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.
Matched MeSH terms: Pupa/drug effects; Pupa/growth & development
Natural peptides in insect vectors played an important role in the control of
pathogens. Musca domestica Linnaeus and Chrysomya megacephala Fabricius were
two species of local fly chosen to detect presence of antimicrobial peptide substance.
The screening of the antimicrobial activity was carried using a spectrophotometric
method. Results were obtained much quicker and less laborious. The results showed
larva hemolymph of M. domestica lysed Bacillus subtilis and two Gram negatives,
Escherichia coli and Pseudomona. aeruginosa. The pupae hemolymph only lysed E.
coli. Whereas, the hemolymph of C. megacephala larva showed bactericidal effect
against both of the Gram positives tested, i.e. B. subtilis and Staph. aureus. and no
effect was against the Gram negatives. The pupa showed lytic activity against Staph.
aureus and P. aeruginosa. As a conclusion, the larva and pupa hemolymph of M.
domestica and C. megacephala demonstrated antibacterial activity. However, larva
hemolymph of M. domestica and C. megacephala has broader antibacterial activity
against both Gram positive and negative bacteria.
This article presents characteristics of the habitats of Melitaea gina Higgins, 1941 and describes the behavior of adults under natural conditions, their host plant, egg chorion, caterpillars, and pupa morphology. The morphology of the early stages and the taxonomy of M. gina are discussed.
Species of the Simulium (Simulium) melanopus species-group in Sabah are taxonomically revised by examining type specimens of S. (S.) crassimanum S. (S.) laterale, and S. (S.) nigripilosum, all described from females by Edwards in 1933, and newly collected samples from the vicinity of Mt. Kinabalu. The females of these three species are redescribed, and their males and pupae are described for the first time based on adults reared from pupae. Simulium (S.) liewi Takaoka, 2007 and S. (S.) kinabaluense Smart & Clifford, 1969 are synonymized with S. (S.) crassimanum and S. (S.) laterale, respectively. Simulium (S.) cheedhangi Takaoka, Sofian-Azirun & Ya'cob, 2015 is newly recorded from Sabah. Two new related species, S. (S.) lardizabalae and S. (S.) timpohonense, are described from males reared from pupae. Keys to identify eight species of the S. melanopus species-group in Sabah are provided for females, males, pupae and mature larvae.
The effects of four temperatures (15, 23.5, 28, and 35 degrees C) on the biological characteristics of the rove beetle Paederus fuscipes Curtis were studied, and its cuticular permeability also was measured. Specimens successfully developed to adulthood at each temperature tested, but development time of each preadult stage significantly decreased with increasing temperature. Both egg and L1 stages required at least 80 degree days above a threshold of approximately 10 degrees C to develop to the subsequent stage. The lengthy development time and high survival rate of preadults at 15 degrees C suggests that P. fuscipes can survive in a harsh environment during cold weather by hibernating, and this ability could allow preadults to succeed ecologically in temperate countries. However, adult longevity was short, and no fecundity was recorded at 15 degrees C. At 28 degrees C, P. fuscipes exhibited a high survival rate of adults, which had a longer life span and high fecundity; thus, the population had the highest intrinsic rate of increase (0.0788 +/- 0.0051 d(-1)) and the shortest mean generation time (48.57 +/- 1.43 d) at 28 degrees C. At this temperature, the population might reach a size that could facilitate invasion into residential areas. However, in the absence of a hygric environment, P. fuscipes was unable to survive despite favorable temperature. Unlike in adults and pupae, high cuticular permeability values were found in the larval stages. This indicates that larvae are highly susceptible to desiccation, and it explains why the distribution of P. fuscipes is restricted to moist habitats.
The effects of eight diets (atta flour, wheat flour, self-rising flour, rice flour, custard powder, corn flour, tapioca starch, and potato starch) on the development of the red flour beetle, Tribolium castaneum (Herbst), reared at 29-31 degrees C and 66-70% RH were assessed. Five pairs of male and female T. castaneum were reared on the respective diets for 28 d before the experimental setup was dismantled and adult counts were recorded. In another experiment, the insects were allowed to mate and oviposit in each flour or starch type over a period of 7 d before being removed. The counting of pupae and adult emergence began on the day of emergence and was continued on a daily basis until day 140. Proximate analysis was performed for chemical composition of each diet, and the numbers of new adults that developed were found to be positively correlated (r2 = 0.97; P < 0.05) with the protein content and negatively correlated (r2 = 0.93; P < 0.05) with the carbohydrate content. For T. castaneum, the suitable diets were ranked as follows: atta flour > wheat flour > self-rising flour > rice flour > custard powder > corn flour > tapioca starch > potato starch. T. castaneum larval development to the pupal and adult stages developed significantly faster in atta flour (P < 0.05) than in the other diets, and the greatest number of progeny was produced from beetles reared on atta flour. Fewer adults emerged from wheat flour, self-rising flour, and rice flour, and no new emergences were recorded for the remaining diets. Developmental rate was much slower in beetles reared on diets in which a low number in progeny was produced. These data illustrate that different diets can influence the sustainability of these insects and affect their development and growth.
The presence of predators can have dramatic consequences on prey communities, not only by the direct effects of consumption but also through sublethal effects. We investigated the survival rate and subsequent life history of the mosquito Culex pervigilans Bergroth under the influence of its major predator, the backswimmer Anisops wakefieldi White. We established a field experiment with various treatments: 1) control without predators, 2) free-roaming A. wakefieldi (with one, three, or nine A. wakefieldi per container), 3) caged A. wakefieldi (empty cage without predators, with one, three, or nine A. wakefieldi in each cage, and 4) A. wakefieldi cues (with cues concentrations of one, three, or nine A. wakefieldi). Cx. pervigilans eggs were then taken from these four experimental treatments and reared in two different laboratory conditions: 1) in clean water without any traces of predators, or 2) in water with the same treatments as in field. The survival rate of Cx. pervigilans was significantly reduced by the presence of predators or their cues. Even after a brief exposure to waters containing predators or residual cues, the subsequent progeny and the ontogeny of the remaining survivors were still affected. The percentage of eggs that hatched, and the resulting mosquito population, was influenced by the presence of predators or their cues. Our results suggest that sublethal effects may be carried by surviving individuals primarily through the effects of stress, perhaps by epigenetic mechanisms. We may expect to observe similar plasticity in species or populations with high temporal or spatial variability in predation.
Bactrocera carambolae is a highly polyphagous fruit pest of agricultural importance. This study reports the bacterial communities associated with the developmental stages of B. carambolae. The microbiota of the developmental stages were investigated by targeted 16S rRNA gene (V3-V4 region) sequencing using the Illumina MiSeq. At 97% similarity, there were 19 bacterial phyla and unassigned bacteria, comprising 39 classes, 86 orders, 159 families and 311 genera. The bacterial composition varied among the specimens of developmental stage and across developmental stages as well as exuviae. Four phyla of bacteria (with relative abundance of ≥1% in at least one specimen)-Actinobacteria, Bacteroidetes, Firmicutes and Proteobacteria-were recovered from the larva, pupa, adult stages and exuviae. Proteobacteria was the predominant phylum in all the developmental stages as well as the exuviae. Enterobacteriaceae (Proteobacteria) was the predominant family in the adult flies while the family [Weeksellaceae] (Bacteroidetes) was predominant in the larval and pupal stages. Among the genera occurring in more than one developmental stage of B. carambolae, Erwinia was more abundant in the larval stage, Halomonas more abundant in adult female, Stenotrophomonas more abundant in adult male, and Chryseobacterium more abundant in the larval and pupal stages. The results indicate transmission of bacteria OTUs from immatures to the newly emerged adults, and from exuviae to the environment.
Simulium (Gomphostilbia) laosense sp. nov. is described based on adults, pupae, and mature larvae from Laos. This new species is placed in the Simulium batoense species-group of the subgenus Gomphostilbia Enderlein. It is characterized by the pupal gill with eight filaments arranged as 3 + 3 + 2 from dorsal to ventral, of which an inner filament of the ventral pair is slightly longer than its counter filament, and is 1.7-1.8 times as long as filaments of the middle triplet. Taxonomic notes are provided to distinguish this new species from Simulium (G.) johorense Takaoka, Sofian-Azirun & Ya'cob from Peninsular Malaysia and four other related species. The phylogenetic position of this new species in the S. batoense species-group is also presented based on the mitochondrial COI gene. This new species represents the second species known from Laos.
To better understand the population dynamics and dispersal ability of insect species, it is often helpful to derive a life table containing fundamental demographic data. The aim of this study was to determine a life table for the predatory necrophagous species Synthesiomyia nudiseta (van der Wulp, 1883) on a pig liver diet and under controlled laboratory conditions (29.5 ± 2. 5°C, RH 50 ± 15%, and a photoperiod of 12:12). This species has medical and veterinary importance and its distribution extends in tropical and subtropical areas and now it has been established in the southwestern of Europe. The mean adult longevity was 36. 18 ± 2. 06 d and the net reproduction rate, R, was 27.65 offspring/female, the mean generation time, T, was 22. 09 d, the finite rate of increase, λ, was 1. 16 d-1, and the intrinsic rate of increase, r, was 0. 15 d-1. These results indicate that S. nudiseta cannot be considered an r-strategist as the most common synanthropic necrophagous blowflies due to its predatory behavior; however, its invasive and colonist abilities are discussed. This is the first life table study of this species from Palearctic region to analyze the effect of its dispersal ability.
The Malaysian fruit fly, Bactrocera latifrons (Hendel), is a pest of peppers (Capsicum spp.) in Thailand. A field trial was undertaken to determine whether five commonly used cultivars of C. annuum, with marked differences in morphology and pungency, varied in their susceptibility to infestation by B. latifrons. Experiments carried out in both the dry and rainy seasons showed temporal differences in the number of fruits per cultivar, but there was no effect of variety or season on the proportion of fruits attacked or the number of pupae obtained per infested fruit However, the number of dead larvae per infested fruit was significantly higher, and the percent of pupae giving rise to adults was lower for the larger sweet pepper than other cultivars tested.
Bemisia tabaci (Gennadius) merupakan spesies lalat putih utama dan berbahaya kepada pertanian. Kajian telah dijalankan di Stesen MARDI Jalan Kebun, Klang, Selangor dari 9 September 2006 hingga 11 November 2007. Objektif kajian ini adalah untuk menilai kesan populasi lalat putih terhadap tanaman cili yang diberi kadar nitrogen yang berbeza (0, 33, 43, 53 g/pokok). Keputusan kajian menunjukkan pokok cili yang dibaja dengan kadar nitrogen yang tinggi menyebabkan peningkatan yang bererti (P<0.05) kepada populasi B. tabaci peringkat belum matang berbanding pada pokok cili yang dibajakan nitrogen pada kadar rendah. Min bilangan B. tabaci pada peringkat belum matang per aras kanopi adalah berbeza secara signifikan (P<0.05) antara aras kanopi dan antara perlakuan. Secara amnya, min bilangan telur dan larva B. tabaci adalah lebih tinggi secara bererti (P<0.05) pada aras kanopi atas berbanding tengah dan bawah. Walau bagaimanapun, min bilangan pupa B. tabaci adalah tinggi secara signifikan (P<0.05) pada aras kanopi bawah berbanding aras kanopi atas dan tengah. Min bilangan B. tabaci pada peringkat belum matang adalah berbeza secara bererti (P<0,05) mengikut minggu selepas pokok cili ditanam pada semua perlakuan. Secara amnya, populasi B. tabaci lebih tinggi semasa awal musim penanaman dan menurun selepasnya hingga ke akhir musim kecuali pada minggu ketiga dan ketujuh selepas pokok cili di tanam.
Accurate estimation of the minimum post-mortem interval (minPMI) is important in the investigation of forensic cases. Various thanatological methods are being used to estimate this interval. However, entomology approach is the most reliable method for this minPMI estimation especially when death has occurred over 72 hours and involved insects or other arthropods evidence at the death scene. The current methods of age estimation are daunting and destructive especially when dealing with pupal stage. The aims of this study were to characterize the morphological changes during intra-puparial period of Chrysomya megacephala (Fabricius) (Diptera: Calliphoridae) and their relation with minPMI estimation by using a high resolution micro-Computed Tomography (micro-CT). Gravid C. megacephala were collected from a rural area in Sungai Buloh, Selangor and cultured in the laboratory at 23.83±0.25°C with light: dark hour of 12:12 to initiate oviposition. The resulting larvae were reared until pupal stage. A pupa was collected at first (24 hours), second (48 hours), third (72 hours), and fourth quarter (96 hours) of the intra-puparial period. The pupal samples were placed directly into 70% ethanol for preservation. Micro-CT scanning was employed to acquire microstructural information following pupal sample staining for contrast enhancement. Eight age-informative internal morphological landmarks were mapped from the micro-CT scanning. The present study enhanced the potential value of micro-CT for the estimation of minPMI based on the internal morphological changes of C. megacephala pupae. This novel method is a promising tool for improving medico-legal investigations in forensic entomology.
One of the factors that influence the development of mosquitoes is the water container. This study was performed to determine the relationship between the characteristics of water containers and the preferable conditions for laying eggs by Aedes sp. A single larva method was conducted during March 2019 in 300 houses in two villages (Turikale and Adatongeng) at Maros Regency, Indonesia. In total, 1,269 water containers were considered, and among them buckets were found to be the most common container. Logistic regression analysis showed that the type, container location, and weekly drainage were related to the presence of larvae/pupae in the Maros Regency (p-value < 0.05). Non-water containers, which are kept indoors and are not drained at least once a week, have a greater chance of breeding Aedes sp. More attention is given to non-water containers that are located inside the house. Prevention activities, especially draining water containers properly at least once a week ensures that they do not become breeding sites for Aedes sp. mosquitoes and helps to prevent the transmission of dengue viral fever.
Chironomus javanus (Kieffer) and Chironomus kiiensis Tokunaga were redescribed from materials collected from a rice field in Pulau Pinang, Malaysia. The larvae can only be distinguished after careful preparation and examination using a compound microscope, but the pupae were not useful to differentiate C. javanus from C. kiiensis. The adult specimens showed clear body and wing characteristics for rapid and accurate identification.
Cosmopolitan scuttle fly, Megaselia scalaris (Loew) (Diptera: Phoridae) is one of the commonest forensic species recorded colonizing human corpse indoors and in concealed environment. The occurrence of this species in such environments provides a higher evidential value to assist estimation of postmortem interval (PMI) compared to other forensically important dipterans. However, developmental and size data of M. scalaris are still lacking and they are derived from a limited range of thermal values. The objective of this study is to develop the growth model of M. scalaris by emphasizing the size range of larvae and puparia at different constant temperatures. This species was reared in six replicates at eight varying constant temperatures ranging from 23 to 36 °C and cow's liver was provided as food source. Larvae and puparia were sampled at set time intervals and measured by their length and weight. Because interpretation of forensic entomological evidence is subject to application of different techniques, development of M. scalaris is expressed herein by using developmental table, length/morphological stage diagrams and linear/nonlinear estimation methods. From the findings, it is very important to highlight that sexual dimorphism of M. scalaris during post feeding larva and pupa stage could be observed based on size and developmental periods. Mean length and weight ratios of male to female puparia are approximately 0.8 and 0.3-0.5, respectively, indicating sexual dimorphism of this species. Developmental period in female are 4.0-11.4 h (post feeding larval stage), 3.7-24.0 h (pupal stage), and 3.0-20.1 h (total developmental period) longer in male. Due to this dimorphism, PMI estimation using M. scalaris post feeding larva or puparium specimens must be carried out carefully by to avoid inaccuracy and misinterpretation.
Scuttle flies (Diptera: Phoridae) are small-sized insects of forensic importance. They are well known for diversified species and habitats, but in the context of forensic entomology, scuttle flies' inhabitance of corpses remains inadequately explored. With recent reports indicating the existence of more scuttle fly species possibly inhabiting these environments, a decomposition study using animal carcasses in enclosed environments was conducted. The aim was to record the occurrence of scuttle flies on rabbit carcasses placed in sealed plastic waste bins for a 40-day period. The study was conducted as two replicates in Bangi, Selangor. Sampling was carried out at different time intervals inside a modified mosquito net as a trap. Inside the trap, adult scuttle flies were aspirated and preserved in 70% ethanol. The fly larvae and pupae were reared until their adult stage to facilitate identification. From this study, six scuttle fly species were collected, i.e., Dahliphora sigmoides (Schmitz) ♂, Gymnoptera simplex (Brues) ♀, Megaselia scalaris (Loew) ♂♀, Puliciphora borinquenensis (Wheeler) ♂, Puliciphora obtecta Meijere ♀ and Spiniphora sp. ♀. Both D. sigmoides and P. obtecta were newly recorded in Malaysia, whilst the Spiniphora sp. was considered an unknown species until it was linked to its male counterpart. The sealed waste bins were found to be accessible for the scuttle flies with delayed arrival (day 4-5). Megaselia scalaris was the primary scuttle fly species attracted to the carcass, and its occurrence could be observed between days 4-7 (replicate 1) and days 5-33 (replicate 2). This study also revealed Sarcophaga spp. (Diptera: Sarcophagidae) as the earliest species to colonize the remains and the longest to inhabit them (days 2-40). The larvae of Hermetia illucens (Linneaus) (Diptera: Stratiomyidae) and Fannia sp. (Diptera: Fanniidae) were found on the carcasses during the mid-advanced decay period. These findings expand the knowledge on the diversity of forensically important scuttle flies and coexisting dipterans in enclosed environments in Malaysia.
Simulium (Gomphostilbia) leparense sp. nov. is described from females, males, and pupae collected from Peninsular Malaysia. This new species is assigned to the ceylonicum species-group of the subgenus Gomphostilbia, and is characterized by the female and male scuta covered with dark-brown short hairs, smaller number of male upper-eye facets, presence of shiny paired spots on the male abdominal segments 2-8, and absence of grapnel-shaped hooklets on the pupal abdominal segment 9. The male and pupa of S. capillatum Takaoka, which was originally described from larvae collected from Sarawak and Sabah, are described for the first time. Keys to identify all 32 species of the Simulium ceylonicum species-group including 27 species from other countries are provided for females, males, pupae, and mature larvae.
Matched MeSH terms: Pupa/anatomy & histology; Pupa/classification; Pupa/growth & development
Simulium (Simulium) lomkaoense sp. nov. is described from females, males, pupae, and larvae in Thailand. This new species is assigned to the Simulium malyschevi Dorogostaisky, Rubtsov & Vlasenko species-group of the subgenus Simulium, and appears to be closely related to Simulium baimaii Kuvangkadilok & Takaoka from Thailand in having a similar shape of the female and male genitalia, pupal gill with two inflated filaments, and simple wall-pocket-shaped cocoon. This new species is compared taxonomically with S. baimaii and other related species. It represents the third species of the S. malyschevi species-group known from Thailand.