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The structure and possible function of the signum of Glossina tabaniformis Westwood

Published online by Cambridge University Press:  06 April 2009

A. M. Jordan
A. M. Jordan
Affiliation:
West African Institute for Trypanosomiasis Research, Kaduna, Northern Nigeria
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Extract

1. In all species of the fusca group of tsetse flies (Glossina), except G. brevipalpis Newstead, a gelatinous structure, the genital fossa, is present at the anterior end of the uterus. On the surface of the genital fossa is a toughened structure known as the signum.

2. Probably chitin and certainly calcium are present in the substance of the signum of G. tabaniformis Westwood. An opaque concretion develops on the signum after the female has been fertilized. The concretions may be caused by a reaction between sperms or secretions from the male accessory glands and materials in the substance of the genital fossa; the possibility that the concretions are ‘mating scars’ produced by pressure of the harpes of the male on the signum is considered unlikely. Concretions are not present on the signa of all species.

3. A possible mechanism of fertilization in G. tabaniformis is discussed, and it is suggested that the signum may act as a protective shield for the anterior part of the uterus and common oviduct of the female from the harpes of the male which are inserted into the uterus during coitus. The views of Machado (1959) are discussed and it is agreed that the signum probably acts as a protective shield in all species in which it occurs and differences in the form of the signum between species may be related to differences in the form of the harpes of the male.

I wish to thank Dr J. Williamson for chromatography, Dr L. E. Stephen and Mr K. E. Broomfield for advice and assistance with the sectioning of the signa, Dr F. Peers for operating the Flame Photometer, Dr D. G. Godfrey for suggesting that the signa should be examined for calcium, and Mr W. Petana for taking the photomicrographs.

I am indebted to Dr K. C. Willett, Director of the West African Institute for Trypanosomiasis Research, for criticism of the manuscript.

Type
Research Article
Information
Parasitology , Volume 53 , Issue 1-2 , May 1963 , pp. 145 - 153
Copyright
Copyright © Cambridge University Press 1963

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