First record of Megaselia scalaris (LOEW) (DIPTERA: PHORIDAE) infesting a spinose ear tick, Otobius megnini, colony in Sri Lanka.

This research article reports a new record of infestation of the tick species Otobius megnini by the small fly Megaselia scalaris in Sri Lanka. The researchers discovered the parasitic relationship between these two species while examining ticks sourced from the ears of thoroughbred horses.

Background

• Megaselia scalaris (Loew) is a small fly species that is known to be highly versatile in its exploitation of numerous ecological niches worldwide. It can act as a detritivore, parasite, and parasitoid of a wide range of plant and animal matter in both natural and laboratory environments.
• Otobius megnini, also known as the spinose ear tick, is a known vector of Q fever, a bacterial disease that can cause serious illness in humans. These ticks can also cause paralysis, toxic conditions, otoacariasis, and otitis in humans and other animals.

Research Methodology and Findings

• The researchers obtained tick samples from the ear canals of 14 thoroughbred horses and brought them to the laboratory for study.
• A few days after the ticks were collected, it was observed that larvae of M. scalaris had begun feeding on the immature stages of the ticks.
• Once their development was complete, the pupae of the M. scalaris were found to be attached to adult ticks, and all tick nymphs were found dead. This suggested that M. scalaris was using O. megnini as a host for development, effectively parasitising them.

Implications of the Findings

• The study reveals that M. scalaris can survive and complete its developmental stages on O. megnini. This is the first official record of this type of infestation.
• These findings indicated a potential risk of M. scalaris invading the ear canals of horses. Consequently, it could also present a risk to other animals and humans.
• The study also raises queries about the potential for M. scalaris to act as a vector of diseases that are normally transmitted by O. megnini. This concern needs to be addressed by further research.