionidae) from southern Kazakhstan. Zoologichesky Zhurnal 86: 1446–1451. Miller MP. 2005. Alleles in Space (AIS): computer software for the joint analysis of interindividual spatial and genetic information. Journal of Heredity 96: 722–724. Miller MP, Haig SM, Wagner RS. 2005. Conflicting patterns of genetic structure produced by nuclear and mitochondrial markers in the Oregon slender salamander (Batrachoseps wrighti): implications for conservation efforts and species management. Conservation Genetics 6: 275–287. Miller MP, Bellinger R, Forsman ED, Haig SM. 2006. Effects of historical climate change, habitat connectivity, and vicariance on genetic structure and diversity across therange of the red tree vole (Phenacomys longicaudus) in the Pacific northwestern United States. Molecular Ecology 15: 145–159. Ngamprasertwong T, Mackie IJ, Racey PA, Piertney SB. 2008. Spatial distribution of mitochondrial and microsatellite DNA variation in Daubenton’s bat within Scotland. Molecular Ecology 17: 3243–3258. Nylander JAA. 2004. MrModeltest, Version 2. Program distributed by author. Evolutionary Biology Centre, Uppsala University. Peakall R, Smouse PE. 2006. GENALEX 6: genetic analysis in Excel. Population genetic software for teaching and research. Molecular Ecology Notes 6: 288–295. Peakall R, Ruibal M, Lindenmayer DB. 2003. Spatial autocorrelation analysis offers new insights into gene flow in the Australian bush rat, Rattus fuscipes. Evolution 57: 1182–1195. Peters JL, Zhuravlev Y, Fefelov I, Logie A, Omland KE. 2007. Nuclear loci and coalescent methods support ancient hybridization as cause of mitochondrial paraphyly between gadwall and falcated duck (Anas spp.). Evolution 61: 1992– 2006. © 2010 The Linnean Society of London, Biological Journal of the Linnean Society, 2010, 99, 424–444 440 M. POLIHRONAKIS and M. S. CATERINO Rich KA, Thompson JN, Fernandez CC. 2008. Diverse historical processesshape deep phylogeographical divergence in the pollinating seed parasite Greya politella. Molecular Ecology 17: 2430–2448. Rissler LJ, Hijmans RJ, Graham CH, Moritz C, Wake DB. 2006. Phylogeographic lineages and species comparisons in conservation analyses: a case study of California herpetofauna. American Naturalist 167: 655–666. Rodríguez-Robles JA, Denardo DF, Staub RE. 1999. Phylogeography of the California mountain king snake, Lampropeltis zonata (Colubridae). Molecular Ecology 8: 1923–1934. Segraves KA, Pellmyr O. 2001. Phylogeography of the yucca moth Tegeticula maculata: the role of historical biogeography in reconciling high genetic structure with limited speciation. Molecular Ecology 10: 1247–1253. Sgariglia EA, Burns KJ. 2003. Phylogeography of the California thrasher (Toxostoma redivivum) based on nestedclade analysis of mitochondrial-DNA variation. Auk 120: 346–361. Simon C, Frati F, Beckenback A, Crespi BJ, Liu H, Flook P. 1994. Evolution, weighting, and phylogenetic utility of mitochondrial gene sequences and a compilation of conserved polymerase chain reaction primers. Annals of the Entomological Society of America 87: 651–701. Smouse PE, Peakall R. 1999. Spatial autocorrelation analysis of individual multiallele and multilocus genetic structure. Heredity 82: 561–573. Spinks PQ, Shaffer HB. 2005. Range-wide molecular analysis of the western pond turtle (Emys marmorata): cryptic variation, isolation by distance, and their conservation implications. Molecular Ecology 14: 2047–2064. Spinks PQ, Shaffer HB. 2007. Conservation phylogenetics of the Asian box turtles (Geomydidae, Cuora): mitochondrial introgression, numts, and inferences from multiple nuclear loci. Conservation Genetics 8: 641–657. Starrett J, Hedin M. 2007. Multilocus genealogies reveal cryptic species and biogeographical complexity in the California turret spider Antrodiaetus riversi (Mygalomorphae, Antrodiaetidae). Molecular Ecology 16: 583–604. Stephens M, Scheet P. 2005. Accounting for decay of linkage disequilibrium in haplotype inference and missing data imputation. American Journal of Human Genetics 76: 449– 462. Stephens M, Smith NJ, Donnely P. 2001. A new statistical method for haplotype reconstruction from population data. American Journal of Human Genetics 68: 978–989. Swofford DL. 2002. PAUP*. Sunderland, MA: Sinauer Associates. Tajima F. 1989. Statistical method for testing the neutral mutation hypothesis by DNA polymorphism. Genetics 123: 585–595. Weisrock DW, Shaffer HB, Storz BL, Storz SR, Voss SR. 2006. Multiple nuclear gene sequences identify phylogenetic species boundaries in the rapidly radiating clade of Mexican ambystomatid salamanders. Molecular Ecology 15: 2489– 2503. Zhang DX, Hewitt GM. 2003. Nuclear DNA analyses in genetic studies of populations: practice, problems and prospects. Molecular Ecology 12: 563–584. Zhang AB, Sota T. 2007. Nuclear gene sequences resolve species phylogeny and mitochondrial introgression in Leptocarabus beetles showing trans-species polymorphisms. Molecular Phylogenetics and Evolution 45: 534– 546. Zink RM, Barrowclough GF. 2008. Mitochondrial DNA under siege in avian phylogeography. Molecular Ecology 17: 2107–2121. Zwickl DJ. 2006. Genetic algorithm approaches for the phylogenetic analysis of large biological sequence data sets under maximum likelihood criterion, PhD Dissertation, University of Texas at Austin. © 2010 The Linnean Society of London, Biological Journal of the Linnean Society, 2010, 99, 424–444 PHYLOGEOGRAPHY OF N. CARINATA 441 APPENDIX SAMPLING LOCALITIES BY REGION, WITH HAPLOTYPES REPRESENTED IN EACH (LOCALITY NUMBERS REFER TO POINTS ON FIG. Population 1) N Locality Coordinates COI haplotypes GFT haplotypes 1. Northern Santa Lucias 10 1.1 – CA: Monterey Co., Arroyo Seco County Park 36.2341°N, 121.4886°W N88, N89, N90, N91 G04, G55, G56, G57 Total 2. Southern Santa Lucias 10 5 2.1 – CA: San Luis Obispo Co., LPNF, Cuesta Ridge 2.2 – CA: San Luis Obispo Co., Santa Rosa Creek 35.3731°N, 120.6859°W N13, N14, N15 G04, G09, G10 35.5861°N, 121.0057°W N93 G60 3.1 – CA: Fresno Co., Sequoia NF, SE of Hume Lake 3.2 – CA: Tulare Co., Sequoia NF, UC Whitaker Forest 3.2 – CA: Tulare Co., Sequoia NF, F.S. 14S75 36.7718°N, 118.8854°W N78, N79 G39, G40, G41, G42 36.7025°N, 118.9322°W N72, N73, N74, N75, N76, N77 G32, G33, G34, G35, G36, G37, G38, G49 36.6720°N, 118.9798°W N80 G43 4.1 – CA: Kern Co., Sequoia NF, Kern Cyn. 35.4753°N, 118.7284°W N02 – 5.1 – CA: Kern Co., Oak Creek Cyn. 5.1 – CA: Kern Co., Oak Creek Cyn. 5.1 – CA: Kern Co., Tehachapi Mountain Park 5.1 – CA: Kern Co., Woodford-Tehachapi Rd 35.0487°N, 118.3605°W 35.0506°N, 118.3567°W 35.0673°N, 118.4820°W N61, N62 G01 N61, N63 G01 N81, N82 G01, G44, G45, G46, G47 35.1807°N, 118.5150°W N81 G45, G48 34.4855°N, 120.1423°W N64, N65, N66 – 34.4855°N, 120.1417°W N7, N8 G07 34.47°N, 119.73°W N44 G14 34.5009°N, 119.3899°W 34.4504°N, 119.1207°W 34.293°N, 119.204°W N50, N51, N52, N53, N54 N42 G26, G05, G04, G27, G17, G28 G05, G22 N28, N29, N30 G05, G17, G01, G18 1 Total 3. Southwestern Sierra Nevada 6 2 8 1 Total 4. Breckenridge Mountains Total 5. Tehachapi Mountains 11 2 2 2 5 3 1 Total 6. Santa Ynez Mountains 11 3 2 1 5 1 3 6.1 – CA: Santa Barbara Co., Arroyo Hondo Preserve 6.1 – CA: Santa Barbara Co., Arroyo Hondo Preserve 6.2 – CA: Santa Barbara Co., Santa Barbara 6.3 – CA: Ventura Co., LPNF, Murrietta Tr. 6.4 – CA: Ventura Co., Upper Ojai Valley 6.5 – CA: Ventura Co., Ventura © 2010 The Linnean Society of London, Biological Journal of the Linnean Society, 2010, 99, 424–444 442 M. POLIHRONAKIS and M. S. CATERINO APPENDIX Continued Population N Total 7. Northwest Transverse Ranges 15 1 1 2 1 1 1 1 2 1 1 1 1 1 2 2 1 Total 8. Central Transverse Ranges 20 2 4 Locality Coordinates COI haplotypes GFT haplotypes 7.1 – CA: Santa Barbara Co., UC Sedgwick Reserve 7.1 – CA: Santa Barbara Co., UC Sedgwick Reserve 7.1 – CA: Santa Barbara Co., UC Sedgwick Reserve 7.1 – CA: Santa Barbara Co., UC Sedgwick Reserve 7.1 – CA: Santa Barbara Co., UC Sedgwick Reserve 7.1 – CA: Santa Barbara Co., UC Sedgwick Reserve 7.1 – CA: Santa Barbara Co., UC Sedgwick Reserve 7.1 – CA: Santa Barbara Co., UC Sedgwick Reserve 7.1 – CA: Santa Barbara Co., UC Sedgwick Reserve 7.1 – CA: Santa Barbara Co., UC Sedgwick Reserve 7.1 – CA: Santa Barbara Co., UC Sedgwick Reserve 7.2 – CA: Santa Barbara Co., LPNF, Sunset Valley 7.3 – CA: Santa Barbara Co., LPNF, Rancho Alegre 7.4 – CA: Santa Barbara Co., LPNF, Big Pine Mountain 7.4 – CA: Santa Barbara Co., LPNF, Big Pine Mountain 7.5 – CA: Ventura Co., LPNF, north slope Pine Mountain 34.6796°N, 120.0387°W N9 G04 34.6825°N, 120.0445°W N9 34.6842°N, 120.0459°W N11, N12 G04 34.6889°N, 120.0428°W N49 G24, G25 34.7127°N, 120.0396°W N35 G04, G20 34.7132°N, 120.0395°W N41 G04 34.7164°N, 120.0396°W N23 G04, G13 34.7197°N, 120.0366°W N31, N39 G04 34.7261°N, 120.0483°W N43 G20, G23 34.7269°N, 120.0474°W N9 G04, G08 34.7197°N, 120.0415°W – G04 34.7538°N, 119.9429°W N3 G04 34.5410°N, 119.9110°W N24 G14, G15 34.7021°N, 119.6547°W N4 G04 34.7032°N, 119.6526°W N36, N38 G04 34.6585°N, 119.3800°W N1 – 8.1 – CA: Kern Co., LPNF, Tecuya Rd. 8.1 – CA: Kern Co., LPNF, Tecuya Trail 34.8484°N, 119.0697°W 34.8300°N, 119.0078°W N94, N96 G01 N94, N95 G01 © 2010 The Linnean Society of London, Biological Journal of the Linnean Society, 2010, 99, 424–444 PHYLOGEOGRAPHY OF N. CARINATA 443 APPENDIX Continued Population N Total 9. Sierra Pelona 6 7 Total 10. San Gabriel Mountains 7 7 2 3 2 2 Total 11. San Bernardino Mountains 16 1 1 1 2 4 2 Total Locality Coordinates COI haplotypes GFT haplotypes 9.1 – CA: Los Angeles Co., Angeles NF, Grass Mountain 34.6408°N, 118.4148°W N10, N18, N26, N37, N46, N47, N48 G01, G02, G03 10.1 – CA: Los Angeles Co., Placerita Cyn. Co. Pk. 10.2 – CA: Los Angeles Co., Angeles NF, Angeles Crest Hwy. 10.2 – CA: Los Angeles Co., Angeles NF, Hwy N3 10.2 – CA: Los Angeles Co., Angeles NF, Hwy N3 10.3 – CA: Los Angeles Co., Angeles NF, San Dimas Exp. Forest 34.3764°N, 118.4403°W N55, N56, N57, N58, N59, N60 G01 34.2717°N, 118.0608°W N25, N27 G16 34.2964°N, 118.1625°W N25, N67, N68 G16, G29, G30 34.2910°N, 118.1695°W N71, N85 G01, G50 34.2012°N, 117.7736°W N86, N87 G51, G52, G53, G54 34.2955°N, 117.2134°W N84 G05, G31 34.1864°N, 117.1836°W N45 G05, G21 34.1741°N, 116.9844°W N40 G06, G21 34.1678°N, 116.9143°W N05, N06 G05, G06 34.1819°N, 116.8884°W N06, N70 G05, G06 34.1646°N, 116.9366°W N69 G05 11.1 – CA: San Bernardino Co., SBNF, Hwy 173 11.2 – CA: San Bernardino Co., SBNF, City Ck. 11.3 – CA: San Bernardino Co., SBNF, Deer Creek 11.3 – CA: San Bernardino Co., SBNF, W. of Barton Flats 11.3 – CA: San Bernardino Co., SBNF, Santa Ana R. 11.3 – CA: San Bernardino Co., SBNF, Camp Cedar Falls 11 © 2010 The Linnean Society of London, Biological Journal of the Linnean Society, 2010, 99, 424–444 444 M. POLIHRONAKIS and M. S. CATERINO APPENDIX Continued Population 12. San Jacinto Mountains N 8 1 1 1 Total 13. Santa Cruz Islands 11 2 4 Total Locality Coordinates COI haplotypes GFT haplotypes 12.1 – CA: Riverside Co., UC James Reserve 12.1 – CA: Riverside Co., UC James Reserve 12.1 – CA: Riverside Co., SBNF, F.S. 4S01 12.1 – CA: Riverside Co., SBNF, Marion Mountain 33.8092°N, 116.7650°W N16, N17, N19, N20, N21, N22 G05, G11 33.8081°N, 116.7784°W N83 G11 33.8448°N, 116.7322°W N19 G05 33.7949°N, 116.7214°W N32 G05 34.0191°N, 119.6878°W N33, N34 G04, G04, G19 34.0222°N, 119.6906°W N97, N98, N99, N100 G04, G19, G61, G62 13.1 – CA: Santa Barbara Co., Santa Cruz Islands 13.1 – CA: Santa Barbara Co., Pelican Bay Tr. 6 SUPPORTING INFORMATION Additional Supporting Information may be found in the online version of this article: Appendix S1. Haplotypes and GenBank accession numbers. ‘N’ haplotypes refer to the Nyctoporis carinata COI sequence; ‘G’ haplotypes refer to the Nyctoporis carinata GFT sequence. Please note: Blackwell Publishing are not responsible for the content or functionality of any supporting materials supplied by the authors. Any queries (other than missing material) should be directed to the corresponding author for the article. © 2010 The Linnean Society of London, Biological Journal of the Linnean Society, 2010, 99, 424–444
© Copyright 2026 Paperzz