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.
Malathion ; Chrysomya megacephala ; development aspects ; Adult ; Carbon ion

The anatomical structures of the first, second and third instars of Chrysomya rufifacies (Macquart) were examined by light microscopy. Observations were documented on the three main characteristics; the cephalopharyngeal skeleton, anterior spiracle and posterior spiracle. The first instar larva bore cornuae of fairly pigmented delineation with slim hypostomal sclerite and distinct dental sclerite. First instar did not have obscured anterior spiracle but posterior spiracles were obscured with thin lining of opened peritreme. Intersegmental spines were evident. The second instar larva displayed a prominent anterodorsal process approaching closer to hypostomal sclerite while upper margin of the dorsal cornua was slightly pigmented. Each anterior spiracle consisted of nine to ten papillae, arranged in a single row. Peritreme of the posterior spiracle thick, opening at the end of peritreme was not wide and confined to two spiracular slits. The third instar larva showed a prominent arch of the ventral cornua with broad and bold appearance. It approached the dorsal cornua and became narrow at the incision median. The anterior spiracle consisted of a single row of nine to ten papillae while intersegmental spine could be identified with one to three dark pigmented tips. A dark pigmented and wide periterime was observed confining three short and thick spiracular slits while button was poorly pigmented. The most distinctive feature of this second and third instar larva was the slender, thorn-like tubercle with numerous spined tips on the middle line segment of the body. These findings provide identification features of C. rufifacies larvae instars.

Chrysomya megacephala (Fabricius) and Chrysomya rufifacies (Macquart) are two important species of blow flies that could be utilised as indicators to estimate the Post Mortem Interval (PMI) of corpses in forensic science. Determination of PMI of corpses is based on the larva size and its development stages. Development studies of eggs, larvae and pupae of Ch. megacephala and Ch. rufifacies at 27ºC, 30ºC and 33ºC were carried out using an insect growth chamber. Data from these studies were used to construct growth curves and Accumulated Degree Hours (ADH) for both species. Ch. megacephala needs 9.15 days to complete one life cycle at 27ºC, 8.54 days at 30ºC and 6.76 days at 33ºC. Development for Ch. rufifacies is slower than Ch. megacephala and takes 9.92 day at 27ºC, 9.13 days at 30ºC and 7.44 days at 33ºC. Eggs of the two species hatch faster at 33ºC compared to the two other temperatures. Low value of ADH shows shorter life cycle of that particular species. This study’s findings are useful in estimating PMI of the corpses found under various environmental temperatures.

During a forensic entomological study conducted at an oil palm plantation in Tanjung Sepat, Kuala Langat, Selangor, a Bengalia emarginata Malloch, 1927 (Diptera: Calliphoridae: Calliphorinae: Bengalini) was collected for the first time. Two adults were collected nearby the pig carcass by the first author and identified by the second. Prior to this finding, nine species of Bengalia were recorded from peninsular Malaysia or Borneo. Male of B. emarginata are different from Bengalia varicolor Fabricious by the following characters: Sternite 5 projection rounded with small identation and mid tibia double-fringed in ventral surface.
Calliphoridae ; Malaysia ; Diptera ; Upper case Bee ; Status pre-