Entomologi forensik adalah satu bidang ilmu yang menggunakan serangga sebagai bahan bukti untuk menganggarkan selang masa kematian atau selang post-mortem (PMI). Penentuan PMI tersebut berdasarkan kepada saiz dan peringkat perkembangan serangga. Chrysomya villeneuvi merupakan salah satu spesies langau yang boleh dijadikan sebagai petunjuk yang baik untuk menganggarkan PMI apabila ia ditemukan pada mayat. Kajian ini bertujuan untuk menghasilkan suatu data asas dan graf perkembangan bagi lalat Ch. villeneuvi pada suhu yang berbeza. Data yang diperoleh juga digunakan untuk membangunkan jadual jam darjah terkumpul (ADH). Justifikasi kajian dijalankan kerana data perkembangan lalat spesies ini belum dibangunkan di Malaysia. Penentuan PMI terpaksa dilakukan dengan berpandukan kepada data perkembangan Ch. megacephala. Ini akan menyebabkan pengiraan PMI menjadi kurang tepat. Kajian terdahulu juga hanya melibatkan kajian berkaitan morfologi dan tingkah laku spesies ini. Kajian perkembangan telur, larva dan pupa lalat Ch. villeneuvi dijalankan pada suhu bawah 25, 27, 30, 33 dan 37ºC di makmal dengan menggunakan kebuk pertumbuhan serangga. Sumber asal lalat dewasa diperoleh dengan meletakkan bangkai tikus di Pusat Penyelidikan Universiti Malaya, Batu 16, Gombak. Lalat dewasa dipelihara di makmal untuk dijadikan sumber koloni. Lebih kurang 150 biji telur dibiakkan dengan meletakkannya ke dalam bekas yang mengandungi 200 g hati lembu sebagai sumber makanan untuk larva yang baru menetas. Lima ekor larva diukur panjangnya setiap tiga jam untuk mendapatkan satu nilai purata untuk setiap suhu. Pemprosesan slaid dan pengambilan foto larva dilakukan untuk mengetahui peringkat perkembangan larva. Ch. villeneuvi mengambil masa selama 9.40 ± 0.02 hari pada suhu 25ºC, 9.34 ± 0.04 hari (27ºC), 9.00 ± 0.07 hari (30ºC), 7.95 ± 0.02 hari (33ºC) dan 7.51 ± 0.02 hari (37ºC) untuk melengkapkan satu kitar hidup. Pada suhu pembiakan yang berbeza, terdapat perbezaan signifikan (p<0.001) ke atas masa perkembangan kitar hidup lalat Ch. villeneuvi. Semakin tinggi suhu dan nilai ADH, semakin pendek satu kitar hidup lalat Ch. villeneuvi. Kajian ini menyatakan tentang tempoh peringkat dalam kitar hidup berdasarkan suhu membantu dalam pembangunan data ADH. Penyiasat forensik di Malaysia boleh menganggarkan PMI berdasarkan graf perkembangan dan data ADH yang diperoleh daripada kajian ini apabila Ch. villeneuvi ditemui pada mayat.
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.
Ahmad Firdaus Mohd Salleh, Anita Talib, Mohamed Abdullah Marwi, Noor Hayati Mohd Isa, Syamsa Rizal Abdullah, Raja Muhammad Zuha Raja Kamal Bashah, et al.
Chrysomya megacephala (Fabricius) dan Chrysomya rufifacies (Macquart) adalah merupakan dua spesies lalat penting yang boleh dijadikan sebagai penunjuk terbaik untuk menganggarkan selang masa kematian atau Post Mortem Interval (PMI) untuk kegunaan dalam sains forensik. Penentuan PMI adalah berdasarkan kepada saiz dan peringkat perkembangan larva. Kajian perkembangan telur, larva dan pupa lalat Ch. megacepahala dan Ch. rufifacies dijalankan di bawah suhu 27ºC, 30ºC dan 33ºC di makmal dengan menggunakan kebuk pertumbuhann serangga. Data daripada kajian digunakan untuk menghasilkan satu graf pertumbuhan dan Jam Darjah Terkumpul (ADH) bagi kedua-dua spesies. Ch. megacephala mengambil masa selama 9.15 hari pada suhu 27ºC, 8.54 hari (30ºC) dan 6.76 hari (33ºC) untuk melengkapkan satu kitar hidup. Pada C. rufifacies pula, kitar hidupnya lebih lama berbanding Ch. megacephala iaitu 9.92 hari pada suhu 27ºC, 9.13 hari (30ºC) dan 7.44 hari (33ºC). Telur bagi kedua-dua spesies menetas lebih cepat pada suhu 33ºC berbanding dua suhu yang lainnya. Nilai ADH yang rendah pada sesuatu suhu, menunjukkan sesuatu spesies lebih cepat melengkapkan suatu kitar hidup. Penemuan ini berguna dalam menganggarkan selang masa kematian bagi mayat yang dijumpai pada suhu persekitaran yang berlainan.
Insects found associated with corpse can be used as one of the indicators in estimating postmortem interval (PMI). The objective of this study was to compare the stages of decomposition and faunal succession between a partially burnt pig (Sus scrofa Linnaeus) and natural pig (as control). The burning simulated a real crime whereby the victim was burnt by murderer. Two young pigs weighed approximately 10 kg were used in this study. Both pigs died from pneumonia and immediately placed in an oil palm plantation near a pig farm in Tanjung Sepat, Selangor, Malaysia. One pig was partially burnt by 1-liter petrol while the other served as control. Both carcasses were visited twice per day for the first week and once thereafter. Adult flies and larvae on the carcasses were collected and later processed in a forensic entomology laboratory. Results showed that there was no significant difference between the rate of decomposition and sequence of faunal succession on both pig carcasses. Both carcasses were completely decomposed to remain stage after nine days. The species of flies visiting the pig carcasses consisted of blow flies (Chrysomya megacephala, Chrysomya rufifacies, Hemipyrellia ligurriens), flesh fly (Sarcophagidae.), muscid fly (Ophyra spinigera), soldier fly (Hermetia illucens), coffin fly (Phoridae) and scavenger fly (Sepsidae). The only difference noted was in the number of adult flies, whereby more flies were seen in the control carcass. Faunal succession on both pig carcasses was in the following sequence: Calliphoridae, Sarcophagidae, Muscidae, Phoridae and lastly Stratiomyidae. However, there was overlap in the appearance of members of these families. Blowflies continued to oviposit on both carcasses. Hence postmortem interval (PMI) can still be estimated from the partially burnt pig carcass.
Forensic entomology refers to the science of collection and analysis of insect evidence in order to determine the minimum time period since death. This study aimed to investigate the occurrence of forensically important flies on 34 human remains referred to Universiti Kebangsaan Malaysia Medical Centre over a period of three years. Entomological specimens were collected at the death scenes and/or during autopsies. Live specimens were reared into adults while preserved specimens were processed for species identification. Five families, seven genera and nine species of flies were identified from human remains. The results of the study showed Chrysomya megacephala (Calliphoridae) maggots occurred on corpses with the highest frequency (70.6%), followed by Ch. rufifacies (Calliphoridae) (44.1%), sarcophagid fly (Sarcophagidae) (38.2%), Synthesiomya nudiseta (Muscidae) (20.6%), Megaselia scalaris (Phoridae) (14.7%), Lucilia cuprina (Calliphoridae) (5.9%), Ch. nigripes (Calliphoridae) (5.9%), Eristalis spp. (Syrphidae) (5.9%) and Hydrotaea spinigera (Muscidae) (2.9%). The greatest fly diversity occurred on remains recovered indoors (eight species) compared to outdoors (three species). Whilst, single and double infestations were common for both indoor and outdoor cases, multiple infestation of up to six species was observed in one of the indoor cases. Although large numbers of fly species were found on human remains, the predominant species were still those of Chrysomya, while S. nudiseta was found only on human remains recovered from indoors. The present study provides additional knowledge in the context of Malaysian forensic entomology and the distribution of forensically important flies which is of relevance to forensic science.