Notes on the Distribution of<i>Cephus Pygmaeus</i>, Linn., and of its Parasite,<i>Collyria calcitrator</i>, Gray

Walker, Marjory G.

doi:10.1017/s0007485300040700

Cited by 9 publications

(3 citation statements)

References 8 publications

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“…Many studies have shown that the number of hosts attacked per parasite decreases with increasing parasite density (Burnen, 1953(Burnen, , 1956(Burnen, , 1958aDeBach and Smith, 1947;Ullyett, 1949a, b). It is not possible to verify these two points in the field data of Ullyett (1947), Varley (1941) or Walker (1940) because in their studies the effect of N, was confounded by N,. However, it has been possible to sort out the effects of N, and N, in unpublished data of Miller which were collected according to a sophisticated sampling scheme over many plots and years (Miller, 1955), and his figures confirm the laboratory studies.…”

Section: The Canadian Entomologist Mzrch 1959mentioning

confidence: 96%

A Mathematical Model for the Effect of Densities of Attacked and Attacking Species on the Number Attacked

Watt

1959

Can Entomol

210

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Section: The Canadian Entomologist Mzrch 1959mentioning

confidence: 96%

A Mathematical Model for the Effect of Densities of Attacked and Attacking Species on the Number Attacked

Watt

1959

Can Entomol

210

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“…At points where the caterpillars are scarcer they are thus less exposed to the attacks of their primary parasites". Walker (1940) interprets this, perhaps rightly, to mean that the percentage of parasitism is high where host density is high, and argues therefore that search is not random. However, her own data, which refer to the percentage of parasitism of Cephus by Collyria, show no trace of this effect, and she concludes that "the behaviour of Collyria within the specific environment of the wheat field has been shown to be a fairly good example of 'random searching' in the sense of Nicholson".…”

Section: (I) Eurytoma Robustamentioning

confidence: 99%

On the search for hosts and the egg distribution of some chalcid parasites of the knapweed gall-fly

Varley¹

1941

Parasitology

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1. The egg distributions of five chalcid parasites of the knapweed gall-fly have been studied in a small area.2. A distinction is made between search for hosts by random movements, and random search in the sense of Nicholson; these terms are defined. Random movements may give rise to a distribution of parasitism different from that expected if search were purely random.3. The species discussed do not all distribute their eggs at random amongst the hosts. Some species superparasitize the hosts more, and one (Eurytoma curta) much less than would be expected if the egg distribution were purely random, owing to peculiarities in oviposition behaviour.4. Parasitism by E. curta is unevenly distributed in space, being higher in areas of high host density. This suggests that search is not exactly random, but is also concentrated in space. A tentative explanation is advanced based on the assumption that search is by random movements.5. Parasitism by E. robusta is very patchy. This non-random distribution is attributed to random movements performed by a very few parasites.6. It is concluded that these spatial discrepancies do not seriously affect the numerical accuracy of the assumption that search is random in small areas, and that the theory of Nicholson & Bailey may be accurate to a first approximation.

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“…Examples of this include the arrestment of Eurytoma curta (Varley, 1941) on flower heads, of Collyria calcitrator Grav. (Walker, 1940) on wheat stems and of Apecthis rufata Gmel. (Zwolfer & Kraus, 1957) and Ephedrus pulchellus Stelfox (Stary, 1962) on curled leaves.…”

Section: Introductionmentioning

confidence: 99%

Arrestment responses of the parasitoid, Nemeritis canescens, to a contact chemical produced by its host, Plodia interpunctella

Waage

1978

Physiological Entomology

161

103

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The locomotory response of walking parasitoids to a contact chemical from their host is reviewed, and in particular the response of the ichneumonid, Nemeritis cunescens Grav., to the mandibular gland secretion of its host, Plodia interpunctellu Hubn., is investigated. In response to the presentation of the host chemical on a surface, a walking Nemeritis exhibits a complex orthokinetic response involving stopping, walking at a reduced speed and probing with the ovipositor. In response to the removal of the chemical following presentation, as would occur when the insect left the edge of the chemical patch, the wasp exhibits a klinotactic response which directs it back to the patch at an average angle of 157" relative to the orientation at the moment of stimulation. This turning-back response at the patch edge greatly increases the time spent on a patch of contact chemical. The waning of this response determines when a host patch is abandoned. This waning is retarded by increasing the concentration of contact chemical on the patch and by oviposition while on the patch. w ch c, % 2 9 B k T References Ahmad, T. (1936) The influence of ecological factors o n the Mediterranean Flour Moth, Ephestiu kuhniella and its parasite, Nemeritis canescens. Journal of Animal Ecology, 5 , 61-93.

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Notes on the Distribution ofCephus Pygmaeus, Linn., and of its Parasite,Collyria calcitrator, Gray

Cited by 9 publications

References 8 publications

A Mathematical Model for the Effect of Densities of Attacked and Attacking Species on the Number Attacked

A Mathematical Model for the Effect of Densities of Attacked and Attacking Species on the Number Attacked

On the search for hosts and the egg distribution of some chalcid parasites of the knapweed gall-fly

Arrestment responses of the parasitoid, Nemeritis canescens, to a contact chemical produced by its host, Plodia interpunctella

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