A simple larval diet for population studies on the blowfly Lucilia sericata (Diptera: Calliphoridae)

1. A simple artificial diet was devised for larvae of Lucilia sericata Meigen. 2. A basic diet of 20 g/l agar with 20% horse blood and added yeast sustained normal growth and development, as compared with a lamb meat control. 3. When yeast was added to the blood agar diet at 50 g/l, both peak and final larval weights were increased by 25-50% at higher larval densities (2-8 larvae/g diet) and the hatchling-adult development period was reduced by about 3 days. 4. No adult insects emerged on an agar-yeast diet without blood. Increasing the concentration of blood from 10% to 20% increased adult weight at emergence by 50%, though developmental period was not significantly affected. 5. Increasing larval density significantly reduced the weights of pupae and emergent adults (by up to 50%), both on the blood-agar-yeast diet and the lamb meat control. Percentage survival fell from 80-90% to below 10% on the blood-agar-yeast diet at the highest densities of 4 or 8 larvae/g diet, though survival on lamb was not significantly affected by density.     

Winter survival of larvae and pupae of the blowfly, Lucilia sericata (Diptera: Calliphoridae)

The mortality of larvae and pupae of the blowfly Lucilia sericata (Meigen) were examined during winter and spring, for two or three years. In soil cores in the field, 70-95% of the larvae died overwinter. Larvae congregated in the top 10 cm of the soil core and did not move extensively throughout the column during the winter. Larvae and pupae at greater depth were less likely to pupariate and emerge successfully than larvae closer to the surface. Under semi-natural conditions, where pupae were placed outside in sawdust filled tubes, in the absence of the usual biotic mortality factors, the mortality of larvae was considerably lower and was also unaffected by low winter temperatures. Hence, low temperatures did not appear to be the primary cause of high overwintering mortality in the field which, it is suggested, is more likely to be the result of the action of biotic mortality factors, such as entomopathogenic nematodes and fungi.     

Antimicrobial compounds from the excretions of surgical maggots, Lucilia sericata (Meigen) (Diptera, Calliphoridae)

Maggots of Lucilia sericata are widely used in the therapy of infected wounds and skin ulcers. Antimicrobial materials released by the insects during their feeding period in order to suppress microbial competitors and potential pathogens play the key role both in the maggots’ survival in their natural habitats (animal corpses) and their therapeutic efficacy. Although the antimicrobial activity of the maggots’ excretion was demonstrated about a hundred years ago, little is known about the nature of its active compounds. We studied the structural characteristics and antimicrobial activities of the compounds released by L. sericata maggots into the environment. To isolate the compounds, excretion was collected from the culture of actively feeding last instar larvae, active compounds were purified using a combination of liquid chromatography and antibacterial growth inhibition assay and characterized by mass spectrometry. Two groups of antibacterial compounds were isolated from the excretion: polypeptides with molecular masses ranging from 6466 to 9025 Da and small molecules with molecular masses ranging from 130 to 700 Da. The polypeptides characterized by the masses of 8882 and 9025 Da and showing selective activity against Gram-negative bacteria correspond well to diptericins, antimicrobial peptides previously found in the hemolymph of Calliphoridae maggots and known to be part of immune response to bacterial pathogens. Other high-molecular compounds with masses 6466, 6633, 5772, and 8631 Da have no clear analogs among antimicrobial peptides present in the hemolymph. The nature of small molecules present in the excretion awaits further study. Thus, the diversity of antimicrobial compounds discovered in Lucilia excretion demonstrates a sophisticated strategy that helps the maggots to fight bacteria and other microorganisms settling their environment. The strategy combines secretion of a set of antibacterial peptides involved in insect immune response as well as molecules which function outside the host organism.     

丝光绿蝇触角鞭节感受器官超显微形态研究

【目的】观察研究重要的医学昆虫丝光绿蝇Lucilia sericata触角感受器的形态,以明确不同类型感受器的结构及功能。【方法】采用透射电镜与激光共聚焦显微镜技术相结合的方法。【结果】明确并详细描述了毛型感受器、锥型感受器、腔锥型感受器及感觉囊的形态结构。【结论】毛型感受器和锥型感受器可能为化学感受器,腔锥型感受器可能为温湿度感受器;感觉囊中的无孔锥型感受器可能为温湿度感受器,类锥型感受器及类腔锥型感受器可能为化学感受器,各类型感受器同时行使功能,表明感觉囊为一个功能复合体。蝇类触角的感器类型多样、囊结构复杂,可作为研究昆虫触角感器形态、功能及演化的模式类群。     

Morphological identification of Lucilia sericata,Lucilia cuprina and their hybrids (Diptera,Calliphoridae)

Hybrids of Lucilia sericata and Lucilia cuprina have been shown to exist in previous studies using molecular methods, but no study has shown explicitly that these hybrids can be identified morphologically. Published morphological characters used to identify L. sericata and L. cuprina were reviewed, and then scored and tested using specimens of both species and known hybrids. Ordination by multi-dimensional scaling indicated that the species were separable, and that hybrids resembled L. cuprina, whatever their origin. Discriminant function analysis of the characters successfully separated the specimens into three unambiguous groups – L. sericata, L. cuprina and hybrids. The hybrids were morphologically similar irrespective of whether they were from an ancient introgressed lineage or more modern. This is the first evidence that hybrids of these two species can be identified from their morphology. The usefulness of the morphological characters is also discussed and photographs of several characters are included to facilitate their assessment.     

Developmental variation of the blow fly Lucilia sericata (Meigen, 1826) (Diptera: Calliphoridae) by different substrate tissue types

The green bottle blow fly Lucilia sericata is recognized as being among the first wave of the faunal succession on human cadavers. Thus, it is used to estimate the postmortem interval (PMI). The nutritional intake of larvae is likely to vary subject to the part of a corpse on which they are feeding. A study was therefore conducted to investigate the effect for the type of food substrate on larval growth in this species. Larvae were reared on cow liver, brain, heart, lung, kidney, intestine or minced meat. Results showed significant differences in the duration of the feeding, postfeeding larval, and pupal stages from different substrata (F = 42.43; 74.71 and 655.71; P < 0.0001, respectively). Larval growth measured as length varied significantly between different tissues (F = 3.56; P < 0.05). Larvae that were reared on heart were smaller than those reared on other tissues. Also, there was a significant effect for the type of tissue on the adult size of males (F = 2.41, P < 0.05) and females (F = 2.85, P < 0.05). These results may have important implications for forensic entomologists, since initial infestations commonly occur in wounds or in the cranial area. Therefore, the position at which larvae have been feeding on a body will be a crucial observation at a crime scene and is very important in PMI estimation.     

Maternal induction of larval diapause and its sensitive stage in the blow fly Lucilia sericata (Meigen) (Diptera: Calliphoridae)

Lucilia sericata has a facultative diapause in the third larval instar after cessation of feeding. Induction of the diapause is influenced by the photoperiod and temperature conditions experienced by insects in the parental generation as well as those experienced by the larvae themselves. The sensitive stage of the parental generation for induction of diapause was examined using diapause‐averting conditions of 16 h light : 8 h darkness (LD 16:8) at 25°C and diapause‐inducing conditions of LD 12:12 at 20°C. The incidence of diapause in the progeny was predominantly determined by the conditions experienced by the parents in the adult stage. Moreover, the results of reciprocal crosses showed that only the mother's experience is involved in the induction of diapause in the progeny.     

Canine Wound Myiasis Caused by Lucilia sericata (Diptera: Calliphoridae) in Korea

Myiasis is a relatively common infection of animals kept as pets, although only 1 case of canine myiasis has been described so far in the Republic of Korea. In the present study, we report an additional case of canine wound myiasis with identification of its causative agent, Lucilia sericata. An 8-year-old male Siberian husky dog was referred with anorexia, vomiting, and diarrhea to the Chungbuk National University Veterinary Medical Center, Cheongju-si (city), Chungcheongbuk-do (province), Korea in July 2013. Physical examination indicated the patient had a deep wound filled with a maggot swarm as a left gluteal lesion. A total of 216 maggots were removed by forceps, and the wounded area was sponged with gauzes and disinfected with 70% alcohol and a povidone-iodine solution. After daily care and suturing the wound, the patient was discharged at day 19 after admission. Recovered worms possessed morphological characteristics similar to those of L. sericata, namely, a sub-cylindrical body with 6–8 lobed anterior spiracles, round shaped with a button surrounded by a peritremal ring with no gaps, and similar distances between dorsal, median, and outer papillae of the 12th segment. Additionally, cox1 partial sequences (528 bp) obtained in the present study showed 100% identity with those of L. sericata (GenBank no. {"type":"entrez-nucleotide","attrs":{"text":"KT272854.1","term_id":"992320795","term_text":"KT272854.1"}}KT272854.1). L. sericata is indicated as a pathogen of myiasis infection not only in humans, but also in animals kept as pets in Korea.     

Waning of repetitive hopping in the blowfly Phormia regina Meigen (Diptera: Calliphoridae)

Wingless blowflies (Phormia reginaMeigen)released on a flat uniform substrate hop repeatedly. The rate of hopping decreases with time. Decremental responsiveness resembles behavioral habituation. It can be reestablished by tactile stimulation and is due neither to muscle fatigue nor to sensory receptor adaptation. No effects of age or circadian rhythms were observed. The initial rate of hopping increases with increasing food deprivation, as does the time for waning to be completed. Decapitated flies and isolated wingless thoraxes hop almost as well as control flies and wane at the same rates.     

A Case of Oral Myiasis Caused by Lucilia sericata (Diptera: Calliphoridae) in Korea

We report here a case of oral myiasis in the Republic of Korea. The patient was a 37-year-old man with a 30-year history of Becker''s muscular dystrophy. He was intubated due to dyspnea 8 days prior to admission to an intensive care unit (ICU). A few hours after the ICU admission, 43 fly larvae were found during suction of the oral cavity. All maggots were identified as the third instars of Lucilia sericata (Diptera: Calliphoridae) by morphology. We discussed on the characteristics of myiasis acquired in Korea, including the infection risk and predisposing factors.     

A simple, sterile food source for rearing the larvae of Lucilia sericata (Diptera: Calliphoridae)

arvae of the sheep blowfly Lucilia sericata (Meigen) were reared on various mixtures of puréed liver, agar, brewer's yeast and trypsin, in order to develop a simple, sterile, tissue-based diet. Growth and survival rates of larvae reared on a sterile 1:1 mixture of puréed liver with 3% Bacto agar equalled or exceeded those of larvae reared on raw liver. The addition of yeast and/or trypsin to the medium was of no additional benefit. This sterile, homogenous, tissue-based substrate offers a simple, convenient, inexpensive growth medium for rearing larvae for maggot therapy, and for testing the effects of various chemicals and dietary constituents on necrophagous insect larvae. It may be useful, therefore, in studies of myiasis, forensic entomology, and toxicology. This rearing medium also has the advantage that it can be stored for many months at room temperature without progressive decomposition or offensive odour.     

Seasonal population dynamics in Lucilia eximia (Wiedemann) (Diptera: Calliphoridae)

In this study the seasonal variation of fecundity, wing and tibia sizes were investigated in natural populations of Lucilia eximia (Wiedemann) as an attempt to determine the variations in life history of the species associated to seasonality. Specimens of L. eximia were monthly collected in Botucatu, S?o Paulo, Brazil, during two years and the adult females dissected to estimate fecundity. Body size was estimated by measuring wing and tibia. Fecundity and body size were seasonally analysed. A relatively constant temporal trajectory was found for fecundity, wing and tibia size over twenty-four months. Strong positive correlations between wing and tibia size, fecundity and wing and fecundity and tibia were observed. The maintenance of stable values in L. eximia indicates that it has suffered little seasonal influence over the period analysed. This result confirms the demographics and life history stable profile of the species in spite of seasonal climatic changes observed in the study area.     

Effects of temperature and photoperiod on the termination of larval diapause in Lucilia sericata (Diptera: Calliphoridae)

Larvae of the blow fly, Lucilia sericata (Meigen), enter diapause in the third instar after cessation of feeding. The effects of temperature and photoperiod on the termination of diapause were examined. The diapause terminated spontaneously under the diapause-inducing condition of 20 degrees C and LD 12:12, although pupariation was not synchronous. Diapause development proceeded under a low temperature of 7.5 degrees C. Transfer to long-day conditions of LD 16:8 or to a high temperature of 25 degrees C induced prompt and synchronous pupariation. Low temperatures in winter probably play a predominant role in the termination of diapause under natural conditions.     

Longevity of Lucilia sericata (Meigen, 1826) used as pollinator

Pollinators play an important role in the production of many agricultural products. Honeybees, Apis mellifera L., are leading pollinators, but the number of honeybees in the world is declining. Finding alternatives is beginning to be important. In the present study, we compared the longevity of Lucilia sericata (Meigen, 1826), which is used as a pollinator, in cages in the laboratory and in a vinyl greenhouse under controlled feeding conditions. First, we showed that the longevity of the flies was significantly extended (c.a. 40 days) in the laboratory when water and sugar were supplied compared to the cases without sugar and/or water. Second, we found that the average longevity was 20 days with water and sugar in cages kept in a vinyl greenhouse during the summer. Finally, we released marked flies into a vinyl greenhouse where strawberries were cultivated without feeding water or sugar in the spring. As a result, fewer than 10% of the flies survived 10 days after release. Based on the result, we discuss the use of this species as a pollinator in the context of its survival rate.     

Flies in the ointment: a morphological and molecular comparison of Lucilia cuprina and Lucilia sericata (Diptera: Calliphoridae) in South Africa

Abstract.  Complementary nuclear (28S rRNA) and mitochondrial (COI) genes were sequenced from blowflies that phenotypically resembled Lucilia cuprina (W.), Lucilia sericata (Meigen) or exhibited characters of both species. The aim was to test a long-held hypothesis that these species hybridize under natural conditions in South Africa ( Ullyett, 1945 ). Blowflies were obtained predominantly from the Cape Town metropolitan area, but reference samples were acquired for L. sericata from Pretoria. Several L. cuprina -like flies were shown to possess a conflicting combination of nuclear and mitochondrial genes that has also been seen in Hawaiian specimens. Homoplasy, sampling of pseudogenes, hybridization and incomplete lineage sorting are discussed as possible hypotheses for the pattern and the latter is concluded to represent the most likely explanation.     

Neurosecretory cells in the central nervous system of the adult blowfly, Phormia regina Meigen (Diptera: Calliphoridae)

• 1 Neurosecretary cells in the central nervous system of the adult blowfly, Phormia regina Meig., have been examined histologically using the parparaldehyde-fuchsin and Gomori's staining method. Six groups of the neurosecretory cells occur in each hemisphere of the brain, the medial, frontal, lateral A, lateral B, posterior I and posterior II groups. In the subesophageal ganglion, four B-cells and two A-cells are present. In the thoracico-abdominal ganglion, ten A-cells are found in the thoracic region and a total of about 50 A- and B-cells in the hind part of the abdominal region.
• 2 A comparison with the neurosecretory system of two other species of blowfly, Calliphora erythrocephala Meig., Sarcophaga bullata Parker, and the housefly, Musca domestica L., showed similar arrangements and grouping.
• 3 Neurosecretory granules have been observed along the axons originating from the medial neurosecretory cells of the brain, and the thoracico-abdominal ganglion. The granules originating from the medial groups can be traced directly to the corpus cardiacum from which they move to the aorta, crop duct and cardia through axons.
• 4 There is with advancing age a gradual increase in the size of cell bodies and nuclei of the median neurosecretory cells in both females and males of Phormia regina, and also a decrease in stainable granules. This increase in size is dependent on nutrition, with no increase in water alone, a slight increase on sugar, and a maximum increase on sugar and liver. Corresponding increases in size occur in the ovaries in connection with feeding the same substances.

     

Polytene chromosomes and linkage group-chromosome correlations in the Australian sheep blowfly Lucilia cuprina (Diptera: Calliphoridae)

The trichogen cell polytene chromosome maps for the Australian sheep blowfly Lucilia cuprina dorsalis R.-D. are presented. Correlations between the autosomal linkage groups and the polytene and mitotic chromosomes were accomplished using autosome-autosome and sex chromosome-autosome translocations. It is suggested that the sex chromosomes are largely inert.This work was completed during the tenure of a Fulbright fellowship and was supported in part by Public Health Service grant 2T1 GM 373-08.