Syntormon Loew (Diptera, Dolichopodidae) from Inner Mongolia, China, with the description of a new species

Previously, no records of Syntormon Loew, 1857 species were known from Inner Mongolia (China). The genus is reported here from Inner Mongolia for the first time, with the description of a new species, S.sinicum sp. nov., along with two previously described species, S.dukha Hollis, 1964 and S.henanense Yang & Saigusa, 2000. Syntormonsinicum sp. nov. and S.dukha Hollis, 1964 are barcoded for the first time to support the species delimitation. A key to Syntormon species in China is provided.

A new species of Thinophilus Wahlberg (Diptera: Dolichopodidae: Hydrophorinae) from coastal India with re-description of Thinophilus tesselatus Becker (Diptera: Dolichopodidae: Hydrophorinae)

A new peculiar species of marine dolichopodid fly from West Bengal, India is described: Thinophilus maritimus Mukherjee & Pramanik sp. nov. COI barcodes of the new species were compared to other available Thinophilus sequences. Despite the lack of lateral setae on its hind coxa, this species clusters within the Thinophilus group. Males of Thinophilus tesselatus Becker, 1922 were also obtained from the same area, and a detailed redescription of the species is presented here. A checklist of 70 Oriental Thinophilus species is also provided.

Multiple, independent colonizations of the Hawaiian Archipelago by the family Dolichopodidae (Diptera)

The family Dolichopodidae forms two of the four largest evolutionary radiations in the Hawaiian Islands across all flies: Campsicnemus (183 spp) and the Eurynogaster complex (66 spp). They also include a small radiation of Conchopus (6 spp). A handful of other dolichopodid species are native to the islands in singleton lineages or small radiations. This study provides a phylogenetic perspective on the colonization history of the dolichopodid fauna in the islands. We generated a multi-gene data set including representatives from 11 of the 14 endemic Hawaiian dolichopodid genera to examine the history of colonization to the islands, and analyzed it using Bayesian and maximum likelihood phylogenetic methods. We used a subset of the data that included Conchopus and the eight genera comprising the Eurynogaster complex to estimate the first phylogenetic hypothesis for these endemic groups, then used Beast to estimate their age of arrival to the archipelago. The Eurynogaster complex, Campsicnemus and Conchopus are clearly the result of independent colonizations. The results strongly support the Eurynogaster complex as a monophyletic group, and also supports the monophyly of 4 of the 8 described genera within the complex (Adachia, Arciellia, Uropachys and Eurynogaster). Members of the family Dolichopodidae have been dispersing over vast distances to colonize the Hawaiian Archipelago for millions of years, leading to multiple independent evolutionary diversification events. The Eurynogaster complex arrived in the Hawaiian Archipelago 11.8 Ma, well before the arrival of Campsicnemus (4.5 Ma), and the even more recent Conchopus (1.8 Ma). Data presented here demonstrate that the Hawaiian Dolichopodidae both disperse and diversify easily, a rare combination that lays the groundwork for field studies on the reproductive isolating mechanisms and ecological partitioning of this group.

Analysis of three leafminers' complete mitochondrial genomes

Liriomyza trifolii (Burgess), Liriomyza huidobrensis (Blanchard), and Liriomyza bryoniae (Kaltenbach), are three closely related and economically important leafminer pests in the world. This study examined the complete mitochondrial genomes of L. trifolii, L. huidobrensis and L. bryoniae, which were 16,141 bp, 16,236 bp and 16,183 bp in length, respectively. All of them displayed 37 typical animal mitochondrial genes and an A+T-rich region. The genomes were highly compact with only 60-68 bp of non-coding intergenic spacer. However, considerable differences in the A+T-rich region were detected among the three species. Results of this study also showed the two ribosomal RNA genes of the three species had very limited variable sites and thus should not provide much information in the study of population genetics of these species. Data generated from three leafminers' complete mitochondrial genomes should provide valuable information in studying phylogeny of Diptera, and developing genetic markers for species identification in leafminers.

Infections with the microbe Cardinium in the Dolichopodidae and other Empidoidea

Maternally transmitted reproductive parasites such as Wolbachia and Cardinium can drastically reshape reproduction in their hosts. Beyond skewing sex ratios towards females, these microbes can also cause cytoplasmic incompatibility. Wolbachia probably infects two thirds of insects, but far less is known about the occurrence or action of other bacteria with potentially similar effects. In contrast with the two more widespread reproductive parasites, Wolbachia and Spiroplasma, far less is known of infections with Cardinium (Bacteroidetes) and possible consequences in the Diptera. Here, in an extensive survey, 244 dipteran species from 67 genera belonging to the Dolichopodidae, Empididae, and Hybotidae were assessed for the presence of the microbe Cardinium. Although 130 of the species screened tested positive (ca. 53%), the presence of Cardinium could only be confirmed in 10 species (ca. 4%) based on analysis of sequences. Numerous additional sequences were found to be assignable to known or unknown Bacteroidetes. Considering the known issues concerning specificity of Cardinium primers and the phylogenetic uncertainties surrounding this microbe, the actual prevalence of this symbiont is worthy of further scrutiny. Potential directions for future research on Cardinium-host interactions in Diptera and in general are discussed.

Infections with Wolbachia, Spiroplasma, and Rickettsia in the Dolichopodidae and other Empidoidea

Vertically transmitted reproductive parasites are both extraordinarily widespread and diverse in their effects on their invertebrate hosts. In addition to causing skewed population sex ratios via male-killing or feminization, such bacteria can further cause cytoplasmic incompatibility or parthenogenesis. Previous surveys show that the microbes Wolbachia and Spiroplasma are common in some dipteran families, e.g. Drosophilidae or Scathophagidae, and are known to be heritable symbionts and affect reproduction in the Diptera. However, little is known of Rickettsia infections and detailed surveys targeting other Dipteran families are lacking. Here 329 samples of 247 species of Diptera belonging to the Dolichopodidae, Empididae, and Hybotidae (superfamily Empidoidea) are surveyed for the presence of the endosymbionts Wolbachia, Spiroplasma, and Rickettsia. The superfamily Empidoidea contains numerous species, which have been the targets of intense research concerning reproductive traits involved in sexual selection. 151 of the species (i.e. ca. 61%) screened here, including species from key genera such as Dolichopus, Poecilobothrus or Empis, harboured one or more symbionts. Reproductive parasites are thus also common in the Empidoidae, yet effects on hosts remain unclear. Potential endosymbiont-host interactions in this group would hence be worthy of further investigation.

Molecular data sheds light on the classification of long-legged flies (Diptera:Dolichopodidae)

Dolichopodidae (long-legged flies) is the world’s fourth largest dipteran family, but a phylogeny based on a broad global taxon sample is still lacking. We present here a first molecular phylogenetic hypothesis for Dolichopodidae, based on 157 dolichopodid species in 68 genera and 15 subfamilies from the Old and New World, and seven empidoid species (Empididae, Hybotidae) as outgroups. Both relatively fast-evolving mitochondrial markers (COI, 12S, 16S) and a more conserved nuclear marker (18S) were used, the latter being widely employed to study the phylogeny at higher taxonomic levels. We present strong evidence for Microphorinae as sister group to Dolichopodidae sensu stricto, and for the monophyletic Parathalassiinae as part of Dolichopodidae sensu stricto. Monophyly of Achalcinae, Dolichopodinae, and Sciapodinae is supported and Stolidosomatinae are placed within Sympycninae. Diaphorinae, Medeterinae, Neurigoninae, Rhaphiinae, and Sympycninae are paraphyletic, and Hydrophorinae and Peloropeodinae polyphyletic. Our broad taxon sample allows us to gain new insights into the complex systematics of Dolichopodidae. Our results highlight several problems with the traditional classification, which have considerable consequences for the systematic status of some taxa. The poor resolution observed in deep divergences supports previous hypotheses suggesting a rapid early radiation of Dolichopodidae.

Hypotheses from mitochondrial DNA: congruence and conflict between DNA sequences and morphology in Dolichopodinae systematics (Diptera:Dolichopodidae)

The molecular phylogeny of the subfamily Dolichopodinae (Diptera : Dolichopodidae) is reconstructed based on 79 species of 7 dolichopodine genera as ingroup, and 10 non-dolichopodine species from different genera as outgroup. A Bayesian analysis based on a mitochondrial DNA dataset consisting of 1702 characters (COI : 810; 12S : 366; 16S : 526) was carried out. Genital and non-genital morphological characters from a hitherto unpublished data matrix (based on 57 Dolichopodidae species) were used to explain and support the lineages hypothesised by our molecular phylogenetic analysis. The monophyly of the subfamily Dolichopodinae, and of the genera Dolichopus and Gymnopternus, was confirmed. The molecular analysis yielded nine species groups in Dolichopus that were proposed in previous studies using COI and Cyt-b. No evidence was found to support a clade including Dolichopus, Ethiromyia, and Gymnopternus. The genus Hercostomus proved polyphyletic with respect to Poecilobothrus, Sybistroma, and Gymnopternus. The following lineages were represented by strongly supported clades: Hercostomus germanus species group, H. vivax species group, H. nigrilamellatus species group, H. plagiatus species group, H. longiventris species group, H. fulvicaudis species group, and Poecilobothrus, Gymnopternus, Tachytrechus and Sybistroma (including Hercostomus nanus and H. parvilamellatus). Two clades that were previously established on the basis of morphology were confirmed in our phylogenetic analysis: (i) Poecilobothrus and the flower-feeding Hercostomus germanus species group, and (ii) the H. longiventris lineage and Sybistroma. In most cases, the groups identified in the molecular analysis could be supported and explained by morphological characters. Species of the Hercostomus germanus species group, Poecilobothrus, the Hercostomus longiventris species group, and a Sybistroma subclade have a similar microhabitat affinity.