### 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) |
---|---|

Pages (from-to) | 189-196 |

Number of pages | 8 |

Journal | Ecological Modelling |

Volume | 77 |

Issue number | 2-3 |

DOIs | |

State | Published - Feb 1995 |

### Fingerprint

### Keywords

- Parasitism
- Species interactions

### ASJC Scopus subject areas

- Ecological Modeling

### Cite this

*Ecological Modelling*,

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

**Species density distributions as null models for ecologically significant interactions of parasite species in an assemblage.** / Janovy, J.; Clopton, R. E.; Clopton, D. A.; Snyder, Scott D.; Efting, Aris; Krebs, Laura.

Research output: Contribution to journal › Article

*Ecological Modelling*, vol. 77, no. 2-3, pp. 189-196. https://doi.org/10.1016/0304-3800(93)E0087-J

}

TY - JOUR

T1 - Species density distributions as null models for ecologically significant interactions of parasite species in an assemblage

AU - Janovy, J.

AU - Clopton, R. E.

AU - Clopton, D. A.

AU - Snyder, Scott D.

AU - Efting, Aris

AU - Krebs, Laura

PY - 1995/2

Y1 - 1995/2

N2 - 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.

AB - 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.

KW - Parasitism

KW - Species interactions

UR - http://www.scopus.com/inward/record.url?scp=0028992195&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0028992195&partnerID=8YFLogxK

U2 - 10.1016/0304-3800(93)E0087-J

DO - 10.1016/0304-3800(93)E0087-J

M3 - Article

AN - SCOPUS:0028992195

VL - 77

SP - 189

EP - 196

JO - Ecological Modelling

JF - Ecological Modelling

SN - 0304-3800

IS - 2-3

ER -