HEMOLYMPH ECDYSTEROIDS AND THE PROTHORACIC GLANDS IN THE SOLITARY ANDGREGARIOUS ADULTS OF SCHISTOCERCA-GREGARIA

The haemolymph titre of ecdysteroids rises in the adults of both sexes to a brief peak in the first week after emergence. A major rise begin s on days 8-10, coincidentally with intensive vitellogenesis in the fe males and aggregation pheromone production in the males, The titre rea ches about 400 ng of 20-hydroxyecdysone (20E) equiv./ml in the solitar y, but less than 150 ng/ml in the gregarious adults of both sexes, In the females, the titre drops after oviposition (prior to day 20) and r emains low until the next egg batch matures; then it increases in eith er phase to 150-180 ng/ml, A similar titre reduction in the males occu rs just after day 20: in the solitary males the titre declines slowly to about 110 ng/ml on day 40, whereas in the gregarious males ecdyster oids virtually disappear by day 25, The blood of females contains simi lar levels of 20E and ecdysone, whereas in the males 20E makes up 73% (solitary) or 94% (gregarious) of total ecdysteroids, Minor components include a compound behaving as makisterone A and highly polar metabol ites, The prothoracic glands are well preserved in both solitary and g regarious adults for at least 1 week after hedging and in some females they seem to persist for the lifetime, but in contrast to the glands of larvae, do not produce significant amounts of ecdysteroids when cul tured in vitro. (C) 1997 Elsevier Science Ltd.