Search results for "Herb"
showing 10 items of 856 documents
Host plant use by the Heath fritillary butterfly, Melitaea athalia : plant habitat, species and chemistry
2008
We present a study of habitat use, oviposition plant choice, and food plant suitability for the checkerspot butterfly Melitaea athalia Rottemburg (Lepidoptera: Nymphalidae) in Aland, Finland. We found that in Aland, unlike in the mainland of Finland and many parts of its range, M. athalia flies mainly in open meadows. When offered an array of plants in a large (32 × 26 m) field cage, they predominately oviposited upon Veronica chamaedrys L., V. spicata L. and Plantago lanceolata L. (Plantaginaceae), which grow in open meadows. The relative abundance of the butterfly in Aland, and its habitat and host plant use there, may reflect local adaptation to land use practices and geology that mainta…
The Plant as a Habitat for Entomophagous Insects
2017
International audience; Populations of herbivorous insects are naturally consumed by other predacious or predatory insect species. These entomophagous insects are thus plant-dwelling organisms that use the plant for several vital functions and are affected by plant traits at the evolutionary, organism and population levels. Many entomophagous species are used for the biological control of insect pests worldwide. The aim of this chapter is to provide an exhaustive review of mechanisms underlying the interactions between plants and entomophagous insects, including those governing life history traits at the individual level, as well as those acting on population and community structure and dyn…
Preferential induction of 20S proteasome subunits during elicitation of plant defense reactions: towards the characterization of "plant defense prote…
2003
Plants have evolved efficient mechanisms to resist pathogens. The earliest defense response is the hypersensitive response (HR) considered as the main step leading to plant systemic acquired resistance (SAR) that protects the whole plant against a large spectrum of pathogens. We showed previously that elicitation of defense reactions in tobacco cells by cryptogein, a proteinaceous elicitor of plant defense reactions, leads to a rapid and differential accumulation of transcripts corresponding to genes encoding defense-induced (din) subunits of 20S proteasome: beta1din, alpha3din and alpha6din.Here, expression of these three subunits was investigated by Northern blotting and by Western blotti…
Can Indirect Herbicide Exposure Modify the Response of the Colorado Potato Beetle to an Organophosphate Insecticide?
2018
AbstractOrganisms live in complex multivariate environments. In agroecosystems, this complexity is often human-induced as pest individuals can be exposed to many xenobiotics simultaneously. Predicting the effects of multiple stressors can be problematic, as two or more stressors can have interactive effects. Our objective was to investigate whether indirect glyphosate-based herbicide (GBH) exposure of the host plant has interactive effects in combination with an insecticide (azinphos-methyl) on an invasive pest Colorado potato beetle (Leptinotarsa decemlineata Say). We tested the effects of GBH and insecticide on the survival, insecticide target genes expression (acetylcholinesterase genes)…
Exploiting chemical ecology to manage hyperparasitoids in biological control of arthropod pests
2020
Abstract Insect hyperparasitoids are fourth trophic level organisms that commonly occur in terrestrial food webs, yet they are relatively understudied. These top‐carnivores can disrupt biological pest control by suppressing the populations of their parasitoid hosts, leading to pest outbreaks, especially in confined environments such as greenhouses where augmentative biological control is used. There is no effective eco‐friendly strategy that can be used to control hyperparasitoids. Recent advances in the chemical ecology of hyperparasitoid foraging behavior have opened opportunities for manipulating these top‐carnivores in such a way that biological pest control becomes more efficient. We p…
Pest management under climate change: The importance of understanding tritrophic relations.
2018
11 pages; International audience; Plants and insects depend on climatic factors (temperature, solar radiation, precipitations, relative humidity and CO2) for their development. Current knowledge suggests that climate change can alter plants and insects development and affect their interactions. Shifts in tritrophic relations are of particular concern for Integrated Pest Management (IPM), because responses at the highest trophic level (natural enemies) are highly sensitive to warmer temperature. It is expected that natural enemies could benefit from better conditions for their development in northern latitudes and IPM could be facilitated by a longer period of overlap. This may not be the ca…
Preconditioning of the generalist herbivoreTrialeurodes vaporariorumto greenhouse monocultures and its subsequent performance on wild polycultures
2016
Generalist herbivores can face many challenges when choosing their host plant. This can be particularly difficult if their choice and performance are affected by host experience. Greenhouse whitefly, Trialeurodes vaporariorum Westwood (Hemiptera: Aleyrodidae), is an invasive generalist herbivore, which has established in year-round greenhouses at northern latitudes where it cannot overwinter outdoors. It mainly uses crops such as cucumber (Cucumis sativus L.), tomato (Solanum lycopersicum L.), and ornamentals as host plants. However, every summer the insect escapes greenhouses and is exposed to natural vegetation. We evaluated the performance of T. vaporariorum on diverse vegetation outside…
Performance of secondary parasitoids on chemically defended and undefended hosts
2012
Defensive chemicals produced by plants can travel up the food chain by being sequestered by herbivores, and then in turn being sequestered by their parasitoids. Insect species with wide host ranges are predicted to perform poorly in the face of specific chemical defence. However, a species at a high trophic level is expected to have a wide host range. This creates a conflict for hyperparasitoids, many of which depend on specialized hosts. We studied the performance of two hyperparasitoids, Lysibia nana and Gelis agilis, both of which have wide host ranges, on two host species, one chemically defended and the other not. We predicted that both hyperparasitoids would perform better using the u…
Oviposition Cues for a Specialist Butterfly–Plant Chemistry and Size
2008
The oviposition choice of an insect herbivore is based on a complex set of stimuli and responses. In this study, we examined the effect of plant secondary chemistry (the iridoid glycosides aucubin and catalpol) and aspects of size of the plant Plantago lanceolata, on the oviposition behavior of the specialist butterfly Melitaea cinxia. Iridoid glycosides are known to deter feeding or decrease the growth rate of generalist insect herbivores, but can act as oviposition cues and feeding stimulants for specialized herbivores. In a previous observational study of M. cinxia in the field, oviposition was associated with high levels of aucubin. However, this association could have been the cause (b…
Potential Effects of Essential Oils Extracted from Mediterranean Aromatic Plants on Target Weeds and Soil Microorganisms
2020
Essential oils (EOs), extracted from aromatic plants, have been proposed as candidates to develop natural herbicides. This study aimed to evaluate the herbicidal potential of Thymbra capitata (L.) Cav., Mentha ×