ABSTRACT
The influence of larval diet and population density on pre-adult developmental rate, larval survival, pupal survival, adult survival and sex ratio was investigated. Diet and density had no effect on pre-adult developmental rate (P>0.05). Diet did not significantly affect the proportion of larval survival and pre-adult survival (P>0.05) whereas density did (P<0.05). Both diet and density significantly affected the pupal survival (P<0.05). The sex ratio varied significantly from 1:1 ratio in favour of the males, only in those raised from yeast diet died out, liver diet had the same effect at density of 300L/300ml of water. This indicates that yeast diet may not be as good as liver diet. The mean pre-adult developmental period from 1st instar larva to adult stage for liver; liver/yeast; yeast at different densities of 30,60,150 and 300L per 300ml of water were 10.25±0.25 ,9.75±0.25 ,9.75±0.25; 11.75±0.75,11.0±0.50 ,10.25±3.5; 11.75±1.25 ,13.5±0.00 4.75± 7.5; 12.0±1.5, 15.0±1.0, 6.0±5.0 respectively. The pre-adult survival for liver; liver/yeast; yeast at different densities of 30,60,150 and 300L per 300ml of water were 36.7±10.8%, 63.3±9.4%, 63.3±5.4%; 51.7±5.4%, 26.7±16.5%, 30.0±14.1%; 6.0±31.1%, 44.7±3.7%, 2.7±33.4%; 2.7±33.4%, 22.0±19.8%, 3.3±28.7% respectively. The frequency of male and female raised from adults fed with liver; liver/yeast; and yeast at densities of 30L,60L,150L,300L per ml were 7,12,12 and 5,7,7; 16,7,7 and 15,9,11; 5,27,3 and 4,40,1; 3,32,7 and 5,34,3 respectively. Since pupae do not feed, the effect of diet and density became overwhelming. Analysis of the results shows that intra-specific competition was high for diet and the effect of densities was vital at extreme densities.
