| dc.description.abstract | In order to develop realistic options and control
strategies which are enviromentally acceptable, sustainable
utilization of indigenous botanical resoursesought to be
established.
Flight performance was reduced in the desert locust, S.
gregaria Forskal after injections of 0.01 gland pairs of
co,rpora cardiaca as a standard dose and treatment with a
definable triterpenoids (limonoid) fraction extracted from
A. indica and Melia volkensii, family Meliaceae. The
cc extract only produced a hyperlipaemic response which was
approximately double the initial resting lipid levels. From
the data obtained in this study a rise in the haemolymph lipid
level from 11.98 ± 1.63 ~g/~l at zero time to 28.76 ±
2.97~g/~1 60 minutes from commencement of flight was
realised and was significant at p < 0.05. In contrast, the
blood lipid levels in azad i"'raoht i n-ct.r eat.ed and flown locusts
were less than those in the controls, which received cc
extract only. Doses ranged between O.l~g to 2~g of
azadirachtin per locust. Using 0.1 ~g - 0.25 ~g/locust of
~ volkensii triterpenoid fraction,the difference in
total lipid concent~ation between resting levels and 60
minutes after treatment ranged from 1.!.to 8.9 ~g/~l. A higher
M. volkensii dose (0.5-2~g/locust) was not effective in
inducing hyperlipaemic response at 60 minutes.
Unflown locusts wh.i crr were in jected with cc extract and
treated with azadirachtin or ,IvI. volkensii extract showed
increased hyperlipaemic response with maximal blood lipid
xvi
level occur ing bet.weeri 60 and 90 mini ut.es . The CUllLrol gruup
which received cc extract unly responded maximally within
30 minutes of treatlllent.
The poor flight activity observed in treated lucusts
confirmed earlier reports un the physiological effects of
triterpenoid compounds. A indica extract showe the highest
effect on the reduction of flight speed within the initial 30
minutes. The mean flight speed in control locusts which
received cc extract only was 2292 revolutions, while locust
treated with 0.1M9 of azadirachtin attained a mean flight
speed value of 1688 revolutiuns in the first 30 minutes (76rpm
and 56rpm respectively), a difference which was significant at
P < 0.05. M. volkensii treaced locusts also had significantly
reduced speed compared to the controls. The flight pattern of
locusts treated with M. volkensii extract showed a continued
drop throughout the experimental period. The control group
showed a mean speed of 14rpm "between 60-90 minutes. This was a
signicantly high value compared to 6rpm in the treated group
for N. volkensii doses above 0 .1ug.
A high dose of the M. volkensii extract (0. 5-2 ug/
locust) caused hind leg paralysis two days after treatment in
adult S. gregaria. | en |
