Effect of Ecdysterone on Food Intake of Locusta migratoria Hoppers

Insect growth and developm ent are controlled by hormones [1, 2], The horm ones were also shown to control food intake and utilization in som e insects [3-8]. Ecdysone is associated not only w ith m oult­ ing and m etam orphosis but also with processes preparatory to a moult, such as cessation o f feeding and the onset o f the w andering stage [9]. Recently evidence for a relationship between feeding phases, ecdysone and puparia tion [8] and an inverse rela­ tionship between ecdysteroid titres and total body metabolism of insects was also obtained [10]. In­ creased ecdysterone titres by injection were shown to lead either to reduction or cessation o f feeding in the larvae o f Calliphora vicina [8] and Galleria mellonella [10]. Although considerable inform ation on p ro tho­ racic gland activity, blood titres o f ecdysone and ecdysterone, its regulation and m etabolism in Locusta migratoria is available [11 -13 ], the effect o f this horm one on food intake and w eight gain o f this insect was not studied. W hether it causes effects sim ilar to those observed on feeding in holom etab-