Nasopharyngeal bot flies in red deer (Cervus elaphus) from southern Spain.

The nasopharyngeal bot flies Pharyngomyia picta and Cephenemyia auribarbis (Diptera: Oestridae) are parasites that have an impact on the health of wild ruminants. Little is known about their biological and epidemiological characteristics in multi-host habitats such as the Sierra de Cazorla, Segura y Las Villas Natural Park (CNP), in south-east Spain. This paper describes the main epidemiological features of bot fly larvae parasitising the population of red deer in CNP during 2003-2005. The results reveal an overall bot fly prevalence of 37.5%, with a P. picta and C. auribarbis co-infection rate of 12.5%. Although the statistical analyses were not significant(p > 0.05), a higher prevalence in males and in calves was observed, which has to be explained from a multifactorial viewpoint. Unfavourable climatic conditions during January induced the overwintering of larvae inside the host and, accordingly, a higher prevalence of the first instar (L1) was detected, while a higher prevalence of L2 and L3 was recorded in February and March. Further studies are needed to investigate in more detail the environmental characteristics that influence the chronobiology of bot flies in south-east Spain.