Contents - Faperta

482 Biotechnological Approaches for Pest Management and Ecological Sustainability
genomic DNA libraries in China. The expected heterozygocity of a novel set of fi ve polymorphic
di- or trinucleotide microsatellite loci suitable for population genetic studies
were developed from an enriched genomic library, and the cross amplifi ability of these
and other published loci was tested in a closely related species, Helicoverpa assulta Guen. (Ji,
Wu, and Zhang, 2005). The expected heterozygocity at these loci ranged from 0.62 to 0.91,
and the allele number varied from 4 to 12, and these can be used for population studies of
H. armigera in the future.
Phylogenetic studies have been carried out using allozymes (Richardson, Baverstock,
and Adams, 1996) or DNA-based markers, for example, regions of the nuclear ribosomal
RNA cluster (rDNA) such as 18S (Sanchis et al., 2000), and 28S rDNA (Mardulyn and
Whitfi eld, 1999), mitochondrial DNA (mDNA) including 12S and 16S (Cameron and
Williams, 2003), Cytochrome oxidase subunit1 (CO1) (Machado et al., 2001), Cytochrome
oxidase subunit II (COII) (Despres et al., 2002), and Cytochrome B (Kerdelhue, Le Clainche,
and Rasplus, 1999). Nuclear coding genes such as elongation factor 1a (Belshaw and
Quicke, 1997) and DNA internal transcribed spacer regions (ITS) (Thomson et al., 2003)
have also been found to be useful. Microsatellites are useful for detecting relationships
between closely related taxa, for example, taxonomy of host races of A. pisum (Simon et al.,
2003). A number of studies have used rDNA and mtDNA markers for parasitic Hymenoptera
(18S, 28S, 16S, CO1, Cytochrome B, and adenine dehydrogenase subunit1 (NDI) (Quicke
and Belshaw, 1999; Smith et al., 1999; Belshaw et al., 2000; Schmidt, Naumann, and De
Barro, 2001). Some phylogenetic studies have also been carried out on predatory beetles
using 28S and nuclear wingless gene (Ober, 2002) and ND5 (Su, Imura, and Osawa, 2005),
and on vespid wasps using 16S and 28S (Schmitz and Moritz, 1998; Carpenter, 2003).
Application of Molecular Markers for Studying
Population Genetics
Using RAPD-PCR markers, population structure and dynamics of the parasitoid, D. rapae
within the agricultural systems has been studied by Vaughn and Antolin (1998) on cabbage
aphid, Brevicoryne brassicae (L.) and Russian wheat aphid, D. noxia. Diaeretiella rapae populations
1 km apart have been genetically differentiated on a spatial scale corresponding to
host use patterns. Using microsatellite markers, heterogeneity in the populations was
detected even on the same plant (Loxdale and MacDonald, 2004), and populations at two
sites (40 km apart) were found to be quite distinct (Vaughn and Antolin, 1998). Allozyme
markers have been used to study population structure in relation to habitat heterogeneity
or attitude of beetle predators (Liebherr, 1986, 1988). Genetic structure of the carabids,
Carabus nemoralis Muller and C. punctatoauratus Germar has been found to be quite distinct
at distances of 13.6 km through the use of microsatellite markers (Brouat et al., 2003).
Populations of the specialist predator, C. punctatoauratus were more structured spatially
than those of the generalist predator, C. nemoralis.
Several molecular markers have been used for tracking insects in space and time (Caterino,
Cho, and Sperling, 2000). Microsatellites, mtDNA sequences, RAPDs, AFLPs, and introns
have been used widely. Microsatellites have been used in studies on parasitoid wasps
(Hufbauer, Bogdanowicz, and Harrison, 2004), carabid beetles (Brouat et al., 2003), and honeybees,
Apis mellifera L. (De la Rua et al., 2003). The use of mitochondrial DNA in population
genetic studies has been quite effective due to intraspecifi c polymorphism. This has