Search results for " rap"
showing 10 items of 561 documents
Effects of root hemiparasitic infection on host performance: Reduced flower size and increased flower asymmetry
2001
We conducted two pot experiments to examine the relationship between hemiparasitic plant (Rhinanthus serotinus, Scrophulariaceae) infection and host (Linum usitatissimum, Linaceae and Brassica rapa ssp. oleifera, Brassicaceae) performance. We were especially interested in the effects of hemiparasitism on the size and shape asymmetry of host flowers, since neither subject has been studied before. We also conducted a field experiment to examine the effects of shape asymmetry of B. rapa ssp. oleifera flowers on pollination success. The shape of flowers produced by both L. usitatissimum and B. rapa ssp. oleifera plants grown without parasites was less asymmetric, and for both host species, the …
Volatile-mediated foraging behaviour of three parasitoid species under conditions of dual insect herbivore attack
2016
Infochemicals play an important role in structuring intra-and interspecific interactions. Many parasitoid wasp species rely on herbivory or oviposition-induced plant volatiles (HIPVs/OIPVs) to locate their herbivorous hosts, and must cope with variation in the volatile blends due to factors such as plant/host species, herbivore density or attack by several herbivores. However, little is known about how dual herbivory or changes in herbivore density affect multiple parasitoid species, each attacking a different herbivore, in the same system. In a natural system, we investigated the effect of dual attack on the ability of three parasitoid species to differentiate between volatiles induced by …
Positive demographic effects of nest surveillance campaigns to counter illegal harvest of the Bonelli's eagle in Sicily (Italy)
2017
Illegal trade in wildlife has been identified as one of the main challenges to wildlife conservation. In 2010, an illegal trade-ring trafficking in birds of prey was uncovered in Sicily (southern Italy). This illegal trade targeted the three most endangered species in Italy: Bonelli's eagle Aquila fasciata, Lanner falcon Falco biarmicus and Egyptian vulture Neophron percnopterus, all of them long-lived territorial raptors threatened with extinction across their European distribution. Illegal harvest primarily involved young birds and eggs taken from nests. After the discovery of these activities, surveillance camps and camera traps connected to the mobile Global System for Mobile communicat…
Fitness of backcross six of hybrids between transgenic oilseed rape (Brassica napus) and wild radish (Raphanus raphanistrum
2002
The process of introgression between a transgenic crop modified for better agronomic characters and a wild relative could lead potentially to increased weediness and adaptation to the environment of the wild species. However, the formation of hybrid and hybrid progeny could be associated with functional imbalance and low fitness, which reduces the risk of gene escape and establishment of the wild species in the field. Our work compares the fitness components of parents and different types of backcross in the sixth generation of hybrids between transgenic oilseed rape (Brassica napus, AACC, 2n = 38) resistant to the herbicide glufosinate and wild radish (Raphanus raphanistrum, RrRr, 2n = 18)…
A preliminary approach for modelling the effects of cropping systems on the dynamics of broomrape ( Phelipanche ramosa) in interaction with the non-p…
2011
International audience; The current decrease in herbicide use may increase and diversify weed flora in crops as well as companion bioagressors spreading via weeds. Among these bioagressors is Phelipanche ramosa (L.) Pomel, a parastic plant which is very harmful on oilseed rape. The objective of the present work was to develop a new model (called PheraSys) of the effects of cropping systems on parasite dynamics, in interaction with non-parasitic weed hosts. The structure of this first model version was based on models developed for other parasitic plants and on FlorSys which quantifies the effects of cropping systems on non-parasitic weed flora. PheraSys was parametrized with preliminary val…
Understanding the coexistence of competing raptors by Markov chain analysis enhances conservation of vulnerable species.
2016
Understanding ecological interactions among protected species is crucial for correct management to avoid conflicting outcomes of conservation planning. The occurrence of a superior competitor may drive the exclusion of a subordinate contestant, as in Sicily where the largest European population of the lanner falcon is declining because of potentially competing with the peregrine falcon. We measured the coexistence of these two ecologically equivalent species through null models and randomization algorithms on body sizes and ecological niche traits. Lanners and peregrines are morphologically very similar (Hutchinson ratios <1.3) and show 99% diet overlap, and both of these results predict …
Emergence and growth of hybrids between Brassica napus and Raphanus raphanistrum.
2003
Summary • Risk assessment studies of transgenic crops have recently brought evidence of a low spontaneous hybridization frequency of Brassica napus with Raphanus raphanistrum. The fate of the first generation hybrids is crucial to determine the initial rate of spread of transgenes. • This work aims to compare the fitness components of parents and F1 hybrids at the first step of the life cycle. The ability to emerge, establish seedling, cover the soil and develop adult plant was examined in controlled and field conditions, alone or in competition. • The F1 hybrids showed a lower seedling emergence, a significant delay of emergence, and a lower survival than for both parents. Rosette diameter…
Current and future suitability of wintering grounds for a long-distance migratory raptor
2017
Conservation of migratory species faces the challenge of understanding the ecological requirements of individuals living in two geographically separated regions. In some cases, the entire population of widely distributed species congregates at relatively small wintering areas and hence, these areas become a priority for the species’ conservation. Satellite telemetry allows fine tracking of animal movements and distribution in those less known, often remote areas. Through integrating satellite and GPS data from five separated populations comprising most of the breeding range, we created a wide habitat suitability model for the Eleonora’s falcon on its wintering grounds in Madagascar. On this…
Using the GENESYS model quantifying the effect of cropping systems on gene escape from GM rape varieties to evaluate and design cropping systems.
2004
Gene flow in rapeseed is a process taking place both in space and over the years and cannot be studied exclusively by field trials. Consequently, the GENESYS model was developed to quantify the effects of cropping systems on transgene escape from rapeseed crops to rapeseed volunteers in neighbour plots and in the subsequent crops. In the present work, this model was used to evaluate the risk of rape harvest contamination by extraneous genes in various farming systems in case of co-existing GM, conventional and organic crops. When 50 % of the rape varieties in the region were transgenic, the rate of GM seeds in non-GM crop harvests on farms with large fields was lower than the 0.9 % purity t…
The aquaculture supply chain in the time of covid-19 pandemic: Vulnerability, resilience, solutions and priorities at the global scale
2022
13 pages, 3 tables, 5 figures