Rhodnius prolixus

Reduviid blood-sucking bug, vector of Trypanosoma cruzi in South America. Much used by insect physiologists because the the transition from one instar to the next is triggered by a blood meal. The blood meal, which may exceed substantially the body weight of the insect, triggers complex changes in the mechanical properties of abdominal cuticle allowing the insect to swell, and activates excretory mechanisms. The haemolymph contains relatively few haemocytes, which made some of the classical parabiosis experiments much easier.