Recent introductions reveal differential susceptibility to parasitism across an evolutionary mosaic

ECU Author/Contributor (non-ECU co-authors, if there are any, appear on document)

Carolyn K.,Darling,John A.,Blakeslee,April M. H.,Fowler,Am Tepolt (Creator)

Institution

East Carolina University (ECU )

Web Site: http://www.ecu.edu/lib/

Abstract: Parasitism can represent a potent agent of selection, and introduced parasites havethe potential to substantially alter their new hosts' ecology and evolution. While sig-nificant impacts have been reported for parasites that switch to new host species,the effects of macroparasite introduction into naïve populations of host species withwhich they have evolved remain poorly understood. Here, we investigate how theestuarine white-fingered mud crab (Rhithropanopeus harrisii) has adapted to parasit-ism by an introduced rhizocephalan parasite (Loxothylacus panopaei) that castratesits host. While the host crab is native to much of the East and Gulf Coasts of NorthAmerica, its parasite is native only to the southern end of this range. Fifty years ago,the parasite invaded the mid-Atlantic, gradually expanding through previously naïvehost populations. Thus, different populations of the same host species have expe-rienced different degrees of historical interaction (and thus potential evolutionaryresponse time) with the parasite: long term, short term, and naïve. In nine estuariesacross this range, we examined whether and how parasite prevalence and host sus-ceptibility to parasitism differs depending on the length of the host's history with theparasite. In field surveys, we found that the parasite was significantly more preva-lent in its introduced range (i.e., short-term interaction) than in its native range (long-term interaction), a result that was also supported by a meta-analysis of prevalencedata covering the 50 years since its introduction. In controlled laboratory experi-ments, host susceptibility to parasitism was significantly higher in naïve hosts than inhosts from the parasite's native range, suggesting that host resistance to parasitismis under selection. These results suggest that differences in host--parasite historicalinteraction can alter the consequences of parasite introductions in host populations.As anthropogenically driven range shifts continue, disruptions of host--parasite evo-lutionary relationships may become an increasingly important driver of ecologicaland evolutionary change.

Additional Information

Publication

Other

Language: English

Date: 2019

Keywords

adaptation in invasion, biological introductions, host--parasite evolution, Loxothylacus panopaei, mud crabs, parasite biogeography, Rhithropanopeus harrisii, rhizocephalans

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