Molecular phylogeny of Cryptocercus wood-roaches based on mitochondrial COII and 16S sequences, and chromosome numbers in Palearctic representatives.

Woodroaches of the genus Cryptocercus are subsocial and xylophagous cockroaches, distributed in North America and Asia. Studies on male chromosome number in Nearctic species have shown that diploid numbers vary from 2n=37 to 2n=47; numbers from Palearctic species were heretofore unknown. Two hypotheses have been proposed to explain the varying number of chromosomes among Nearctic species: the serial reduction hypothesis, and the parallel scenario. We performed phylogenetic analyses of the COII gene in these species and found evidence for the topology (47(45(43(39,37), which is congruent with the serial reduction hypothesis. We also determined chromosome numbers for the first time in Palearctic species, and found Cryptocercus primarius and Cryptocercus relictus to have relatively low chromosome numbers (2n=17-21) compared to their Nearctic relatives. Finally, our study determined the phylogenetic position of Cryptocercus primarius among other Asian taxa.

Independent gene phylogenies and morphology demonstrate a malagasy origin for a wide-ranging group of swallowtail butterflies.

Madagascar is home to numerous endemic species and lineages, but the processes that have contributed to its endangered diversity are still poorly understood. Evidence is accumulating to demonstrate the importance of Tertiary dispersal across varying distances of oceanic barriers, supplementing vicariance relationships dating back to the Cretaceous, but these hypotheses remain tentative in the absence of well-supported phylogenies. In the Papilio demoleus group of swallowtail butterflies, three of the five recognized species are restricted to Madagascar, whereas the remaining two species range across the Afrotropical zone and southern Asia plus Australia. We reconstructed phylogenetic relationships for all species in the P. demoleus group, as well as 11 outgroup Papilio species, using 60 morphological characters and about 4 kb of nucleotide sequences from two mitochondrial (cytochrome oxidase I and II) and two nuclear (wg and EF-1alpha) genes. Of the three endemic Malagasy species, the two that are formally listed as endangered or at risk represented the most basal divergences in the group, while the more common third endemic was clearly related to African P. demodocus. The fifth species, P. demoleus, showed little differentiation across southern Asia, but showed divergence from its subspecies sthenelus in Australia. Dispersal-vicariance analysis using cladograms derived from morphology and three independent genes indicated a Malagasy diversification of lime swallowtails in the middle Miocene. Thus, diversification processes on the island of Madagascar may have contributed to the origin of common butterflies that now occur throughout much of the Old World tropical and subtemperate regions. An alternative hypothesis, that Madagascar is a refuge for ancient lineages resulting from successive colonizations from Africa, is less parsimonious and does not explain the relatively low continental diversity of the group.

Genetic differentiation across a latitudinal gradient in two co-occurring butterfly species: revealing population differences in a context of climate change.

Genetic differentiation within a species' range is determined by natural selection, genetic drift, and gene flow. Selection and drift enhance genetic differences if populations are sufficiently isolated, while gene flow precludes differentiation and local adaptation. Over large geographical areas, these processes can create a variety of scenarios, ranging from admixture to a high degree of population differentiation. Genetic differences among populations may signal functional differences within a species' range, potentially leading to population or ecotype-specific responses to global change. We investigated differentiation within the geographical range of two butterfly species along a broad latitudinal gradient. This gradient is the primary axis of climatic variation, and many ecologists expect populations at the poleward edge of this gradient to expand under climate change. Our study species inhabit a shared ecosystem and differ in body size and resource specialization; both also find their poleward range limit on an island. We find evidence for divergence of peripheral populations from the core in both taxa, suggesting the potential for genetic distinctiveness at the leading edge of climate change. We also find differences between the species in the extent of peripheral differentiation with the smaller and more specialized species showing greater population divergence (microsatellites and mtDNA) and reduced gene flow (mtDNA). Finally, gene flow estimates in both species differed strongly between two marker types. These findings suggest caution in assuming that populations are invariant across latitude and thus will respond as a single ecotype to climatic change.

Phylogeny, historical biogeography, and taxonomic ranking of Parnassiinae (Lepidoptera, Papilionidae) based on morphology and seven genes.

We tested the taxonomic utility of morphology and seven mitochondrial or nuclear genes in a phylogenetic reconstruction of swallowtail butterflies in the subfamily Parnassiinae. Our data included 236 morphological characters and DNA sequences for seven genes that are commonly used to infer lepidopteran relationships (COI+COII, ND5, ND1, 16S, EF-1alpha, and wg; total 5775 bp). Nuclear genes performed best for inferring phylogenies, particularly at higher taxonomic levels, while there was substantial variation in performance among mitochondrial genes. Multiple analyses of molecular data (MP, ML and Bayesian) consistently produced a tree topology different from that obtained by morphology alone. Based on molecular evidence, sister-group relationships were confirmed between the genera Hypermnestra and Parnassius, as well as between Archon and Luehdorfia, while the monophyly of the subfamily was weakly supported. We recognize three tribes within Parnassiinae, with Archon and Luehdorfia forming the tribe Luehdorfiini Tutt, 1896 [stat. rev.]. Three fossil taxa were incorporated into a molecular clock analysis with biogeographic time constraints. Based on dispersal-vicariance (DIVA) analysis, the most recent common ancestor of Parnassiinae occurred in the Iranian Plateau and Central Asia to China. Early diversification of Parnassiinae took place at the same time that India collided into Eurasia, 65-42 million years ago.

Molecular phylogeny, historical biogeography, and divergence time estimates for swallowtail butterflies of the genus Papilio (Lepidoptera: Papilionidae).

Swallowtail butterflies are recognized as model organisms in ecology, evolutionary biology, genetics, and conservation biology but present numerous unresolved phylogenetic problems. We inferred phylogenetic relationships for 51 of about 205 species of the genus Papilio (sensu lato) from 3.3-Kilobase (kb) sequences of mitochondrial and nuclear DNA (2.3 kb of cytochrome oxidases I and II and 1.0 kb of elongation factor 1 alpha). Congruent phylogenetic trees were recovered within Papilio from analyses of combined data using maximum likelihood, Bayesian analysis, and maximum parsimony bootstrap consensus. Several disagreements with the traditional classification of Papilio were found. Five major previously hypothesized subdivisions within Papilio were well supported: Heraclides, Pterourus, Chilasa, Papilio (sensu stricto), and Eleppone. Further studies are required to clarify relationships within traditional "Princeps," which was paraphyletic. Several biologically interesting characteristics of Papilio appear to have polyphyletic origins, including mimetic adults, larval host associations, and larval morphology. Early diversification within Papilio is estimated at 55-65 million years ago based on a combination of biogeographic time constraints rather than fossils. This divergence time suggests that Papilio has slower apparent substitution rates than do Drosophila and fig-pollinating wasps and/or divergences corrected using best-fit substitution models are still being consistently underestimated. The amount of sequence divergence between Papilio subdivisions is equivalent to divergences between genera in other tribes of the Papilionidae, and between genera of moths of the noctuid subfamily Heliothinae.