Development and characterization of novel microsatellite markers for a dominant parasitoid Stethynium empoasca (Hymenoptera: Mymaridae) in tea plantations using high-throughput sequencing

Abstract

Stethynium empoasca Subba Rao (Hymenoptera: Mymaridae) is an egg parasitoid of the predominant tea pest, Empoasca onukii Matsuda (Hemiptera: Cicadellidae), and is regarded as the most promising candidate for both augmentative and conservative biological control on E. onukii. However, little is presently known about its biology, ecology, and genetics. Here, we developed and characterized novel microsatellite markers for S. empoasca from transcriptome sequences generated using high-throughput sequencing. A total of 54,520 microsatellites were isolated from 117 Mb clean sequences. Fifty primers were developed and used to characterize 98 individuals from five geographically distinct populations, of which 18 loci were demonstrated to be polymorphic, stable, and repetitive. These loci also showed a low frequency of null alleles, suggesting little effect on their use in the estimation of genetic diversity and structure. Additionally, the assessed populations showed low to moderate levels of genetic differentiation, in which individuals clearly grouped into two clusters, indicating that the loci could reveal a pattern of spatial structure and gene flow in S. empoasca populations according to geographic variability. This work provides an important basis for future studies on how these markers can be used in studies of the biology, genetics, and ecology of this important parasitoid.