DOI: 10.5061/dryad.bnzs7h476
title: Data from: Variable resistance to spinetoram in populations of Thrips palmi across a small area unconnected to genetic similarity

description: The melon thrips, Thrips palmi, is an increasingly important pest of
 vegetables in northern China. Some populations have developed resistance
 in the field to the insecticide spinetoram. Understanding the origin and
 dispersal of insecticide-resistant populations can shed light on
 resistance management strategies. In this study, we tested susceptibility
 of seven greenhouse populations of T. palmi to spinetoram collected from a
 small area of about 300 km2 in Shandong province, and examined population
 genetic structure across the area based on a segment of mitochondrial cox1
 gene and 22 microsatellite loci to infer the possible origin and dispersal
 of insecticide resistance. Levels of resistance to spinetoram differed
 among seven populations, which included one population with high
 resistance (LC50 = 759.34 mg/L), three populations with medium resistance
 (LC50 ranged from 28.69 to 34.79 mg/L) and three populations with low
 resistance (LC50 ranged from 7.61 to 8.97 mg/L). The populations were
 genetically differentiated into two groups unrelated to both levels of
 resistance and geographic distance. The molecular data indicated high
 levels of gene flow between populations with different levels of
 resistance to spinetoram and low gene flow among populations with the same
 level of resistance, pointing to a likely separate history of resistance
 evolution. Resistance levels of two tested populations to spinetoram
 decreased 23 and 4.6 times after five generations without any exposure to
 the pesticide. We therefore suspect that resistance of T. palmi most
 likely evolved in response to local applications of the insecticide. Our
 study suggests that the development of resistance could be avoided or
 resistance even reversed by reducing usage of spinetoram.
description: Total DNA was extracted from individual specimens using DNeasy
 Blood and Tissue Kit (Qiagen, Germany). For nuclear markers, we used 22
 microsatellite loci developed in a previous study (Gao, Gong, Ma, et al.,
 2019). A fluorescence‐labeled PC‐tail (5′ CAGGACCAGGCTACCGTG 3′) was used
 to label the PCR products (Schuelke, 2000; Blacket et al., 2012).
 Conditions for PCR amplification were described in Gao, Gong, Ma, et al.
 (2019). The size of amplified PCR products was determined using an ABI
 3730xl DNA Analyzer with GeneScan 500 LIZ size standards. Alleles were
 identified with GENEMAPPER version 4.0 (Applied Biosystems,
 USA). For the mitochondrial gene, a segment of
 cytochrome c oxidase subunit I (<i>cox1</i>) was amplified
 with primer pairs TP-AF (5′ TTTCGTCTAACCATAAAGATATCGG 3′) and TP-AR
 (5′TAAACTTCTGGGTGCCCAAAAAATCA 3′) (Cao et al., 2019). Polymerase chain
 reaction (PCR) was conducted with the following program: an initial
 denaturation for 3 min at 94 °C, followed by 35 cycles of 10 s at 94 °C,
 15 s at 52 °C and 1 min at 68 °C, and a subsequent final extension for 10
 min at 68 °C. Amplified products were purified and sequenced directly from
 both strands using an ABI 3730xl DNA Analyzer by Tsingke Biotechnology Co.
 Ltd (Beijing, China).
description: Microsatellite data (genepop format) and mitochondrial cox1 gene
 sequences (fasta format) for populations of Thrips palmi.
 tp_22ssr_4populations_field_lab.genepop, microsatellite data for
 two field populations and two laboratory populations;
 tp_22ssr_7populations from Shouguang.genepop, microsatellite data
 for seven field populations collected from Shouguang, Shandong province,
 China; tp_cox1_4haps.fas, cox1 haplotypes;
 tp_cox1_7populations.fas