Relationship between the Removal of the Frontal Ganglion and Protein Starvation in Locusta migratoria L.

Abstract

IT has been shown¹ that the removal of the frontal ganglion in Locusta migratoria L. stopped any further growth in weight of the insect. Based on co-related changes in the endocrine system, it was suggested that failure to grow was basically a failure of protein metabolism. The possibility that cessation of growth was brought about by gross or partial starvation due to the operation interfering with the insect's ability to eat or pass food through its gut was rejected for the following reasons:

(1) The operated locusts were observed to eat frequently and to defaecate often; no obvious differences between these and normal locusts were observed in this matter.

(2) Dissections of the operated locusts revealed the presence of grass throughout the leDgth of the gut.

(3) The operated locusts live four or five times as long as starved ones and arc fully active throughout their lives. In adults, night is not impaired in any way.

(4) The operated locusts remain at a constant weight for the rest of their lives. It is extremely improbable that just that amount of damage is done by the operation which would allow the locust to take in just that amount of food which would (a) make good the loss of weight due to post-operative treatment, (6) precisely make good the daily energy expenditure of the animal.

(5) The oxygen consumption of operated locusts was not significantly different from normal locusts, while that of starved animals is always significantly lower.

(6) The effects of starvation could be reversed by simply giving the locusts food, but no way of correcting the results of the removal of the frontal ganglion was found.