This paper reports the infestation of psocid, Liposcelis bostrychophila Badonnel (Psocoptera: Liposcelidae) in the insect museum at Medical Entomology Unit, Institute for Medical Research, Kuala Lumpur. These tiny organisms were recognised as museum insect pest and found frequently in the insect boxes containing mosquitoes, flies, cockroaches and butterflies. They feed on dead insect specimens and cause severe physical damages to the valuable reference specimens collected in the early 20th century. Hence, it is important to control their population immediately to prevent them from causing further deterioration to the museum collection.
This study was carried out in an oil palm plantation in Tanjung Sepat, Selangor in September 2007 by using pigs (Sus scrofa L.) as a carcass model in a forensic entomological research. A 2.5 month old pig (10 kg) which died naturally was hanged on a palm tree to observe the insect succession and decomposition stages. Observation was made for 16 days; one afternoon visit per day and all climatological data were recorded. On the first day, adult muscids of Ophyra spinigera Stein and Musca domestica L. were observed, however no blowfly (Calliphoridae) activities were sighted. Fly eggs wer seen on the second day on both sides of the face, inside nostrils and genitourinary area. Adults of Chrysomya megacephala Fabricius and Chrysomya rufifacies (Macquart) congregated on the head and anal areas. Adult flies and maggots (first and second instars) were observed in the mouth and anus of the pig on the third day of hanging. Adult yellow jackets (Vespidae) and spiders (Arachnida) were found preying on some adult flies. Rove beetles (Staphilinidae) were also discovered on the pig carcass. Only a few ants (Formicidae) were sighted. Maggot masses were found in eye orbits, neck, and genital organs on the fourth day of hanging and some maggots were seen falling down to the ground. The dominant maggot species identified on this day was Ch. megacephala. On the sixth day, the head, neck, and anus were in the stage of active decay. Maggots of Ch. rufifacies were abundant on the seventh day and was the dominant species. On day eight the carcass fell onto the ground. Chrysomya rufifacies maggots were found underneath the pig carcass and they started to migrate and pupated under the soil. On the tenth day, third instar Op. spinigera maggots were found under the carcass. The rate of carcass decomposition slowed down and became stable from tenth day onwards to the sixteenth day of decomposition. Thereafter, most of the remaining parts of the body remained dried and devoid of any insects.
The likelihood of dipteran maggots colonizing a corpse due to nocturnal oviposition can be used to challenge the postmortem interval (PMI) estimated assuming diurnal oviposition. Earlier experiments tested nocturnal oviposition behavior by exposing fresh baits once during a single night. In this pilot study, oviposition behavior was studied using beef baits, which, simulating the decay of the body seen in case situations, decomposed inside cages designed to open and close at scheduled intervals during consecutive night or twilight periods. Freshly hatched maggots from diurnally oviposited eggs emerged in control baits on the third day, while a limited number of maggots attributable to nocturnal or twilight oviposition were observed in experimental baits only on the fifth or sixth day, indicating a categorical delay. These results suggest that such delayed and limited nocturnal oviposition is not forensically significant since the larger maggots deriving from diurnal oviposition would be the ones considered when estimating PMI.
This study was carried out in an oil palm plantation in Bandar Baharu, Kedah using monkey carcasses and focuses in documenting the decomposition and dipteran colonization sequences in 50 days. This is the first study of Diptera associated with the exploitation of carcasses conducted in the north of peninsular Malaysia during the dry and wet seasons thereat. During the process of decomposition in both seasons, five phases of decay were recognized namely fresh, bloated, active decay, advance decay and dry remain. In this decomposition study, biomass loss of carcass occurred rapidly during the fresh to active decay stage due to the colonization and feeding activity of the Diptera larvae. The duration of the fresh and bloated stages of decay were the same in wet and dry seasons but later stages of decay were markedly shorter during the wet season. Twenty one species of adult Diptera were identified colonizing carcasses in the study period. Among the flies from the family Calliphoridae, Chrysomya megacephala Fabricius and Chrysomya nigripes Aubertin were recognized as the earliest arrivals on the first day of exposure. Adult Ch. nigripes was abundant for approximately two weeks after placement of the carcasses. By comparing the percentages of adults collected during the study period, the calliphorids abundance in percentages in wet season was 50.83%, but in dry season, the abundance was only about 35.2%. In contrast, the percentage of Sphaeroceridae in wet season was only 3.33%, but in the dry season, the abundance was 20.8%. Dipteran in family Phoridae, Piophilidae, Sepsidae, Drosophilidae and Dolichopodidae colonized the carcasses for a long period of time and were categorized as long term colonizers.
Signal fly, Scholastes sp. (Diptera: Platystomatidae) was observed associated with animal carcasses in Malaysia. The first observation was on a monkey carcass, which was killed by using a handgun and immediately placed in a forested area in Gombak, Selangor while the second observation was on a pig that died of natural causes and whose carcass was placed in an oil palm plantation in Tanjung Sepat, Selangor. Both animal carcasses were visited by Scholastes sp. flies during the fresh decomposition period. However, the role Scholastes flies in the decomposition process remains unknown. In this paper, we report the occurrence of Scholastes sp. on animal carcasses in Malaysia for the first time.
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.
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.
Piophila casei (Linnaeus) (Diptera: Piophilidae) is reported from human cadavers in two separate forensic cases for the first time in Malaysia. Both bodies were found indoors. The first case, was that of a male of unknown nationality and age and also contained maggots of the muscid Ophyra spinigera (Stein). The second case was a female Chinese whose body also contained other species of maggots but these were not identifiable.
During a forensic entomological study conducted in a palm oil plantation in Tg.Sepat, Selangor in September 2007, a spider (Arachnida), Oxyopes sp. (Oxyopidae) was found to predate on a calliphorid fly (Chrysomya rufifacies). The female spider laid a silk thread, or "drag line", behind it as it moved. This spider bites its prey by using a pairs of chelicerae, and injecting venom into the fly. The fly was moving its wing trying to escape, however, it succumbed to the deadly bite.
This entomological study was conducted in a man-made freshwater pond in a palm oil plantation in Tanjung Sepat, Selangor from 23 July 2007 by using pig (Sus scrofa) as a carcass model. A 1.5 month old piglet (5 kg), which died of asphyxia after being accidentally crushed by its mother, was thrown into a pond. Observation was made for ten days; one visit per day and climatological data were recorded. On the first two days, the piglet carcass sunk to the bottom of the pond. The carcass floated to the surface on the third day but no fly activities were seen. The blow fly, Chrysomya megacephala and Chrysomya rufifacies started to oviposit on the fourth day. Other than adult flies, a spider (Arachnida) was also observed on the carcass. Bubbles accumulated at the mouthpart, and the abdomen was greenish black. A lot of blow fly eggs were seen on the body surface on the fifth day (floating decay), along with first and second instars C. megacephala crawling under the piglet's skin. On the sixth day, adult blow fly, C. megacephala,and C. rufifacies,and muscid flies, Ophyra spinigera and Musca domestica were observed on to the carcass. High numbers of first and second instars of flies were observed wandering around the body surface with C. megacephala larvae being the predominant species. Two prominent maggot masses occurred on seventh and eighth days. Bloated deterioration stage began on day eighth exposing rib bones, humerus bones and intestines. Carcass was partially sinking and the maggot masses were at the water level. On day ninth, the carcass was partially sinking and three maggot masses were observed on the exposed surface. There were very few adult flies, including a scarab beetle was sighted on the carcass at this stage. The carcass along with the maggots sunk on day tenth, leaving an oily layer on the water surface.
Analysis on fly artifacts produced by forensically important blowfly, Chrysomya megacephala (Fabricius) (Diptera:Calliphoridae), revealed several unique patterns. They can be divided into fecal spots, regurgitation spots and swiping stains. The characteristics of fecal spots are round with three distinct levels of pigmentation; creamy, brownish and darkly pigmented. Matrix of the spots appears cloudy. The round spots are symmetrical and non-symmetrical, delineated by irregular and darker perimeter which only visible in fairly colored fecal spots. Diameter of these artifacts ranged from 0.5 mm to 4 mm. Vomit or regurgitation spots are determined by the presence of craters due to sucking activity of blowflies and surrounded by thickly raised and darker colored perimeter. The size of these specks ranged from 1 mm to 2 mm. Matrix of the spots displays irregular surface and reflective under auxiliary microscope light. Swiping stains due to defecation by flies consists of two distinguishable segments, the body and tail. It can be seen as a tear drop-like, sperm-like, snake-like and irregular tadpole-like stain. The direction of body and tail is inconsistent and length ranged between 4.8 mm to 9.2 mm. A finding that should be highlighted in this observation is the presence of crater on tadpole-like swiping stain which is apparent by its raised border characteristic and reflective under auxiliary microscope light. The directionality of this darkly brown stain is random. This unique mix of regurgitation and swiping stain has never been reported before. Highlighting the features of artifacts produced by flies would hopefully add our understanding in differentiating them from blood spatters produced from victims at crime scenes.
This preliminary study was carried out in a palm oil plantation in Tanjung Sepat, Selangor in 17 May 2007 by using pig (Sus scrofa) as a carcass model in forensic entomological research. A 3 month old pig (8.5 kg) that died of pneumonio was placed in the field to observe the decomposition stages and the fauna succession of forensically important flies. Observation was made for two weeks; two visits per day and all climatological data were recorded. The first visitor to the pig carcass was a muscid fly, seen within a minute, and followed by ants and spiders. Within half an hour, calliphorid flies came over. On the second day (fresh), few calliphorid and sarcophagid flies were found on the carcass. Two different species of moths were trapped in the hanging net. The first larva mass occurred on the third day (bloated) around the mouthpart, with some L1 and L2 found in the eyes. Reduvid bugs and Staphylinidae beetles were recovered on the fourth day (active decay), and new maggot masses occurred in the eyes and anus. L3 larvae could be found beneath the pig carcass on the fourth day. On the fifth day (active decay), new maggot masses were found on neck, thorax, and hind legs. Advance decay occurred on the sixth day with abundant maggots covering all over the body. The main adult fly population was Chrysomya megacephala (day 2 to day 6), but the larvae population was mainly those of Chrysomya rufifacies (day 4 to day 14). The dry stage began on the eighth day. Hermetia illucens adult was caught on day-13, and a larvae mass of Chrysomya rufifacies was seen burrowing under the soil. This forensic entomological research using pig carcass model was the first record in this country.
Forensic entomological specimens received by the Unit of Medical Entomology, IMR., from hospitals and the police in Malaysia in the last 3 decades (1972 - 2002) are reviewed. A total of 448 specimens were received. From these, 538 identifications were made with the following results: Eighteen species of cyclorrphaga flies were identified consisting of Chrysomya megacephala (Fabricius) 215 cases (47.99%), Ch. rufifacies (Masquart) 132 (29.46%), Ch. villeneuvi Patton 10 (2.23%), Ch. nigripes Aubertin 7 (1.56%), Ch. bezziana Villeneuve 4 (0.89%), Ch. pinguis (Walker) 1 (0.22%), Chrysomya sp. 47 (10.49%), Sarcophaga sp. 28 (6.25%), Lucilia sp. 21 (4.69%), Hermetia sp. 15 (3.35%), He. illucens (Linnaeus) 1 (0.22%), Hemipyrellia ligurriens (Wiedemann) 3 (0.67%), Hemipyrellia sp. 2 (0.45%), Ophyra spinigera 1 (0.22%), Ophyra sp. 6 (1.34%), Calliphora sp. 24 (5.36%), Synthesiomyia nudiseta (Wulp) 1 (0.22%) and Eristalis sp. 1 (0.22%). Other non - fly insect specimens are Pthirus pubis (Linnaeus) (Pubic louse) 2 (0.45%) and Coleoptera (Beetles) 1 (0.22%). Ch. megacephala and Ch. rufifacies were the commonest species found in cadavers from different ecological habitats. Sy. nudiseta is an uncommon species, thus far found only on cadavers from indoors. Sy. nudiseta is reported for the second time in Peninsular Malaysia. A total of 329 cases (73.44%) had a single fly infestation, 109 cases (24.33%) had double fly infestation and 10 cases (2.23%) had triple fly infestation. Five cases (1.12%) had eggs and 3 cases (0.67%) had larval stages that were not identifiable. No arthropods were retrieved from cadavers in 8 cases (1.79%). In conclusion, although large number of fly species were found on human cadavers, the predominant species are still those of Chrysomya.
Establishing time of death has been extensively studied for the last 30 years. Parameters that have been studied included body temperature, biochemistry of rigor mortis, putrefactive changes and entomology. Despite an extensive study in these parameters it was found that all of the parameters were very much dependent on external factors like changes in surrounding temperature and activities done prior to death. To solve this problem, we decided to monitor the mechanism that occurs during death. Until now, various researches have found that during the early stage of death, heart and perfusion to the cells will stop. This will cause the cells to start the death process. The death of the cell will occurs either through apoptosis or necrosis. During apoptosis the cells will switch on and off a few proteins in a sequence. Based on this understanding, a study was conducted to determine if area ratio of apoptosis: necrosis and apoptotic p53 and Bcl-2 markers can be used as a reliable postmortem interval marker (PMI). Sampling of the study had involved 100 dead human skins with a known PMI. All samples were obtained from forensic unit of Hospital Kuala Lumpur (UFHKL). Ratio of apoptosis: necrosis areas were determined using hematoxilin and eosin staining while apoptosis p53 and Bcl-2 markers were done using an apoptosis kit. All staining were then indexed and plotted against PMI data obtained from UFHKL. Results indicated that there were no significant correlations between ratio of apoptosis: necrosis area against PMI (p = 0.144). Whereas for both apoptotic markers p53 and Bcl-2 PMI had shown a significant correlation (p < 0.000 for both results). In conclusion, we suggest that p53 and Bcl-2 parameters should be studied further since it is very likely that it could be a good indicator for PMI.
Collections of adult anopheline mosquitos were made from a cow-baited trap in nine coastal villages located along nearly 160km of northwest peninsular Malaysia. Two collections, separated by 1.5 to 6 months, were made at each site. Nearly 6,000 anophelines of 19 species were collected. The dominant species were Anopheles peditaeniatus. An. sinensis, An. subpictus and An. lesteri paraliae. Small numbers of the malaria vectors An. maculatus (at one site) and An. campestris (at four sites) were collected, but no An. sundaicus were recorded.
In a coastal village in northwest Malaysia, 3231 fed Anopheles females of eight to 10 species were collected, marked with fluorescent dust, and released on three consecutive nights. In collections made on the 10 nights after the first release, 58 mosquitoes of three species, An. lesteri paraliae, An. subpictus and An. vagus, were recaptured; the recapture rates were 3.42%, 1.19% and 0.97%, respectively. The data for An. subpictus and An. vagus were insufficient for further analysis. Those for An. l. paraliae were plotted against time of recapture and, from the regression coefficient, an estimate of 0.68 was obtained for the daily survival rate. An independent estimate based on the parous rate during the previous year was 0.55. The temporal distribution of the recaptures strongly suggested a gonotrophic cycle and oviposition cycle of two days.