INSECT BLOOD MEAL STUDIES USING RADIOSODIUM NA-24 AND NA-22

Rabbits were infused with 3.7 GBq (100 MCi) of [Na-24]Na ion in a 100- ml sodium carbonate solution. Beta particles were detected using a Ten nelec Counting System(R); background counts were 1.6 +/- 1 counts per minute (cpm). Counts for one nanoliter of blood ranged from 22 to 30 c pm. Blood volumes on the mouthparts of tabanids following a 15-sec int errupted feeding were estimated to be 12.5 nl for Tabanus fuscicostatu s, 10.8 nl for T. nigrovittatus and 6.12 nl for Chrysops fuliginosus. Estimates of the quantity of blood adhering to 22-gauge needles and in sect pins (size 2) following a percutaneous intramuscular needle-stick were 8.8 +/- 1.0 nl and 5.7 +/- 1.8 nl, respectively. Mosquitoes, Aed es aegypti females, were fed to repletion with a Na-22-artificial diet , and radioactivity was measured using a Packard Autogamma 5650. The e stimated average blood meal size was 2.80 +/- 0.94 mul.