Karsten Mody - Academia.edu (original) (raw)
Papers by Karsten Mody
... V. Organisation of Arthropod Assemblages in Individual African Savannah Trees .....31 VI. ...... more ... V. Organisation of Arthropod Assemblages in Individual African Savannah Trees .....31 VI. ... of processes connected with anthropogenic alterations and with conservation and restoration efforts (Dobson et al. ...
Arthropod herbivores reduce the quantity and quality of apple yield. Resistant apple varieties ho... more Arthropod herbivores reduce the quantity and quality of apple yield. Resistant apple varieties hold promise to increase the sustainability of pest management in orchards, but little is known on the genetic basis of apple resistance to most arthropod herbivores. Knowledge on the apple genome and QTL (quantitative trait locus) analysis is now facilitating the identification of gene regions associated with resistance. 160 F1-progeny plants of a cross of the apple varieties 'Fiesta' and 'Discovery' were surveyed at three different sites in Switzerland. Herbivore infestation per genotype as a measure of resistance was quantified for the apple aphids Dysaphis plantaginea, Dysaphis cf. devecta and Aphis pomi, the apple rust mite Aculus schlechtendali, and the codling moth Cydia pomonella. The influence of the environmental factor 'drought stress' on apple resistance to a chewing and a sap-feeding herbivore (caterpillar; aphid) was studied in laboratory experiments c...
German with English Abstract (see below German Abstract) Bäume sind eine wichtige Nahrungsgrundla... more German with English Abstract (see below German Abstract) Bäume sind eine wichtige Nahrungsgrundlage für viele pflanzenfressende (phytophage) Tiere. Phytophage Arthropoden (Gliederfüßer) zeigen besonders enge Beziehungen zu ihren Wirtsbäumen. Die mit bestimmten Baumarten assoziierten Arthropodengemeinschaften unterscheiden sich zum Teil stark in ihrer Artenzahl und Artenzusammensetzung. Der Wildapfel, Malus sylvestris, beherbergt im Vergleich zu anderen heimischen Baumarten eine Phytophagenfauna mittlerer Artenvielfalt, wobei Kleinschmetterlinge und Blattläuse besonders artenreich vertreten sind. Da der Wildapfel neben vegetativen Pflanzenteilen auch zahlreiche insektenbestäubte Blüten und große Früchte entwickelt, deckt er ein Ressourcenspektrum für Phytophage ab, wie es nur noch wenige andere Waldbäume zur Verfügung stellen. Die große Ähnlichkeit des Wildapfels mit dem Kulturapfel, Malus domestica, kann zum Austausch von Phytophagen und ihren Antagonisten (zum Beispiel parasitoide ...
Agroforestry Systems, Apr 22, 2011
Green alder Alnus viridis is a characteristic woody plant of the subalpine zone of the Alps, whic... more Green alder Alnus viridis is a characteristic woody plant of the subalpine zone of the Alps, which is expanding rapidly on many abandoned pastures. Although green alder dominates the vegetation in many parts of the Alps, little is known on its relevance as habitat for arthropods. We sampled arthro- pods on green alder in the Urseren valley, canton Uri, Switzerland at four different dates at six differ- ent locations across altitudinal gradients. We found that rove beetles (Coleoptera: Staphylinidae) were the numerically dominating beetle family, with 433 identified individuals belonging to 15 species in seven genera. Most abundant was the predacious genus Anthophagus, which was represented by seven species. The six species Eusphalerum stramineum, Amphichroum canaliculatum, Anthophagus spec- tabilis, Anthophagus fallax, Stenus impressus and Amischa decipiens were first records for the can- ton Uri. This study emphasises that green alder may be an important habitat for several rove be...
Agricultural and Forest Entomology, 2015
ABSTRACT 1 Plant resistance strongly depends on plant characteristics that affect herbivore prefe... more ABSTRACT 1 Plant resistance strongly depends on plant characteristics that affect herbivore preference or performance. Different plant genotypes may express specific characteristics that lead to differential resistance to herbivores. Few studies have investigated these aspects for weevils, a particularly speciose taxon of insect herbivores, on fruit tree cultivars, which are vegetatively propagated. 2 We studied the influence of apple cultivar on preference and performance of a fruit tree herbivore, the flower-feeding apple blossom weevil Anthonomus pomorum (Coleoptera: Curculionidae). We quantified field infestation of five different apple genotypes by the weevil at different collection dates as measure of preference, as well as the mass and emergence time of weevils developing on these cultivars as measures of performance. 3 Infestation of apple flower buds by A. pomorum differed significantly between cultivars. The collection date affected the number of infested flowers in a cultivar-specific way. 4 Weevil mass differed significantly between apple cultivars. The average mass of weevils from Ariwa, the cultivar producing the heaviest weevils, was 40% higher than the mass of weevils from Rewena, the cultivar producing the lightest weevils. 5 Weevil emergence time from infested flowers differed significantly between cultivars. Weevils emerged earliest from cultivars Ariwa and Retina, at an intermediate time from Discovery and Florina, and latest from Rewena. 6 The present study demonstrates that preference and performance of florivores feeding on fruit trees can strongly differ between apple cultivars representing specific tree genotypes. These differences may directly and indirectly affect herbivore and antagonist populations and can be considered for pest management.
Tree Genetics & Genomes, 2009
Planta, 2011
Induction of plant resistance by herbivory is a complex process, which follows a temporal dynamic... more Induction of plant resistance by herbivory is a complex process, which follows a temporal dynamic and varies spatially at the within-plant scale. This study aimed at improving the understanding of the induction process in terms of time scale and within-plant allocation, using apple tree seedlings (Malus × domestica) as plant model. Feeding preferences of a leaf-chewing insect (Spodoptera littoralis) for previously damaged and undamaged plants were assessed for six different time intervals with respect to the herbivore damage treatment and for three leaf positions. In addition, main secondary defense compounds were quantified and linked to herbivore feeding preferences. Significant herbivore preference for undamaged plants (induced resistance) was first observed 3 days after herbivore damage in the most apical leaf. Responses were delayed in the other leaf positions, and induced resistance decreased within 10 days after herbivore damage simultaneously in all tested leaf positions. Chemical analysis revealed higher concentrations of the flavonoid phloridzin in damaged plants as compared to undamaged plants. This indicates that herbivore preference for undamaged apple plants may be linked to phloridzin, which is the main secondary metabolite of apple leaves. The observed time course and distribution of resistance responses within plants contribute to the understanding of induction processes and patterns, and support the optimal defense theory stating young tissue to be prioritized. Moreover, induced resistance responses occurred also basipetally in leaves below the damage site, which suggests that signaling pathways involved in resistance responses are not unidirectional.
... V. Organisation of Arthropod Assemblages in Individual African Savannah Trees .....31 VI. ...... more ... V. Organisation of Arthropod Assemblages in Individual African Savannah Trees .....31 VI. ... of processes connected with anthropogenic alterations and with conservation and restoration efforts (Dobson et al. ...
Arthropod herbivores reduce the quantity and quality of apple yield. Resistant apple varieties ho... more Arthropod herbivores reduce the quantity and quality of apple yield. Resistant apple varieties hold promise to increase the sustainability of pest management in orchards, but little is known on the genetic basis of apple resistance to most arthropod herbivores. Knowledge on the apple genome and QTL (quantitative trait locus) analysis is now facilitating the identification of gene regions associated with resistance. 160 F1-progeny plants of a cross of the apple varieties 'Fiesta' and 'Discovery' were surveyed at three different sites in Switzerland. Herbivore infestation per genotype as a measure of resistance was quantified for the apple aphids Dysaphis plantaginea, Dysaphis cf. devecta and Aphis pomi, the apple rust mite Aculus schlechtendali, and the codling moth Cydia pomonella. The influence of the environmental factor 'drought stress' on apple resistance to a chewing and a sap-feeding herbivore (caterpillar; aphid) was studied in laboratory experiments c...
German with English Abstract (see below German Abstract) Bäume sind eine wichtige Nahrungsgrundla... more German with English Abstract (see below German Abstract) Bäume sind eine wichtige Nahrungsgrundlage für viele pflanzenfressende (phytophage) Tiere. Phytophage Arthropoden (Gliederfüßer) zeigen besonders enge Beziehungen zu ihren Wirtsbäumen. Die mit bestimmten Baumarten assoziierten Arthropodengemeinschaften unterscheiden sich zum Teil stark in ihrer Artenzahl und Artenzusammensetzung. Der Wildapfel, Malus sylvestris, beherbergt im Vergleich zu anderen heimischen Baumarten eine Phytophagenfauna mittlerer Artenvielfalt, wobei Kleinschmetterlinge und Blattläuse besonders artenreich vertreten sind. Da der Wildapfel neben vegetativen Pflanzenteilen auch zahlreiche insektenbestäubte Blüten und große Früchte entwickelt, deckt er ein Ressourcenspektrum für Phytophage ab, wie es nur noch wenige andere Waldbäume zur Verfügung stellen. Die große Ähnlichkeit des Wildapfels mit dem Kulturapfel, Malus domestica, kann zum Austausch von Phytophagen und ihren Antagonisten (zum Beispiel parasitoide ...
Agroforestry Systems, Apr 22, 2011
Green alder Alnus viridis is a characteristic woody plant of the subalpine zone of the Alps, whic... more Green alder Alnus viridis is a characteristic woody plant of the subalpine zone of the Alps, which is expanding rapidly on many abandoned pastures. Although green alder dominates the vegetation in many parts of the Alps, little is known on its relevance as habitat for arthropods. We sampled arthro- pods on green alder in the Urseren valley, canton Uri, Switzerland at four different dates at six differ- ent locations across altitudinal gradients. We found that rove beetles (Coleoptera: Staphylinidae) were the numerically dominating beetle family, with 433 identified individuals belonging to 15 species in seven genera. Most abundant was the predacious genus Anthophagus, which was represented by seven species. The six species Eusphalerum stramineum, Amphichroum canaliculatum, Anthophagus spec- tabilis, Anthophagus fallax, Stenus impressus and Amischa decipiens were first records for the can- ton Uri. This study emphasises that green alder may be an important habitat for several rove be...
Agricultural and Forest Entomology, 2015
ABSTRACT 1 Plant resistance strongly depends on plant characteristics that affect herbivore prefe... more ABSTRACT 1 Plant resistance strongly depends on plant characteristics that affect herbivore preference or performance. Different plant genotypes may express specific characteristics that lead to differential resistance to herbivores. Few studies have investigated these aspects for weevils, a particularly speciose taxon of insect herbivores, on fruit tree cultivars, which are vegetatively propagated. 2 We studied the influence of apple cultivar on preference and performance of a fruit tree herbivore, the flower-feeding apple blossom weevil Anthonomus pomorum (Coleoptera: Curculionidae). We quantified field infestation of five different apple genotypes by the weevil at different collection dates as measure of preference, as well as the mass and emergence time of weevils developing on these cultivars as measures of performance. 3 Infestation of apple flower buds by A. pomorum differed significantly between cultivars. The collection date affected the number of infested flowers in a cultivar-specific way. 4 Weevil mass differed significantly between apple cultivars. The average mass of weevils from Ariwa, the cultivar producing the heaviest weevils, was 40% higher than the mass of weevils from Rewena, the cultivar producing the lightest weevils. 5 Weevil emergence time from infested flowers differed significantly between cultivars. Weevils emerged earliest from cultivars Ariwa and Retina, at an intermediate time from Discovery and Florina, and latest from Rewena. 6 The present study demonstrates that preference and performance of florivores feeding on fruit trees can strongly differ between apple cultivars representing specific tree genotypes. These differences may directly and indirectly affect herbivore and antagonist populations and can be considered for pest management.
Tree Genetics & Genomes, 2009
Planta, 2011
Induction of plant resistance by herbivory is a complex process, which follows a temporal dynamic... more Induction of plant resistance by herbivory is a complex process, which follows a temporal dynamic and varies spatially at the within-plant scale. This study aimed at improving the understanding of the induction process in terms of time scale and within-plant allocation, using apple tree seedlings (Malus × domestica) as plant model. Feeding preferences of a leaf-chewing insect (Spodoptera littoralis) for previously damaged and undamaged plants were assessed for six different time intervals with respect to the herbivore damage treatment and for three leaf positions. In addition, main secondary defense compounds were quantified and linked to herbivore feeding preferences. Significant herbivore preference for undamaged plants (induced resistance) was first observed 3 days after herbivore damage in the most apical leaf. Responses were delayed in the other leaf positions, and induced resistance decreased within 10 days after herbivore damage simultaneously in all tested leaf positions. Chemical analysis revealed higher concentrations of the flavonoid phloridzin in damaged plants as compared to undamaged plants. This indicates that herbivore preference for undamaged apple plants may be linked to phloridzin, which is the main secondary metabolite of apple leaves. The observed time course and distribution of resistance responses within plants contribute to the understanding of induction processes and patterns, and support the optimal defense theory stating young tissue to be prioritized. Moreover, induced resistance responses occurred also basipetally in leaves below the damage site, which suggests that signaling pathways involved in resistance responses are not unidirectional.