Hostname: page-component-cd9895bd7-mkpzs Total loading time: 0 Render date: 2024-12-26T00:47:44.107Z Has data issue: false hasContentIssue false
  • English
  • Français

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

Published online by Cambridge University Press:  06 April 2009

G. C. Varley
G. C. Varley
Affiliation:
From the Department of Entomology, Zoological Laboratory, Cambridge
Get access Rights & Permissions [Opens in a new window]

Extract

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.

Type
Research Article
Information
Parasitology , Volume 33 , Issue 1 , March 1941 , pp. 47 - 66
Copyright
Copyright © Cambridge University Press 1941

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

REFERENCES

Clausen, C. P., Jaynes, H. A. & Gardner, T. R. (1933). Further investigations of the parasites of Popillia japonica in the far East. Tech. Bull. U.S. Dep. Agric. no. 366.Google Scholar
Collin, J. E. (1937). Trypeta vectensis sp.n. and other new or little known British species of Trypetidae (Diptera). Ent. Rec. 49, 1–7.Google Scholar
Fisher, R. A. (1925). Statistical Methods for Research Workers. Oliver and Boyd.Google Scholar
Fiske, W. F. (1910). Superparasitism: an important factor in the natural control of insects. J. earn. Ent. 3, 88–97.Google Scholar
Fulton, P. B. (1933). Notes on Habrocytus cerealellae . Ann. ent. Soc. Amer. 26, 536–53.Google Scholar
Howard, L. O. (1897). A study in insect parasitism: a consideration of the parasites of the white-marked tussock moth, with an account of their habits and interrelations, and with descriptions of new species. Tech. Ser. U.S. Dep. Agric. no. 5, pp. 5–57.Google Scholar
Laing, J. (1937). Host finding by insect parasites. 1. J. Anim. Ecol. 6, 298–317.Google Scholar
Lloyd, D. C. (1938). A study of some factors governing the choice of hosts and the distribution of progeny by the chalcid Ooencyrtus kuvanae How. Philos. Trans. B, 229, 275–322.Google Scholar
Lloyd, D. C. (1940). Host selection by hymenopterous parasites of the moth Plutella maculipennis Curtis. Proc. roy. Soc. B, 128, 451–84.Google Scholar
Lotka, A. J. (1925). Elements of Physical Biology. Baltimore.Google Scholar
Morris, K. R. S. (1938). Eupelmella vesicularis Retz. (Chalcididae) as a predator of another chalcid Mieroplectron fuscipennis Zett. Parasitology, 30, 20–32.CrossRefGoogle Scholar
Nicholson, A. J. (1933). The balance of animal populations. J. Anim. Ecol. 2, 132–87.CrossRefGoogle Scholar
Nicholson, A. J. & Bailey, V. A. (1935). The balance of animal populations. Proc. Zool. Soc. Lond. pp. 551–98.Google Scholar
Noble, N. S. (1932). Studies of Habrocytus cerealellae Ashm., a Pteromalid parasite of the Angoumis grain moth Sitotroga cerealeUa (Olivier). Univ. Calif. Publ. Ent. 5, 311–54.Google Scholar
Paillot, A. (1923). Étude morphologique et biologique de Neurotoma nemoralis L. Ann. Epiphyt. 10, 150–237.Google Scholar
Parsons, P. S. & Ullyett, G. C. (1936). Investigations on Trichogramma lutea Gir. as a parasite of the cotton boll worm, Heliothis obsoleta Fabr. Bull. ent. Res. 27, 219–35.Google Scholar
Salt, G. (1934). Experimental studies in insect parasitism. 2. Superparasitism. Proc. roy. Soc. B, 114, 455–76.Google Scholar
Salt, G. (1936). Experimental studies in insect parasitism. 4. The effect of superparasitism on populations of Trichogramma evanescens . J. exp. Biol. 13, 363–75.CrossRefGoogle Scholar
Salt, G. (1937). The sense used by Trichogramma to distinguish between parasitized and unparasitized hosts. Proc. roy. Soc. B, 122, 57–75.Google Scholar
Smith, H. S. (1939). Insect populations in relation to biological control. Ecol. Monogr. 9, 311–20.CrossRefGoogle Scholar
Smith, H. S. & Flanders, S. E. (1931). Is Trichogramma becoming a fad? J. earn. Ent. 24, 666–72.Google Scholar
Thompson, W. R. (1939). Biological control and theories of interactions of populations. Parasitology, 31, 299–388.Google Scholar
Varley, G. C. (1937 a). Description of the eggs and larvae of four species of Chalcidoid Hymenoptera parasitic on the knapweed gall fly. Proc. Roy. ent. Soc. Lond. B, 6, 122–30.Google Scholar
Varley, G. C. (1937 b). The life-history of some Trypetid flies with descriptions of the early stages (Diptera). Proc. Roy. ent. Soc. Lond. A, 12, 109–22.Google Scholar
Varley, G. C. & Butler, C. G. (1933). The acceleration of development in insects by parasitism. Parasitology, 25, 263–8.CrossRefGoogle Scholar
Volterra, V. (1926). Variazioni e fluttuazioni del numero d' individui in specie animali conviventi. Mem. Acad. Lincei, ser. 6, 2, fasc. 3, pp. 31–113.Google Scholar
Walker, M. G. (1940). Notes on the distribution of Cephus pygmaeus Linn., and of its parasite, Collyria calcitrator Grav. Bull. ent. Res. 30, 551–73.Google Scholar