PAPER PATHOLOGY/BIOLOGY Simonetta Lambiase, 1 Ph.D.; Giulia Murgia, 1 M.S.; Roberto Sacchi, 2 Ph.D.; Michele Ghitti, 2 M.S.; and Valeria di Lucia, 1 M.S. Effects of Different Temperatures on the Development of Dermestes Frischii and Dermestes Undulatus (Coleoptera, Dermestidae): Comparison Between Species ABSTRACT: Dermestidae could be useful in forensic investigations to assess the PMI as adults and larvae colonize dried remains. We reared two species of Dermestidae (Dermestes frischii and Dermestes undulatus) to understand the effects of different temperatures on the length of their whole life cycle and on their immature stages. Both species were reared at 23°C Æ 0.5, RH 75% and at 26°C Æ 0.5, 75% RH. Our result shows that the temperature is the main factor that influences the development of those species; in fact, increasing temperature leads to a shorter development cycle (59.8 Æ 0.5 and 38.1 Æ 0.2 for D. frischii; 50.6 Æ 0.6 and 36.2 Æ 0.2 for D. undulatus). Furthermore, we found that the number of the molts before the pupa decreases from 5–7 to 5–6 for D. frischii and from 4–6 to 4–5 for D. undulatus, respec- tively, at 23°C and 26°C. KEYWORDS: forensic science, forensic entomology, dermestidae, Dermestes frischii, Dermestes undulatus, temperatures, development The Dermestidae family contains about one hundred species throughout Italy, including Dermestes frischii Kugelann, 1792 and Dermestes undulatus Brahm, 1790. These species are widely distributed all over the world; in fact, the presence of D. frischii is verified in Europe, Asia, Africa, Madagascar, and North America (1), while that of D. un- dulatus in the entire Holartic region (2). Both species, adults and immature stages, are described to be pest of foods warehouses (3); for example, Mathai (1) described D. frischii to be a pest for dried fish, silkworm cocoons, and other stored products, and Khan & Naghat (4) recorded D. undu- latus infest silkworm farms and storehouses. For this reason, many authors studied the effects of environ- mental variables (mainly temperature and humidity) on the development of different species belonging to this family to pre- vent and counteract the economic damage they are able to pro- duce (5–9). Moreover, some species of Dermestidae could be useful in forensic investigations as an aid to assess the PMI. Like reported by Voigt (10), Dermestidae could be responsible for the transfor- mation of the soft part of the body and can linger on the remains as the only colonizer of a skeletonized body; according to Schroeder (11), larder beetles (adults and larvae) are able to skeletonize a human corpse in less than five months in indoor environments, and Charabidze (12), reviewing 81 forensic case, observed a peculiar decomposition pattern with the face, hands, and feet as preferential feeding area for the Dermestidae that can completely disarticulate those areas from the body. He also describes D. frischii and D. undulatus as predominant species in outdoor cases and that if more of two species are involved in the decomposition, the association of D. frischii and D. undula- tus is the most common. However, in the case of forensic assessment it is essential to assign a certain age to the samples to trace the time of their col- onization. Dating Dermestidae’s immature stages is very difficult as those insects pass through a number of larval stages which vary with the species and the temperature (13); moreover, the different instars do not show typical morphological markers that could make them distinguishable. For this reasons, it is important to understand the effects of environmental variables (temperature in the first place) on each immature stage of the life cycle of larder beetles; the only data related to this issue regard a study performed on D. frischii reared at a constant temperature of 27°C (8,14). The present study was carried out to increase the knowledge related to two species (D. frischii and D. undulatus) reared at different temperatures, especially of the larval stages never tested before by other authors. In particular, the study aimed to under- stand the effects of different temperatures on the length of their whole life cycle and on their immature stages. We also want to appraise whether different growth conditions could change the number of the larval stages in D. frischii and D. undulatus as happens for other species of Dermestidae (15– 17). 1 Dipartimento di Sanit  a Pubblica, Medicina Sperimentale e Forense, Universit  a degli Studi di Pavia, via Forlanini 12, I-27100 Pavia, Italy. 2 Dipartimento di Scienze della Terra e dell’Ambiente, Universit  a degli Studi di Pavia, via Ferrata 1, I-27100 Pavia, Italy. Received 28 Mar. 2017; and in revised form 2 May 2017; accepted 18 May 2017. 1 © 2017 American Academy of Forensic Sciences J Forensic Sci, 2017 doi: 10.1111/1556-4029.13580 Available online at: onlinelibrary.wiley.com