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PubMed2005

Molecular phylogenetic analysis of nycteribiid and streblid bat flies (Diptera: Brachycera, Calyptratae): implications for host associations and phylogeographic origins.

Bat flies are a small but diverse group of highly specialized ectoparasitic, obligatory bloodsucking Diptera. For the first time, the phylogenetic relationships of 26 species and five subfamilies were investigated using four genes (18S rDNA, 16S rDNA, COII, and cytB) under three optimality criteria (maximum parsimony (MP), maximum likelihood (ML), and Bayesian inference). Tree topology tests of previous hypotheses were conducted under likelihood (Shimodaira-Hasegawa test). Major findings include the non-monophyly of the Streblidae and the recovery of an Old World- and a New World-Clade of bat flies. These data ambiguously resolve basal relationships between Hippoboscidae, Glossinidae, and bat flies. Recovered phylogenies resulted in either monophyly (Bayesian approach) or paraphyly (MP/ML topologies) of the bat flies, thus obscuring the potential number of possible associations with bats throughout the history of this group. Dispersal-vicariance analysis suggested the Neotropical region as the possible ancestral distribution area of the New World Streblidae and the Oriental region for the Old World bat flies. The genes examined show conflicting support across the nodes of the tree, particularly in the basal positions. Additionally, there is poor character support among all genes for the nodes associated with early hippoboscoid diversification. This results in extremely short basal branches, adding support to the idea of a rapid radiation among the four major groups of Hippoboscoidea.

Animals↗
PubMed2006

Evolutionary history of Stratiomyidae (Insecta: Diptera): the molecular phylogeny of a diverse family of flies.

Stratiomyidae is a cosmopolitan family of Brachycera (Diptera) that contains over 2800 species. This study focused on the relationships of members of the subfamily Clitellariinae, which has had a complicated taxonomic history. To investigate the monophyly of the Clitellariinae, the relationships of its genera, and the ages of Stratiomyidae lineages, representatives for all 12 subfamilies of Stratiomyidae, totaling 68 taxa, were included in a phylogenetic reconstruction. A Xylomyidae representative, Solva sp., was used as an outgroup. Sequences of EF-1alpha and 28S rRNA genes were analyzed under maximum parsimony with bootstrapping, and Bayesian methods to recover the best estimate of phylogeny. A chronogram with estimated dates for all nodes in the phylogeny was generated with the program, r8s, and divergence dates and confidence intervals were further explored with the program, multidivtime. All subfamilies of Stratiomyidae with more than one representative were found to be monophyletic, except for Stratiomyinae and Clitellariinae. Clitellariinae were distributed among five separate clades in the phylogeny, and Raphiocerinae were nested within Stratiomyinae. Dating analysis suggested an early Cretaceous origin for the common ancestor of extant Stratiomyidae, and a radiation of several major Stratiomyidae lineages in the Late Cretaceous.

Animals↗
PubMed1988

Isolation of two neuropeptides in the AKH/RPCH-family from horseflies (Diptera).

Two neuropeptides (DCCI and DCCII) in the adipokinetic/red pigment concentrating hormone-family have been isolated and purified from the corpora cardiaca of horseflies (Diptera : Tabanidae). Both peptides were purified by a sequence of three reversed phase-high performance liquid chromatographic steps. Amino acid analysis of the purified peptides indicated the following composition for DCCI: Glx(l), Gly(1), Leu(1), Phe(1), Pro(1), Thr(2) and for DCCII: Glx(1), Gly(2), Leu(1), Phe(1), Pro(1), Thr(2), and Tyr(1). Photodiode array ultraviolet spectroscopy indicated the presence of tryptophan in both DCCI and II. Both DCCI and II had red pigment concentrating hormone activity in the crab, Uca pugilator.

Amino Acids↗
PubMed1999

Mature and developing visual system of Ceratitis capitata (Diptera, Tephritidae): histochemical evidence of nitric oxide synthase in the wild type and the white eye mutant strains.

Nitric oxide (NO) is acknowledged as a messenger molecule in the nervous system. It has a role in the modulation of the chemosensory information and seems implicated also in visual processes and visually guided behaviour of some insects. In the present study, we used two different strains of the medfly Ceratitis capitata (Diptera, Tephritidae), a wild type eye colour and a white eye mutant line, as models to clarify the involvement of NO in the mature and developing visual system. The comparison between the pattern of enzyme histochemical localization of NO synthase (NOS), through NADPH diaphorase (NADPHd) staining, in the optic lobes of the two strains revealed for adults a stronger intensity of reaction in all the neuropiles and the sub-retinic monopolar cell layer of the wild type flies, with respect to the white eye mutant correspondent areas. Anti-NOS immunocytochemistry correlated with these results, underlying reactivity both in fine fibres and varicosities and in cell bodies and supporting the idea of presence of NOS also in the retina of the medfly optic lobes. NADPHd reactivity was present in the first developmental stages of the white eye mutant also, but at lower intensity than wild type, and it decreased in some areas during the transition to adult fly stage both in the wild type and in the white eye mutant. All these observations together indicate that changes in the NO system of C. capitata could be related to the visual information processing, when the visual response or discrimination are altered. Furthermore, NO may be involved in the establishment of the retinal projection pattern and in the control of optic lobes morphogenesis.

Animals↗
PubMedDate not supplied

Expression of functional hypodermin A, a serine protease from Hypoderma lineatum (Diptera, Oestridae), in Schneider 2 cells.

Hypodermin A (HA) is a serine protease secreted by first-instar Hypoderma lineatum larvae (Oestridae, Diptera). It plays a crucial role in induced immunosuppression during hypodermosis. This report describes the production of recombinant HA in Drosophila melanogaster Schneider 2 cells, its purification and its characterization, and compares it with the protease extracted form parasite larvae. The recombinant protein and the native HA have similar biochemical and biological features. Activity of the recombinant protease on the lymphocyte proliferation inhibition and on membrane antigen cleavage was tested and shown to be similar to the native one. Tunicamycin treatment of the recombinant HA shows that the two putative glycosylation sites carry glycan residues. Unglycosylated recombinant HA has the same enzymatic activity as the fully glycosylated protein, indicating that glycosylation is not important for the protease activity of HA.

Animals↗
PubMed1997

The evolution of ectoparasitism in the genus Lucilia (Diptera:Calliphoridae).

To consider the evolutionary origin of the ectoparasitic habit in the blowfly genus Lucilia (Diptera:Calliphoridae), phylogenetic analyses of mitochondrial DNA sequence data were performed for 10 species, including all the common Lucilia agents of myiasis, collected from Africa, Australasia, North America and Europe. Complementary genetic distance and parsimony analyses are used to consider inter and intraspecific relationships within the genus with reference to previous morphological work. The results support the hypothesis of independent multiple evolution of the ectoparasitic habit in Lucilia sericata, Lucilia cuprina and the Lucilia caesar/Lucilia illustris group and suggest that it has coevolved in relatively recent history along with the domestication and husbandry of sheep. The geographic differences in pathogenic importance of various species of Lucilia also suggest that there is a strong climatic influence determining which species has dominated. Lucilia cuprina has become the predominant pathogenic species in sub-tropical and warm temperate habitats (e.g., Australia and South Africa), L. sericata in cool temperate habitats (e.g., Europe and New Zealand) and L. caesar and L. illustris become more common in sheep myiasis in more northerly Palaearctic regions.

Africa↗
PubMed1979

Hemoglobins, XXIX. Sequence analysis of a dimeric hemoglobin (erythrocruorin), CTT-X, of Chironomus thummi thummi (Diptera).

The amino acid sequences of one of the dimeric hemoglobin components, CTT-X, of Chironomus thummi thummi (Diptera) are given. The sequences were determined by automatic Edman degradation of tryptic peptides and peptides obtained by specific chemical cleavages. CTT-X has two different polypeptide chains, each with 151 amino acid residues. The two polypeptide chains differ only in one amino acid. The sequences are discussed in the light of the sequences of other related heme-proteins.

Amino Acid Sequence↗
PubMed2000

Persistence of cattle grubs (Diptera: Oestridae) on a Canadian ranch with long-term, continuous therapeutic control.

Sero-prevalence of cattle grubs (Diptera: Oestridae) was monitored on two large western Canadian ranches from 1992 to 1999. One ranch has had a long-term programme for therapeutic control of cattle grubs as required by legislation in the province of Alberta. The other ranch, located in southeast Saskatchewan, has not used any treatment for grub control for an extended period of time. Serum from calves was tested each fall for the presence of antibodies to Hypoderma spp. using an ELISA. Percent positive sera on the Ranch 1 ranged from 8.0 to 73.3%. There was substantial variation among years and among two separate herds maintained on the ranch. Percent infested calves on the Ranch 2 ranged from 76.5 to 99.0%. Improved surveillance for cattle grubs using serological techniques is the only effective means to monitor the status of this important parasite.

Alberta↗
PubMed2001

Sheep oestrosis (Oestrus ovis Linné 1761, Diptera: Oestridae) in Sardinia, Italy.

Oestrosis, the nasal myiasis of sheep and goats, is caused by the larvae of Oestrus ovis L. 1758 (Diptera, Oestridae) that develop from the first to the third stage larva in the nasal cavities and frontal sinuses of affected animals. The authors report the results of an epidemiological study of oestrosis of sheep in Sardinia, Italy. Heads of 6-month to 10-year-old Sardinian sheep (n=566) from 124 free-ranging flocks were examined for the presence and location O. ovis larvae from December 1996 to November 1997. Larvae were collected, counted, and larval stages were identified. O. ovis larvae were found in 100% of examined flocks and in 91% (514/566) of examined sheep. The monthly prevalence ranged from 69% in May to 100% in July. First stage larvae were found in 82% (463) of all heads examined, second stage larvae in 65% (367) and third stage larvae in 10% (56). The majority of sheep harboured first stage larvae, with prevalences of over 80% throughout most of the study period. The prevalence of O. ovis found in this study of Sardinian sheep is the highest reported in the Mediterranean area. The high percentage of first stage larvae found throughout the entire study period may be due to a brief period of decreased rate of larval maturation, in particular in December 1996 (96%) and January-October 1997 (94%). Third stage larvae were consistently present, often however, with extremely low prevalences compared to total larval burden.

Animals↗
PubMed2003

Molecular differentiation of Hypoderma bovis and Hypoderma lineatum (Diptera, Oestridae) by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP).

The most variable region of the cytochrome oxidase I (COI) gene of Hypoderma bovis(1) and Hypoderma lineatum(2) (Diptera, Oestridae) was amplified by PCR and the amplicons were sequenced and analysed. PCR products were digested with three restriction enzymes, namely BfaI, HinfI and TaqI, providing informative profiles. H. bovis and H. lineatum sequences revealed an inter-specific variation rate of 8.5%, and an intra-specific variation rate of 0.87 and 0.29%, respectively. The results showed that the COI gene region examined was useful for the differentiation of H. bovis and H. lineatum and that a PCR-RFLP assay is a practical tool for their identification, offering additional diagnostic and epidemiological instruments for the study of cattle grub infestation.

Animals↗
PubMed2000

Use of detomidine hydrochloride as an adjunct for studying first-stage Gasterophilus intestinalis (Diptera: Gasterophilidae) in the tongue of the horse.

A synthetic alpha-2 adrenergic agonist, detomidine hydrochloride, was used in the study of in vivo activity of Gasterophilus intestinalis (Diptera: Gasterophilidae) during migration in the tongue of the horse. Use of the drug allowed the investigator to manipulate the tongue and closely observe the movement patterns and tissue disturbance caused by burrowing first-stage larvae. Detomidine hydrochloride should be utilized in studies of drug efficacy and larval biology, whenever possible, to avoid the need to sacrifice the horse.

Analgesics↗
PubMed2004

Phylogeny of the Baldratiina (Diptera: Cecidomyiidae) inferred from morphological, ecological and molecular data sources, and evolutionary patterns in plant-galler relationships.

The phylogeny of the gall-midge subtribe Baldratiina (Diptera: Cecidomyiidae) was reconstructed from molecular (partial sequence of the mitochondrial 12S rDNA), morphological and ecological data sets, using 16 representative species of most of the genera. The morphological and ecological data were combined in a single character matrix and analyzed separately from the molecular data, resulting in an eco-morphological cladogram and a molecular cladogram. Attributes of galls and host associations were superimposed on the molecular cladogram in order to detect possible trends in the evolution of these traits. The cladograms resulting from the two independent analyses were statistically incongruent, although both provide evidence for the monophyly of the genera Baldratia and Careopalpis and the paraphyly of the genera Stefaniola and Izeniola. The results suggest a minor impact of the morphological characters traditionally used in the classification of the Baldratiina, whereas ecological data had a major impact on the phylogenetic inference. Mapping of gall and host attributes on the molecular cladogram suggests that multi-chambered stem galls constitute the ancestral state in the subtribe, with several subsequent shifts to leaf galls. It is concluded that in contrast to other studied groups of gall insects, related baldratiine species induce different types of galls, attesting to speciation driven by gall-type shifts at least as often as host shifts.

Animals↗
PubMed2003

Fossil evidence of phorid parasitism (Diptera: Phoridae) by allantonematid nematodes (Tylenchida: Allantonematidae).

Howardula helenoschini sp. n. (Tylenchida: Allantonematidae) is described from 40 million year-old Baltic amber. The nematodes are parasitic in the body cavity of an adult fly of the genus Triphleba (Phoridae: Diptera). Characteristics of the fossil species are the large size of the pre-adult juveniles and a small number of progeny compared with extant Howardula parasites of flies. Reasons are given why these features suggest that this species was at an early stage of adapting, evolutionarily, to its insect host.

Amber↗
PubMed2006

Prolonged diapause in the ectoparasite Carnus hemapterus (Diptera: Cyclorrhapha, Acalyptratae) - how frequent is it in parasites?

Prolonged diapause is usually interpreted as an adaptation to unpredictable environmental conditions and resource availability. Many parasites usually face highly unpredictable environments, therefore prolonged diapause should be common among these organisms. Here we examine the occurrence and frequency of prolonged diapause in the ectoparasite Carnus hemapterus (Diptera: Cyclorrhapha, Acalyptratae). We found that the studied population is polymorphic with respect to diapause duration. Emergence of carnid flies after 2 and 3 wintering seasons was therefore detected in around 17% and 21% of the samples respectively. The number of flies with prolonged diapause ranked 0.88-50% with respect to the number of flies emerging during the first spring. Both the occurrence of prolonged diapause and the number of flies with a long life-cycle are related to the number of flies emerging during the first spring. The emergence pattern of flies with prolonged diapause was very similar to that observed for flies with a short cycle and occurred in synchrony with the occurrence of hosts. Prolonged diapause has been frequently reported in plant-feeding insects and in some host-parasitoid systems, but this is, to our knowledge, the second report ever on prolonged diapause in true parasites of animals. We discuss the reasons for the apparent rarity of prolonged diapause among these organisms.

Adaptation, Physiological↗
PubMed2000

Unequal X chromosomes in Bradysia hygida (Diptera:Sciaridae) females: karyotype assembly and morphometric analysis.

The mitotic chromosomes of Bradysia hygida (Diptera:Sciaridae) neuroblast cells are described together with their morphometric data. Giemsa-stained neuroblast chromosomes from female and male larvae confirm the chromosome number of this species, 2n = 8 (XX) and 2n = 7 (XO), respectively. The karyotype assembly reveals two metacentric autosomic pairs, the A and B chromosomes; a subtelocentric, the C chromosome, the smallest one; and a sexual unequal metacentric pair, X chromosome, in female karyotype and a one sexual metacentric X chromosome in male. The implications of the unequal X chromosome pair are discussed.

Animals↗
PubMed1997

Biochemistry of esterases associated with organophosphate resistance in Lucilia cuprina with comparisons to putative orthologues in other Diptera.

Esterase activities associated with organophosphate insecticide resistance in the Australian sheep blowfly, Lucilia cuprina, are compared with similar activities in other Diptera. The enzymes making the major contribution to methyl butyrate hydrolysis ("ali-esterase") in L. cuprina, M. domestica, and D. melanogaster comigrate during electrophoresis. The enzymes in L. cuprina and D. melanogaster correspond to the naphthyl acetate hydrolyzing E3 and EST23 isozymes of those species. These and previously published data suggest that the ali-esterases of all three species are orthologous. Strains of L. cuprina fall into four groups on the basis of quantitative determinations of their ali-estesterase, OP hydrolase, and malathion carboxylesterase activities and these groups correspond to their status with respect to two types of OP resistance. Strains susceptible to OP's have high ali-esterase, low OP hydrolase, and intermediate MCE activities; those resistant to malathion but not diazinon have low ali-esterase, intermediate OP hydrolase, and high MCE activities; those resistant to diazinon but not malathion have low ali-esterase, high OP hydrolase, and low MCE activities; those resistant to both OPs have low ali-esterase, high OP hydrolase, and high MCE activities. The correlated changes among the three biochemical and two resistance phenotypes suggest that they are all properties of one gene/enzyme system; three major allelic variants of that system explain OP susceptibility and the two types of OP resistance. Models are proposed to explain the joint contribution of OP hydrolase and MCE activities to malathion resistance and the invariant association of low ali-esterase and elevated OP hydrolase activities in either type of resistance.

Animals↗
PubMed2004

Maintenance of clonal diversity in Dipsa bifurcata (Fallén, 1810) (Diptera: Lonchopteridae). II. Diapause stabilizes clonal coexistence.

We analyze a selection model analogous to a one-locus, two-allele haploid system that can explain recurrent seasonal changes in diversity for communities with diapausing species or populations with diapausing clones. The model demonstrates the potential influence of differential diapause on the stability of species and clonal coexistence and, by extension, on the maintenance of genetic polymorphism in general. Using estimates of clonal fitness values from populations of the parthenogenetic spear-winged fly Dipsa bifurcata (Fallén, 1810) (Diptera: Lonchopteridae), the model explains the long-term stable oscillation of clonal frequencies exhibited by these populations. In general, clones or species that share the same spatial habitat can persist in stable coexistence if there are differences not only in their temporarily fluctuating fitness values but also in their dormancy patterns.

Animals↗
PubMed2006

Evolution of cis-regulatory sequence and function in Diptera.

Cis-regulatory sequences direct patterns of gene expression essential for development and physiology. Evolutionary changes in these sequences contribute to phenotypic divergence. Despite their importance, cis-regulatory regions remain one of the most enigmatic features of the genome. Patterns of sequence evolution can be used to identify cis-regulatory elements, but the power of this approach depends upon the relationship between sequence and function. Comparative studies of gene regulation among Diptera reveal that divergent sequences can underlie conserved expression, and that expression differences can evolve despite largely similar sequences. This complex structure-function relationship is the primary impediment for computational identification and interpretation of cis-regulatory sequences. Biochemical characterization and in vivo assays of cis-regulatory sequences on a genomic-scale will relieve this barrier.

Animals↗