Traditionally it was thought that fitness-related traits such as male mating frequency, with a history of strong directional selection, should have little additive genetic variance and thus respond asymmetrically to bidirectional artificial selection. However, recent findings and theory suggest that a balance between selection for increased male mating frequency and opposing selection pressures on physiologically linked traits will cause male mating frequency to have high additive genetic variation and hence respond symmetrically to selection. We tested these hypotheses in the stalk-eyed fly, Cyrtodiopsis dalmanni, in which males hold harems comprising many females and so have the opportunity to mate at extremely high frequencies. We subjected male stalk-eyed flies to artificial selection for increased ('high') and decreased ('low') mating frequency in the presence of ecologically realistic, high numbers of females. High line males mated significantly more often than control or low line males. The direct response to selection was approximately symmetric in the high and low lines, revealing high additive genetic variation for, and no significant genetic constraints on, increased male mating frequency in C. dalmanni. In order to investigate trade-offs that might constrain male mating frequency under natural conditions we examined correlated responses to artificial selection. We measured accessory gland length, testis length and eyespan after 7 and 14 generations of selection. High line males had significantly larger accessory glands than low line males. No consistent correlated responses to selection were found in testis length or eyespan. Our results suggest that costs associated with the production and maintenance of large accessory glands, although yet to be identified, are likely to be a major constraint on mating frequency in natural populations of C. dalmanni.
The bee fly genus Euchariomyia Bigot is reviewed and new records from the Oriental Region are given. Five names (for four species-level taxa) have been associated with species in the genus. Examinations of types, as well as homotypic and topotypic specimens, shows all five names to belong to a highly variable single species, Euchariomyia dives Bigot. The following species are here shown to be the same as Euchariomyia dives Bigot: Bombylius pulchellus Wulp, 1880, Bombylius scintillans Brunetti, 1909, and Bombylius brunettii Senior-White, 1922, n. syn. The genus is known primarily from the southern and eastern Oriental Region and ranges into the Palaearctic in eastern China. We extend the distribution of the genus with new records in the southeastern Oriental Region [Indonesia (Sumatra), Laos, Peninsular Malaysia, and Vietnam].
Matched MeSH terms: Diptera/anatomy & histology; Diptera/classification*; Diptera/growth & development
In a forensic acarology study, conducted in a secondary forest of Forensic Science Simulation Site, Universiti Kebangsaan
Malaysia (UKM) in Bangi, Selangor, six carcasses consisted of three monkeys and three rabbits were placed individually
in steel enclosures and observed for 35 days. The carcasses, the soil beneath them and pitfall traps were checked daily
for insects and mites. A species of mesostigmatid mite, Macrocheles scutatiformis was discovered and this is a first time
reported in Malaysia. There are about 94.0% of Macrocheles present inside the cages of the monkey and rabbit carcasses.
Most mites in this study were collected from soil beneath the carcasses, on a dung beetle and a Chrysomya rufifacies
larva. Our findings showed that M. scutatiformis have a potential role in forensic investigation involving dead animals
perhaps corpses especially during the dry stage of decomposition.
In addition to causing myiasis in humans, Megaselia spiracularis Schmitz has also been reported as a forensically important fly. In this study, we presented the morphology of all larval instars and puparium of M. spiracularis using scanning electron microscopy. The first instar larva was composed of 12 segments. Antennae and maxillary palp complex were visible. Two spiracular slits could be seen at the posterior spiracle. The branch of posterior spiracular hairs was approximately equal to the palm-formed base in length. Second and third larval instars were very similar to first instar, except for the presence of anterior spiracle. The labium of the second instar larva was triangular and ventrally curved, whereas it was a bilobed structure and the tip forked in the first instar. The bubble membrance comprised of ≈40 globules presented at the third instar larvae. Puparia showed a retracted cephalic region and a pair of pupal respiratory horns on the dorsum. A comparison of the morphological features between immature stages of M. spiracularis and M. scalaris, a forensically important fly indoors in Germany, Malaysia, and China, was discussed.
Chrysomya bezziana is an obligate, myiasis-causing fly in humans and warm-blooded animals throughout the tropical and subtropical Old World. We report a case of cutaneous myiasis due to C. bezziana in a dog from Guangxi province in China. A total of 35 maggots were removed from the lesions. Direct sequencing of the mitochondrial cytochrome b gene showed that the specimen belonged to haplotype CB_bezz02, which was previously reported in Malaysia and the Gulf region. This paper also reviews reported cases of screwworm myiasis from humans and animals in China. Geographical records indicate that the distribution of C. bezziana is expanding, suggesting that an integrated pest management control should be taken into consideration in China.
Innovative solutions are needed to limit environmental effect and optimise resource use as food waste generation rises worldwide. This study investigates the potential of upcycling food waste from fresh markets using Black Soldier Fly (Hermetia illucens) larvae (BSFL) as a sustainable approach. This study explored four fresh market food waste substrates for BSFL bioconversion: discarded fish waste (FI), slaughtered chicken waste (CHI), vegetable waste (VEG), and a 1:1:1 combination of all three (MIX). Soybean curd residue (SCR) was treated as the control substrate. The effects on larval growth, nutritional content, and waste bioconversion rates were examined. The larvae growth rate was strongly impacted by waste type, with BSF-fed CHI and MIX gaining 18.0 and 16.7 mg/d, respectively, followed by BSF-fed with SCR (12.2 mg/d), FI (8.9 mg/d) and VEG (7.6 mg/d). The waste type did not substantially alter BSFL length. The survival rate of the BSFL fed with the food waste studied ranges from 95 to 98.47%, with SCR being the highest. Our findings indicated that BSFL can effectively convert a variety of fresh market food waste into valuable biomass. CHI waste produced the highest larval biomass and bioconversion rate followed by MIX, SCR, FI and VEG. The different waste stream has a major influence on BSFL biomass nutrition. BSFL nutritional composition is independent of the substrate's nutritional content, indicating no direct correlation between substrate and BSFL biomass nutritional composition. SCR waste produced the highest protein content of BSFL (50.49%), followed by VEG (32.61%), MIX (32.57%), FI (31.03%) and CHI (29.06%). SCR waste also produced BSFL biomass with lowest lipid content (26.55%) compared to other waste which resulted into BSFL with lipid levels ranging from 42.92% to 53.72%. BSFL-fed with SCR is the most suitable to be used as an alternative animal's feed based on the protein and lipid levels, while defatting procedure is necessary for the other waste-fed BSFL to render it suitability as animal feed alternatives. Based on bioconversion rate, BSFL growth, and lipid content, the MIX and CHI waste might be viable substrates for future research.
Two new black fly species, Simulium (Gomphostilbia) brinchangense and S. (G.) tanahrataense, are described on the basis of reared adult females, males, pupae and larvae from Cameron's Highlands, Peninsular Malaysia. These new species are assigned to the asakoae species-group within Simulium (Gomphostilbia) and taxonomic notes are given to distinguish each new species from six known species in Malaysia. Revised keys to identify all 21 species including 13 species from other countries are provided for females, males, pupae and mature larvae. The species diversity of the asakoae species-group in Cameron's Highlands is briefly noted.
Two types of municipal solid waste (MSW), newly arrived and 2 weeks old, were sampled from a sanitary landfill in Pulau Pinang, Malaysia at a fortnightly interval and kept under field conditions for 2 weeks. A total of 480 kg of each type of MSW was sampled to study species composition and impact of delays in cover soil applications on filth fly emergence. Out of 960 kg of MSW sampled, 9.2 ± 0.5 flies emerged per kilogram. Weekly adult fly emergence rates of newly arrived and 2-week-old waste did not differ significantly and MSW remained suitable for fly breeding for up to 1 month. Eight species of flies emerged from the MSW: namely, Musca domestica, Musca sorbens, Synthesiomyia nudiseta, Hydrotaea chalcogaster, Chrysomya megacephala, Lucilia cuprina, Hemipyrellia ligurriens and Sarcophaga sp. Newly arrived waste was determined to be the main source for M. domestica, C. megacephala and L. cuprina in the landfill owing to significantly higher mean emergence compared with 2-week-old waste. Musca sorbens was found in newly arrived waste but not in 2-week-old waste, suggesting that the species was able to survive transportation to landfill but unable to survive landfill conditions. Hemipyrellia ligurriens, H. chalcogaster and S. nudiseta were not imported into the landfill with MSW and pre-existing flies in and around the landfill itself may be their source. The results show that landfills can be a major source of fly breeding if cover soil or temporary cover is not applied daily or on a regular schedule.
Riparian areas hold vast number of flora and fauna with exceptional contributions to the ecosystem. A study was conducted in Sungai Sepetang, Sungai Rembau and Sungai Chukai to identify the insect community in a riparian zone of Peninsular Malaysia. Sampling was conducted in six consecutive months from December 2017 to May 2018 during both day and night using sweep nets. Twenty sampling stations (S1-S20) had been assembled along the riverbanks with an average distance of 200 m between each station. The 17,530 collected insects were from 11 orders and consisted of Diptera, Coleoptera, Hemiptera, Hymenoptera, Lepidoptera, Neuroptera, Orthoptera, Blattodea, Thysanoptera, Mantodea and Odonata. The three most abundant orders were Diptera (33.84%; 5933 individuals), Coleoptera (28.82%; 5053 individuals) and Hemiptera (25.62%: 4491 individuals). The collected insect community consisted of different guilds such as the scavenger, predator, herbivore, pollinator and parasitoid. Sungai Sepetang and Sungai Rembau were dominated by mangrove flora, Sonneratia caseolaris (Myrtales: Lythraceae), while Sungai Chukai was dominated by Barringtonia racemosa. There was a significant difference (p < 0.05) in the composition of insects between the three rivers though clustering analysis showed that the insect communities in Sungai Sepetang and Sungai Rembau were 100% similar compared to Sungai Chukai which consisted of a totally different community. There is a significant negative correlation between abundance of insects with salinity and wind speed at Sungai Chukai and Sungai Sepetang.
The stages of decomposition and the faunal succession on rabbit carcasses in three different habitats, namely jungle, rural, and highland areas, were studied. Three New Zealand White rabbit (Oryctolagus cuniculus) carcasses weighing ∼2 kg were sampled daily until the decomposition process was completed. Representative specimens of adult flies, larvae, pupa, and mites were collected from the carcasses and processed in the laboratory. There were differences in decomposition rate and faunal succession between the carcasses. The fastest rate of decomposition was recorded in rural area, and the slowest rate of decomposition was recorded in highland area. The carcasses exhibited the same pattern of colonization by adult flies, but the dominant species of larvae and adult flies on each carcass in specific habitats were different. The primary species of flies recorded in jungle were Chrysomya megacephala F., Chrysomya rufifacies (Macquart), Chrysomya chani Kurahashi, Chrysomya villenuevi Patton, Chrysomya nigripes Aubertin, Chrysomya pinguis (Walker), Hemipyrellia ligurriens (Wiedemann), Hemipyrellia tagaliana (Bigot), Hypopyiopsis fumipennis (Walker), Hypopygiopsis violacea (Macquart), and Hydrotaea spinigera Stein represented by both adults and larvae. Musca domestica L., Atherigona sp., Lioproctia pattoni (Senior-White), Lioproctia saprianovae Pape & Bänziger, and Seniorwhitea princeps (Wiedemann) were represented by adults only. The biodiversity of flies in the rural area were C. megacephala, C. rufifacies, H. ligurriens, Fannia canicularis L., Hydrotaea chalcogaster (Wiedemann), and Hyd. spinigera represented by both adults and larvae, meanwhile M. domestica, Atherigona sp., Boettcherisca peregrina (Robineau-Desvoidy), Parasarcophaga taenionota Wiedemann, Parasarcophaga scopariiformis Senior-White, and S. princeps were represented by adults only. The species of flies collected in the highland area were Lucilia porphyrina (Walker), C. megacephala, C. rufifacies, C. villenuevi, C. pinguis, H. ligurriens, Hyd. spinigera, Hyd. chalcogaster, F. canicularis, and Boettcherisca highlandica Kurahashi & Tan represented by both adults and larvae, whereas C. nigripes, Chrysomya thanomthini Kurahashi & Tumrasvin, M. domestica, Atherigona sp., Parasarcophaga albiceps Meigen, P. taenionota, Sepsidae, Phoridae, and Millichidae were represented by adults only. Faunal succession followed the sequence of dominant flies, i.e., Calliphoridae, Sarcophagidae, Muscidae, Sepsidae, and lastly Stratiomyidae for jungle, or Sepsidae for rural and highland studies. Mites, from suborders Mesostigmata, Prostigmata, Astigmatina, and Oribatida, were also recovered throughout decomposition, which could be used for future implementation in forensic investigations. The data obtained from this study could provide more accurate indicators for local forensic scientists in solving criminal cases especially on the determination of time and primary location of death.
Meliponiculture, the keeping of domesticated stingless bees such as Geniotrigona thoracica (Smith, 1857) (Hymenoptera: Apidae), is an increasingly popular agricultural industry in Malaysia. This study reports the soldier fly (Diptera: Stratiomyidae) species of the genus Hermetia colonizing stingless bee colonies in Malaysia. The larvae were reared in the laboratory to the adult stage and identified through molecular and morphological approaches. Hermetia illucens (Linnaeus, 1758) and Hermetia fenestrata de Meijere, 1904 (Diptera: Stratiomyidae) were identified from the sample provided. Earlier records of stratiomyids in stingless bee nests were misidentified as H. illucens. This paper represents the first identified record of H. fenestrata colonizing a "spoiled" stingless bee colony. In addition, adult and larval morphological differences between both species and the roles of both species in bee nest decomposition are discussed.
INTRODUCTION: Psychoda sp. is often collected from patchy habitats such as sewers, drains and decomposing organic matters. The discovery of Psychoda sp. in forensic studies indicated that it might have noteworthy value in assisting death investigations.
PURPOSE: This study reports on the first finding of Psychoda larvae collected from decomposing rabbit carcasses placed in Cameron Highlands, Pahang, Malaysia.
METHODS: The larvae were first observed on rabbit carcasses and were collected using tweezers and carefully preserved in 70% ethanol. They were subsequently mounted on microscopy slides using Hoyer's medium and identified as Psychoda sp. morphologically. The identification was also confirmed through a DNA barcoding analysis.
RESULTS: Psychoda sp. larvae were collected on day-10 post-mortem where the rabbit carcasses were at the advanced decay stage of decomposition. The cytochrome c oxidase I (COI) gene sequences of the larvae had 90% similarity with the Psychoda spp. in the database.
CONCLUSION: The finding of these larvae on carrion may provide additional valuable insights into forensic entomology and may assist in death investigations.
This case study reports on two unrecorded Coleopteran species found together on a human corpse in Malaysia. The mummified human remains were discovered in a house in Selangor, Malaysia. The pathologist confirmed that the death was due to a traumatic chest injury. Maggots, beetles, and fly pupal casings were found mainly on the front part of the body. Empty puparia of Diptera were collected during the autopsy and identified later as the muscid Synthesiomyia nudiseta (van der Wulp, 1883) (Diptera: Muscidae). Also, the insect evidence received included larvae and pupae of Megaselia sp. (Diptera: Phoridae). According to the insect development data, the minimum postmortem period was estimated by the time to reach the pupal developmental stage (in days). The entomological evidence included the first record of Dermestes maculatus De Geer, 1774 (Coleoptera: Dermestidae) and Necrobia rufipes (Fabricius, 1781) (Coleoptera: Cleridae), which have not previously been recorded on human remains in Malaysia.
A partially skeletonized human corpse was found in bushes in Selangor, Malaysia in June 2020. Entomological evidence was collected during the autopsy and sent to the Department of Medical Microbiology and Parasitology, Faculty of Medicine, Universiti Teknologi MARA (UiTM) for minimum postmortem interval (PMImin) analysis. Standard protocols were applied when processing preserved and live insect specimens of both larval and pupal stages. Entomological evidence revealed that the corpse was colonized by Chrysomya nigripes Aubertin, 1932 (Diptera: Calliphoridae) and Diamesus osculans (Vigors, 1825) (Coleoptera: Silphidae). Chrysomya nigripes was chosen as the PMImin indicator as this fly species is an earlier colonizer compared to D. osculans beetle larvae which their presence is the indicative of late stage of decomposition. For the present case, the pupae of C. nigripes were the oldest insect evidence collected and based on the available developmental data, the estimated minimum PMI was established between 9 and 12 days. It is noteworthy to highlight that this is the first record of D. osculans colonization on a human corpse.
The estimation of the postmortem interval (PMI) is an essential information in death investigations. It is necessary to know the developmental data of the most important necrophagous insect species in every geographical area. Chrysomya megacephala (Fabricius, 1794) (Diptera: Calliphoridae) is one of the most common species associated with human body decomposition, especially in the tropics, so a precise knowledge of its life cycle is crucial. However, despite its ubiquity, developmental data in a range of tropical temperatures is scarce. For this reason, the aim of this study is to provide the developmental data of the blowfly, C. megacephala, in a range of tropical temperatures and to apply these data in forensic entomology. Four temperatures were examined (i.e., 27.0°C 29.5°C, 32.0°C and 34.5°C) and the time of developments from egg to adult were recorded. To build the growth curves, five larvae per day were measured with a digital caliper. Accumulated degree-days were calculated and the isomorphen diagram for this species was plotted. As we predicted, the results showed that the life cycle of this species was affected by the increasing temperature. The implications of these new data for determining the minimum PMI in forensic entomology were discussed.
The role of some adult flies (Diptera: Cyclorrhapha) as carriers of helminth parasites of man was studied at four sites in Malaysia: a refuse dump, where no helminth-positive flies were detected, and in three peri-domestic situations where four species of flies carried up to three types of nematodes. The dominant fly species Chrysomya megacephala (Fabricius) carried eggs of the roundworm Ascaris lumbricoides L., the pinworm Trichuris trichiura (L.) and hookworm on the adult external body surface and in the gut lumen, in association with Bukit Lanjan aborigines. Chrysomya rufifacies (Macquart) and Sarcophaga spp. also had Ascaris lumbricoides and Trichurus trichiura eggs in their gut contents. Human helminths were not recovered from Lispe leucospila (Wiedemann), Lucilia cuprina (Wiedemann) or the housefly Musca domestica L. In an urban slum area of Kuala Lumpur city, filariform larvae identified as the hookworm Necator americanus (Stiles) occurred in the intestines of the face-fly Musca sorbens Wiedemann (22 larvae per 100 flies) and of Chrysomya megacephala (4.5 larvae per 100 flies). This concentration of apparently infective N. americanus in M. sorbens, a fly which often breeds in faeces and browses on human skin, could have transmission potential.
Horse flies (Diptera: Tabanidae) are of medical and veterinary importance, as their blood-sucking feeding habit enables them to transmit several disease-causing agents. In Malaysia, the family Tabanidae consists of 120 species belonging to eight genera. The current study describes two new species (Chrysops idlani sp. nov. and Tabanus ekor sp. nov.) and presents new records for seven species: Tabanus fontinalisSchuurmans Stekhoven, 1926; Tabanus fuscifronsSchuurmans Stekhoven, 1926, Tabanus latifasciesSchuurmans Stekhoven, 1926, Tabanus megalops (Walker, 1854), Tabanus rhinargusPhilip, 1962, Tabanus salvazai (Surcouf, 1922), and Tabanus tristisWulp, 1881. Complete descriptions and illustrations are provided for the new species, and species variations for the new records are discussed. Male Tabanus latifasciesSchuurmans Stekhoven, 1926 and Tabanus perakiensis Ricardo, 1911 are thoroughly described herein.
Long columns of migrating larval sciarid armyworms were discovered in central and northern Japan, specifically Kanagawa, Gunma, Miyagi and Akita prefectures, as well as Hokkaido. This is the first examination of armyworms in East Asia. In Europe, armyworms have been identified as Sciara militaris, belonging to the family Sciaridae (sciarid flies or black fungus gnats), by rearing them to adulthood. In Japan, we were unable to obtain live samples for rearing; therefore, DNA barcodes were obtained from the samples of armyworms collected in the Gunma and Miyagi prefectures. The DNA barcodes were compared with those obtained from the following samples: pupae of S. militaris from UK, adults of Sciara kitakamiensis, Sciara humeralis, Sciara hemerobioides, Sciara thoracica, Sciara helvola and Sciara melanostyla from Japan, and adults of one undescribed Sciara species from Malaysia. Neighbour-joining, maximum parsimony, and maximum likelihood analyses revealed that the armyworms discovered in Japan are S. kitakamiensis. Although adults of this species have been recorded in several locations in Japan, this is the first report of migrating larval armyworms. DNA barcodes were effectively used to link different life stages of this species. The average intraspecific and interspecific pairwise genetic distances of the genus Sciara were 0.3% and 12.6%, respectively. The present study illustrates that DNA barcodes are an effective means of identifying sciarid flies in Japan.
This study investigated the influence of paraquat, a prevalent poison used by suicides, on initial oviposition and development of Chrysomya megacephala (Fabricius) using minced-beef substrates. Paraquat in lethal dose for human (40 mg/kg), two times the lethal dose (80 mg/kg) and five times the lethal dose (200 mg/kg) were mixed thoroughly with respective minced-beef substrates (1 kg each) that were decomposed in a shaded habitat fully protected from rain. Results of four replications of the above experiment revealed that the presence of paraquat neither delayed initial oviposition nor prolonged the developmental stages of C. megacephala. Therefore, estimation of postmortem interval (PMI) based on empirical baseline data obtained using animal models devoid of any poisons would still be appropriate for estimating PMI in paraquat-related deaths.
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.