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PubMed2001

Immunolocalization of odorant-binding proteins in noctuid moths (Insecta, Lepidoptera).

Odorant-binding proteins were studied in the noctuid moths Agrotis segetum, Autographa gamma, Helicoverpa armigera, Heliothis virescens and Spodoptera littoralis using antisera raised against the pheromone-binding protein (PBP) and general odorant-binding protein 2 (GOBP2) of Antheraea polyphemus (Saturniidae). Proteins immunoreacting with these antisera were only found on the antennae and PBP and GOBP2 could be identified on western blots of males and females of all five species. PBPs were predominantly localized in sensilla trichodea and GOBP2 in sensilla basiconica, in good correlation with the stimulus specificity of the receptor cells in these sensilla. In H. armigera and H. virescens the majority of the s. trichodea immunoreacted with the antiserum against PBP of A. polyphemus; in A. segetum, A. gamma and S. littoralis, on the other hand, a high percentage of s. trichodea remained unlabelled. Probably, the PBP expressed in these sensilla is so different that it does not immunoreact with the antiserum used. Such a protein was found by native PAGE of antennal extracts of A. segetum and S. littoralis. These data correlate with the fact that the two heliothine species use pheromones with the same alkyl chain length as A. polyphemus, while the other three species use pheromones with shorter chains. In H. armigera, H. virescens, A. gamma and S. littoralis female antennae were also immunolabelled and a large number of PBP-expressing s. trichodea was consistently found. In S.littoralis this fits with the electrophysiologically recorded high pheromone sensitivity of female s. trichodea, whereas in females of H. armigera and H. virescens no or only weak responses to pheromone stimulation have been reported. Therefore, PBP expression in a sensillum does not necessarily imply pheromone sensitivity of its receptor cells.

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PubMed2005

Extracting single genomes from heterogenous DNA samples: a test case with Carsonella ruddii, the bacterial symbiont of psyllids (Insecta).

Analysis of many bacterial genomes is impeded by the inability to separate individual species from complex mixtures of cells or to propagate cells in pure culture. This problem is an obstacle to the study of many bacterial symbionts that live intracellularly in insects and other animals. To recover bacterial DNA from complex samples, we devised a method that facilitates the cloning of DNA fragments of distinctive G+C contents in order to generate shotgun DNA libraries enriched in inserts having a specific base composition. DNA preparations are first treated with a restriction enzyme having a common cleavage site in a particular genome and then shotgun cloned following size-fractionation. This method was applied to whole bacteriomes of the psyllid, Pachypsylla venusta, which harbors the bacterial symbiont Candidatus Carsonella ruddii. The resulting libraries were highly enriched in bacterial sequences. Through the use of alternate enzymes and partial digests, this technique can be adapted to yield virtually pure DNA libraries for individual bacterial species.

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PubMed1991

Apparent incompetence of Dermacentor variabilis (Acari: Ixodidae) and fleas (Insecta: Siphonaptera) as vectors of Borrelia burgdorferi in an Ixodes dammini endemic area of Ontario, Canada.

From April to October 1990, white-footed mice, Peromyscus leucopus (Rafinesque), were examined for ectoparasites on Long Point, Ontario, the only endemic area for Ixodes dammini Clifford, Spielman, Piesman & Corwin and Borrelia burgdorferi Johnson, Schmid, Hyde, Steigerwalt & Brenner known in Canada. Larval and nymphal I. dammini and Dermacentor variabilis (Packard), and adult fleas Orchopeas leucopus (Baker), Epitedia wenmanni (Rothschild), and Ctenophthalamus pseudagrytes Baker were common on trapped mice. Questing ticks were collected by dragging, near the sites of mouse trapping, from April to November 1990. Indirect immunofluorescent assay established that 58.3% of adult, 17.3% of nymphal, and 0.15% of larval I. dammini questing at Long Point were infected with B. burgdorferi, indicating that infected mammalian reservoir hosts are common. None of 593 adult, 2 nymphal, and 4 larval D. variabilis collected while questing were infected; and only 1 of 322 fleas (O. leucopus) removed from white-footed mice was infected. The fact that no unfed adult D. variabilis and only one flea were infected, in a situation where the probability of exposure of hematophagous ectoparasites is moderately high, suggests that this species of tick and the fleas examined are poor vectors for the Lyme disease spirochete.

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PubMed1992

Laboratory and field trials of permethrin-treated cotton used as nesting material to control fleas (Insecta: Siphonaptera) on cricetid rodents.

Upholstery cotton treated with four different concentrations (0.25-2.0%) (2,500-20,000 ppm) of an aqueous permethrin solution, used as nesting material by white mice, was laboratory-tested against the potential plague vectors Oropsylla montana (Baker), Thrassis bacchi (Rothschild), and Orchopeas howardi (Baker) and found highly effective (P less than 0.001) for 1 yr. Similarly treated cotton gauze was tested under ambient and 75% RH and was found to be highly effective (P less than 0.001) in both environments for 1 yr. A separate test determined that the LD50 of permethrin-treated cotton was less than 10 ppm. Cotton tested with 0.5% permethrin and distributed under field conditions to cricetid rodents for use as nesting material was found to be highly effective (P less than 0.001 as a pulicide for greater than 4 mo when tested during winter in Larimer County, Colo. Permethrin-treated cotton was less successful in controlling fleas on cricetid rodents during the summer months in a New Mexico hyperendemic plague area.

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PubMed1998

Fleas in French Guiana (Insecta: Siphonaptera).

Based on a collection of approximately 760 fleas, of which 520 were collected in 1994-1995 during scientific studies at the Petit Saut dam site in French Guiana, 12 species and subspecies are discussed. Two taxa, Rhopalopsyllus garbei Guimarães, 1940 and Adoratopsylla intermedia copha (Jordan, 1926), are new records for French Guiana. The fleas collected during the 1994-1995 study were obtained from 35 species of mammals (3,484 specimens); of which, 21 (60%) species were negative for fleas. The mammals were captured primarily by live-trapping during a capture-release study along a portion of the Sinnamary River and its tributaries up to a distance of 70 km upstream from the Petit Saut dam site.

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PubMed1998

Résumé of the Siphonaptera (Insecta) of the world.

The world fauna of the order Siphonaptera is reviewed with respect to undescribed taxa, endangered species, taxonomic specialists, developmental stages, ultrastructure, taxonomic characters, host specificity, literature, fossil record, and the phylogenetic affinities of and within the order. The 15 currently recognized families are discussed with respect to their subfamilial, tribal, and generic classification. The numbers of species in these taxa are discussed and their general distribution and host preferences are briefly outlined. The current numbers of tribes, genera, and species, including invalid names, are listed.

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PubMed1998

Reproductive status of four species of fleas (Insecta: Siphonaptera) on Richardson's ground squirrels (Rodentia: Sciuridae) in Manitoba, Canada.

To test the hypothesis that oogenesis in 4 species of fleas is dependent on the reproductive cycle of their monoestrous host Spermophilus richardsonii, 6,416 Oropsylla (Oropsylla) rupestris (Baker), 5,893 Oropsylla (Opisocrostis) bruneri (Baker), 813 Neopsylla inopina (Rothschild), and 223 Rhadinopsylla (Actenophthalmus) fraterna (Baker) females were collected from active hosts at 3 locations in Manitoba during 1987, 1988, and 1989 and dissected. Based on morphological changes in the ovaries, female fleas were categorized as immature, nulliparous or parous. Nulliparous N. inopina predominated in April and early May. Immature and nulliparous O. bruneri predominated throughout April and May. Nulliparous O. rupestris were most prevalent in early June but occurred sporadically throughout the season. Nulliparous R. fraterna predominated only in April. The percentage of mated females was usually correlated with percentage parity for all species. Oogenesis in each of the 4 flea species was apparently independent of the reproductive cycle of their host. Female fleas of all reproductive categories were frequently collected before, during, and following reproduction in their hosts.

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PubMed1998

Taxonomic study of the genus Ctenocephalides Stiles & Collins, 1930 (Insecta: Siphonaptera: Pulicidae) by using aedeagus characters.

To define more accurately the taxonomic position of the species of Ctenocephalides Stiles & Collins, 1930 (Siphonaptera), a morphological study of the aedeagus was conducted an all taxa of this genus. Based on some phallosome structures (hamulus, lobes, tubus interior), an identification key is constructed to complement the existing taxonomic criteria. C. orientis and C. damarensis are confirmed to specific rank.

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PubMed1992

Chemical distribution of glycosphingolipids in third-instar larval organs of the blowfly, Calliphora vicina (Insecta: Diptera).

As a first approach to testing the working hypothesis that glycosphingolipids are functionally involved in the ontogeny of insects, their chemical distribution in larval organs was determined and any stadium-correlated differences documented. Selected organs, i.e., the fatbody, striated muscle, intestinal tract, salivary glands, imaginal discs, and central nervous system, were dissected from seven-day-old larvae of the blowfly, Calliphora vicina, and their glycolipids isolated. Two-dimensional, high-performance thin-layer chromatography was used to separate the neutral and acidic glycolipids of each organ. Significantly different total glycolipid component-patterns were obtained for the individual organs, whereby, except for a number of additional uncharacterized components in the intestinal tract, the neutral glycolipids of all organs were found to be qualitatively similar. However, major quantitative differences between the selected organs were found in their total glycolipid-carbohydrate contents, as well as the respective quantitative neutral glycosphingolipid-component distributions. The acidic glycolipids showed pronounced qualitative as well as quantitative organ-dependent variations. Whereas the highest proportion of uncharged glycolipids was characteristic of the fatbody, a high proportion of zwitterionic glycolipid-components was observed to be typical of the central nervous system and imaginal discs, i.e., of organs persisting during larval life and throughout metamorphosis. Imaginal disc glycolipids were distinguished by their high content of acidic glycolipids, a putative reflection of the functional role of these glycoconjugates in regulated cell reorganization during metamorphosis.

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PubMed1997

Phylogenetic utility of elongation factor-1 alpha in noctuoidea (Insecta: Lepidoptera): the limits of synonymous substitution.

To test its phylogenetic utility, nucleotide sequence variation in a 1,240-bp fragment of the elongation factor-1 alpha (EF-1 alpha) gene was examined in 49 moth species representing the major groups of the superfamily Noctuoidea. Both parsimony and distance analyses supported the monophyly of nearly all groups for which there are clear morphological synapomorphies. Clades of subfamily rank and lower, probably mid-Tertiary and younger, were strongly supported. The third codon position contains 88% of variable sites, and approaches saturation at approximately 20% sequence divergence, possibly due to among-site rate heterogeneity and composition bias; higher divergences occur only in association with shifts in composition. Surprisingly, the few nonsynonymous changes appear no more phylogenetically reliable than synonymous changes. Signal strength for basal divergences is weak and fails to improve with character weighting; thus, dense taxon sampling is probably needed for strong inference from EF-1 alpha regarding deeper splits in Noctuoidea (probably early Tertiary). EF-1 alpha synonymous changes show promise for phylogeny reconstruction within Noctuidae and other groups of Tertiary age.

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PubMed1988

Uptake of 226Ra by established vegetation and black cutworm larvae, Agrotis ipsilon (class Insecta: order Lepidoptera), on U mill tailings at Elliot Lake, Canada.

Radium-226 levels in samples from an inactive U tailings site at Elliot Lake, Ontario, Canada, were: 9,140 +/- 500 mBq g-1 dry weight in the substrate; 62 +/- 1 mBq g-1 dry weight in rye, Secale cereale, and less than 3.7 mBq g-1 dry weight in oats, Avena sativa, the dominant species established by revegetation of the tailings; and 117 +/- 7 mBq g-1 dry weight in washed and unwashed black cutworm larvae. Concentration ratios were: vegetation to tailings 0.001-0.007; black cutworms to vegetation 3.6 and black cutworms to tailings 0.01. The values are considered too low to be considered a hazard to herring gulls, Larus argentatus, which occasionally feed on cutworms.

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PubMed2006

Fossil Liposcelididae and the lice ages (Insecta: Psocodea).

Fossilized, winged adults belonging to the psocopteran family Liposcelididae are reported in amber from the mid-Cretaceous (ca 100 Myr) of Myanmar (described as Cretoscelis burmitica, gen. et sp. n.) and the Miocene (ca 20 Myr) of the Dominican Republic (Belaphopsocus dominicus sp. n.). Cretoscelis is an extinct sister group to all other Liposcelididae and the family is the free-living sister group to the true lice (order Phthiraptera, all of which are ectoparasites of birds and mammals). A phylogenetic hypothesis of relationships among genera of Liposcelididae, including fossils, reveals perfect correspondence between the chronology of fossils and cladistic rank of taxa. Lice and Liposcelididae minimally diverged 100 Myr, perhaps even in the earliest Cretaceous 145 Myr or earlier, in which case the hosts of lice would have been early mammals, early birds and possibly other feathered theropod dinosaurs, as well as haired pterosaurs.

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PubMed2006

Feminizing Wolbachia in Zyginidia pullula (Insecta, Hemiptera), a leafhopper with an XX/X0 sex-determination system.

Zyginidia pullula is a grass-dwelling leafhopper characterized by a bisexual reproduction mode. In this species, some females collected in Northern Italy, when mated with males, gave origin to an exclusively female brood. Here, we demonstrated that in these lineages an infection by a new strain of Wolbachia pipientis-designated as wZygpul-was detected by amplifying and sequencing the wsp and 16S rRNA genes. About half of the female progeny were characterized by intersexual phenotypes, i.e. showing upper pygofer appendages, a typical male secondary sexual feature. The karyological analysis proved that while phenotypically normal females had a female genotype, those with upper pygofer appendages had a male genotype and were thus feminized males. The complete removal of W. pipientis after tetracycline treatment of morphologically normal females, and the consequent re-appearance of males in the brood, permitted us to connect the feminizing effect with the presence of the bacterium. This is the first case of feminization by W. pipientis in an XX/X0 sex-determination system, and is the second case reported in insects.

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PubMed1993

A centromeric satellite DNA of the unisexual Bacillus atticus (Insecta: Phasmatodea).

In the parthenogenetic Bacillus atticus atticus, widespread over most of the Mediterranean basin, a highly repeated satellite DNA (BaB300) has been detected and analysed. BgI II, Taq I and Alu I restriction enzymes cut 316 bp long repeating units from the BaB300 family. These are non-coding, AT rich and well conserved in the three isolated populations studied. By in situ hybridization, the satellite has been located in the centromeric heterochromatin of a subset of medium- and small-sized chromosomes, including the Xs. Related sequences have been found in the bisexual B. grandii grandii and in its specific hybrid B. whitei (=B. rossius/grandii grandii), while they are absent from B. rossius redtenbacheri. These data support the genetic affinity relationships within the genus Bacillus inferred from morphological, allozymic and karyological data. They also encourage further comparisons among Bacillus hybrids, in order to trace their parental genomes in the hybrid nuclei, and within the B. atticus complex (i.e. additional samples of B. a. atticus and diploid/triploid cytotypes of B. a. carius) to study repetitive DNA turnover in unisexual organisms.

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PubMed2006

Extraordinary number of gene rearrangements in the mitochondrial genomes of lice (Phthiraptera: Insecta).

The arrangement of genes in the mitochondrial (mt) genomes of most insects is the same, or near-identical, to that inferred to be ancestral for insects. We sequenced the entire mt genome of the small pigeon louse, Campanulotes bidentatus compar, and part of the mt genomes of nine other species of lice. These species were from six families and the three main suborders of the order Phthiraptera. There was no variation in gene arrangement among species within a family but there was much variation in gene arrangement among the three suborders of lice. There has been an extraordinary number of gene rearrangements in the mitochondrial genomes of lice!

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PubMed1985

Glycosphingolipids in insects. Chemical structures of ceramide monosaccharide, disaccharide, and trisaccharide from pupae of Calliphora vicina (Insecta: Diptera).

The presence of glycosphingolipids in the pupae of the blowfly, Calliphora vicina, was established. The thin layer chromatographic pattern of the total neutral glycolipids revealed the presence of more than 13 components, the major one being ceramide monohexoside. By the use of high performance liquid chromatography, the three simplest components were isolated and their chemical structures determined: Glc(beta 1-1)Cer, Man(beta 1-4)-Glc(beta 1-1)Cer [with minor component Gal(beta 1-4)Glc(beta 1-1)Cer] and GlcNAc(beta 1-3)Man(beta 1-4)Glc(beta 1-1)-Cer. The ceramide composition of the parent insect glycosphingolipids is dominated by the 20:0 fatty acid, arachidic acid, and the sphingoid tetradecasphing-4-enine.

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