Forensic Science International 239 (2014) e1–e9 Contents lists available at ScienceDirect Forensic Science International jou rnal homepage: www.elsevier.com/locate/forsciint Short Communication Ultramorphological characteristics of mature larvae of Nitidula carnaria (Schaller 1783) (Coleoptera: Nitidulidae), a beetle species of forensic importance a,1, b,1 b c Alexander Ortloff *, Noelia Zanetti , Ne´stor Centeno , Ricardo Silva , a ´ a Felipe Bustamante , Alvaro Olave a Laboratorio de Entomologı´a Forense, Escuela de Medicina Veterinaria, Facultad de Recursos Naturales, Universidad Cato´lica de Temuco, Manuel Montt 056, Temuco, Chile b Laboratorio de Entomologı´a Aplicada y Forense, Departamento de Ciencia y Tecnologı´a, Universidad Nacional de Quilmes, Sa´enz Pen˜a 352, Bernal (1876), Provincia de Buenos Aires, Argentina c Laboratorio de Microscopı´a Electro´nica, Instituto de Anatomı´a, Histologı´a y Patologı´a, Facultad de Medicina, Universidad Austral de Chile, Isla Teja s/n., Valdivia, Chile A R T I C L E I N F O A B S T R A C T Article history: Beetles of the genus Nitidula Fabricius are forensically important, and their adults and larvae have been Received 3 August 2013 found associated with human corpses and animal carcasses in many places of the world. The external Received in revised form 28 January 2014 morphology of the larvae of Nitidula carnaria (Schaller 1783) was examined by scanning electron Accepted 14 March 2014 microscopy (SEM) to provide a description enabling identification of this forensically important species. Available online 26 March 2014 The ultrastructure of the head was examined, antennae, mandibles, epipharynx, maxillary and labial palpi, spiracles, thorax, legs, and abdominal segments (especially segments 9 and 10); the tegument was Keywords: also emphasised in this examination. Several types of sensilla were observed on the maxillary and labial Nitidula carnaria palpi, including sensilla basiconica, sensilla styloconica, and perhaps a different type of sensilla Larvae SEM digitiformia. In abdominal segment 10, a sensilla campaniformia was observed. Two types of plates were Morphology noticed in the abdominal tegument. The characteristics described here can be used to identify this Forensic species. No other study of the ultrastructure of Nitidulidae larvae is available for comparison. This is the first report of N. carnaria in carcasses in Chile. ß 2014 The Authors. Published by Elsevier Ireland Ltd. This is an open access article under the CC BY-NC- ND license (http://creativecommons.org/licenses/by-nc-nd/3.0/). 1. Introduction dry human skeletal remains are recovered in the later stages of decomposition, Coleoptera represent the main entomological Forensic entomology is the study and analysis of insect evidence that is used for the determination of the PMImin [5]. evidence for legal purposes [1,2]. The primary use of entomology In general, beetles are associated with advanced stages of in a forensic context involves the examination of succession decomposition [6–8] although some are observed during active patterns and the developmental rates of successive insects and decay stages [9]. The most common families of Coleoptera that are other arthropods to estimate the minimum post-mortem interval important in forensic entomology are Silphidae, Staphylinidae, (PMImin) [3]. Histeridae, Trogidae, Dermestidae, Cleridae and Nitidulidae. Animal carrion can be colonised by a variable number and Nitidulidae (‘‘sap beetles’’) is a large family of more than 2000 diversity of arthropods that belong to several taxa, which provide species [10,11] that are mostly sap-feeders on trees or on the juices useful information for forensic investigations. Two orders of of fruits [10,12,13]. The defining characteristics of the family insects, Diptera and Coleoptera, are of primary forensic interest Nitidulidae and its subfamilies as well as new genera were first due to their activity and frequency on human remains [4]. When described by Erichson [14]. The members of this family are pests that feed on a variety of fields and stored products, including trees and small fruits, field and sweet corn, dried fruit, peanuts, honey [15,16] and grain [17]. Their feeding behaviours include mycoph- * Corresponding author. Tel.: +56 45205586. agy [18–21], phytophagy [22], saprophagy [23] and necrophagy. E-mail address: [email protected] (A. Ortloff). 1 They colonise animal remains in the late stages of decomposition Both the authors should be considered as first authors. http://dx.doi.org/10.1016/j.forsciint.2014.03.010 0379-0738/ß 2014 The Authors. Published by Elsevier Ireland Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc- nd/3.0/). e2 A. Ortloff et al. / Forensic Science International 239 (2014) e1–e9 and are particularly associated with bones and dried carrion slaughterhouses, without creating skin lesions. The Ethical [10,24,25] along with species of Dermestidae [26,27]. Nitidulids Commission of the Universidad Cato´ lica de Temuco approved this are well-known as important members of the carrion feeding procedure. The carcasses were placed in a left lateral decubitus community [28–30]. Indeed, in the study of Shubeck et al. [30], position and exposed to direct sun in boxes consisting of metallic nitidulids composed over 35% of all of the beetles collected from mesh with dimensions of 100 cm  80 cm  60 cm to avoid the the carrion. Perris [31] first associated the larvae of Nitidulidae intervention of carrion-feeding vertebrates but allowing ready with carcasses when he reported his findings of the larvae of access to the entomofauna. The interval between the boxes Nitidula quadripustulata Fabricius (now called Nitidula carnaria containing the carcasses was 20 m. Photographic recording of the Schaller) in the carcass of a hedgehog [31]. Carpophilus Stephens, carcasses and classification of the stage of decomposition Omosita Erichson and Nitidula Fabricius have all been reported on according to the definition of Payne [28] and Anderson and carrion and thus may be useful in forensic research [10]. Vanlaerhoven [56] were conducted daily. Nitidulidae species have been found on animal carcasses and human cadavers in North America [30,32–38], Europe [39–44], 2.3. Capture and rearing of adults to obtain N. carnaria larvae Japan [45], and China [46]. In South America, few studies have mentioned the presence of Nitidulidae on carcasses. However, Samples were collected from the carcasses each day throughout investigations by Martı´nez et al. [47] and Wolff et al. [48] in the entire decomposition process. Crawling insects (adults and Colombia noted that all nitidulids observed on pigs were present at larvae) were captured manually with forceps. At day 22 of the an advanced stage of decay, occurring 13–51 days after death. A postmortem interval (PMI), the carcasses were in advanced decay; review of forensic cases in Argentina revealed records of from that day forward, we found N. carnaria adults, which were Carpophilus hemipterus Linnaeus recovered from the medullar collected and maintained in the laboratory as recommended by cavities of bones [49], nitidulids were collected from pig carcasses Byrd and Castner [55]. The insects were reared in 20-cm  15- near Co´ rdoba [50], and the recent finding and preliminary cm  10-cm plastic containers at 60% mean humidity, 15 8C and a description of the larva and life cycle of N. carnaria Schaller in 12:12 light/dark cycle. The food substrate was pork meat with Bahı´a Blanca [51]. In addition, Carpophilus and three unidentified semi-dry subcutaneous fat. Conditions were maintained in a species of Nitidulidae were collected from a pig carcass during a refrigerated Foc225E VELP Thermostat. Breeding resulted in larvae survey of Coleoptera conducted in southern Brazil [52]. In Chile, that were processed for SEM as described below. there is only a brief mention of the finding of two adults of Carpophilus sp. that were collected from a rabbit carcass in 2.4. Collection of N. carnaria larvae from the carcasses Valparaiso [53]. Despite the many references that mention the presence of the At day 32 of the PMI, the first larvae of N. carnaria were seen. In family Nitidulidae associated with cadaveric decomposition, the following weeks, larvae of different sizes were collected from including a report of the extraction of human mitochondrial the carcasses, particularly from areas of the carcasses that had DNA from an Omosita sp. larvae recovered from human bone [54], abundant fat and moist skin (Fig. 1A). The larvae were fixed few studies have been conducted to establish the value of nitidulid according to the protocol described below. The larvae obtained in beetles at the species-level in forensic investigations [55]. The aims the laboratory were compared morphologically with those of this study were to use scanning electron microscopy (SEM) to collected from the carcasses to confirm that both belonged to describe the morphology of N. carnaria larvae collected from pig the same species using a Zeiss Discovery.V12 stereoscopic carcasses to provide information regarding the identification of microscope and later confirmed by SEM. this forensically important species and to report the presence of this species in carcasses in Chile. 2.5. Fixation and observation by SEM 2. Materials and methods The larvae reared in the laboratory (n = 15) and those collected from the carcasses (n = 20) were fixed in 4% paraformaldehyde and 2.1. Experimental area 2% glutaraldehyde in phosphate buffer pH 7.4 for 24 h. The larvae were then post-fixed in 1% OsO4 in a 0.1 M phosphate buffer for 2 h This investigation was conducted in the spring of 2012 at 4 8C, were subsequently washed three times for 5 min each with (October). The study location was a semi-urban community of a 0.1 M phosphate buffer and were dehydrated using a series of 0 00 Temuco (Chile) located 3 km from the city centre at 38842 10 S, increasing concentrations of ethanol (15–100%).