## 1 Introduction  
Forensic entomology is involved in several segments of forensic investigations: the determination of the probable time of death through the analysis of entomological fauna succession on the corpse (exogenous factors); its infestation with parasites, virus, bacteria, yeasts, etc. ; and the presence of pesticides and other substances in the insects coming from different biotopes, etc. [1; 2; 3]. The colonization and developmental rates of blowfly species are used to estimate the minimum post-mortem interval (mPMI) [4]. The fauna of interest is represented by the Diptera, Calliphoridae, Sarcopagidae and Muscidae families, specific to the areas where the investigation takes place and according to the respective biotopes. The order Diptera predominates, in most cases, on corpses undergoing decay under the influence of biotic exogenous factors, combined with microclimatic factors (temperature, humidity, and illumination). We must mention that they can only infest the corpse in favorable climatic conditions. Excluding cold periods, the activity period of _Calliphora viciina_ starts with temperatures of between 13 and 16 \({}^{\circ}\)C (which places the activity threshold of this species at a lower temperature than other species of flies) [5]. Their activity can be accelerated by high temperatures and levels of humidity in the environment, as well as the presence of other endogenous factors of cadaveric system decay (infestation prior to the time of death). The presence or absence of bacteria on a corpse may affect the development and survival of maggots that infest it. Understanding the microbial interactions with the maggot's system is important for the improvement in the interpretation of PMI [4, 5]. For example, a series of authors have studied the effect of two bacteria (_Escherichia coli_ and _Staphylococcus aureus_) [6] on the rate of development and survival of three species of _Diptera_ of forensic importance (_Lucilia sericata, Calliphora vicina_, and _Calliphora vomitoria_). It is well known that different endogenous contaminations of a corpse indicate the potential of bacteria on maggots during their development by the alteration of maggot development and weight. This inter regnum interaction is of great importance for forensic entomology, where the development data of certain fly species are used to estimate the minimum post-mortem interval (mPMI) [7, 8]. Flies are usually the primary colonizers of a human corpse [9, 10]. The colonization interval (the time between death and colonization) of an exposed corpse may vary from minutes to days. If a corpse has been hidden, it may vary even more [11]. As we have shown before, environmental factors, such as temperature [12, 13, 14], humidity [13, 15], and solar light [13, 16], directly influence the rate of colonization and development. Bacteria that populate the corpse may also be extremely influential in terms of the regulation of the attraction and selection of the sites for oviposition [4, 17]. A recent study mentioned that _Calliphora vicina_ maggots develop significantly slower on decayed than on fresh liver and suggested that temporal changes in the bacteria colonizing the liver are responsible for that [18]. Other studies indicate that microbial infections modify significantly during the post mortem interval based on the rate of decay [19]. The initial bacteria community varies based on the age [20] and health of the victim [21], the colonization area [22], environmental temperature and humidity [23], as well as depending on the season [24, 25]. Taking these into consideration, this study has been conducted on the Calliphoridae family and its development on two organs, different in terms of biochemical content, but frequently exposed in cases of suspect deaths, humid tissues (orifices of the nose, mouth, eyes, ears, genitals, etc.) being the first ones targeted in the succession of necrophagous insects.