Search results for "Insect Science"
showing 10 items of 1011 documents
Comparative population genetic structures of the fruit flyUrophora carduiand its primary parasitoidEurytoma robusta
2003
The interaction between two species may depend on geographic scale and this in turn can affect co-evolution among them. The present study comparatively examines population genetic structures of the tephritid gall fly Urophora cardui and its primary ectoparasitoid Eurytoma robusta for inference of relative dispersal patterns and host parasitoid specificity. Genetic differentiation patterns indicated two levels of hierarchical structure in both species: locally similar distance-dependencies but globally differences. Locally, both species showed isolation by distance and a high correlation between host anti parasitoid F ST for the same population-pairs was found. At the local level, E. robusta…
Responses in metabolic rate to changes in temperature in diapausing Colorado potato beetleLeptinotarsa decemlineatafrom three European populations
2015
Many insects survive adverse periods in seasonal environments by entering diapause, a deep resting stage, during which energy consumption is typically low and gas exchange is in the form of a discontinuous gas exchange cycle (DGC). Because insects in high-latitude environments are severely time constrained during summer, an effective diapause termination with careful regulation of metabolic rate is important. The present study examines whether diapausing Colorado potato beetles Leptinotarsa decemlineataSay originating from three latitudinally different regions in Europe differ in their quantitative or qualitative gas exchange patterns in response to an increasing temperature. Overall produc…
Functional interactions between members of the REPAT family of insect pathogen-induced proteins
2012
Studies on the transcriptional response to pathogens in the insect larval gut have shown the regulation of several genes after the infection. Repat (REsponse to PAThogens) genes were first identified in Spodoptera exigua midgut as being up-regulated in response to the exposure to Bacillus thuringiensis toxins and baculovirus. Recently, new members of the REPAT family showed a constitutive up-regulation in a B. thuringiensis-resistant population. Based on a yeast two-hybrid screening, we have detected the interaction of REPAT1 with other members of the REPAT family, leading to the discovery of a new member: REPAT8. The functional role of this interaction was shown by following the changes of…
Variation in mortality among populations is higher for pymetrozine than for imidacloprid and spiromesifen inTrialeurodes vaporariorumin greenhouses i…
2014
BACKGROUND Insecticide resistance in Trialeurodes vaporariorum W. is unknown in the species' northern distribution range where it inhabits mainly commercial greenhouses. Resistance development in whiteflies feeding on year-round crops in greenhouses is possible owing to the use of chemical treatments to back up biocontrol. The authors tested the response levels to spiromesifen, pymetrozine and imidacloprid in whiteflies collected from seven greenhouses within a 35 km radius in western Finland. RESULTS All except one (PR) population had LC50 values below the recommended concentrations for the tested compounds. However, some populations showed reduced susceptibility to pymetrozine in comparis…
Occurrence of three different binding sites forBacillus thuringiensisδ-endotoxins in the midgut brush border membrane of the potato tuber moth,phthor…
1994
The potato tuber moth is susceptible to at least three insecticidal crystal proteins (ICPs) from Bacillus thuringiensis: CrylA(b), CrylB, and CrylC. To design useful combinations of toxin genes either in transgenic plants or in new genetically modified B. thuringiensis strains, it is necessary to determine the binding characteristics of the different ICPs so as not to combine a pair sharing the same binding site. This has been accomplished using two different techniques: 125I-labeling of the ICPs with further measurement of the radioactivity bound to brush border membrane vesicles, and microscopic visualization of the bound ICPs by enzyme-linked reagents such as antibodies or streptavidin u…
Involvement of circadian oscillation(s) in the photoperiodic time measurement and the induction of reproductive diapause in a northern Drosophila spe…
2013
An ability to predict forthcoming changes in environmental conditions and get prepared for them in advance is crucial for the survival and reproduction of organisms living in a seasonally changing environment. We have studied the possible involvement of circadian oscillator(s) in the photoperiodic timer controlling seasonal responses by tracing Drosophila montana females' diapause induction in constant darkness and in a classical Nanda-Hamner experiment. Nearly all females developed ovaries in continuous darkness, which shows the direct development to be their default developmental pathway in the absence of photoperiods. In Nanda-Hamner experiment the females' diapause incidence was close t…
Mapping and quantification of cryptochrome expression in the brain of the pea aphid Acyrthosiphon pisum.
2021
Aphids are paradigmatic photoperiodic animals often used to study the role of the circadian clock in the seasonal response. Previously, we described some elements of the circadian clock core (genes period and timeless) and output (melatonin, AANATs and PTTH) that could have a role in the regulation of the aphid seasonal response. More recently we identified two opsins (C-ops and SWO4) as candidate input photoperiodic receptors. In the present report, we focus on the study of cryptochromes (cry) as photoreceptors of the circadian clock and discuss their involvement in the seasonal response. We analyze the expression of cry1 and cry2 genes in a circadian and seasonal context, and map their ex…
Locust neuropeptides stimulating sex pheromone production in female European corn borer moth, Ostrinia nubilalis
1990
Abstract The presence of a pheromonotropically active hormone (PBAN-like substance) from locust organs, ( Locusta migratoria ) has been demonstrated. Extracts of brain, corpora cardiaca, corpora allata, suboesophageal ganglia and thoracic ganglia of L. migratoria caused highly pheromonotropic responses in decapitated females of the European corn borer moth ( Ostrinia nubilalis ). The highest activity per unit weight of tissue was found in the corpora cardiaca and corpora allata of the locust followed by the brain plus suboesophageal ganglion of O. nubilalis . Following 8 days of disconnection, separating the corpora allata from the corpora cardiaca and suboesophageal ganglion, the pheromono…
The King’s Lace Bug Recaredus rex Distant, 1909 (Hemiptera: Heteroptera: Tingidae): Systematic Position, First Palaearctic and Afrotropical Rec…
2022
The systematic position and actual distribution of Recaredus rex, for a long time one of the most enigmatic lace bug genus and species, is very obscure because only the type specimen and three other individuals from India are known to date. In the present paper, we report the first records of R. rex from the Palaearctic region (Iran) and tropical Africa (Ghana). Based on the occurrence localities and climatic variables, we predict potentially useful ecological niches for this species using Maxent software. The areas with the best environmental conditions for R. rex indicated in our studies suggest its possible Palaeotropical distribution. Moreover, we regard these results as a good starting…
Reproductive Physiology ofAedes(Aedimorphus)vexans(Diptera: Culicidae) in Relation to Flight Potential
2001
Total protein, lipid, and glycogen of Aedes vexans (Meigen) were related linearly to body size at eclosion. Starvation after emergence led to the determination of minimal irreducible amounts of protein, lipid, and glycogen and the availability of the teneral reserves, whereas access to sucrose revealed the potential for reserve synthesis. Glycogenesis and lipogenesis increased reserves approximately 10-fold the teneral value within 1 and 2 wk after emergence, respectively. Carbohydrate feeding was an essential behavior before blood feeding and oogenesis commenced. Female flight was tested on a flight mill. Maximal flights of 10-17 km in a single night occurred at 2 wk posteclosion and paral…