Allee effects may slow the spread of parasites in a coastal marine ecosystem

  • Author(s) / Creator(s)
  • Allee effects are thought to mediate the dynamics of population colonization, particularly for invasive species. However, Allee effects acting on parasites have rarely been considered in the analogous process of infectious disease establishment and spread. We studied the colonization of uninfected wild juvenile Pacific salmon populations by ectoparasitic salmon lice (Lepeophtheirus salmonis) over a 4-year period. In a data set of 68, 376 fish, we observed 85 occurrences of precopular pair formation among 1, 259 preadult female and 613 adult male lice. The probability of pair formation was dependent on the local abundance of lice, but this mate limitation is likely offset somewhat by mate-searching dispersal of males among host fish. A mathematical model of macroparasite population dynamics that incorporates the empirical results suggest a high likelihood of a demographic Allee effect, which can cause the colonizing parasite populations to die out. These results may provide the first empirical evidence for Allee effects in a macroparasite. Furthermore, the data give a rare detailed view of Allee effects in colonization dynamics and suggest that Allee effects may dampen the spread of parasites in a coastal marine ecosystem.

  • Date created
    2012-01-01
  • Subjects / Keywords
  • Type of Item
    Article (Published)
  • DOI
    https://doi.org/10.7939/R3SS2P
  • License
    © 2012 University of Chicago. This version of this article is open access and can be downloaded and shared. The original author(s) and source must be cited.
  • Language
  • Citation for previous publication
    • Krkošek, M., Connors, B. M., Lewis, M. A. & Poulin, R. (2012). Allee effects may slow the spread of parasites in a coastal marine ecosystem. The American Naturalist, 179(3), 401-412. doi: 10.1086/664458.