Physiology of tsetse flies (Glossinaspp.) (Diptera: Glossinidae): a review

Abstract

Since no major review of the literature on tsetse physiology has hitherto been undertaken, relevant papers up to the beginning of 1977 are included in the present work. The physiology of Glossina is dealt with under three major headings; reproductive, developmental and nutritional events in the life of this haematophagous and viviparous insect are discussed in relation to general principles of insect physiology gained from the study of other genera. The role of adult maturation and the possible involvement of a sex pheromone in successful mating are considered. The difficulties of studying neuroendocrine function in relation to reproductive physiology in a viviparous insect, where reproductive and developmental events are not always separated chronologically, are emphasised. Nevertheless, the role of the neuroendocrine system in the control of such events as ovarian development, ovulation, parturition, pupariation and metamorphosis is considered, and the contribution that recent work on Glossina has made to an increased understanding of general principles in this field is discussed. Laboratory observations have demonstrated circadian components of behaviour in Glossina that can influence interpretation of field observations and likewise should influence the design of physiological experiments. Utilisation of nutritional reserves for larval growth and for flight activity has received considerable attention recently. The general pattern seems to be one of rapid mobilisation of blood-meal amino acids and the involvement of a large lipid reserve. The combined haematophagous and viviparous habit of Glossina has led to some interesting modifications of basic physiology particularly in regard to flight metabolism, female accessory gland function and Malpighian tubule activity. The relevance of physiological studies to current developments in the field of tsetse control is discussed and the importance of exploiting our knowledge in the quest for novel insecticidal techniques emphasised.

Rapid changes in the reproductive cycle of wild-caught tsetse, Glossina pallidipes Austen, when brought into the laboratory

“…1, laboratory females retained the third instar larva for longer than the field flies, possibly related to the lower temperature conditions they experienced. The mean full-term CRDW observed in the laboratory (17.26 ± 0.30 mg) was therefore probably greater than the field condition, but as the adult female post-partum CRDW was the same, the pupae produced in the laboratory must have been larger than the fieldproduced pupae, although the ratio of their mean fat (3.38 +0.131 mg) to mean RDW (7.14 +0.213 mg) (0.47:1) was similar to that reported for G. morsitans and G. austeni by Langley (1977 , Table 1, mean ratio 0.52:1). 5).…”

The Obligate Mutualist Wigglesworthia glossinidia Influences Reproduction, Digestion, and Immunity Processes of Its Host, the Tsetse Fly

“…It is quite possible that the longevity cost we observed in Gmm WigϪ flies may be due to inefficient digestion of nutrients. Tsetse flies require a blood meal approximately every 48 h, and flies consume a large volume, which in wild-type flies undergoes diuresis quickly, followed by complete digestion within 48 to 72 h (20). In the case of female Gmm WigϪ flies, blood digestion was significantly inhibited on the basis of both visual observations of flies and measurements of gut hemoglobin content.…”

Regulation of last reproduction steps in tsetse flies (Glossina:Diptera)

“…A particularly precise and consequently complex control thus appears to be required, which stimulated a great number of investigations since Mellamby (1937). Ten years after the publication of the last reviews in the field (Langley, 1977;Tobe and Langley, 1978). it is interesting to reexamine the question.…”