Bremer Support (bremer + support)

Distribution by Scientific Domains


Selected Abstracts


From kissing to belly stridulation: comparative analysis reveals surprising diversity, rapid evolution, and much homoplasy in the mating behaviour of 27 species of sepsid flies (Diptera: Sepsidae)

JOURNAL OF EVOLUTIONARY BIOLOGY, Issue 11 2009
N. PUNIAMOORTHY
Abstract Our understanding of how fast mating behaviour evolves in insects is rather poor due to a lack of comparative studies among insect groups for which phylogenetic relationships are known. Here, we present a detailed study of the mating behaviour of 27 species of Sepsidae (Diptera) for which a well-resolved and supported phylogeny is available. We demonstrate that mating behaviour is extremely diverse in sepsids with each species having its own mating profile. We define 32 behavioural characters and document them with video clips. Based on sister species comparisons, we provide several examples where mating behaviour evolves faster than all sexually dimorphic morphological traits. Mapping the behaviours onto the molecular tree reveals much homoplasy, comparable to that observed for third positions of mitochondrial protein-encoding genes. A partitioned Bremer support (PBS) analysis reveals conflict between the molecular and behavioural data, but behavioural characters have higher PBS values per parsimony-informative character than DNA sequence characters. [source]


A phylogenetic analysis of the monogenomic Triticeae (Poaceae) based on morphology

BOTANICAL JOURNAL OF THE LINNEAN SOCIETY, Issue 1 2001
OLE SEBERG FLS
A cladistic analysis, primarily based on morphology, is presented from 40 diploid taxa representing the 24 monogenomic genera of the Triticeae. General problems related to the treatment of hybrids and supposedly allopolyploid heterogenomic taxa are highlighted. Special emphasis is given to taxa not traditionally included in Aegilops s.J. Most of the 33 characters used in the analysis are coded as binary. The only four multistate characters in the matrix are treated as unordered. Three diploid species of Bromus are used as outgroup. The number of equally parsimonious trees found is very large (approx. 170000; length = 107, ci = 0.36, ri = 0.75) and the strict consensus tree has an expectedly low level of resolution. However, most of the equally parsimonious trees owe their existence to an unresolved Aegilops clade. If this clade is replaced by its hypothetical ancestor, the number of equally parsimonious trees drops dramatically (48; length = 78, ci = 0.45, ri = 0.76). When trees for which more highly resolved compatible trees exist are excluded, only two trees remain. Bremer support is used as a measure of branch support. The trees based on morphology and on molecular data are largely incongruent. [source]


Higher-level phylogeny of the Ithomiinae (Lepidoptera: Nymphalidae): classification, patterns of larval hostplant colonization and diversification

CLADISTICS, Issue 4 2006
Keith R. Willmott
We present a higher-level phylogenetic hypothesis for the diverse neotropical butterfly subfamily Ithomiinae, inferred from one of the largest non-molecular Lepidoptera data sets to date, including 106 species (105 ingroup) and 353 characters (306 informative) from adult and immature stage morphology and ecology. Initial analyses resulted in 1716 most parsimonious trees, which were reduced to a single tree after successive approximations character weighting. The inferred phylogeny was broadly consistent with other past and current work. Although some deeper relationships are uncertain, tribal-level clades were generally strongly supported, with two changes required to existing classification. The tribe Melinaeini is polyphyletic and Athesis + Patricia require a new tribe. Methona should be removed from Mechanitini into the restored tribe Methonini. Dircennini was paraphyletic in analyses of all data but monophyletic based on adult morphology alone, and its status remains to be confirmed. Hypothyris, Episcada, Godyris, Hypoleria and Greta are paraphyletic. A simulation analysis showed that relatively basal branches tended to have higher partitioned Bremer support for immature stage characters. Larval hostplant records were optimized on to a reduced, generic-level phylogeny and indicate that ithomiines moved from Apocynaceae to Solanaceae twice, or that Tithoreini re-colonized Apocynaceae after a basal shift to Solanaceae. Ithomiine clades have specialized on particular plant clades suggesting repeated colonization of novel hostplant niches consistent with adaptive radiation. The shift to Solanum, comprising 70% of neotropical Solanaceae, occurs at the base of a clade containing 89% of all ithomiines, and is interpreted as the major event in the evolution of ithomiine larval hostplant relationships. © The Willi Hennig Society 2006. [source]


Phylogeny of Mysis (Crustacea, Mysida): history of continental invasions inferred from molecular and morphological data

CLADISTICS, Issue 6 2005
Asta Audzijonyt
We studied the phylogenetic history of opossum shrimps of the genus Mysis Latreille, 1802 (Crustacea: Mysida) using parsimony analyses of morphological characters, DNA sequence data from mitochondrial (16S, COI and CytB) and nuclear genes (ITS2, 18S), and eight allozyme loci. With these data we aimed to resolve a long-debated question of the origin of the non-marine (continental) taxa in the genus, i.e., "glacial relicts" in circumpolar postglacial lakes and "arctic immigrants" in the Caspian Sea. A simultaneous analysis of the data sets gave a single tree supporting monophyly of all continental species, as well as monophyly of the taxa from circumpolar lakes and from the Caspian Sea. A clade of three circumarctic marine species was sister group to the continental taxa, whereas Atlantic species had more distant relationships to the others. Small molecular differentiation among the morphologically diverse endemic species from the Caspian Sea suggested their recent speciation, while the phenotypically more uniform "glacial relict" species from circumpolar lakes (Mysis relicta group) showed deep molecular divergences. For the length-variable ITS2 region both direct optimization and a priori alignment procedures gave similar topologies, although the former approach provided a better overall resolution. In terms of partitioned Bremer support (PBS), mitochondrial protein coding genes provided the largest contribution (83%) to the total tree resolution. This estimate however, appears to be partly spurious, due to the concerted inheritance of mitochondrial characters and probable cases of introgression or ancestral polymorphism. © The Willi Hennig Society 2005. [source]


Morphology versus molecules: resolution of the positions of Nymphalis, Polygonia, and related genera (Lepidoptera: Nymphalidae)

CLADISTICS, Issue 3 2003
Niklas Wahlberg
The debate on whether to combine different data sets for simultaneous analysis has continued to the present day unabated. We have studied the effects of combining one morphological data set with four molecular data sets (two mitochondrial gene sequences and two nuclear gene sequences) for a group of butterflies belonging to the tribe Nymphalini using partitioned Bremer support. We particularly focus our attention on a group of species belonging to the genera Aglais, Inachis, Roddia, Nymphalis, Kaniska, and Polygonia. We find that, despite significant incongruence between most data partitions, all data partitions contribute positively to the support of most nodes in the most parsimonious trees found for the combined data set. We also find that the morphological data set resolves one particular node (Kaniska basal to Polygonia) with good support, while the molecular data sets are ambiguous about the existence of this node. We suggest that partitioned Bremer support allows one to critically appraise the robustness of each node in a given tree and thereby identify nodes that may change with the addition of new data and nodes that are likely to remain unchanged with new data. We also suggest that morphological data are still crucial to our being able to understand the relationships of extant organisms, despite published views to the contrary. Based on our results we suggest that Inachis should be synonymized with Aglais, Roddia with Nymphalis, and Kaniska with Polygonia. [source]


Partitioned Bremer support and multiple trees

CLADISTICS, Issue 4 2002
Christine L. Lambkin
Partitioned Bremer support (PBS) is a valuable means of assessing congruence in combined data sets, but some aspects require clarification. When more than one equally parsimonious tree is found during the constrained search for trees lacking the node of interest, averaging PBS for each data set across these trees can conceal conflict, and PBS should ideally be examined for each constrained tree. Similarly, when multiple most parsimonious trees (MPTs) are generated during analysis of the combined data, PBS is usually calculated on the consensus tree. However, extra information can be obtained if PBS is calculated on each of the MPTs or even suboptimal trees. [source]