Development of microsatellite markers and genetic diversity of the velvetbean caterpillar Anticarsia gemmatalis (Lepidoptera: Erebidae)

The velvetbean caterpillar Anticarsia gemmatalis (VBC) is widely distributed in the Americas and causes severe damage to soybean foliage. This insect presents high ecological plasticity, a feature that is of great importance to understand its genetic diversity and potential gene flow to assist in resistance management strategies. With this objective, we developed microsatellite markers for VBC and applied them to five populations from Brazil. Nine primers were polymorphic, with high values of polymorphic information content (PIC > 0.5), and 134 alleles were identified in 155 individuals. These primers indicated deviation from the Hardy–Weinberg equilibrium for all populations (observed heterozygosity, Ho = 0.48, expected heterozygosity, He = 0.76), with moderate to high levels of genetic diversity and a moderate fixation index (F_ST = 0.14) among the populations. Analysis of population structure indicated the formation of two principal clusters. The northern one can be divided into the two populations that formed the cluster, with high genetic differentiation between them. The other cluster is formed by three populations, and we found evidence of low gene flow between them in the south–north direction, indicating that these populations may be migratory in certain conditions. These findings indicate that the designed primers were effective in describing the genetic diversity of VBC, with major implications for integrated pest management. Given the little gene flow and the high genetic diversity of populations, they present great potential to become resistant to control practices, which can lead to increased management costs.