Hostname: page-component-76fb5796d-45l2p Total loading time: 0 Render date: 2024-04-25T14:29:44.870Z Has data issue: false hasContentIssue false
  • English
  • Français

The variability of fly-round catches in field studies of Glossina.

Published online by Cambridge University Press:  10 July 2009

J. P. Glasgow
J. P. Glasgow
Affiliation:
East African Trypanosomiasis Research Organization, Tororo, Uganda.
Get access Rights & Permissions [Opens in a new window]

Extract

In an attempt at some assessment of the errors to which fly-round data obtained for the study of populations of Glossina are subject, three fly-rounds at Shinyanga, Tanganyika, were worked every weekday for four weeks. The species studied was G. swynnertoni Aust. One of the rounds was a ‘transect fly-round ’, the others, the older type, divided into a few long sections according to the vegetation. The catches showed no obvious trend during the experiment, suggesting that the true population had not altered in the period, but in all three rounds there were considerable day-to-day variations in catch and, in this respect, the transect fly-round did not differ from the older method. An analysis of variance of the transect fly-round data showed that the variance between days was greater than could be accounted for by random errors

By considering separately the data collected on certain days of the week, it is concluded that a 7,500-yd. fly-round done once a week could not detect less than a five-fold change in the mean catch. To detect a two-fold change, a 15,000-yd. fly-round done twice a week would be necessary.

The relation between fly-round catch and true density is discussed. This relation is usually termed ‘ availability ’. Earlier workers have shown that its mean value, over periods of about one month, is not necessarily constant; the present work shows that it varies in one place from day to day.

Type
Research Paper
Information
Bulletin of Entomological Research , Volume 51 , Issue 4 , January 1961 , pp. 781 - 788
Copyright
Copyright © Cambridge University Press 1961

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

Ford, J., Glasgow, J. P., Johns, D. L. & Welch, J. R. (1959). Transect fly-rounds in field studies of Glossina.—Bull. ent. Res. 50 pp. 275–285.CrossRefGoogle Scholar
Glasgow, J. P. (1954). Glossina palpalis fuscipes Newst. in lake-side and in riverine forest.—Bull. ent. Res. 45 pp. 563–574.CrossRefGoogle Scholar
Glasgow, J. P. & Bursell, E. (1961). Seasonal variations in the fat content and size of Glossina swynnertoni Austen.—Bull. ent. Res. 51 pp. 705–713.CrossRefGoogle Scholar
Harley, J. M. B. (1958). The availability of Glossina morsitans Westw. in Ankole, Uganda.—Bull. ent. Res. 49 pp. 225–228.CrossRefGoogle Scholar
Jackson, C. H. N. (1944). The analysis of a tsetse-fly population. II.—Ann. Eugen. 12 pp. 176–205.CrossRefGoogle Scholar
Jackson, C. H. N. (1953). A mixed population of Glossina morsitans and G. swynnertoni.—J. Anim. Ecol. 22 pp. 78–86.Google Scholar
Skellam, J. G. (1958). The mathematical foundations underlying the use of line transects in animal ecology.—Biometrics 14 pp. 385–400.CrossRefGoogle Scholar
Welch, J. R. (1959). Observations on the vegetation of Block 9, Shinyanga, Tanganyika.—Rep. E. Afr. Tryp. Res. Org. 1958 pp. 64–67.Google Scholar
Williams, C. B. (1937). The use of logarithms in the interpretation of certain entomological problems.—Ann. appl. Biol. 24 pp. 404–414.CrossRefGoogle Scholar