Laboratory studies on the biology ofSyntomosphyrum albiclavusKerrich (Hym., Eulophidae), a parasite of tsetse flies

Abstract

SummaryLaboratory studies are reported onSyntomosphyrum albiclavusKerrich, a Eulophid of interest as a pupal parasite of tsetse flies. Material for a laboratory culture was obtained from puparia ofGlossina morsitansWestw. collected in Tanganyika and sent to London by air.‘ Natural’ and ‘unnatural’ hosts of this parasite were investigated.S. albiclavusparasitised all species of Cyclorrhaphous puparia offered in the laboratory, but has only been recorded from puparia ofGlossinaunder natural conditions. The conditions which make a host suitable forS. albiclavusare discussed. The most important of these is the presence of the ‘sub-puparial space’ in which the eggs are laid, without which the host is unacceptable.S. albiclavuswill also breed on dead pupae and in puparia containing other parasites.The number of parasites emerging from the host puparium is shown to be directly proportional to its weight.The fecundity ofS. albiclavusis shown to be very variable and dependent upon the weight of host material consumed during larval life, which, in turn, reflects the density of parasites in the host puparium from which the females emerged.The duration of the parasitic phase of the life-cycle and the length of life of the adults are shown to be functions of the temperature. Length of life is also affected by the relative humidity, increased mortality occurring in low humidities and in saturated air, with an optimum for survival at about 80 per cent. R.H.It is shown that a constant temperature of 35°C. is fatal to the eggs ofS. albiclavus.The age at which females ofS. albiclavusbecome mature was investigated at three temperatures and it is shown that the rate of maturation of the ovaries is a function of the temperature.At 25°C., females ofS. albiclavusare unable to lay eggs until the third day after emergence. The number of offspring produced then falls off with increasing age of the female and very old females, although attacking hosts, are unable to oviposit.