S7.2-3 Monday, Jan. 6 11:00 Jack-of-all-trades or Master of one? Does location of infection predict host specificity in behavior-manipulating parasites? FREDENSBORG, Brian L; Univ. of Copenhagen email@example.com
Parasite modification of host behavior leading to increased trophic transmission is widespread across parasite and host taxa. The exact mechanisms causing altered host behavior, and relationship to host specificity, remain unclear in most cases. Sophisticated mechanisms such as tissue-specific migration and alteration of host neuromodulation may indicate a narrow ecological niche where parasites are fine-tuned to the physiology of a small group of closely related hosts. Similarly, parasites remaining in close proximity to the point of entry to the host, e.g. body cavity or muscle tissue, may display a broader host range. However, other factors related to host-parasite interaction (host immune response, host-parasite body size ratio, parasite-induced pathology) may override those predictions. Here, I investigated if location of larval helminths in intermediate hosts could predict host specificity. Data on intermediate host use of known parasite manipulators, taxonomic grouping, and location in the host, were derived from published records. Host specificity was measured according to Poulin & Mouillot (2003) where phylogenetic relationship among hosts rather than just the number of host species is considered. As expected, parasites located on the CNS demonstrate a more taxonomically distinct host range compared to parasites in muscle. However, some helminths in the body cavity were more host specific than predicted by location, and eye flukes in the lens of fishes display low host specificity despite tissue-specific migration. In sum, the location of parasites inside intermediate hosts seems to be a good indicator of host specificity, but other factors are also important to the observed specificity in some parasite groups.