No abstract

No abstract

No abstract

Nymphs of Rhodnius prolixus usually take a meal that is nine times the body weight before feeding. Adults usually take only three times their body weight as a blood meal. During the first 24 hours after feeding, the insect eliminates over 40% of the weight of the blood meal as dilute urine. The weight loss after this period is much more gradual.The minimum blood meal which promoted molting in various instars varied between 24.7 and 42.8% of the standard "maximum meal" for each instar; the minimum meal that promoted egg production was 31.3%. Limiting the size of the blood meal to these levels does not extend the time required for molting or egg production.Third- and fifth-instar nymphs, brought to a high level of nutrition by being fed a series of meals that are too small to cause molting, can be made to molt by a terminal meal that is about half the minimum single meal required to induce molting. Thus the amount of abdominal distension required to initiate molting can be lowered if the animals have been brought to a high level of nutrition.Up to a limit of 28 eggs, the number of eggs produced by a female shows good correlation with the amount of blood taken as food.

No abstract

No abstract

Rhodnius prolixus nymphs confined in an artificial feeding apparatus could be induced to gorge on 0.15 M NaCl solutions at pH 7.0 containing 10−3 M concentrations of chemicals having phosphate bonds of high energy release. The di- and tri-phosphates of adenosine, guanine, inosine, cytosine, and uridine all showed high gorging factor activity. Creatine phosphate and tetrasodium pyrophosphate were slightly less active. Riboflavin-5-phosphate, 5′-adenylic acid, and 3′5′ cyclic adenylic acid also stimulated gorging to a marked degree. Addition of Ca++ ions to the solution decreased the gorging factor activity of adenosine triphosphate.Gorging appears to be triggered by chemicals which can act as phosphate donors or can initiate phosphorylation in a non-specific and unknown manner.

No abstract