Molecular phylogeny and population structure of Eurygaster integriceps (Hemiptera: Scutelleridae) in the Southeastern Anatolia Region of Türkiye

The aim of this study was to determine the identity and distribution of the sunn pest Eurygaster spp. and to quantify the population density in wheat fields across Southeastern Anatolia, Türkiye. A total of 309 samples were collected from 76 fields in 54 districts across all provinces within the study region, where wheat production is intensive. A combination of morphological and molecular techniques was employed to identify the collected specimens. Morphological identification was based on male genitalia, and PCR amplification of the COI mitochondrial gene region was used for DNA barcoding. Both morphological and molecular analyses confirmed that all collected samples belonged to the species Eurygaster integriceps, revealing five distinct morphotypes and 17 haplotypes. The results indicate that the sunn pest is widespread across all provinces in the Southeastern Anatolia region. Among these provinces, Gaziantep exhibited the highest pest density, whereas Siirt had the lowest. Morphologically, 46.27% of the samples exhibited a distinctive contrast pattern on the scutellum—a feature previously associated with increased pesticide resistance. Combined morphological and molecular analyses confirmed the presence of E. integriceps in all sampled wheat fields, revealing that it is widely distributed in Southeastern Anatolia and has varying population densities among provinces. The combined use of morphological and molecular identification techniques provided a comprehensive understanding of E. integriceps populations. Morphological analysis enabled the identification of distinct morphotypes, while molecular analysis confirmed species identity and revealed genetic diversity within the population, providing essential baseline information for accurate identification and the development of effective pest management strategies.