why are there so few aphid clones?in europe, aphids contribute significantly to the so-called 'aerial plankton' during the spring to autumn months (growing season), although individual flight behaviour has been found, especially from molecular ecological studies, to be species-specific in terms of migratory range (ambit). many of these species individuals may be assumed to be clonal in origin, that is, derived from a single asexual foundress. we are presently studying two specialist aphid species on tansy, tanacetum vulgare l. f ...201020504382
metapopulation structure of the specialized herbivore macrosiphoniella tanacetaria (homoptera, aphididae).we investigated population dynamics, genetic diversity and spatial structure in the aphid species macrosiphoniella tanacetaria, a specialist herbivore feeding on tansy, tanacetum vulgare. tansy plants (genets) consist of many shoots (ramets), and genets are grouped in sites. thus, aphids feeding on tansy can cluster at the level of ramets, genets and sites. we studied aphid population dynamics in 1997 and 2001 and found that within sites: (i). at any time, aphids used only a fraction of the avai ...200212453236
patterns of genetic differention between populations of the specialized herbivore macrosiphoniella tanacetaria (homoptera, aphididae).for herbivorous insects, studies of isolation by distance (ibd) are available for large spatial scales, whereas studies over small geographic distances are relatively rare, in particular for species where population turnover is high. in this study, we investigated ibd and population genetic structure in the aphid macrosiphoniella tanacetaria, a specialist herbivore of tansy (tanacetum vulgare). owing to clonal growth, an individual plant (genet) has one to many shoots (ramets), which can host ap ...200415329663
hierarchical metapopulation dynamics of two aphid species on a shared host plant.we modeled hierarchical multiscale colonization-extinction dynamics of two aphid species living in a shared host plant. we parameterized the model with data collected at the level of individual ramets of the host plant, with the plants being organized as groups within islands. as expected, the extinction rates and per capita colonization rates decreased with increasing spatial scale. the per capita colonization rates were greater for winged than for unwinged individuals, but as the unwinged indi ...200919637939
how aphids decide what is good for them: experiments to test aphid feeding behaviour on tanacetum vulgare (l.) using different nitrogen regimes.leaf-chewing herbivores select food with a protein/carbohydrate ratio of 0.8-1.5, whereas phloem sap, which aphids feed on, has a ratio of approximately 0.1. enhanced n fertilization increases the amino acid concentration in phloem sap and elevates the n/c ratio. the study examines: (1) whether aphids select between plants of different n nutrition, (2) whether feeding time correlates with the amino acid composition of phloem sap, and (3) at which stage of probing aphids identify the quality of t ...201020461410
evidence for a quiet revolution: seasonal variation in colonies of the specialist tansy aphid, macrosiphoniella tanacetaria (kaltenbach) (hemiptera: aphididae) studied using microsatellite cyclical parthenogens, clonal diversity is expected to decrease due to selection and drift during the asexual phase per number of asexual generations. the decrease in diversity may be counteracted by immigration of new genotypes. we analysed temporal variation in clonal diversity in colonies of the monophagous tansy aphid, macrosiphoniella tanacetaria (kaltenbach), sampled four times over the course of a growing season. in a related field study, we recorded aphid colony sizes and the occurren ...201121062524
multiple cues for winged morph production in an aphid metacommunity.environmental factors can lead individuals down different developmental pathways giving rise to distinct phenotypes (phenotypic plasticity). the production of winged or unwinged morphs in aphids is an example of two alternative developmental pathways. dispersal is paramount in aphids that often have a metapopulation structure, where local subpopulations frequently go extinct, such as the specialized aphids on tansy (tanacetum vulgare). we conducted various experiments to further understand the c ...201323472179
complex effects of fertilization on plant and herbivore performance in the presence of a plant competitor and activated carbon.plant-herbivore interactions are influenced by host plant quality which in turn is affected by plant growth conditions. competition is the major biotic and nutrient availability a major abiotic component of a plant's growth environment. yet, surprisingly few studies have investigated impacts of competition and nutrient availability on herbivore performance and reciprocal herbivore effects on plants. we studied growth of the specialist aphid, macrosiphoniella tanacetaria, and its host plant tansy ...201425078980
effects of intraspecific and intra-individual differences in plant quality on preference and performance of monophagous aphid species.plant chemistry is one of the main drivers of herbivore distribution. monophagous herbivore species are highly specialized, but even within their only host species the chemistry varies. the herbivore's choice is initially mainly guided by volatile plant compounds. once on the plant, particularly for aphids the phloem quality affects their performance. however, little is known about the intraspecific and intra-individual variation in phloem sap and their influences on monophagous aphids. to deter ...201829143149
coexistence through mutualist-dependent reversal of competitive hierarchies.mechanisms that allow for the coexistence of two competing species that share a trophic level can be broadly divided into those that prevent competitive exclusion of one species within a local area, and those that allow for coexistence only at a regional level. while the presence of aphid-tending ants can change the distribution of aphids among host plants, the role of mutualistic ants has not been fully explored to understand coexistence of multiple aphid species in a community. the tansy plant ...201829375795
ant-aphid mutualisms: the impact of honeydew production and honeydew sugar composition on ant preferences.the honeydew composition and production of four aphid species feeding on tanacetum vulgare, and mutualistic relationships with the ant lasius niger were studied. in honeydew of metopeurum fuscoviride and brachycaudus cardui, xylose, glucose, fructose, sucrose, maltose, melezitose, and raffinose were detected. the proportion of trisaccharides (melezitose, raffinose) ranged between 20% and 35%. no trisaccharides were found in honeydew of aphis fabae, and honeydew of macrosiphoniella tanacetaria co ...199928307416
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