Diptera: Muscidae), a Rare Muscid Species Or Just Ignored So Far in Forensic Entomology?
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NORTH-WESTERN JOURNAL OF ZOOLOGY 12 (1): 196-198 ©NwjZ, Oradea, Romania, 2016 Article No.: e152201 http://biozoojournals.ro/nwjz/index.html Seek, and ye shall find – the example of Neohydrotaea lundbecki (Michelsen) (Diptera: Muscidae), a rare muscid species or just ignored so far in forensic entomology? Andrzej GRZYWACZ1*, Jens AMENDT2 and Heike FREMDT2 1. Chair of Ecology and Biogeography, Nicolaus Copernicus University, Lwowska 1, 87-100 Toruń, Poland 2. Institute of Forensic Medicine, Goethe-University Frankfurt, Kennedyallee 104, D-60596 Frankfurt am Main, Germany *Corresponding author, A. Grzywacz, Tel. 0048 56 611 26 49, E-mail: [email protected] Received: 02. December 2014 / Accepted: 12. June 2015 / Available online: 30. May 2016 / Printed: June 2016 Abstract. Neohydrotaea lundbecki (Michelsen) is a muscid species considered rare as known only from four specimens reported so far from Denmark and Great Britain. Five females of the species were collected during a surveillance study of necrophagous insects active in flight in June 2009 and June 2010 in Germany. It is the first record of N. lundbecki from Germany and the first report since the last documented finding of the species in 1968. We discuss this event in the light of quality assurance in forensic entomology and the ability of experts and researchers to identify relevant taxa at the genus or species level by using keys designed for the identification of forensically important Diptera, especially. The present example should make researchers more sensitive to the importance of surveillance studies, looking for hidden species by different tools and to complete the list of potential taxa which could be present on a corpse. Key words: Diptera, Muscidae, Neohydrotaea lundbecki, new record, forensic entomology. Legal case investigations and carrion succession 1994). Furthermore the only known specimens of experiments have hitherto revealed association of this taxon are three males and just one female. numerous arthropod species with decomposing Originally described in the monotypic genus Cryp- remains of human and animal origin. Manual tophyra Michelsen, Pont (1986) synonymised it sampling and surveillance studies using baited with Hydrotaea Robineau-Desvoidy. Savage & traps help to determine spatial and temporal pref- Wheeler (2004) revealed a sister-group relation- erences of forensically relevant species (Hwang & ship between Hydrotaea and Neohydrotaea Malloch Turner 2005; Fremdt & Amendt 2014) and to col- and boundaries of the latter group were expanded lect material for both faunistic (Prado e Castro et by the authors. al. 2010) and systematic approaches (Domínguez & Aballay 2008). Some rare dipteran species, e.g. We trapped flies from September 2008 to May 2011 in five Thyreophora cynophila (Panzer) (Martín-Vega et al. locations in and close to Frankfurt am Main, Germany. 2010) and Fannia conspecta Rudzinski (Grzywacz & Beneath two urban and one suburban habitat, traps were placed at a semi-natural and a rural site, representing a Prado e Castro 2012) have been recorded in such typical German mixed forest dominated by beeches. Ap- studies. Our knowledge on the biology and the proximately 500 µl dimethyl trisulfide and 10 g beef liver morphology, at least of the immature stages, of were used as bait (for details see Fremdt & Amendt 2014). many carrion visiting taxa is still scanty, and often Muscid flies were determined according to Gregor et al. are considered only as accidental invaders, not (2002) and Savage & Wheeler (2004). ovipositing on cadavers (Matuszewski et al. 2008). Nevertheless it remains unclear if an occurrence of During this study five females of N. lundbecki were juvenile stages is just hidden by a probably low collected: three in the semi-natural habitat in June number of specimens and the difficulty to separate 2009 and two in the rural habitat in June 2010 (Fig. them from better known taxa or if those taxa really 1). do not colonise a cadaver. Recently, Fremdt et al. Information about the biology of Neohydrotaea (2012) showed that such a rare taxa, the blow fly is scarce. Bygarski & LeBlanc (2013) reported oc- Lucilia silvarum Meigen, which has been ignored in currence of Neohydrotaea on pig carcass, where important forensic keys (Smith 1986; Szpila 2010), adult flies were sampled during the bloated stage colonises human cadavers. of decomposition. Neohydrotaea lundbecki occurs in Neohydrotaea lundbecki (Michelsen) is a rare forest habitats (Pont et al. 1994). Larvae of N. lund- species hitherto found at one locality in Denmark becki are likely to be predators, at least as faculta- (Michelsen 1978) and two in Britain (Pont et al. tive carnivores in the third instar, since other Neohydrotaea lundbecki reported from Germany 197 Figure 1. Female of Neohydrotaea lundbecki (Michelsen), a: habitus; b: head in lateral view; c and d: head in frontal view. closely related species of Azeliini reveal such be- association of species considered rare and in any haviour (Skidmore 1985) and the species holotype doubtful identifications consult with expert tax- was reared from larvae collected in decaying onomists. beech wood (Michelsen 1978). Adults of N. lundbecki can be discriminated Among factors allowing to recognize species from European Hydrotaea species by the simple, as a rare, range size, population size and habitat i.e. not modified, fore femur and tibia as well as requirements can be listed (Fontaine et al. 2007). linear parafacials in males and spatulate palpi in The former, i.e. limited geographic distribution, females (Fig. 1c) (Michelsen 1978). Application of was for several years the case of N. lundbecki. Some keys intended to identify forensically important have to ask if the present findings reflect the actual dipterans solely does not lead to N. lundbecki, since frequency of N. lundbecki or if they are just high- it was not formerly considered a relevant species. lighting one dilemma in taxonomy in general and Thus for identification of adult Muscidae associ- especially in biodiversity studies: the presence or ated with carrion, keys including broad taxon absence of species can be just proven by someone group are recommended, e.g. Gregor et al. (2002) who is having the skills to identify correctly and is for Central Europe. Identification of immature searching for this particular species. Species rarity stages should be done with some reserve, since in general, especially in invertebrates, can be just such stages e.g. of Neohydrotaea still remain un- an artifact arising from the lack of complete spe- known (Skidmore 1985). Hence it is not valid to cies inventories and expert taxonomists instead of conclude that there were no larvae of N. lundbecki actual species frequency. Forensic entomology when researchers in the past did not key it out of studies, due to the mass sampling, are of great their samples of succession experiments or legal importance for biodiversity studies since they can cases. In the worst case there could be the mis- reveal taxa considered as rare. However in order identification of N. lundbecki larvae as e.g. Hydro- to allow proper species identification of collected taea spp., leading to a misinterpretation of a possi- material, researchers should be aware of possible ble PMI. Molecular methods support or enable 198 A. Grzywacz et al. identification of especially the juvenile stages. Szeptycki, A., Thibaud. J. M., Thomas, A., Timm, T., Van Tol, J., Vervoort, W., Willmann, R. (2007): The European union’s 2010 Here, DNA barcoding provides a useful option target: Putting rare species in focus. Biological Conservation 139: where so called „universal primers“ are used for 167–185. investigating a standard sequence in all organ- Fremdt, H., Amendt, J. (2014): Species composition of forensically important blowflies (Diptera: Calliphoridae) and fleshflies isms. It was shown that the mitochondrial cyto- (Diptera: Sarcophagidae) through space and time. Forensic chrome c oxidase I (coI) gene is an appropriate Science International 236: 1–9. marker to identify forensically important fly spe- Fremdt, H., Szpila, K., Huijbregts, J., Lindström, A., Zehner, R., Amendt, J. (2012): Lucilia silvarum Meigen, 1826 (Diptera: cies (Wells & Stevens 2008). Our project provides a Calliphoridae) - a new species of interest for forensic 549 bp fragment of the coI-sequence (GenBank entomology in Europe. Forensic Science International 222: 335– Acc. 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