6533b7d0fe1ef96bd125b7ea

RESEARCH PRODUCT

Proximate factors affecting the larval life history of Acanthocephalus lucii (Acanthocephala).

Daniel P. BeneshE. Tellervo Valtonen

subject

MaleMoltingIntraspecific competitionAcanthocephalaHost-Parasite InteractionsFecesFish DiseasesParasite hostingHelminthsAnimalsAsellus aquaticusSex RatioIntestinal Diseases ParasiticEcology Evolution Behavior and SystematicsLarvaLife Cycle StagesbiologyHost (biology)EcologyIntermediate hostbiology.organism_classificationPerchesLarvaMultivariate AnalysisParasitologyFemaleHelminthiasis AnimalAcanthocephalaIsopoda

description

The growth and eventual size of larval helminths in their intermediate hosts presumably has a variety of fitness consequences. Therefore, elucidating the proximate factors affecting parasite development within intermediate hosts should provide insight into the evolution of parasite life histories. An experimental infection that resulted in heavy intensities of an acanthocephalan (Acanthocephalus lucii) in its isopod intermediate host (Asellus aquaticus) permitted the examination of parasite developmental responses to variable levels of resource availability and intraspecific competition. Isopods were infected by exposure to egg-containing fish feces, and larval infrapopulations were monitored throughout the course of A. lucii development. The relative rate of parasite growth slowed over time, and indications of resource constraints on developing parasites, e.g., crowding effects, were only observed in late infections. Consequently, the factors likely representative of resource availability to larval parasites (host size and molting rate) primarily affected parasite size in late infections. Moreover, at this stage of infection, competitive interactions, gauged by variation in worm size, seemed to be alleviated by greater resources, i.e., larger hosts that molted more frequently. The relatively rapid, unconstrained growth of young parasites may be worse for host viability than the slower, resource-limited growth of larger parasites.

10.1645/ge-1094r.1https://pubmed.ncbi.nlm.nih.gov/17918351