This study was conducted to examine the effect of malathion on the development of
Chrysomya megacephala. A total of 12 adult Sprague-Dawley rats was divided into 4 groups.
Each animal in the 4 groups was given orally 0 (control), 10, 25 and 50ml/kg body weight of
malathion, respectively. Chrysomya megacephala larvae were then allowed to grow on the liver
of carcass. Larvae development was estimated by means of weight and length, time of adult
emergence and survival rate. Results indicated that for the first 6 to 30 hours, larvae from control
group developed more rapidly than larvae feeding on tissue containing malathion. However, the 3
doses of malathion did not exhibit significant impact on larvae length and weight. The time
required for adult emergence was significantly greater for malathion-treated colony which was
10 days compared to 7 days in control colony. Control larvae of C. megacephala had higher survival
rate compared to larvae exposed to the three different doses of malathion. Analysis of the tissues
indicated that all rats and fly samples were positive for malathion. Malathion concentration was
highest in liver. It was concluded that the presence of malathion altered the development rate of
C. megacephala and thus disrupted normal postmortem interval estimation.