The predatory mite Neoseiulus womersleyi (Schicha) (Acari: Phytoseiidae) is an important natural enemy of the Kanzawa spider mite, Tetranychus kanzawaki Kishida (Acari: Tetranychidae), in tea fields. Attraction and preservation of natural enemies by habitat management to reduce the need for acaricide sprays is thought to enhance the activity of N. womersleyi. To better conserve N. womersleyi in the field, however, it is essential to elucidate the population genetic structure of this species. To this end, we developed ten microsatellite DNA markers for N. womersleyi. We then evaluated population structure of N. womersleyi collected from a tea field, where Mexican sunflower, Tithonia rotundifolia (Mill.), was planted to preserve N. womersleyi. Seventy-seven adult females were collected from four sites within 200 m. The fixation indexes FST among subpopulations were not significantly different. The kinship coefficients between individuals did not differ significantly within a site as a function of the sampling dates, but the coefficients gradually decreased with increasing distance. Bayesian clustering analysis revealed that the population consisted of three genetic clusters, and that subpopulations within 100 m, including those collected on T. rotundifolia, were genetically similar to each other. Given the previously observed population dynamics of N. womersleyi, it appears that the area inhabited by a given cluster of the mite did not exceed 100 m. The estimation of population structure using microsatellite markers will provide valuable information in conservation biological control.

Orius strigicollis is a predatory bug that attacks small arthropods, such as thrips, and augmentative release of commercial strains has been widely conducted in greenhouses in Japan. The accurate evaluation of its effectiveness is essential for successful biological control programs. However, because Orius species occur naturally in the field, it is difficult to discriminate O. strigicollis from other Orius species. Furthermore, it is necessary to discriminate commercial strains of O. strigicollis from field populations. In this review, we introduce two types of molecular procedures: (1) a multiplex polymerase chain reaction technique to identify Japanese Orius species, and (2) microsatellite DNA markers that can be used to measure genetic diversity within populations of O. strigicollis and to discriminate field and commercial strains. The usefulness of molecular ecological approaches is also discussed.

No abstract

No abstract

We developed 14 polymorphic microsatellite markers for the minute pirate bug Orius sauteri (Heteroptera: Anthocoridae), and tested them with five markers previously developed in O. strigicollis. Except at one locus from O. strigicollis, we obtained amplified fragments from a field population of O. sauteri. The number of alleles ranged from 2 to 14, and observed heterozygosity ranging from 0.000 to 0.900. The observed heterogeneity was negatively correlated with null allele frequencies. Linkage disequilibrium was detected in three pairs of loci. The 19 microsatellite loci were also tested for amplification and polymorphism in two congeneric species, O. minutus and O. strigicollis. Markers could be amplified at many loci, although null allele frequencies were higher in cross-species amplification than in intra-specific amplification. These microsatellite markers will be used in studies of genetic diversity in these species.