INFLUENCE OF DIET COMPOSITION ON MEAL SIZE AND RATE OF EXCRETION OF THE TSETSE FLY GLOSSINA PALPALIS PALPALIS

Abstract

The suitability of various diets for the tsetse fly Glossina palpalis palpalis has been investigated in terms of food‐uptake and primary excretion. Serum substitutes were prepared reflecting the composition of bovine serum and offered to teneral female flies, on a few occasions in combination with erythrocytes. Routinely, all diets contained 10−3 M ATP. There was no difference in meal size when flies were fed on serum or serum‐substitutes, alone, or in combination with erythrocytes. The rate of primary excretion was reduced in diets, where serum was substituted by an isotonic saline containing bovine albumin or bovine albumin + gamma‐globulin. Glucose, added to a diet containing albumin, induced a normal excretion rate. In all cases a combination of erythrocytes and serum (‐substitutes) caused a reduced primary excretion as compared to the sera (‐substitutes) alone. The rate of excretion was highly correlated with the meal size, regardless of the diet composition. RÉSUMÉ L'INFLUENCE DE LA COMPOSITION DU RÉGIME SUR L'IMPORTANCE DU REPAS ET DU TAUX D'EXCRÈTION DE GLOSSINA PALPALIS PALPALIS On a étudié plusieurs régimes alimentaires destinés à la mouche tsé‐tsé, Glossina palpalis palpalis, pour déterminer s'ils permettent une absorption des aliments et une excrétion primaire satisfaisantes. On a préparé et proposé à des nymphes femelles des substituts de sérum ayant la même composition que le sérum bovin et associés dans certains cas à des érythrocytes. Tous les régimes étudiés contenaient 10−3 M ATP. Les quantités ingérées par les mouches nourries sur sérum ou substituts de sérum seuls ou associés à des érythrocytes ont été les mêmes. L'excrétion primaire avec régimes où le sérum avait été remplacé par une solution saline isotonique contenant de l'albumine bovine ou un mélange d'albumine bovine et de gamma‐globuline était réduite. L'adjonction de glucose à un régime contenant de l'albumine a entrainé une excrétion normale. Dans tous les cas, la combinaison d'érythrocytes et de sérums (ou de substituts) a réduit l'excrétion primaire par rapport aux régimes composés de sérums (ou de substituts) seuls. Quel que soit le régime le taux d'excrétion était fortement lié aux quantités absorbées.

INFLUENCE OF SERUM ALBUMIN ON FECUNDITY AND WEIGHT OF THE PROGENY OF THE TSETSE FLY GLOSSINA PALPALIS PALPALIS

“…In the present study, G, p. palpalis failed to reproduce when they were fed on a suspension of erythrocytes. This cannot have been caused by a lower intake of food since the ingestion rates of flies fed on whole blood (RBC + serum) or on semi-artificial blood (RBC + serum-substitute) were similar (Takken, 1980). Although erythrocytes provide the bulk of protein in the diet of tsetse flies (>90%), they apparently lack vital elements which are necessary for successful reproduction in G. p. palpalis.…”

“…The diets were 1-7 days old when they were offered to the flies and were stored at 4 ° . Details of physical parameters and food-uptake and primary excretion have been described in a previous paper (Takken, 1980).…”

“…As a first step in the preparation of such a diet, it would seem useful to investigate the composition of vertebrate blood and then test artificial diets resembling blood in composition on the flies. In a previous paper (Takken, 1980) I have reported on some effects of various serum substitutes in the diet of Glossina palpalis palpalis (Rob.-Desv.) on ingestion and excretion.…”

Development of a synthetic diet for Glossina (Diptera: Glossinidae)

“…Physiological studies on the feeding behaviour of tsetse flies (Langley, 1976) and on the metabolic conversion and mode of utilization of a number of radiolabelled compounds (amino acids, fatty acids and sugars) have been reported (Moloo, 1976;Langley and Pimley, 1974;Bursell et al, 191 A). Manipulation of the blood diet and the influence of diet composition on feeding behaviour and on various physiological functions of tsetse flies have also been studied (Langley et al, 1978;Moloo & Pimley, 1978;Langley & Pimley, 1979;Kabayo, 1979Kabayo, , 1982Takken, 1980;Kabayo & Langley, 1985). Attempts to identify the nutritionally important constituents of mammalian blood (Kabayo & Langley, 1985) established that preparations of haemoglobin and albumin could replace the erythrocyte and serum fractions of bovine blood, respectively.…”