مطالعه ریخت‌سنجی گونه‌های شته جنس Aphis روی گیاهان تیره نعنائیان

Aphids are highly successful organisms with a global distribution and are of particular importance due to the damage they cause to plants. Accurate identification of some aphid taxa is very challenging due to their morphological similarities, the presence of sibling species, and intraspecific variation. The most common method of identifying insect species is the use of morphological traits; however, studies have shown that relying solely on morphological traits is often insufficient for the accurate identification of animal taxa, especially insects. One method used for determining species and differentiating populations is morphometric analysis. This method involves measuring morphological traits and then quantitatively analyzing them to separate species and populations, as well as identifying distinguishing characteristics. The main objective of this research was to conduct a morphometric study of aphid species of the genus Aphis on plants of the Lamiaceae family using multivariate analysis. Another aim was to identify species of the genus Aphis and examine the distinguishing characteristics of species within this genus that are morphologically very similar. This study used 22 collected aphid populations, and a total of 47 traits (variables) were measured, counted, or calculated. Principal component analysis (PCA) and discriminant function analysis (DFA) were used for data analysis. In this study, Aphis gossypii was completely separated from other species based on its morphological characteristics. Individuals belonging to Aphis affinis and Aphis ballotae each formed relatively distinct groups. There were three aphid samples in this study that could not be distinguished to the species level using existing identification keys. Morphometric analysis showed that individuals from Aphis sp.1 and Aphis sp.3 overlapped with Aphis affinis, indicating that they belong to Aphis affinis. The group Aphis sp.2 overlapped with Aphis ballotae, suggesting that these individuals belong to Aphis ballotae. Based on the results of the discriminant function analysis, the most important morphological traits for separating these species were the length of the hind tibia, the ratio of the length of the third antennal segment to the processus terminalis of the sixth antennal segment, the length of the last segment of the rostrum, and the ratio of siphunculi length to body length.