Search results for "Insect Science"
showing 10 items of 1011 documents
Infection of Bois-Noir tuf-type-I stolbur phytoplasma inHyalesthes obsoletus(Hemiptera: Cixiidae) larvae and influence on larval size
2009
Recent dramatic spread of the grapevine yellows disease Bois Noir (BN) in Germany is above all explained by highly increased abundances of the vector Hyalesthes obsoletus (Hemiptera: Cixiidae) associated to the plant Urtica dioica, the reservoir of the BN pathogen stolbur tuf-type-I. The vector acquires BN-phytoplasma as larvae whilst feeding on the roots of infected U. dioica. To understand the dynamics of the Urticacycle, we tested at what instar larvae become infected and whether infection affects larvae size (i.e. growth) at two sites in the Mosel Valley, Germany. Larvae were tested from infected plants and collected at instar-stages 3, 4 and 5. Larvae at stage 3 were already infected b…
Larva-to-adult and pupa-to-adult mortality dynamics in crowded cultures ofDrosophila melanogaster
1985
Pupal mortality is shown here to bear the main responsibility for total mortality duringDrosophila melanogaster development in crowded conditions. The dynamics of the pupa-to-adult and larva-to-adult processes of mortality follows a S-shaped logistic model, like survival in density-dependent processes. Data given here confirm to some extent Wallace's suggestion that pupal mortality is a density-dependent process.
Morphological abnormalities induced by Fenoxycarb on the ectoparasitic larval stage ofPhanerotoma (Phanerotoma) ocularisKohl (Hym., Braconidae)
1993
The Juvenile Hormone Analog Fenoxycarb at concentrations of 0.001 μg/ml, 0.005 μ/ml, 0.01 μg/ml, 0.05 μg/ml and 0.1 μg/ml had an adverse effect on the ectoparasitic larva of Phanerotoma (Phanerotoma) ocularis when topically applied. The total percentage of abnormalities obtained was higher (63.3 %-93.3 %) if the treatment was applied on the third substage than when it was applied on the fourth substage (53.3 %-76.7%). The activity rate was concentration dependent for both substages. Zusammenfassung Durch Fenoxycarb-Behandlung hervorgerufene Abnormitaten bei Larven des Ektoparasiten Phanerotoma (Phanerotoma) ocularis Kohl (Hym., Braconidae) Topikalbehandlung der Larven von Phanerotoma (Phane…
Attempts to re-colonise water insects in German brooks
2009
Attempts were made to reintroduce water insects (five stonefly species and one mayfly species) into several third order streams in Rhineland-Palatine and Hessen, Germany. All these streams had been strongly affected by waste water and rubbish and had lost most of their macroinvertebrates. As a consequence of the installation of several purification plants in the past three decades, water quality has improved. Since no stoneflies returned, 700–1300 eggs of three different species (Isoperla goertzi, I. oxylepis, and I. grammatica) were exposed in the Selz brook (1997). In February 1998 a few larvae and in 1999 about 10,000 eggs of Perla marginata were added in the Walluf brook, and in 1998, 5…
Effects of the insect growth regulator cyromazine on the fecundity, fertility and offspring development of Mediterranean fruit fly,Ceratitis capitata…
1995
Addition of cyromazine to adult diet affected negatively the development of Ceratitis capitata Wied. (Dipt., Tephritidae) offspring. Five concentrations of cyromazine (0.00001 mg/ml, 0.01 mg/ml, 0.1 mg/ml, 1 mg/ml and 10 mg/ml) have been tested. A reduction of Mediterranean fruit fly populations has been found mainly due to the effects of fertility and larval development. At these concentrations, cyromazine does not affect Ceratitis capitata fecundity.
Larval distributions of the ectoparasitoid waspEurytoma robustarelative to the host tephritid gall flyUrophora cardui
2003
Parasitism may explain the patchy distributions of host populations. The present paper is a study of larval distributions of the parasitoid Eurytoma robusta in galls of the tephritid gall fly Urophora cardui . It focuses on E. robusta ’s choice of U. cardui gall and whether this changes relative to the rate of parasitism. Oviposition patterns were inferred by direct counts of larvae in galls and genetically, for both species, using indirect relatedness estimates between gall-members. Furthermore, rates of parasitism in four populations were monitored for 4 years. The modal distribution of E. robusta larvae per gall was one and independent of the level of parasitism. The mean number of E. ro…
Effect of the juvenile hormone analogue fenoxycarb applied via the host on the parasitoid Phanerotoma (Phanerortoma) ocularis Kohl (Hym. Braconidae)
1993
Abstract Concentrations of 0.001, 0.005, 0.01, 0.05 and 0.1 μg/ml of fenoxycarb (Ro 13-5223) were applied topically to larvae of Ephestia kuehniella Zeller parasitized by Phanerotoma (Phanerotoma) ocularis Kohl. The effect of the treatment and concentration on parasitism rates, preimaginal mortality and emergence rates of the parasitoid were studied comparatively for each larval instar of the host considered. The preimaginal mortality was high when the fenoxycarb was applied on the first larval instar of the host (23–46%) and more higher when applied to the sixth larval instar of the host (40–86%). Consequently, fenoxycarb treatment of the last larval instar of the host produced a reduction…
Hymenopteran specificity of Bacillus thuringiensis strain PS86Q3
2008
Abstract The biological activity of Bacillus thuringiensis (Bt) strain PS86Q3 against five Hymenopteran species was determined by means of bioassays adapted to each species. Four species of sawfly that are important pests of conifers (Diprion pini, Gilpinia hercyniae and Pristiphora abietina) or ornamental plants (Arge rosae), as well as the non-target honeybee, Apis mellifera, were studied. Two out of the four sawfly species tested were found to be sensitive to PS86Q3 crystals or spore/crystal suspensions. A sporulated culture of this strain was moderately active on D. pini, and a complete bioassay with solubilized crystals was performed to estimate the LC50 of 4.9 mg/ml. Pristiphora abiet…
First Nearctic Record of Hydrellia albilabris (Meigen) (Diptera: Ephydridae), a Leafminer of Duckweed (Araceae: Lemnoideae), with Comments on Related…
2019
Hydrellia albilabris (Meigen) (Diptera: Ephydridae) is recorded in the Nearctic Region for the first time. Its biology and immature stages are documented, and other miners in duckweeds (Araceae: Lemnoideae) are discussed. One new combination is proposed: Hydrellia jinpingensis (Zhang, Yang, and Hayashi) is transferred from Cavatorella.
An Overview of Genus-Level Taxonomic Problems Surrounding <I>Argyroploce</I> Hübner (Lepidoptera: Tortricidae), with Description of a New…
2002
Argyroploce unedana Baixeras, new species, is described from the Iberian Peninsula. The species is closely related to A. arbutella (L., 1758), which occurs on most of the European continent; the two species are allopatric. Although they share similar biologies, the two can be distinguished by structures of the male and female genitalia. Genitalia variability is analyzed. Forewing patterns and hindwing anal roll are discussed in relation to their systematic significance. The olethreutine wing pattern is reexamined. A review of the genus-level taxonomic problems surrounding Argyroploce Hubner, [1825] and allied genera suggests a fragile situation in the present systematic scenario within the …