Tick Species Infesting Rock Partridges (Alectoris graeca Meisner, 1804) in Croatia: Ecological Significance and Host Associations

Abstract

Ticks (Acari: Ixodidae) are important ectoparasites and vectors of numerous pathogens affecting wildlife, domestic animals, and humans. Although birds play a significant role in tick ecology, information on tick infestations in wild galliform birds remains limited. The aim of this study was to identify tick species associated with rock partridge (Alectoris graeca) populations in Mediterranean and sub-Mediterranean habitats of Croatia, and to evaluate their potential importance in tick ecology. A total of 39 rock partridges were examined from four localities in Croatia (Pag, Lozovac, Primorski Dolac and Svilaja). A total of 47 ticks were collected from 27 birds (69.2%). Molecular analysis based on sequencing of the mitochondrial 16S rRNA gene confirmed the morphological identification of all tick species. Four tick species belonging to the genus Ixodes were identified: Ixodes festai, Ixodes gibbosus, Ixodes ventalloi and Ixodes hexagonus. Ixodes festai was the dominant species (72.3%) and was recorded at all four localities. The remaining ticks belonged to I. gibbosus (10.6%), I. ventalloi (8.5%), and I. hexagonus (8.5%) and were found exclusively on Pag Island. Among the collected ticks, adult stages (55.3%) and nymphs (42.6%) predominated. The results indicate that rock partridges represent important hosts for several Mediterranean tick species of the genus Ixodes and may contribute to the maintenance of their local populations. The dominance and widespread occurrence of I. festai suggest a strong ecological association between this ornithophilic tick species and rock partridge populations. Furthermore, the exclusive occurrence of I. ventalloi, I. gibbosus and I. hexagonus on Pag Island indicates the influence of local ecological conditions and host community composition on tick population structure. The results of this study contribute to a better understanding of tick ecology and provide an important basis for future research on tick-borne pathogens in Mediterranean ecosystems.