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PubMed2002

Distribution of cytoskeletal elements in the ovarioles of Mutilla sp. (Insecta, Hymenoptera).

The ovaries of Mutilla sp., as those of other hymenopterans, consist of meroistic-polytrophic ovarioles. Within each ovariole, a terminal filament, a germarium, and a vitellarium can be distinguished. The germaria contain numerous dividing and/or differentiating groups (clusters) of germ cells. The vitellaria are composed of several, linearly arranged, ovarian follicles; each follicle consists of an oocyte and a group of nurse cells. Distribution of cytoskeletal elements (microfilaments and microtubules) throughout the ovarioles of Mutilla sp. has been studied on whole mount preparations stained with rhodamine-conjugated phalloidin and FITC-labelled anti-tubulin.

Actin Cytoskeleton↗
PubMed1975

[Immunization experiments for producing antibody-like substances in caterpillars of Mamestra brassicae L. (Insecta, Lepid., Noct.)].

The agglutinins against human blood cells described in caterpillars of Mamestra brassicae L. were not demonstrable when feeding the animals with a semisynthetic food. After injection or oral intake of certain bacteria (E. coli or streptococci of group C) or even Pope's broth the "antibody-like substances" known from feeding with natural food are being formed, and they agglutinated all human blood cells. The individual animals showed differences regarding the strength of agglutinin formation. The immune reactions observed possibly indicate the existence of a primitive immune system in these species (arthropods).

Agglutination↗
PubMed2000

More taxa or more characters revisited: combining data from nuclear protein-encoding genes for phylogenetic analyses of Noctuoidea (Insecta: Lepidoptera).

A central question concerning data collection strategy for molecular phylogenies has been, is it better to increase the number of characters or the number of taxa sampled to improve the robustness of a phylogeny estimate? A recent simulation study concluded that increasing the number of taxa sampled is preferable to increasing the number of nucleotide characters, if taxa are chosen specifically to break up long branches. We explore this hypothesis by using empirical data from noctuoid moths, one of the largest superfamilies of insects. Separate studies of two nuclear genes, elongation factor-1 alpha (EF-1 alpha) and dopa decarboxylase (DDC), have yielded similar gene trees and high concordance with morphological groupings for 49 exemplar species. However, support levels were quite low for nodes deeper than the subfamily level. We tested the effects on phylogenetic signal of (1) increasing the taxon sampling by nearly 60%, to 77 species, and (2) combining data from the two genes in a single analysis. Surprisingly, the increased taxon sampling, although designed to break up long branches, generated greater disagreement between the two gene data sets and decreased support levels for deeper nodes. We appear to have inadvertently introduced new long branches, and breaking these up may require a yet larger taxon sample. Sampling additional characters (combining data) greatly increased the phylogenetic signal. To contrast the potential effect of combining data from independent genes with collection of the same total number of characters from a single gene, we simulated the latter by bootstrap augmentation of the single-gene data sets. Support levels for combined data were at least as high as those for the bootstrap-augmented data set for DDC and were much higher than those for the augmented EF-1 alpha data set. This supports the view that in obtaining additional sequence data to solve a refractory systematic problem, it is prudent to take them from an independent gene.

Animals↗
PubMed2002

Effect of anti-mosquito hemolymph antibodies on fecundity and on the infectivity of malarial parasite Plasmodium vivax to Anopheles stephensi (Diptera:Insecta).

Rabbit antibodies to hemolymph antigens (102.5, 101, 100, 96, 88, 80, 64, 55, 43, 29, and 23 kDa) of Anopheles stephensi reduced fecundity as well as viability in An. stephensi. However, ingestion of these antibodies was not associated with a marked effect on the engorgement of mosquitoes but egg laying was significantly delayed. Antisera raised against hemolymph proteins were also used to identify cross reactive antigens/epitopes present in other tissues by Western blotting, as well as by in vivo ELISA. In addition, a significant reduction in oocyst development was also observed in An. stephensi mosquitoes that ingested anti-hemolymph antibodies along with Plasmodium vivax. The results confirmed the feasibility of targeting mosquito antigens as a novel anti-mosquito strategy, as well as confirmed the usefulness of such antigens for the development of a transmission-blocking vaccine.

Animals↗
PubMed2002

AFM study of microstructures on the cornea of the compound eye and ocelli of the hornet Vespa orientalis (Insecta, Hymenoptera).

The present study describes a novel structure occurring on the cornea in the compound eye and the ocellus of the Oriental hornet. This description is based on observations carried out via scanning electron microscopy (SEM) and primarily via atomic force microscopy (AFM). We report herein that the vespan cornea is densely covered with cupola-shaped protrusions, which in the compound eye have bases about 0.2 microm in diameter and an average height of 0.03 microm while upon the ocelli their diameter is rather variable, with some measuring 0.2-0.3 microm, and a length of submicrons to microns. Interspersed among the brief, cupola-shaped structures there are winding, longer structures whose height appears uniform at around 0.03 microm. It appears that the structures are formed from the epicuticular layer of the cornea and we conjecture that in both the compound eye and in the ocelli they serve to enhance the absorption of light, as well as to reduce light reflection.

Animals↗
PubMed2002

Ovary specific immune response during Plasmodium yoelii yoelii infection in malaria vector Anopheles stephensi (Diptera:Insecta).

Innate immune related polypeptides expression during three gonotrophic cycles in the ovaries of major disease vector mosquito A. stephensi has been analyzed following infection by malaria parasite, P. yoelii yoelii. Seventeen polypeptides were induced in the ovaries of various stages due to parasitic infection. Most of proteins were induced systemically during early stages of infection suggesting the possibility of immune related signalling process. The reduction in the quantity of protein contents in infected mosquitoes has been ascribed to the repression of seven polypeptides and in turn correlated with the fecundity reduction. The mechanism of these responses and their significance for malaria transmission and fecundity reduction are discussed.

Animals↗
PubMed2002

Heterochromatic banding patterns on chromosomes of twelve weevil species (Insecta, Coleoptera, Curculionoidea: Apionidae, Curculionidae).

The C-banding patterns of twelve weevil species are presented. The obtained results confirm the existence of two groups of species: with a small or large amount of heterochromatin in the karyotype. The first group comprises seven species (Apionidae: Holotrichapion pisi; Curculionidae: Phyllobius urticae, Ph. pyri, Ph. maculicornis, Tanymecus palliatus, Larinodontes turbinatus, Cionus tuberculosus). In weevils with a small amount of heterochromatin, tiny grains on the nucleus in interphase are visible, afterwards in mitotic and meiotic prophase appearing as dark dots. The absence of C-bands does not indicate a lack of heterochromatin but heterochromatic regions are sometimes so small that the condensation is not visible during the cell cycle. The second group comprises five species (Otiorhynchus niger, O. morio, Polydrusus corruscus, Barypeithes chevrolati, Nedyus quadrimaculatus) which possess much larger heteropicnotic parts of chromosomes visible during all nuclear divisions. The species examined have paracentromeric C-bands on autosomes and the sex chromosome X, except for Otiorhynchus niger, which also has an intercalary bands on one pair of autososomes. All the species examined differ in the size of segments of constitutive heterochromatin. The y heterochromosome is dot-like and wholly euchromatic in all the studied species.

Animals↗
PubMed2003

Efficacy of two 65% permethrin spot-on formulations against induced infestations of Ctenocephalides felis (Insecta: Siphonaptera) and Amblyomma americanum (Acari: Ixodidae) on beagles.

The efficacy of two formulations of a topically applied 65% permethrin spot-on (Defend Exspot Treatment for Dogs, Schering-Plough Animal Health) was evaluated against experimental infestations of the cat flea Ctenocephalides felis and the lone star tick Amblyomma americanum in dogs. Eighteen dogs were randomly assigned to treatment with 65% permethrin in either diethylene glycol monomethyl ether (DGME; original formulation) or propylene glycol monomethyl ether (PGME) or to be untreated as a control. Treated dogs received either 1 (body weight < 15 kg) or 2 ml (body weight > or =15 kg) of the assigned formulation on Day 0. One hundred unfed, adult C. felis were placed on each dog on Days -6, -1, 4, 11, 18, 25, and 32. Fifty unfed, adult ticks were placed on each dog on Days -1, 3, 9, 16, 23, and 30. Live fleas and ticks were counted and removed on Days 3, 7, 14, 21, and 28. Treatment of dogs with the 65% permethrin in DGME reduced flea numbers by 90.4% to 99.9% from Days 3 through 21 (P < or =.05) and by 48.2% 28 days after treatment. Treatment of dogs with 65% permethrin in PGME reduced flea numbers by 93.7% to 99.7% from Days 3 through 28 and by 78.4% 35 days after treatment (P < or =.05). Treatment with 65% permethrin in DGME reduced tick numbers by 90% or more only on Day 7, whereas treatment with 65% permethrin in PGME reduced the number of live ticks by 90%or more on Days 7 and 14 and approached 90%(87.9%) on Day 21. Efficacy against fleas and ticks for the PGME formulation was significantly better (P < or =.05) than for the DGME formulation on Day 28. Findings in this study indicate that both the DGME and PGME formulations of 65% permethrin performed well in reducing numbers of live C. felis and A. americanum on laboratory beagles; however, the PGME formulation was effective approximately 1 to 2 weeks longer than the DGME formulation.

Animals↗
PubMed1992

Complex carbohydrate presence in the gut and Malpighian tubules of Drosophila auraria larvae (Insecta, Diptera): a cytochemical study.

Cytochemical techniques were used for the qualitative characterization of carbohydrates in the foregut, midgut, hindgut and Malpighian tubules of Drosophila auraria larvae. Periodate-reactive (neutral) polysaccharides were present in the foregut cuticle, peritrophic membrane, cells of the proventriculus which produce the peritrophic membrane, as well as the glycocalyx of the midgut and Malpighian tubule cells. Sulphated and carboxylated complex carbohydrates were detected in the cuticle of both foregut and hindgut, as well as the 'vacuoles with granules' in the Malpighian tubules. Periodate-reactive sulphated and carboxylated polysaccharides were detected in dense bodies appearing in all cells 10-20 h before pupation of larvae. The significance of the presence or absence of complex carbohydrates in D. auraria larval digestive system is discussed and compared with results found in the digestive system of other insects. In addition, the efficiency of the HID-TCH-SP and LID-TCH-SP techniques in staining lysosomes is discussed.

Animals↗
PubMed2003

A new approach to the auchenorrhyncha (Hemiptera, Insecta) cytogenetics: chromosomes of the meadow spittlebug Philaenus spumarius (L.) examined using various chromosome banding techniques.

The karyotype of the meadow spittlebug Philaenus spumarius (L.) was studied using conventional chromosome staining, C- and AgNOR- banding, and fluorescent CMA3- and DAPI- techniques. This is the first report on differential staining of the holocentric chromosomes of Auchenorrhyncha. The karyotype of Ph. spumarius includes 2n = 22 + XX/X0. The autosomal pair 1 is large and carries a gap in every homologue. After silver staining, NORs were revealed in both this chromosome pair and a middle-sized pair, most likely 6 or 7. In spermatocyte meiosis, the majority of bivalents formed one chiasma each. The bivalent 1 showed from 1 to 4 chiasmata, the value of 1 or 2 being prevalent. Two further bivalents also showed two chiasmata in some cells. After C-banding, terminal and interstitial dot-type C-heterochromatic blocks were revealed in the chromosomes. In 4 of 11 studied males, the autosomal pair 1 was polymorphic for an extra segment attached to one of the homologues. The segment consisted of both heterochromatic and euchromatic portions. No defined signals were observed in any chromosome treated with DAPI. After CMA3- staining, bright fluorescent signals were obtained in the NOR-bearing chromosomes, suggesting GC-rich DNA bound to the NORs.

Animals↗
PubMed2003

Ultrastructural studies on the formation of egg envelopes in fulgoromorphans (Insecta, Hemiptera, Fulgoromorpha: Dictyopharidae).

Follicular cells in ecuadorian dictyopharids diversify into two subpopulations: the main body cells (MFs) and cells surrounding the anterior pole of the oocyte (AFs). The synthetic activity of both categories of follicular cells is manifested by the presence of numerous cisternae of rough endoplasmic reticulum, Golgi complexes and vacuoles containing electron-dense material in their cytoplasm. The MFs synthesize precursors of the main body chorion, whereas the AFs are responsible for the formation of micropylar apparatus and respiratory tubules. The main body chorion is composed of thin endochorion and exochorion which forms pillar-like projections.

Animals↗
PubMedDate not supplied

[Retransmission of echo-like signals: methods and results of studies on nocturnal moths (Insecta)].

Studies of capability to echolocate in nocturnal moths using the method of echo-signal retransmission are described in detail. During retransmission the insect was presented not with the echo from some real object but with electronically generated echo-like signal which appears following the certain delay after insect's own acoustic signal. In that way the artificial echo from non-existent obstacle is produced. In the current study the delay was set to 0.5 ms that corresponds to a distance of about 8 cm from obstacle. At the same time there was no any single movement of any object near the flying insect therefore the activities of sensory systems other than auditory did not cause systematical influence on results obtained. Noctuid moths (Noctuidae, Lepidoptera) are acoustically active insects. They are capable of producing ultrasonic clicks during flight. The most typical response of a moth to the retransmission of echo-like stimuli is an activation of own clicks emission that is often accompanied with rise in click amplitude. Using the activation of emission as a criterion of moth's response to the echo-like stimulation we measured echolocational thresholds in three species: Amphipyra pyramidea (36 dB SPL), Enargia paleacea (31 dB SPL) and Blepharita satura (26 dB SPL). The ability to echolocate was also demonstrated in 20 species of subfamilies Catocalinae, Amphipyrinae, Cuculliinae, Hadeninae, Noctuinae, Heliothinae.

Acoustic Stimulation↗
PubMed2005

Ultrastructural studies of the ovary of Palaeococcus fuscipennis (Burmeister) (Insecta, Hemiptera, Coccinea: Monophlebidae).

Ovaries of Palaeocoocus fuscipennis are composed of about 100 telotrophic ovarioles that are devoid of terminal filaments. In the ovariole a tropharium ( = trophic chamber) and vitellarium can be distinguished. The tropharium contains 7 trophocytes. A single oocyte develops in the vitellarium. The oocyte is surrounded by follicular cells that do not undergo diversification into subpopulations. The obtained results are discussed in a phylogenetic context.

Animals↗
PubMedDate not supplied

[Acoustic communication and sexual selection in Orthoptera (Insecta)].

Comparison of calling and courtship songs and mating strategies in different groups of Orthoptera shows that acoustic signals in bush crickets (Tettigonioidea) are used for searching conspecific mates at a distance, and song evolution is primarily driven by the acoustic surroundings and simultaneously singing other species. The role of sexual selection in the evolution of acoustic signals in bush crickets is much less important than in the evolution of other nonacoustic signals employed during direct contact. Acoustic signals of crickets (Grylloidea) are involved in both distant and short-range communication. Acoustic courtship signals, along with other courtship components, may offer the material for sexual selection, although, essentially, evolution of acoustic signals in crickets is determined by the acoustic surroundings. Acoustic communication in the grasshoppers of the subfamily Gomphocerinae is mainly a short-distance communication. Acoustic signals of Gomphocerinae are highly variable and elaborate in temporal parameters, and therefore can serve for evaluation of the mate "quality". Song evolution in this group is to a greater extent driven by sexual selection than by the acoustic surroundings and, therefore, could proceed faster than in other groups of Orthoptera and play a major role in speciation.

Acoustic Stimulation↗
PubMedDate not supplied

[Taxonomic relations between forms in evolutionary young complexes of lepidopterans (Insecta, Lepidoptera)].

Morphological characteristics of the prototype wing pattern can be used in lepidopteran population studies as markers of population groups and interpopulation boundaries. The centers of phenotypic variation serving as speciation centers were recognized within the range of polytypic species. Revision of the polytypic complex Polyommatus icarus Rott. allowed us to recognize six specific and six subspecific taxa.

Animals↗