The Pattern of a Host-Parasite Distribution

Schmid, William D.; Robinson, Edwin J.

doi:10.2307/3286584

Cited by 24 publications

(8 citation statements)

References 9 publications

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“…(3) As demonstrated repeatedly for a variety of host>-parasite systems, the negative binomial distribution does not usually differ statistically from observed host-parasite frequency distributions (Crofton, 1971a;Pennycuick, 1971;Schmid & Robinson, 1972;Scott et al 1979;Croll & Ghadirian, 1981;Gordon & Rau, 1982;Scott, 1982;Kennedy, 1984;Bundy et al 1985). This may be a function of the plasticity of this distribution.…”

Section: Discussionmentioning

confidence: 84%

“…The use of theoretical frequency distributions to describe host-parasite populations was more fully investigated by Crofton (1971a,6) and Pennycuick (1971) and their papers have been widely quoted. It is now standard practice for parasite ecologists to report some measure of aggregation in any field surveys undertaken and, with few exceptions, parasites are found to be clumped within the host population (Winfield, 1932;Buxton, 1940;Watkins & Harvey, 1942;Srivastava & James, 1967;Crofton, 1971a,6;Pennycuick, 1971;Schmid & Robinson, 1972;Scott, McLaughlin & Rau, 1979;Croll & Ghadirian, 1981;Evans, Whitfield & Dobson, 1981;Kennedy & Burrough, 1981;Anderson, 1982;Anderson & Gordon, 1982;Gordon & Rau, 1982;Kennedy, 1984;Pence & Windberg, 1984;Scott, 1984;Bundy, Thompson, Golden, Cooper, Anderson & Harland, 1985;Scott & Gibbs, 1986). Anderson investigated in detail the consequences of a variety of biological forces in generating over-dispersion using Monte Carlo simulation techniques.…”

Section: Introductionmentioning

confidence: 99%

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Temporal changes in aggregation: a laboratory study

Scott¹

1987

Parasitology

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Changes in the variance to mean ratio and the parameter k of the negative binomial distribution were used to study temporal changes in the degree of aggregation of the monogenean parasite, Gyrodactylus turnbulli in free-running laboratory populations of the guppy, Poecilia reticulata. The parasite undergoes recurrent epidemic cycles in the host population under conditions of regular immigration of uninfected guppies. During the early phase of the epidemic, heterogeneity among fish together with direct reproduction are thought to contribute to the increasing degree of aggregation. During the increasing phase of the epidemic cycle, parasites become increasingly aggregated in the host population, presumably because of the direct reproduction of the parasite on the surface of a single host. As the peak prevalance and abundance are approached, the parasites become less aggregated with lowest clumping occurring during the declining phase of the cycle. This is thought to be a function of density-dependent death of infected hosts, and density-dependent reduction in parasite survival and reproduction on hosts that recover from infection. This study clearly indicates that the variance to mean ratio and the parameter k of the negative binomial distribution do not quantify the same aspect of the frequency distribution. It is suggested that the variance to mean ratio is a better measure when the prevalence and/or mean burden are changing and when the tail of the distribution is of particular interest, and that k may be a preferred parameter when the zero class or the lightly infected hosts are of primary interest.

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Section: Discussionmentioning

confidence: 84%

Section: Introductionmentioning

confidence: 99%

Temporal changes in aggregation: a laboratory study

Scott¹

1987

Parasitology

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“…Since the publication of the seminal work of Crofton (1971a, b), the observed patterns of parasite dispersion within host populations have been the focus of much attention in the parasitological literature (Pennycuick, 1971;Schmid & Robinson, 1972;Rutledge, Ward & Buckwalter, 1973;Anderson, 1974;Boxshall, 1974;Randolph, 1975;Campbell, Ward & Garrie, 1980).…”

Section: Introductionmentioning

confidence: 99%

Processes influencing the distribution of parasite numbers within host populations with special emphasis on parasite-induced host mortalities

1982

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The paper examines the factors which generate various patterns of dispersion in the distribution of parasites within their host populations. Particular emphasis is placed on the role played by chance elements in the growth and decay of parasite populations and on the influence of different types of demographic processes. It is argued that observed distributions are dynamic, rather than static, entities generated by opposing forces, some acting to create over-dispersion and others acting to generate under-dispersion. Monte Carlo simulation experiments, based on probability models of the growth and decay of host and parasite populations, are used to study the dynamics of parasite dispersion. Attention is specifically focused on the role played by parasite-induced host mortality. It is shown that, for certain types of host-parasite associations, convex curves of mean parasite abundance in relation to age (age-intensity curves), concomitant with a decline in the degree of dispersion in the older age, classes of hosts, may be evidence of the induction in host mortality by parasite infection. Empirical evidence is examined in light of this prediction. In general, however, simulation studies highlight the technical difficulties inherent in establishing clear evidence of parasite-induced host mortality from ecological studies of hosts and parasites in their natural habitats.

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“…Schmid & Robinson (1972) state that clumped distribution patterns are found where habitats are not uniform and individuals are concentrated in the more suitable patches, or where interactions between organisms hold them together in groups although the habitat is uniform. Schmid & Robinson (1972) state that clumped distribution patterns are found where habitats are not uniform and individuals are concentrated in the more suitable patches, or where interactions between organisms hold them together in groups although the habitat is uniform.…”

Section: Discussionmentioning

confidence: 99%

“…Analyses of parasite populations for variations in pattern of distribution among and within host specimens provide a means of defining certain types of host-parasite interaction. Schmid & Robinson (1972) state that clumped distribution patterns are found where habitats are not uniform and individuals are concentrated in the more suitable patches, or where interactions between organisms hold them together in groups although the habitat is uniform. The results obtained here indicate that H. husseyi exhibits a clumped distribution pattern; a situation that seemed likely considering Hussey, Read & Hesling's (1969) observation that flies liberated larval nematodes in batches of 20-40.…”

Section: Nematode Incidencementioning

confidence: 99%

Aspects of the laboratory production of mushroom phorid flies (Megaselia halterata) parasitised by the nematode Howardula husseyi

Richardson¹,

Chanter

1981

Annals of Applied Biology

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parasitised by Howardula husseyi is essential if the release of parasitised Megaselia halterata on farms is to become a practicable alternative to insecticidal control of the pest. The effects on parasite incidence in the succeeding fly generation of two methods of spawning mushroom compost, and of three initial levels of parasitism (numbers of parasitised parental flies), were studied in the laboratory. In emerging flies percentage parasitism, and mean number of adult parasites per fly, were significantly affected by the original number of parasitised females. Estimates showed that for every 10 additional parasitised parental flies there was an increase of 0.166 adult parasites per fly in the next generation. 'Top spawning' resulted in a significantly higher percentage parasitism than 'through spawning'. Emerging female progeny were significantly more highly parasitised than males. Statistical models, used to assess the ability of H . husseyi infectives to parasitise M. halterata larvae in compost, indicated that even at very high host densities (20% of the potential parasites successfully invaded a phorid larva. The results suggest that unless an in vitro method of rearing H. husseyi can be developed the nematode will not be of practical use in phorid control.

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The Pattern of a Host-Parasite Distribution

Cited by 24 publications

References 9 publications

Temporal changes in aggregation: a laboratory study

Temporal changes in aggregation: a laboratory study

Processes influencing the distribution of parasite numbers within host populations with special emphasis on parasite-induced host mortalities

Aspects of the laboratory production of mushroom phorid flies (Megaselia halterata) parasitised by the nematode Howardula husseyi

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