Life-cycle of a spiral gall aphid, Pemphigus spirothecae (Homoptera: Aphididae), on poplar in British Columbia

<i>Pemphigus spirothecae</i> Pass. was inadvertently introduced into North America only recently. Upon hatching in spring on lombardy poplar, the fundatrix feeds on a leaf petiole, which bends and then spirals into a spiral gall. The fundatrix produces about 100 fundatrigeniae within the gall. These produce winged sexuparae which leave the gall and settle on the poplar bark, where they produce up to eight progeny, males and females. Each female lays a single large egg which overwinters on the bark. This aphid is thus monoecious and holocyclic

Life-cycle of a spiral gall aphid, Pemphigus spirothecae (Homoptera: Aphididae), on poplar in British Columbia

Pemphigus spirothecae Pass. was inadvertently introduced into North America only recently. Upon hatching in spring on lombardy poplar, the fundatrix feeds on a leaf petiole, which bends and then spirals into a spiral gall. The fundatrix produces about 100 fundatrigeniae within the gall. These produce winged sexuparae which leave the gall and settle on the poplar bark, where they produce up to eight progeny, males and females. Each female lays a single large egg which overwinters on the bark. This aphid is thus monoecious and holocyclic

Gall-inducing Aphids (Hemiptera: Aphidoidea: Eriosomatinae) Associated with Salicaceae and Ulmaceae in Razavi Khorasan Province, with New Records for Fauna of Iran

A survey of gall-inducing aphids on elm and poplar trees was carried out during 2017 in Razavi Khorasan province, NE Iran. As a result, 15 species of gall-inducing aphids from 5 genera, all belonging to the subfamily Eriosomatinae, were recorded on 6 host plant species. The collected species included the genera Eriosoma, Kaltenbachiella, Pemphigus, Tetraneura and Thecabius. Pemphigus passeki Börner (Hemiptera: Aphididae) and Pemphigus populinigrae (Schrank) (Hemiptera: Aphididae) on Populus nigra var. italica (Salicaceae) were new records for the Iranian aphid fauna. Both new recorded species belong to the tribe Pem-phigini, subfamily Eriosomatinae. Among the identified species, 8 aphid species were new records for Razavi Khorasan province

Neuronal signalling molecules as targets for green peach aphid (Myzus persicae) control via RNA interference

The Green peach aphid (GPA) (Myzus persicae) is an important insect pest which causes substantial economic losses to many glasshouse and field crops. Alarmingly, GPAs are becoming resistant to many conventional insecticides, and this trend indicates that there is a real need to develop alternative strategies to protect crops from this insect pest. The aim of this research project was to investigate the potential of RNA interference (RNAi) technology as a strategy to control GPAs. Genes involved in insect neuronal signalling pathways were selected as RNAi targets. Bioinformatic analysis tools were used to identify ESTs putatively encoding sixty-three Neuronal Signalling Molecules (NSMs) from publicly available sequences and from GPA transcriptome data generated in-house. The NSMs included 30 Neuropeptides (NPs), 24 Neuropeptide Receptors (NPRs), and 9 Biogenic Amine Receptors (BARs). From these, transcripts for 24 NSMs were selected for in vitro RNAi assays to determine their suitability as targets for host-induced gene silencing (HIGS). Successful ingestion of dsRNA of target genes by nymphs was confirmed using the presence of a neutral red dye in the body of aphids, incorporated in the dsRNA+30% sucrose diet. Silencing effects of nine genes, e.g. Ecdysis triggering Hormone (eth), Capability (capa), Juvenille hormone binding protein (jhbp), Leucokinin (lk), Crustacean Cardioactive Peptide (ccap), Octopamine beta 3R (octβ3r), Muscarinic acetylcholine receptor 3 (mAChrM3), Short NPF (snpf ) and Insulin-related peptide 2/3 (irp2/3) were obvious 24 hours after feeding on the dsRNA diet. RNAi phenotypes included incomplete moulting, uncoordinated movement, lethargy, paralysis and lethality, whereas the control GPAs exposed to no-dsRNA and dsRNA of the green fluorescent protein (GFP) gene of the jellyfish, Aequorea victoria moved normally, showing no obvious effects of the treatment. For GPAs treated with dsRNAs of six of these genes (ccap, capa, mAChrM3, lk, octβ3r and irp2/3), silencing also significantly affected survival and fecundity when the aphids were later transferred to tobacco plants for 12 days. Silencing of ccap, capa, irp2/3, lk and octβ3r resulted in 100% lethal phenotypes on the tobacco plants. Knockdown of dscapar1 and dsnplp1 also affected GPA reproduction although no visible effects were observed 24 hours after ingestion of dsRNA. The effectiveness of nine of the 24 genes (ccap, jhbp, nplp1, capar1, irp5, lk, octβ3r, snpf and opsin) as targets for RNAi control of GPAs were evaluated using HIGS, in which two model plants, tobacco and Arabidopsis thaliana were used. Transgenic tobacco plants carrying hairpins (hp) of all nine GPA genes were developed of which those for six genes (except for lk, octβ3r and snpf), were advanced to the T2 generation, and used for GPA bioassays. In T1 tobacco, the mean population was reduced by 97% for hpoctβ3r event 2 and event 5, while significantly lower GPA populations were recorded for all the lines expressing hpccap, hpnplp1 and hplk after 12 days (p<0.05). As for the T1 generation, most of the T2 transgenic events also supported significantly fewer GPA nymphs, with reductions in numbers ranging from 3% to 69%. GPAs feeding on events of hpccap, hpnplp1 and hplk produced fewest nymphs, as was observed for T1 generation. In addition, an 80% to 100% reduction in GPAs was evident for T2 transgenic Arabidopsis plants expressing dsccap, dsjhbp and dsnplp1, and complete mortality was recorded for the hpccap event 3. The results obtained from two transgenic generations and two model plants therefore indicate that the genes studied were vital for the GPA life cycle and knocking down of these genes affects their fecundity or survival. An in vitro study was also conducted to evaluate the effects of silencing five different lengths of dsRNA from different regions of the same EST putatively encoding the JHBP protein, as well as siRNAs of the gene generated in vitro from digestion with an RNAseIII enzyme. The longest dsRNA (284 bp) was the most effective in inducing RNAi effects on treated nymphs, since there were more restricted movements in aphids 24 hours after exposure, and the fewest offspring were produced in the longer-term. One of the shorter dsRNAs (86 bp long, not the shortest,70 bp), also significantly reduced GPA movement, survival and reproduction at levels similar to that of the longest dsRNA. These results show that RNAi effects can vary with the target region from which the hp dsRNA is derived and in this case silencing was more effective for one of the sequences derived from the 3´ region. This study indicates that both the length of the dsRNA and the specific sequence chosen can influence the effectiveness of RNAi. This project provides new information on GPA neuronal genes as novel candidates for its control via gene silencing. It also offers additional data to achieve better RNAi effects related to the target sequence selected. The in planta RNAi study also demonstrated that RNAi can be used as a new strategy to control this important crop pest, and its use, either alone or in combination with other gene targets, is discussed

Empowerment : et paradigmeskifte i spesialpedagogisk rådgivning? : en fagkritisk studie av empowerment som prinsipp for spesialpedagogisk rådgivning

Bakgrunn og formål I løpet av en langt yrkesliv i norsk grunnskole har jeg erfart hvor viktig foreldrenes styrke og mestringsevne er, spesielt når de opplever å få et barn med kronisk sykdom eller funksjonshemming. De er avgjørende for barnets utvikling og framtidsmuligheter. God foreldrerådgivning og gode støtteordninger er helt avgjørende for å skaffe foreldrene et overskudd som kan komme barna til gode. Min interesse for rådgivningsfagets muligheter er utgangspunktet for valg av tema. Bakgrunnen for valg av en fagkritisk tilnærming til empowermentbegrepets relevans for spesialpedagogisk rådgivning, var at fagpersoner på Institutt for spesialpedagogikk (ISP) brukte denne termen til stadighet. Empowerment ble brukt som et begrep én var innforståtte med, men samtidig var det vanskelig for meg å få tak i nøyaktig hva fagpersonene la i det. Min førforståelse av ulike begrepers dominans i forskjellige tidsepoker, gjorde at min forskertrang ble vekket. Hvordan kan empowermentbegrepet være like brukbart i forhold til teambuilding og selvhjelpsgrupper for brystkreftopererte som for utviklingshemmede med ønsker om å bestemme over egen fritid? Hva er det med dette begrepet som rommer så mye god vilje? I en av våre pensumartikler ble empowermentprinsippene karakterisert som et paradigmeskifte i forhold til spesialpedagogisk rådgivning. Jeg stiller med en viss faglig skepsis i forhold til forestillingen om empowerment som en slik radikal endring. Denne påstanden drøftes sammen med dokumentanalysen av pensumartikkelen. Min masteroppgave er i to deler. Den første skisserer et bilde av empowermentbegrepets innhold og betydning, og legger grunnlaget for del to. Her analyseres og drøftes betydningen av empowerment som metode i spesialpedagogisk rådgivning. Problemstilling Med utgangspunkt i Liv Lassens artikkel i Spesialpedagogikk (Befring og Tangen (red.). 2008) granskes: “Empowermentprinsippenes relevans for spesialpedagogisk rådgivning – muligheter og begrensninger?” Metode For å belyse problemstillingen har jeg brukt tidligere forskning på emnet kombinert med litteratur og offentlige dokumenter. Studien er strukturert i to deler. Datainnsamlingen i første del har i stor grad dreid seg om å finne, velge ut, tolke og analysere foreliggende litteratur og kilder. I denne prosessen har kildekritikk vært sentral for å finne og vurdere kilder. Disse har i sin tur blitt analysert, tolket og så benyttet i dokumentanalyse og drøfting av en fagartikkel på masterstudiet for spesialpedagogisk rådgivning. Dokumentanalysen består i en kvalitativ innholdsanalyse som har fulgt en hermeneutisk tilnærming til materialet. Resultat Hovedkonklusjonen i første del av studien dreier seg om å erkjenne kompleksiteten i begrepet empowerment og dets mange uttrykksformer. Utfordringen er å forholde seg til de mange fortolkningene av begrepet på ulike tidspunkt, i mange sammenhenger for å kunne undersøke og bestemme fenomenet. Denne faglige bevisstheten hos profesjonelle hjelpearbeidere er avgjørende for de konsekvenser bruken av empowerment får. Spørsmålet om empowerment¬prinsippenes metodiske relevans for spesialpedagogisk rådgivning og drøftingen av begrepets posisjon i forhold til en konkret fagtekst, viste også betydningen av bevissthet i begreps¬bruken. Empowerment er ikke først og fremst en metode som retter seg mot enkeltindivider. Den begrepsmessige gjennomgang viser at sentrum i den opprinnelige definisjonen av empowerment er fellesskapet, der individets kontroll og ledelse må forstås i sammenheng med dets sosiale og politiske omgivelser. Empowerment forstått på denne måten må sies å ligge utenfor rådgiveroppdragets mandat. I oppgavens tittel stilles spørsmålet om empowerment representerer et paradigmeskifte i rådgivningssammenheng. Drøftingen konkluderer med at til tross for de viktige endringene empowermentprinsippene representerer, kan endringene vanskelig sies å være så gjennomgripende og fornyende at de fortjener å bli kalt paradigmeskifte. Dette vil imidlertid være avhengig av hvordan en definerer begrepet paradigmeskifte

Genetic variation in the aphid Pemphigus spyrothecae

This project used genetic variation to investigate dispersal, inbreeding and social behaviour in the aphid $\textit{Pemphigus spyrothecac}$. \textit{\textit{P. spyrothecae}} is cyclically parthenogenetic, reproducing sexually on the bark of its primary host, $\textit{Populus nigra}$, and asexually within galls on the leaf petioles. Within the gall, a soldier caste defends and cleans the gall, potentially reducing its own fitness. $\textit{P. spyrothecae}$ collected across the UK from 1997 to 1999 and from mainland Europe and America in 1999 were genotyped using seven variable microsatellite markers that I developed in collaboration with William Amos and Kate Llewellyn. Using population genetic analysis, I showed that $\textit{P. spyrothecae}$ populations were temporally stable over three years, and spatially structured. Populations from trees 5 to 1700 km apart were significantly differentiated, and loosely followed an isolation-by-distance model. There was slight evidence of differentiation between neighbouring trees (5 to 500 m apart), but not between samples taken from within trees (less than 5 m apart). By contrast, $\textit{P. bursarius}$, a closely related species that, unlike $\textit{P. spyrothecae}$, has a secondary host, showed no differentiation between populations 150 km apart, suggesting that population isolation in $\textit{P. spyrothecae}$ may be a consequence of losing its secondary host. Populations within trees were highly inbred, probably due to selfing between sexuales from the same clone. This finding corresponds with the theory that female-biased sex ratios in P. spyrothecae evolved through local mate competition. There was no evidence for a correlation between inbreeding and population density. Genetic variation was also found within galls. Of 633 aphids in one gall, 619 shared one genotype, while the remaining 14 were immigrants from at least nine other clones. One immigrant was found among 49 aphids from four other galls. Such a low level of clonal mixing probably favoured the evolution of soldiers, and may represent an investment in dispersal by the clone as an insurance against its death

The biology of Pemphigus spyrothecae galls on poplar leaves

The gall forming aphid Pemphigus spyrothecae is a plant parasite that colonises the leaf petiole of the black poplar Populus nigra and its hybrids and varieties. Models of habitat selection are described and discussed in context with galling aphids. Habitat quality and aphid fitness can be quantified easily. Measures of relative reproductive fitness may be used to determine selection pressures driving habitat selection. The poplar trees differed significantly in budburst phenology, but Pemphigus spyrothecae stem mothers hatched on all trees within two days. Structural differences among and within trees were examined. Within and between host plant variation accounted for a dramatic difference in aphid fecundity. Larger leaves or shoots supported galls containing a higher number of offspring and a lower rate of gall failure. On singly galled shoots, gall position on a shoot did not affect reproductive outcome. Most stem mothers located their galls at the top of the petiole, closest to the base of the leaf, but gall position on the petiole did not affect the number of offspring produced. No relationship between stem mother size and fecundity could be detected. When competitor density increased on the same shoot or petiole, average fitness declined. Gall order on the petiole affected the growth rate of the gall tissue, but not the enclosed colony. However, distal galls (furthest from the leaf) were, on average, heavier and had more offspring than proximal galls. Predators are known to be important in regulating insect populations. Although, predators, on average, approached larger galls more often, this was not statistically significant. Due to the restrictive assumptions of models based on the Ideal Free Distribution, no qualitative fit of the distribution pattern of Pemphigus spyrothecae aphids was attempted. However, the characteristics of this aphid system were found to approximate an unequal competitors model. The availability of closed leaves on shoots at budburst, when stem mothers emerge, appeared to be the most important factor (of those examined) explaining the population distribution seen in spiral galling aphids

The biology of Pemphigus spyrothecae galls on poplar leaves

The gall forming aphid Pemphigus spyrothecae is a plant parasite that colonises the leaf petiole of the black poplar Populus nigra and its hybrids and varieties. Models of habitat selection are described and discussed in context with galling aphids. Habitat quality and aphid fitness can be quantified easily. Measures of relative reproductive fitness may be used to determine selection pressures driving habitat selection. The poplar trees differed significantly in budburst phenology, but Pemphigus spyrothecae stem mothers hatched on all trees within two days. Structural differences among and within trees were examined. Within and between host plant variation accounted for a dramatic difference in aphid fecundity. Larger leaves or shoots supported galls containing a higher number of offspring and a lower rate of gall failure. On singly galled shoots, gall position on a shoot did not affect reproductive outcome. Most stem mothers located their galls at the top of the petiole, closest to the base of the leaf, but gall position on the petiole did not affect the number of offspring produced. No relationship between stem mother size and fecundity could be detected. When competitor density increased on the same shoot or petiole, average fitness declined. Gall order on the petiole affected the growth rate of the gall tissue, but not the enclosed colony. However, distal galls (furthest from the leaf) were, on average, heavier and had more offspring than proximal galls. Predators are known to be important in regulating insect populations. Although, predators, on average, approached larger galls more often, this was not statistically significant. Due to the restrictive assumptions of models based on the Ideal Free Distribution, no qualitative fit of the distribution pattern of Pemphigus spyrothecae aphids was attempted. However, the characteristics of this aphid system were found to approximate an unequal competitors model. The availability of closed leaves on shoots at budburst, when stem mothers emerge, appeared to be the most important factor (of those examined) explaining the population distribution seen in spiral galling aphids

Poplar Tree Response to Feeding by the Petiole Gall Aphid Pemphigus spyrothecae Pass

Pemphigus spyrothecae Pass. which is a member of the subfamily Pemphiginae is one of the gall-inducing aphids that occurs on poplar trees. Phloem feeding of a founding mother on leaf petiole results in the formation of a new organ, i.e., the spiral gall. This study documents aphid development inside the galls during the growing season and the effect of their feeding on leaf architecture and physiology of the host plant. In particular, leaf length, width, and area were measured, as well as hydrogen peroxide (H2O2) content, electrolyte leakage (EL), malondialdehyde (MDA) concentration, and the activity of ascorbate (APX) and guaiacol peroxidase (GPX) were determined in galls and galled leaves. The presence of petiole galls significantly decreased the length, width, and leaf area. Aphid activity increased H2O2 concentration in galls and EL from galls and leaf tissues, which was accompanied by a strong decrease in MDA content and both peroxidase activities, especially in gall tissues. It can be suggested that P. spyrothecae can manipulate physiological machinery of the host plant for its own benefit