Behaviour and regulation of puparium formation in the larva of the tsetse fly Glossina morsitans orientalis Vanderplank in relation to humidity, light and mechanical stimuli

Abstract

From obsevations on larvae from laboratory-reared females of Glossina morsitans orientalis Vanderplank, six stages were recognised between the time of deposition (signalled in these experiments by a simple automatic device) and completion of puparium formation, each characterised by an associated pattern of behaviour. They are termed crawling (during which there is a stron phot-negative response), circling and reversing, head retraction, barrelling (the assumption of the puparial shape), hardening, and darkening. In choice-chamber experiments, crawling larvae markedly preferred moist to dry air but showed no response to gravity. In daylight at 26°C., larvae introduced into translucent plastic tubing travelled up to 65 in. before pupating; under bettwe conditions for locomotion they would probably go further. The interval before pupation was longer the earlier in the day birth occurred and was greater in light (average 108 min.) than in darkness (average 40 min.) and least, perhaps because of the contact stimulation, in sand in darkness. When bodily contact was minimised by suspending larvae by a thread tied round or stuck to the polypneustic lobes, pupation was accelerated; this possible reflected the mechanical stimulation of the handling, for pinching the larva with forceps produced a similar acceleration.

PUPARIAL DURATION IN GLOSSINA MORSITANS ORIENTALIS UNDER CONDITIONS OF CONSTANT TEMPERATURE

“…These field puparia were selected from routine daily collections on the basis of pale colouration. Such puparia were assumed to be less than one hour old (FINLAYSON, 1967) at the commencement of incubation whereas the age of colony puparia tested was only known to be less than 24 hours.…”

BODY CONSTRAINT AND DEVELOPMENTAL ARREST INGALLERIA MELLONELLAL.: FURTHER STUDIES

“…Clarke and Langley (1963) postulated a role for proprioceptive monitoring of crop distension in growth and molting of Locusta, and a similar control system has been suggested in the regulation of digestive enzyme activity in adult tsetse flies (Langley, 1966). Finlayson (1967) has recently demonstrated that mechanoreceptor input plays a role in the initiation of puparium formation in larvae of Glossina. The onset and termination of successive phases of insect molting and maturation is regulated by surface contact and body form in a number of studies cited by Cottrell (1964) and in certain of these, proprioceptive monitoring of body form is implicit.…”

Influence of environmental factors on the wandering phase and pupariation in stable fly, Stomoxys calcitrans, larvae

“…A stage 3 larva (irreversible anterior retraction stage) looks similar to the stage 2 larva; however, it cannot lengthen itself when disturbed. Stage 4 larvae (barrelling stage, as in Finlayson's (1967) description) are oval. the same shape as normal pupae, with the mouthparts inverted, but with no visible tanning.…”