Rapid assessment of the knowledge about Coleoptera (Arthropoda: Insecta) of forensic importance in an urban fragment of the Atlantic Forest in Salvador, Bahia, Brazil

Forensic Entomology can be defined as an area of Biological Sciences that uses the knowledge about insects and other Arthropods in criminal investigations, since decomposing corpses are sources of resources for arthropods, including insects belonging to the Coleoptera order. The objective of this work was to carry out a rapid assessment inventory of beetles of forensic importance in an urban fragment of the Atlantic Forest (Parque Metropolitano de Pituaçu) located in the city of Salvador, State of Bahia, Brazil. We conducted a collection in the dry period (January 2013) and another collection in the rainy period (July 2013). The capture of coleopterans took place through the use of “Pitfall” traps, stocked with a mixed bait (chicken gizzard and sardines). A total of 239 were collected, distributed in three families: Scarabaeidae (96.1%), Staphylinidae (3.0%) and Histeridae (0.9%). The morphospecies Dicothomius sp. 1 (Scarabaeidae), was more abundant with 94.1% of the specimens sampled. The dry period was more representative for both richness and abundance. All species/morphospecies sampled already have previous records as belonging to forensic importance according to previous studies.

Forensic Entomology can be defined as the area of Biological Sciences that uses knowledge about insects and other Arthropoda in legal matters, with the medico-legal aspect as the main one, in which knowledge about the biology and taxonomy of insects is employed in criminal investigations, especially those related to violent deaths (Lord & Stevenson 1986;Ramos et al. 2018). In this context, the presence of both immature and adult insects colonizing corpses is used as an essential tool for calculating the "Post-Mortem" interval (PMI) estimate (Pujol-Luz et al. 2008;Ramos et al. 2018).
Decomposing bodies serve as a source of resources for several groups of organisms. Insects, which are pioneers in locating the body, use this new "micro-habitat" in various ways as copulation and/or reproduction sites, as well as a source of food and hiding (Catts & Goff 1992;Lopes et al. 2018;Pamponet et al. 2019). In this sense, animals that visit carcasses are valuable tools for different studies in forensic sciences (Oliveira-Costa 2007;Mise et al. 2007;Ramos et al. 2018;Lopes et al. 2018;Pamponet et al. 2019).
Among insects of forensic interest, those of the order Coleoptera have attracted remarkable interest (Amendt et al. 2004), as their presence has been noted in carcasses in the final stages (fermentation and skeletonization) of the decomposition process (Mise et al. 2007;Fonseca et al. 2020). Thus, their presence, both as immatures and adults, in cadavers in advanced stages of decomposition is an important evidence from the medico-legal point of view, as it is essential for the determination of PMI of a corpse on advanced state of decomposition (Kulshrestha & Satpathy 2001).
In terms of behavior regarding the colonization of decomposing bodies, Coleoptera has been considered the order of second importance among insects that act on cadaveric decomposition. According to Mise et al. (2007), the families Staphylinidae, Silphidae, Histeridae, Cleridae, Dermestidae, Scarabaeidae and Hydrophilidae are the main families that act in the decomposition process. These insects have a wide variety of eating habits, where some species can act as scavengers and others as predators and/or even as omnivores (Mise et al. 2007;Oliveira-Costa 2007). One example is Oxelytrum discicolle (Brullé, 1840) [Silphidae], where the immature is a scavenger and the adult a predator (Mise et al. 2007).
Brazil is the country with the greatest diversity of insects (Rafael et al. 2012), having about 84,775 described species (Oliveira et al. 2021), accounting for approximately 9% of the total fauna of this group on the planet. Today, this number is much higher due to the constant publications of new species of insects. From the point of view, entomofaunistic inventories are highly relevant for the knowledge of insect fauna in a given area, in addition to serving as a basis for several other studies. Likewise, in Forensic Entomology, local studies are essential to be applied, since each environment has its particularities, such as temperature, humidity, soil type, so increasing the knowledge about the species that act in cadaverous decomposition in the different regions of Brazil and that can be used as tools in this aspect (Oliveira-Costa 2007;Ramos et al. 2018).
Rapid assessment studies, or rapid access to knowledge (Rapid Assessment), is a form of data collection carried out over a relatively short period of time, highly specific for a certain topic, as an opportunity to collect accurate information without the need for a more systematic project (Lima et al. 2016;Mishra et al. 2017). These studies can be used efficiently to obtain, complement, or analyze existing data to answer some specific questions. In this sense, our objective was to carry out a quick assessment of coleoptera of forensic importance residing in an urban fragment of the Atlantic Forest in the city of Salvador, Bahia, in the Northeast of Brazil.
The experiment was carried out in the Parque Metropolitano de Pituaçu (12° 56'S and 38° 24'W), located in the city of Salvador, Bahia,

Scientific Note
Brazil. Currently, this park is the largest Conservation Unit in the city, with about 392 ha of Atlantic Forest (Bahia 2013) in different stages of regeneration. Although it is a conservation unit, the park has been suffering intense anthropic action.
Two sampling campaigns were carried out, one in the dry period (January 2013) and another one in the rainy period (July 2013). In total, 20 sampling points (PA) were determined equidistant in 50 m, along the 15 km that surround the lagoon of Parque Metropolitano de Pituaçu. Each PA received a "Pitfall" type fall trap equipped with fresh mixed bait (chicken gizzards and sardines). The traps remained exposed for 72 hours, with the baits exchanged at 24-hour intervals and the insects collected. To verify the environmental variables, an environmental thermometer and a thermohygrometer were placed in each AP to measure temperature (maximum and minimum) and air humidity, respectively, during the exposure period of the traps.
The captured specimens were stored in 70% alcohol for conservation. All samples were sent to the Bionomy, Biogeography and Systematics Laboratory (BIOSIS) at the Federal University of Bahia (UFBA), where they were screened and the Coleoptera mounted on entomological pins and dried in an oven at 48 °C for about 120 hours (equivalent to 5 days). The specimens were identified using the taxonomic keys present in Borror & Delong (2010) for the family level in Silva et al. (2011) and Almeida & Mise (2009) for genera and, species. After identification, the specimens were deposited at the Museum of Natural History of Bahia (MHNBA). The data generated were tabulated in a spreadsheet and analyzed using the Instat 3.0 software, where they were subjected to ANOVA to evaluate which of the two periods studied was the most abundant and which presented the most richness of individuals.
When subjected to ANOVA, the data collected demonstrated that the rainy period presented a greater significance for richness (P = 0.0102) and the dry period a greater significance for abundance (P < 0.0001). Regarding the environmental variables analyzed, a greater variation in temperature was noted between the two periods; however, the relative humidity of the air did not vary significantly (Fig. 2).
The greater abundance of beetles in the dry period is corroborated by Oliveira-Costa (2007) and can be explained by the fact that the high temperature accelerates the decomposition process, increasing the propagation of the characteristic odors of the decomposition, in addition to directly increasing the activity of the insects (Oliveira-Costa 2007). The collected Coleoptera are of great forensic importance, and their capture in fauna studies in different regions of the country is common (Mise et al. 2007;Fonseca et al. 2020). These individuals act in different stages of the decomposition process and, therefore, can be used as an important tool in the determination of IPM, especially for cadavers found in an advanced state of decomposition (Lord & Steverson 1986;Oliveira-Costa 2007).  Representatives of Scarabaeidae, in addition to their coprophagous habit, can be detritivores, scavengers, or herbivores both as larvae and as adults (Almeida & Mise 2009;Silva et al. 2014). In general, they are  (Oliveira-Costa 2007). The main characteristic of Staphylinidae is their short elytron pair which enables a more efficient flight when compared to other individuals of the order. This is in agreement with Gnaspini et al. (2000), who captured the majority of their individuals in flight interception traps. Its presence is observed by Mise et al. (2010) in all stages of decomposition, generally acting as a predator of Diptera larvae, giving it extreme forensic importance.
The coleoptera of the family Histeridae are morphologically short and compact, with a very hard coat, and are usually generalist predators (Leivas et al. 2013). They are abundant in the decomposition process (Mise et al. 2007), and their abundance is directly related to their habit as a predator of Diptera larvae (Mise et al. 2007). Several researchers have already reported the presence of Histeridae at different stages of carcass decomposition (Mise et al. 2007;Fonseca et al. 2020).
The use of mixed bait (chicken gizzard and sardines) to capture insects of forensic interest has been suggested by other researchers, such as Mise et al. (2007), as it mainly attracts scavenger insects which act directly on cadaveric decomposition. All species/genera sampled in this study have already been considered of forensic importance in other studies (Mise et al. 2007;Almeida & Mise 2009;Almeida et al. 2015), which was corroborated by the collection methodology adopted in the present studies. Finally, this study contributes to the knowledge of the entomofauna of forensic importance in an urban fragment of Salvador, helping to expand the knowledge of the distribution of relevant species in this field of studies.