Aleksei Miroliubov


Body snatchers: parasitic barnacles (Cirrripedia: Rhizocephala) as a promising model for host-manipulation studies.

Zoological institute, Russian Academy of Sciences, St. Petersburg


Host manipulation is one of the most intriguing phenomena in modern parasitology. A variety of parasites from diverse phyla are able to alter the host’s appearance and behaviour to increase their transmission rate and reproductive success. Among these organisms, parasitic barnacles, also known as Rhizocephala (Crustacea: Thecostraca), stand out due to their unique approach to host manipulation. Rhizocephalans are endoparasites that typically infect decapods, including commercially important species (e.g king crabs, portunid and varunid crabs, and caridean shrimps). Due to the endoparasitic lifestyle, rhizocephalans have lost almost all morphological traits of the free-living crustaceans including segmentation, appendages, and gut. Even the concept of body axes cannot be applied to the body of a rhizocephalan adult female. Instead, parasitic barnacles have evolved unique adaptations that allow them to take control of the host's body and manipulate its behaviour. They can alter the appearance, metabolism, hormonal levels, and even behavioural patterns of the infected hosts. At the same time, rhizocephalans do not cause much harm to the host’s organism as some other parasites do. Parasitic barnacles can live for years and it is crucial for them to keep their host alive.

Until recently the mechanisms of such weird host-parasite interactions remained enigmatic. Our studies revealed that special organs of the rhizocephalan female invade the central nervous system of the host and release several neurotransmitters. The manipulation of the host’s neurochemistry could be a basic mechanism for parasitic barnacles, and possibly other parasites, to influence their hosts’ behaviour.

A multidisciplinary approach is needed to further reveal the idiosyncrasies of the host-parasite interplay of rhizocephalans. In our project, we plan to combine genomics, transcriptomics, proteomics, MALDI TOF analysis and morphological methods (CLSM, TEM, SEM etc.).

The obtained data will provide a novel in-depth view of the mechanisms involved in the rhizocephalan host-parasite interaction and determine the role that alterations in neurotransmitter balance play. These data will significantly contribute to our understanding of the evolution of Rhizocephala and clarify the possible mechanisms used by one organism to control another one.