External morphology of Chrysomya pinguis (Walker) (Diptera: Calliphoridae) revealed by scanning electron microscopy.

The external morphology of the adult female blow fly, Chrysomya pinguis (Walker, 1858), was examined using scanning electron microscopy. Ultrastructure of the compound eye, ocellus, antenna, palpus, spiracles and portions of the thorax was highlighted. A great difference was observed in sculpture patterns of the corneal lens surface of the ommatidia of the compound eye and that of the ocelli, with the former being densely pustulate and the latter extremely sinuous. Several sensilla types were observed in this study including: sensilla chaetica, sensilla trichodea, sensilla basiconica and sensilla coeloconica. Their probable functions are discussed with reference to other literature. Morphological information about C. pinguis that was revealed in this study allows us to know such types of structures in much better detail and may eventually provide a basis for understanding some of the biological behavior of this fly species in the future.

Forensic entomology cases in Thailand: a review of cases from 2000 to 2006.

This paper presents and discusses 30 cases of cadavers that had been transferred for forensic entomology investigations to the Department of Forensic Medicine, Faculty of Medicine, Chiang Mai University, northern Thailand, from 2000 to 2006. Variable death scenes were determined, including forested area and suburban and urban outdoor and indoor environments. The fly specimens found in the corpses obtained were the most commonly of the blow fly of family Calliphoridae, and consisted of Chrysomya megacephala (F.), Chrysomya rufifacies (Macquart) Chrysomya villeneuvi Patton, Chrysomya nigripes Aubertin, Chrysomya bezziana Villeneuve, Chrysomya chani Kurahashi, Lucilia cuprina (Wiedemann), Hemipyrellia ligurriens (Wiedemann), and two unknown species. Flies of the family Muscidae [Hydrotaea spinigera Stein, Synthesiomyia nudiseta (Wulp)], Piophilidae [Piophila casei (L.)], Phoridae [Megaselia scalaris (Loew)], Sarcophagidae [Parasarcophaga ruficornis (F.) and three unknown species], and Stratiomyiidae (Sargus sp.) were also collected from these human remains. Larvae and adults of the beetle, Dermestes maculatus DeGeer (Coleoptera: Dermestidae), were also found in some cases. Chrysomya megacephala and C. rufifacies were the most common species found in the ecologically varied death scene habitats associated with both urban and forested areas, while C. nigripes was commonly discovered in forested places. S. nudiseta was collected only from corpses found in an indoor death scene.

Fine structure of Chrysomya nigripes (Diptera: Calliphoridae), a fly species of medical importance.

The fine structure of Chrysomya nigripes Aubertin, a blow fly species of medical importance, is presented using scanning electron microscopy (SEM) to contribute information on the morphology of the adult of this fly species. The surface of the dome-shaped ommatidia exhibits a microscopic granulose appearance. The palpus is equipped with small sensilla basiconica and sensilla chaetica, which provide sensory reception for detecting environmental information. At the apex of the mouthparts, the labellum is endowed with large numbers of sensilla trichodea and basiconic-like sensilla of variable length. The anterior (mesothoracic) spiracle is elliptical in shape and covered with extensively ramified setae except for a small dorsal aperture. The posterior (metathoracic) spiracle is shaped like a rounded isosceles triangle and covered by two valves of unequal size. The larger valve covers the upper approximately 2/3 of the spiracular opening, whereas the smaller valve covers the lower approximately 1/3 of the opening. Extensively ramified setae line and cover the valves over the entire spiracle. SEM analyses of the haltere knob and the prosternal organs, located adjacent to the cervical sclerites, revealed a striking resemblance of the morphological features of their sensilla. Each sensillum emanates from a cuticular ring, is approximately 12-15 mum in length, has a smooth surface, and terminates in a sharp tip. Various types of sensilla were associated with the ovipositor including sensilla trichodea, sensilla basiconica, sensilla placodea and probably sensilla styloconica. The possible function of sensilla distributed in particular regions of the fly integument is discussed.

Sensilla of the antenna and palp of Hydrotaea chalcogaster (Diptera: Muscidae).

Hydrotaea chalcogaster is a fly species of medical and forensic importance in many parts of the world. In this study, we investigated the sensilla of the antenna and palp of the adult female fly using scanning electron microscopy. The antennal scape has one type of sensillum, the sharp-tipped sensillum trichodeum; whereas, the antennal pedicel also possessed this type of sensillum in addition to an unidentified type. Three types of sensilla were found on the flagellum: (1) sensilla basiconica, with both large and small sensilla basiconica showing wall pores, (2) sensilla coeloconica, with a smooth surface, and (3) sensory pits, with wall pores of pegs. The arista is located dorso-laterally on the flagellum and has three segments. Short microtrichia are located around the distal end of its second segment and on the proximal half of the third segment. Both large sharp-tipped sensilla chaetica and small sensilla basiconica with wall pores were observed on the palps. Results of this study contribute to our overall understanding of the ultrastructural morphology of sensilla on the antenna and palp of H. chalcogaster.

Ultrastructure of spiracles of Musca domestica and Hydrotaea chalcogaster (Diptera: Muscidae).

Spiracles are major respiratory openings in the exoskeleton of insects. Oxygen, a necessary gas for cell activity, must pass through the spiracle to enter the respiratory system. In this study, we investigated the fine structure of spiracles of adult females of Musca domestica L. and Hydrotaea chalcogaster (Wiedemann), both medically important fly species in many parts of the world, by utilizing scanning electron microscopy. The mesothoracic spiracle of M. domestica is large and elongate-oval in shape, with its anterior end being gradually tapered. The outer surface is densely covered with slender setae of variable distribution and orientation. The metathoracic spiracle is semicircular or D-shaped, with its rim possessing long, fine, inwardly curved setae. A net-like valve or sieve plate, which has a smooth rim with swollen surface, is located within the atrium of this species. The abdominal spiracles are circular with a symmetrically swollen peritreme surrounding the opening. The inner filtering apparatus is composed of many spiral tubes, each possessing many small spines. As for H. chalcogaster, the tapering mesothoracic spiracle is covered with long setae arranged consistently inward from the peritreme, giving it a "combed" appearance. The metathoracic spiracle is similarly arranged but triangularly rounded in shape, with the anterior and posterior rims possessing long fine setae. The net-like valve within the atrium has a smooth, swollen rim, whereas the inner edge of the atrium bears short, slender setae where it meets with the peritreme of the spiracle. The abdominal spiracles of this species look similar to that of M. domestica, with the exception of the filtering apparatus that bears only a few small spines. The function of these spiracles is discussed.

Surface ultrastructure of prestomal teeth of some flies in the families Calliphoridae, Muscidae and Sarcophagidae.

Prestomal teeth of flies in the families Calliphoridae (Chrysomya pinguis, Chrysomya villeneuvi, and Chrysomya chani), Muscidae (Hydrotaea (= Ophyra) chalcogaster) and Sarcophagidae (Boettcherisca peregrina) were presented using scanning electron microscopy. The slight to deep bifurcation of the tips of their teeth were similarly observed in all species examined. The anatomical feature of prestomal teeth of the flies examined may contribute to the understanding of their feeding behavior and the medical importance of their role in the future.

Forensically important fly maggots in a floating corpse: the first case report in Thailand.

The authors report herein the entomological evidence from the first documented forensic floating corpse in Thailand. The male remains of unknown name and age was found in the waterside of a reservoir in Lampang province, northern Thailand. Approximately 13-16 wounds resulting from sharp-edged material were found on the body. Numerous third-instar of blowflies Chrysomya megacephala (F) and Chrysomya rufifacies Macquart (Diptera: Calliphoridae) were collected, and the entomological evidence of the latter species could be used to estimate approximately 7 days of the postmortem interval. This is the first report of C. megacephala as forensic important fly species in Thailand. Additional research is needed to ascertain the effects of water on the succession and development of both fly species subsequently coming to associate with a corpse so treated in Thailand.

Evaluation of the formalin-Tween concentration technique for parasitic detection

O método de detecção de parasitas por meio de sedimentação com Tween 20Õ foi comparado com o de formalina-éter. De um total de 297 amostras fecais examinadas, 72,1 por cento foram positivas. A técnica de formalina-Tween foi eficaz para demonstrar a presença de helmintos, particularmente ovos de Ascaris lumbricoides, Trichuris trichiura e ancilostomídeos. Entretanto, foi menos capaz de revelar protozoários. Este método é simples, de rápida execução e altamente sensível; revela infecções por parasitas, especialmente por meio da identificação de ovos de helmintos.

Evaluation of the formalin-tween concentration technique for parasitic detection.

The formalin-Tween sedimentation method was compared with the formalin-ether sedimentation for parasitic detection. Of a total 297 fecal specimens examined, 72.1% were positive. The formalin-tween technique was effective for ascertaining helminths, particularly Ascaris lumbricoides, Trichuris trichiura and hookworm eggs; however it has less capability for protozoa detection. This method is simple, inexpensive, less time consuming and highly sensitive when detecting the parasitic infection, particularly when focusing on helminth eggs.