### Abstract

A multiple-kind lottery model is presented for use in determining whether species density distributions in parasite species assemblages reveal regularly occurring species-to-species interactions. The model utilizes a recurrence vector algorithm to rapidly calculate expected frequencies of species per host classes in such assemblages. These calculations have been a computational problem because the probability of a host individual acquiring one species of parasite is not necessarily equal to that of acquiring another species. Thus although the number of possible ways for a host to acquire x parasite species of a possible n is given by the familiar binomial expansion term n! [x!(x!(n - x)!], each of these ways can have a different probability. The model is applicable to any system that mimics a multiple-kind lottery in which (1) successes are independent events and (2) it is possible to fail completely to acquire any parasites or their analogs. The algorithm is thus a null model for species density distributions in general. Application of the model is illustrated by host/parasite systems involving snails and trematodes, fish and their protozoan and platyhelminth parasites, and a relatively rich assemblage of parasites in bats.

Original language | English (US) |
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Pages (from-to) | 189-196 |

Number of pages | 8 |

Journal | Ecological Modelling |

Volume | 77 |

Issue number | 2-3 |

DOIs | |

State | Published - Feb 1995 |

### Keywords

- Parasitism
- Species interactions

### ASJC Scopus subject areas

- Ecological Modeling

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## Cite this

*Ecological Modelling*,

*77*(2-3), 189-196. https://doi.org/10.1016/0304-3800(93)E0087-J