scholarly journals Inferring Modes of Colonization for Pest Species Using Heterozygosity Comparisons and a Shared-Allele Test

Genetics ◽  
2003 ◽  
Vol 163 (2) ◽  
pp. 823-831
Author(s):  
J A Sved ◽  
H Yu ◽  
B Dominiak ◽  
A S Gilchrist
Keyword(s):  
Distance Measure ◽  
Fruit Fly ◽  
Small Samples ◽  
Pest Species ◽  
Long Distance ◽  
Resampling Methods ◽  
Shared Allele ◽  
The Core ◽  
Direct Sampling ◽  
Long Distance Movement

Abstract Long-range dispersal of a species may involve either a single long-distance movement from a core population or spreading via unobserved intermediate populations. Where the new populations originate as small propagules, genetic drift may be extreme and gene frequency or assignment methods may not prove useful in determining the relation between the core population and outbreak samples. We describe computationally simple resampling methods for use in this situation to distinguish between the different modes of dispersal. First, estimates of heterozygosity can be used to test for direct sampling from the core population and to estimate the effective size of intermediate populations. Second, a test of sharing of alleles, particularly rare alleles, can show whether outbreaks are related to each other rather than arriving as independent samples from the core population. The shared-allele statistic also serves as a genetic distance measure that is appropriate for small samples. These methods were applied to data on a fruit fly pest species, Bactrocera tryoni, which is quarantined from some horticultural areas in Australia. We concluded that the outbreaks in the quarantine zone came from a heterogeneous set of genetically differentiated populations, possibly ones that overwinter in the vicinity of the quarantine zone.

scholarly journals Tephritid Fruit Fly Semiochemicals: Current Knowledge and Future Perspectives

Insects ◽  
2021 ◽  
Vol 12 (5) ◽  
pp. 408
Author(s):  
Francesca Scolari ◽  
Federica Valerio ◽  
Giovanni Benelli ◽  
Nikos T. Papadopoulos ◽  
Lucie Vaníčková
Keyword(s):  
Chemical Communication ◽  
Current Knowledge ◽  
Human Mobility ◽  
Fruit Fly ◽  
Pest Species ◽  
Agricultural Pests ◽  
Future Perspectives ◽  
Long Distance ◽  
Specific Chemical ◽  
Wide Range

The Dipteran family Tephritidae (true fruit flies) comprises more than 5000 species classified in 500 genera distributed worldwide. Tephritidae include devastating agricultural pests and highly invasive species whose spread is currently facilitated by globalization, international trade and human mobility. The ability to identify and exploit a wide range of host plants for oviposition, as well as effective and diversified reproductive strategies, are among the key features supporting tephritid biological success. Intraspecific communication involves the exchange of a complex set of sensory cues that are species- and sex-specific. Chemical signals, which are standing out in tephritid communication, comprise long-distance pheromones emitted by one or both sexes, cuticular hydrocarbons with limited volatility deposited on the surrounding substrate or on the insect body regulating medium- to short-distance communication, and host-marking compounds deposited on the fruit after oviposition. In this review, the current knowledge on tephritid chemical communication was analysed with a special emphasis on fruit fly pest species belonging to the Anastrepha, Bactrocera, Ceratitis, and Rhagoletis genera. The multidisciplinary approaches adopted for characterising tephritid semiochemicals, and the real-world applications and challenges for Integrated Pest Management (IPM) and biological control strategies are critically discussed. Future perspectives for targeted research on fruit fly chemical communication are highlighted.

From sand to sea: tracing the production and trade in glass beads from the 10th-century Cirebon shipwreck in the Java Sea

2020 ◽  
Author(s):  
Carolyn Swan
Keyword(s):  
Glass Production ◽  
Glass Beads ◽  
Rock Crystal ◽  
Long Distance ◽  
Merchant Ship ◽  
The Indian Ocean ◽  
Java Sea ◽  
Indian Ocean World ◽  
Long Distance Movement ◽  
Lapis Lazuli

Around the year 970 CE, a merchant ship carrying an assortment of goods from East Africa, Persia, India, Sri Lanka, Southeast Asia, and China foundered and sank to the bottom of the Java Sea. Thousands of beads made from many different materials—ceramic, jet, coral, banded stone, lapis lazuli, rock crystal, sapphire, ruby, garnet, pearl, gold, and glass—attest to the long-distance movement and trade of these small and often precious objects throughout the Indian Ocean world. The beads made of glass are of particular interest, as closely-dated examples are very rare and there is some debate as to where glass beads were being made and traded during this period of time. This paper examines 18 glass beads from the Cirebon shipwreck that are now in the collection of Qatar Museums, using a comparative typological and chemical perspective within the context of the 10th-century glass production. Although it remains uncertain where some of the beads were made, the composition of the glass beads points to two major production origins for the glass itself: West Asia and South Asia.

scholarly journals Maize resistance to Sugarcane mosaic virus

2017 ◽  
Vol 38 (SI 2 - 6th Conf EFPP 2002) ◽  
pp. 542-544
Author(s):  
R. Pokorný ◽  
M. Porubová
Keyword(s):  
Mosaic Virus ◽  
Systemic Infection ◽  
Sugarcane Mosaic Virus ◽  
Resistant Line ◽  
Mechanisms Of Resistance ◽  
Long Distance ◽  
Maize Hybrids ◽  
Resistant Lines ◽  
Maize Resistance ◽  
Long Distance Movement

Under greenhouse conditions 12 maize hybrids derived from crosses of four resistant lines with several lines of different level of susceptibility were evaluated for resistance to Czech isolate of Sugarcane mosaic virus (SCMV). These hybrids were not fully resistant to isolate of SCMV, but the symptoms on their newly growing leaves usually developed 1 to 3 weeks later in comparison with particular susceptible line, the course of infection was significantly slower and rate of infection lower. As for mechanisms of resistance, the presence of SCMV was detected by ELISA in inoculated leaves both of resistant and susceptible lines, but virus was detected 7 days later in resistant line. Systemic infection developed only in susceptible lines. These results indicate restriction of viral long distance movement in the resistant line.

scholarly journals Differential Tropism in Roots and Shoots of Resistant and Susceptible Cassava (Manihot esculenta Crantz) Infected by Cassava Brown Streak Viruses

Cells ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 1221
Author(s):  
Samar Sheat ◽  
Paolo Margaria ◽  
Stephan Winter
Keyword(s):  
Virus Replication ◽  
Central Africa ◽  
Streak Virus ◽  
Virus Infections ◽  
Long Distance ◽  
Manihot Esculenta Crantz ◽  
Cassava Brown Streak Virus ◽  
Cassava Brown Streak Disease ◽  
Long Distance Movement ◽  
Brown Streak

Cassava brown streak disease (CBSD) is a destructive disease of cassava in Eastern and Central Africa. Because there was no source of resistance in African varieties to provide complete protection against the viruses causing the disease, we searched in South American germplasm and identified cassava lines that did not become infected with the cassava brown streak viruses. These findings motivated further investigations into the mechanism of virus resistance. We used RNAscope® in situ hybridization to localize cassava brown streak virus in cassava germplasm lines that were highly resistant (DSC 167, immune) or that restricted virus infections to stems and roots only (DSC 260). We show that the resistance in those lines is not a restriction of long-distance movement but due to preventing virus unloading from the phloem into parenchyma cells for replication, thus restricting the virus to the phloem cells only. When DSC 167 and DSC 260 were compared for virus invasion, only a low CBSV signal was found in phloem tissue of DSC 167, indicating that there is no replication in this host, while the presence of intense hybridization signals in the phloem of DSC 260 provided evidence for virus replication in companion cells. In neither of the two lines studied was there evidence of virus replication outside the phloem tissues. Thus, we conclude that in resistant cassava lines, CBSV is confined to the phloem tissues only, in which virus replication can still take place or is arrested.

Pollen as an Indicator of Long-distance Movement of Heliothis zea (Lepidoptera: Noctuidae)

1987 ◽  
Vol 16 (5) ◽  
pp. 1148-1151 ◽  
Author(s):  
W. H. Hendrix ◽  
T. F. Mueller ◽  
J. R. Phillips ◽  
O. K. Davis
Keyword(s):  
Heliothis Zea ◽  
Long Distance ◽  
Long Distance Movement ◽  
Lepidoptera Noctuidae

scholarly journals The Determinant of Potyvirus Ability to Overcome the RTM Resistance of Arabidopsis thaliana Maps to the N-Terminal Region of the Coat Protein

2009 ◽  
Vol 22 (10) ◽  
pp. 1302-1311 ◽  
Author(s):  
V. Decroocq ◽  
B. Salvador ◽  
O. Sicard ◽  
M. Glasa ◽  
P. Cosson ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
Coat Protein ◽  
Biological Properties ◽  
Terminal Region ◽  
Plum Pox Virus ◽  
Lettuce Mosaic Virus ◽  
Long Distance ◽  
Resistance Breaking ◽  
Viral Determinant ◽  
Long Distance Movement

In Arabidopsis thaliana Columbia (Col-0) plants, the restriction of Tobacco etch virus (TEV) long-distance movement involves at least three dominant RTM (restricted TEV movement) genes named RTM1, RTM2, and RTM3. Previous work has established that, while the RTM-mediated resistance is also effective against other potyviruses, such as Plum pox virus (PPV) and Lettuce mosaic virus (LMV), some isolates of these viruses are able to overcome the RTM mechanism. In order to identify the viral determinant of this RTM-resistance breaking, the biological properties of recombinants between PPV-R, which systemically infects Col-0, and PPV-PSes, restricted by the RTM resistance, were evaluated. Recombinants that contain the PPV-R coat protein (CP) sequence in an RTM-restricted background are able to systemically infect Col-0. The use of recombinants carrying chimeric CP genes indicated that one or more PPV resistance-breaking determinants map to the 5′ half of the CP gene. In the case of LMV, sequencing of independent RTM-breaking variants recovered after serial passages of the LMV AF199 isolate on Col-0 plants revealed, in each case, amino acid changes in the CP N-terminal region, close to the DAG motif. Taken together, these findings demonstrate that the potyvirus CP N-terminal region determines the outcome of the interaction with the RTM-mediated resistance.

Genetic and cytogenetic analysis of the fruit fly Rhagoletis cerasi (Diptera: Tephritidae)

Genome ◽  
2008 ◽  
Vol 51 (7) ◽  
pp. 479-491 ◽  
Author(s):  
Ilias Kounatidis ◽  
Nikolaos Papadopoulos ◽  
Kostas Bourtzis ◽  
Penelope Mavragani-Tsipidou
Keyword(s):  
Salivary Gland ◽  
Sex Chromosomes ◽  
Cytogenetic Analysis ◽  
Polytene Chromosomes ◽  
Fruit Fly ◽  
Pest Species ◽  
Heteromorphic Sex Chromosomes ◽  
Weak Points ◽  
Heterogametic Sex ◽  
Rhagoletis Cerasi

The European cherry fruit fly, Rhagoletis cerasi , is a major agricultural pest for which biological, genetic, and cytogenetic information is limited. We report here a cytogenetic analysis of 4 natural Greek populations of R. cerasi, all of them infected with the endosymbiotic bacterium Wolbachia pipientis . The mitotic karyotype and detailed photographic maps of the salivary gland polytene chromosomes of this pest species are presented here. The mitotic metaphase complement consists of 6 pairs of chromosomes, including one pair of heteromorphic sex chromosomes, with the male being the heterogametic sex. The analysis of the salivary gland polytene complement has shown a total of 5 long chromosomes (10 polytene arms) that correspond to the 5 autosomes of the mitotic nuclei and a heterochromatic mass corresponding to the sex chromosomes. The most prominent landmarks of each polytene chromosome, the “weak points”, and the unusual asynapsis of homologous pairs of polytene chromosomes at certain regions of the polytene elements are also presented and discussed.

scholarly journals On the nature of cross-linguistic transfer: A case study of Andean Spanish

2012 ◽  
Vol 16 (1) ◽  
pp. 111-131 ◽  
Author(s):  
ANTJE G. MUNTENDAM
Keyword(s):  
Language Contact ◽  
Long Distance ◽  
Andean Spanish ◽  
Pragmatic Transfer ◽  
Elicitation Study ◽  
Linguistic Transfer ◽  
Syntactic Properties ◽  
Elicitation Studies ◽  
Long Distance Movement

This paper presents the results of a study on cross-linguistic transfer in Andean Spanish word order. In Andean Spanish the object appears in preverbal position more frequently than in non-Andean Spanish, which has been attributed to an influence from Quechua (a Subject–Object–Verb language). The high frequency of preverbal objects could be explained by focus fronting. The main syntactic properties of focus fronting in Spanish are weak crossover and long distance movement. Two elicitation studies designed to test for these properties in non-Andean Spanish, Andean Spanish and Quechua show no evidence of syntactic transfer from Quechua into Andean Spanish. Rather, the analysis of naturalistic data and an elicitation study on question–answer pairs show that there is pragmatic transfer from Quechua into Andean Spanish. The study has implications for theories of syntax and language contact, and especially for the debate on the nature of cross-linguistic transfer.

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