Anomalies in Hyalomma marginatum larvae (Acari: Ixodidae) in relation to taxonomic studies

Abstract

Morphological anomalies are most frequently noted in adult ticks. Therefore, in this paper, we describe interesting morphological anomalies in Hyalomma marginatum larvae from a laboratory-reared colony of Syrian specimens. Specimens with abnormalities were found among many thousands of larvae and analysed using scanning electron microscopy. Additionally, we analysed changes in the morphological traits (length and width of tarsi I and III; length and width of coxae I, II, and III) in abnormal specimens of H. marginatum larvae. Teratological changes were noted in the larval gnathosoma (reduction or elongation of chelicerae and change in the location of chelicerae on the basis capituli; abnormal shape and size of the palpal segment) and legs (fusion of four segments of adjacent legs and deformations of leg segments). The investigations have shown low variability of the morphometric traits of tarsi I and III as well as coxae I, II, and III in the H. marginatum larvae from the Syrian population, which can be used in the diagnostics of this species. Knowledge of different types of anomalies in tick larvae can prevent mistakes in identification of abnormal specimens collected in natural conditions.