Distribution of scorpion venom in locusts

Abstract

Redissolved freeze dried venom of Leiurus quinquestriatus H. & E. was labelled with I 131, and injected into adults of Locusta migratoria migratorioides R. & F. which were dissected at intervals of 5 min to 216 hr following injection. Radioactivity was measured separately for cell-free haemolymph, circulating haemocytes (obtained by centrifugation), intestine, fat body, muscles, thorax, reproductive system, pericardial cells, Malpighian tubules, faeces, central nervous system, and remaining body parts including body wall, legs, and wings. Two counts were taken for each dissected part, the first immediately following dissection and the second after rinsing the tissue in saline. The difference in radioactivity before and after rinsing indicated that 20–30 per cent of the venom was rinsed out. Part of this was undoubtedly venom from haemolymph adhering to the dissected tissues. A significant part of the venom (about 25 per cent) was found to be absorbed by the pericardial cells. Percentage radioactivity for each consecutive 24 hr collection of pellets was: 50·80, 8·42, 4·45, 1·39, 0·97, and 0·59 respectively. With time, most tissues showed a decline in radioactivity, except the culticular parts of the body where percentage radioactivity remained constant from 5 min to 216 hr following injection of labelled venom.