title: Experimental evidence of size/age-biased infection of Biomphalaria glabrata (Pulmonata: Planorbidae) by an incompatible parasite species: consequences for biological control.
abstract: Because the digenetic trematode Plagiorchis elegans can elicit a rapid, severe and permanent suppression of the reproductive output in the snail Biomphalaria glabrata, it is considered as a potential biological control agent of human schistosomiasis. This assumption however is derived from laboratory experiments that are poor approximations of what occurs in a natural ecosystem. In order to recreate conditions that resemble those found in nature, we exposed B. glabrata as individual populations composed of a young, juvenile and adult snails to various concentrations of P. elegans eggs to assess the probability of encountering the parasite eggs by the different snail sizes/age groups. We demonstrated that within populations composed of different size/age classes, larger/older snails displayed the negative effects typical of exposure to P. elegans, whereas smaller individuals appeared relatively unaffected, particularly at lower levels of exposure. These findings coupled with the difficulty of producing large quantities of parasite eggs suggest that P. elegans has limited efficiency as a biological control agent of human schistosomiasis.
authors.affiliation: Department of Natural Resource Sciences, McGill University (Macdonald Campus), 21111 Lakeshore Road, Ste-Anne-de-Bellevue, QC, Canada, H9X 3V9. simon.payette.daoust@umontreal.ca
authors.forename: Simon P
authors.initials: SP
authors.lastname: Daoust
authors.forename: Brian J
authors.initials: BJ
authors.lastname: Mader
authors.forename: Fanny
authors.initials: F
authors.lastname: Maure
authors.forename: J Daniel
authors.initials: JD
authors.lastname: McLaughlin
authors.forename: Frédéric
authors.initials: F
authors.lastname: Thomas
authors.forename: Manfred E
authors.initials: ME
authors.lastname: Rau
mesh_terms: D000375:Aging; D000818:Animals; D001700:Biomphalaria / Q000033:anatomy & histology / Q000469:parasitology* / Q000502:physiology*; D049628:Body Size / Q000502:physiology*; D006790:Host-Parasite Interactions; D010572:Pest Control, Biological; D014200:Trematoda / Q000502:physiology*