Search results for "Hop"
showing 10 items of 5189 documents
Assessing the influence of the amount of reachable habitat on genetic structure using landscape and genetic graphs.
2021
Genetic structure, i.e. intra-population genetic diversity and inter-population genetic differentiation, is influenced by the amount and spatial configuration of habitat. Measuring the amount of reachable habitat (ARH) makes it possible to describe habitat patterns by considering intra-patch and inter-patch connectivity, dispersal capacities and matrix resistance. Complementary ARH metrics computed under various resistance scenarios are expected to reflect both drift and gene flow influence on genetic structure. Using an empirical genetic dataset concerning the large marsh grasshopper (Stethophyma grossum), we tested whether ARH metrics are good predictors of genetic structure. We further i…
Molecular markers linked to breeding system differences in segregating and natural populations of the cereal aphid Rhopalosiphum padi L.
1999
The aphid Rhopalosiphum padi shows coexistence of sexual and asexual populations, providing an opportunity to study the evolution of breeding system variation in the context of theories on the origin and maintenance of sex. However, assessments of the distribution of sexual and asexual lineages of this aphid are complicated by the difficulties in rapidly characterizing their breeding system. To facilitate this task and to gain insight into the genetic relatedness between sexual and asexual genotypes, molecular markers linked to breeding system differences were recently developed. In this study, we have successfully converted a random amplified polymorphic DNA (RAPD) marker associated with l…
Genetic variation in natural populations of the aphid Rhopalosiphum padi as revealed by maternally inherited markers
1996
A survey on 148 clones of the aphid Rhopalosiphum padi from 11 widespread localities has been carried out to study the genetic structure of populations of this species as revealed by mitochondrial DNA restriction site and length polymorphisms as well as by restriction site analysis of a maternally inherited plasmid carried by the aphid eubacterial endosymbiont Buchnera aphidicola. Our results support the existence in the area under study of two main aphid maternal lineages strikingly coincidental with the two main reproductive categories displayed by this species. Those aphid clones possessing an incomplete life cycle that lacks the sexual phase (anholocyclic or androcyclic clones) show mit…
Are alternative food networks winning strategies to increase organic SMEs profitability? Evidence from a case study
2020
The aim of this study was to understand how and how much alternative food networks (AFNs) contribute to increasing the profitability of the organic SMEs, compared to traditional organic sales channels. For this purpose, an economic analysis and an in-depth interview were carried out in a case study located in the Sicilian northern coast. Findings showed a clear convenience of the participation to alternative food networks compared to the case in which all farm production was conferred to traditional sales channels, highlighting an increase both of farm profit (+76.9%) and net income (+72.1%). However, the in-depth interview revealed that AFNs are a mean, not only to have economic benefits, …
A new species of Pamphagus (Orthoptera: Pamphagidae) from Algeria with a key to all the species of the genus
2017
The authors describe Pamphagus milevitanus n. sp. occurring in the North and South highlands of Constantine, in Mila, Setif and Oum-el Bouaghi provinces, where it is fairly common. They compare the characters of this species with those of the most related species of the genus and present a complete plate and a key to all the species of the genus Pamphagus known to date.
Taxonomy and distribution of some katydids (Orthoptera Tettigoniidae) from tropical Africa
2015
Received 21 March 2015 | Accepted 31 August 2015 | Published 30 September 2015
New genera, species and records of Afrotropical Phaneropterinae (Orthoptera, Tettigoniidae) preserved at the Royal Belgian Institute of Natural Scien…
2017
The results of the study of the rich material of Orthoptera Phaneropterinae at the Royal Belgian Institute of Natural Sciences, Bruxelles, are reported. The following new taxa are described: Dithela longicaudata n. sp. from the Democratic Republic of Congo, Terpnistriella bredoi n. gen. n. sp. from the Democratic Republic of Congo, Mimoscudderia paulyi n. sp. from the Madagascar, Pseudogoetia constanti n. gen. n. sp. from the Democratic Republic of Congo (including a table listing differences with related genera), and Materuana abyssinica n. sp. from the Ethiopia. Some taxonomic and distributional data about the following species are also reported: Melidia claudiae Massa, 2015, Symmetrokars…
Review of the African genera Arantia Stål and Goetia Karsch (Orthoptera: Tettigoniidae: Phaneropterinae)
2017
The genus Arantia is reviewed, the distribution and distinguishing characters given. The three species of Goetia are assigned as subgenus to Arantia. Arantia gestri Griffini is transferred to this new subgenus and synonymized with G. dimidiata Bolívar. Other species synonymized are: A. accrana Karsch with A. rectifolia Brunner von Wattenwyl; A. gabunensis Brunner von Wattenwyl with A. regina Karsch; A. mammisignum Karsch and A. tigrina Bolívar with A. excelsior Karsch; A. ugandana Rehn is synonymized with A. fasciata (Walker). 6 species from Tropical Africa are newly described: A. (Arantia) quinquemaculata n. sp., A. (Arantia) ivoriana n. sp., A. (Euarantia) tanzanica n. sp., A. (Euarantia)…
Revision of the tropical African genus Tetraconcha (Orthoptera: Tettigoniidae: Phaneropterinae) with the description of ten new species.
2017
Only five species of the genus Tetraconcha Karsch, 1890 have been previously known; they inhabit tropical forests of central and western Africa. Generally, specimens belonging to this genus are scarcely represented in museum collections, probably due to the difficulty in finding them, but also for the fragility of their body and legs. During some recent expeditions in the Central African Republic and Ivory Coast it was possible to put together an abundant amount of specimens. This allowed the present author to revise the genus and to find valid characters to distinguish different species. On the whole, ten new species were discovered and the total number now amounts to fifteen species. Inte…
High-speed duetting-latency times of the female acoustic response within the bush-cricket genera Leptophyes and Andreiniimon (Orthoptera, Phaneropter…
2018
To find a mate, male and female bush-crickets of the family Phaneropteridae typically engage in duets. The male sings and the female responds. For mutual recognition, the amplitude pattern of the male song and the species-specific timing of the female response have been shown to be very important. In the seven studied species, belonging to the generaLeptophyesandAndreiniimon, these duets are extremely fast and nearly completely in the ultrasonic range. The females produce very short sounds by fast closing movements of the tegmina. They respond with species-specific delays of 20 to 150 ms after the beginning of the male song. The different latency times are probably not important for species…