Peckia, Robineau-Desvoidy, 1830

During the study, a total of 128 male specimens of

Peckia View in CoL

species were collected, of which 56 were collected in the rainy period and 72 in the dry period ( Tab. 1 View Table 1 ), distributed among the following species: Peckia (Peckia) chrysostoma (Wiedemann, 1830) (n= 52); Peckia (Euboettcheria) collusor (Curran & Walley, 1934) (n= 35); Peckia (Sarcodexia) lambens (Wiedemann, 1830) (n= 31); Peckia (Pattonella) intermutans (Walker, 1861) (n= 4); Peckia (Peckia) pexata (Wulp, 1895) (n= 3); Peckia (Euboettcheria) anguilla (Curran & Walley, 1934) (n= 3) and Peckia (Sarcodexia) tridentata (Hall, 1937) (n= 1).

According to the literature ( Tab. 2 View Table 2 ), the species P. collusor and P. pexata have previously been recorded in the state of Bahia. However, the species P. anguilla , P. tridentata , P. chrysostoma , P. intermutans , and P. lambens were recorded for the first time in the state of Bahia in this study. In the case of P. tridentata , our study also registers, for the first time, its occurrence in the Northeast region.

Species Regions of Brazil Literature cited North Northeast Center-West Southeast South Peckia (Euboettcheria) anguilla (Curran & Walley, 1934) Amazonas Bahia Distrito Federal Minas Gerais Paraná Barros et al. 2008; Buenaventura & Pape 2013; Lopes & Tibana 1991; Madeira-Ott et al. 2022; Pape 1996; Rosa et al. 2011; Sousa et al. 2011; Sousa et al. 2015; Vairo et al. 2014. Roraima Ceará Mato Grosso Rio de Janeiro Maranhão São Paulo Peckia (Euboettcheria) collusor (Curran &Walley, 1934) Amazonas Bahia Distrito Federal Minas Gerais Paraná Barbosa et al. 2009; Sousa et al. 2011; Barros et al. 2008; Buenaventura & Pape 2013; Carmo et al. 2017; Lopes & Tibana 1991; Madeira-Ott et al. 2022; Mello-Patiu et al. 2017; Pape 1996; Rosa et al. 2011; Silva et al. 2023; Sousa et al. 2015; Souza & Von Zuben 2016; Vairo et al. 2014. Roraima Ceará Goias Rio de Janeiro Rio Grande do Sul Maranhão Mato Grosso São Paulo Santa Catarina Pernambuco Mato Grosso do Sul Peckia (Pattonella) intermutans (Walker, 1861) Amazonas Bahia Distrito Federal Minas Gerais Paraná Barbosa et al. 2009; Barbosa et al. 2017; Barros et al. 2008; Buenaventura & Pape 2013; Couri et al. 2000; Lopes & Tibana 1991; Madeira-Ott et al. 2022; Mello-Patiu et al. 2017; Pape 1996; Rosa et al. 2011; Sousa et al. 2011; Sousa et al. 2015; Souza & Von Zuben 2016; Vairo et al. 2011; Vairo et al. 2014. Pará Ceará Goias Rio de Janeiro Santa Catarina Roraima Maranhão Mato Grosso São Paulo Penambuco Peckia (Peckia) chrysostoma (Wiedemann, 1830) Amapá Bahia Distrito Federal Espirito Santo Paraná Alves et al. 2014; Barbosa et al. 2009; Barbosa et al. 2017; Barros et al. 2008; Buenaventura & Pape 2013; Carmo et al. 2017; Couri et al. 2000; Lopes & Tibana 1991; Madeira-Ott et al. 2022; Pape 1996; Rosa et al. 2011; Sousa et al. 2011; Sousa et al. 2015; Vasconcelos et al. 2016.

Amazonas Ceará Minas Gerais Rio Grande do Sul Roraima Maranhão Rio de Janeiro Santa Catarina Paraíba São Paulo Pernambuco

Peckia chrysostoma ( Fig. 2d View Figure 2 ) was the most abundant species, representing 40.6% of the studied sarcophagids ( Tab. 1 View Table 1 ). Its occurrence was observed in the final stages of decomposition during the rainy period and, in the dry period, with a higher occurrence in the initial decomposition phase, which was also observed by Barros et al. (2008) in an experiment conducted in the Federal District using pig carcasses. In this study, P. chrysostoma was the most abundant species in the rainy period, in contrast to Rosa et al. (2009) findings in a study with pig carcasses in Minas Gerais, which observed a higher abundance of this species in the dry period. This species was also found colonizing rodent carcasses ( Moretti et al. 2008), pig carcasses ( Alves et al. 2014; Gomes et al. 2009), and human corpses in Rio de Janeiro, RJ ( Oliveira-Costa et al. 2001), highlighting its importance in forensic sciences.

Peckia collusor ( Fig. 2b View Figure 2 ) was the second most abundant species, comprising 27.3% of the relative samples, showing a similar pattern with higher occurrence in the final stages during the rainy period and greater occurrence in the initial decomposition phase during the dry period. Rosa et al. (2009), in a study with pig carcasses, also observed the occurrence of this species in both dry and rainy periods, while Barros et al. (2008) found its highest occurrence in the initial decomposition phase. This species was equally associated with pig carcasses in Rio de Janeiro ( Barbosa et al. 2009) and Paraná ( Vairo et al. 2011).

Peckia lambens ( Fig. 2f View Figure 2 ) the third species with the highest relative abundance (24.2%), showed a higher occurrence in the advanced decomposition phase, corresponding to the only species with occurrence recorded in the fresh phase, both in the rainy and dry periods, with a higher occurrence in the gaseous phase during the dry period ( Tab. 1 View Table 1 ). This higher abundance of P. lambens in the dry period was also observed by Rosa et al. (2009) in Minas Gerais, and it has also been collected in pig carcasses in different studies by various other authors ( Carvalho & Linhares 2001; Alves et al. 2014; Vairo et al. 2011) and in human corpses in Rio de Janeiro ( Oliveira-Costa et al. 2001), highlighting its forensic importance.

The species Peckia intermutans ( Fig. 2c View Figure 2 ), P. pexata ( Fig. 2e View Figure 2 ), P. anguilla ( Fig. 2a View Figure 2 ), and P. tridentata ( Fig. 2g View Figure 2 ) were recorded with low relative frequencies of 3.1%, 2.3%, 2.3%, and 0.8%, respectively ( Tab. 1 View Table 1 ). Peckia intermutans , P. pexata , and P. tridentata were observed only in the dry period, occurring in the gaseous phase, initial deterioration, and remains ( P. intermutans ). In a study conducted by Rosa et al. (2011) with pig carcasses, P. intermutans and P. pexata were observed in both dry and rainy periods. Among these three aforementioned species, P. intermutans was the only one recorded in a human corpse in Campinas, SP ( Carvalho et al. 2000). Regarding P. tridentata , this species was also collected by Vairo et al. (2014) in a survey conducted with pig carcasses in Amazonas, Brazil.

In this study, P. anguilla ( Fig. 2a View Figure 2 ), was observed in both study periods, a result also found by Rosa et al. (2011) and Barros et al. (2008), with its occurrence recorded in the advanced decomposition phase (rainy period) and initial deterioration phase (dry period).

In light of the aforementioned, when we analyze the occurrence of Peckia species in the two studied periods, we observe a higher incidence during the gaseous and initial decomposition phases in the dry period, and during advanced decomposition in the rainy period. As noted by Carvalho & Linhares (2001) in the Cerrado Biome area, and in the present study in the Atlantic Forest Biome area, there seems to be a close association of Peckia species with the more advanced stages of decomposition during the rainy period. Conversely, in drier periods, their greater abundance appears to be associated with the initial stages of decomposition (gaseous phase and initial deterioration), as observed in this study and also by Barros et al. (2008); in a Cerrado area, which may be related to substrate characteristics and its higher or lower percentage of water.

Although Barros et al. (2008) argue that, unlike the results obtained by Carvalho & Linhares (2001), their study did not demonstrate an association of Sarcophagidae with advanced stages of decomposition, but rather a higher abundance and diversity in the bloating phase of the carcass, it is important to note that their experiment was conducted in BrasÍlia (DF), during the months of June-July, which correspond precisely to the period of lowest precipitation in that municipality (according to the INMET/CFS/ Interpolation website), which fully agrees with the observations made in the present study and with the results of the other aforementioned authors. From the perspective of Forensic Entomology, this is extremely relevant data, as depending on the time of year (higher or lower temperature and humidity), species may be associated with one phase of decomposition or another.

Denno & Cothran (1976) observed that different families of diptera can exploit the carcass in different ways, and this does not necessarily indicates competition. For Sarcophagidae , being ovoviviparous and depositing fewer larvae that are immediately able to feed, their higher occurrence in the advanced stages of decomposition may be linked to this unique developmental characteristic, which provides them an advantage in exploiting the food substrate ( Ramos et al. 2022). On the other hand, species that oviposit require more time for larval hatching and colonization of the substrate, as exemplified by the family Calliphoridae ( Pamponet et al. 2019) . This would result in a pioneering role of the Sarcophagidae family in exploiting the carcass compared to Calliphoridae , for example ( Smith 1986; Oliveira-Costa 2007; Ramos et al. 2018).

As proposed by Bornemissza (1957), during the carcass decomposition process, five phases were observed, which was also reported by other authors who monitored the decomposition of pig carcasses ( Rosa et al. 2009; Souza & Linhares 1997; Salviano et al. 1996). The five phases were observed in both study periods, with the process up to the remains phase lasting 8 days during the dry period, while in the rainy period, this process lasted 11 days. Collections were concluded when the carcasses had been exposed for 50 days in both periods.

The duration of the carcass decomposition phases was the same in the first two stages (1 day and 2 days, respectively). In the other three stages, a difference in decomposition duration was observed between the two study periods. Abiotic factors appear to have directly caused this difference (Campobasso et al. 2001). In the dry period ( Fig. 3 View Figure 3 ), due to the higher average temperatures (26.5 °C) ( Fig. 3a View Figure 3 ), lower relative humidity (74.9%) ( Fig. 3b View Figure 3 ) and precipitation (0.005 mm 3) ( Fig. 3c View Figure 3 ) compared to the rainy period (temperature = 23.7 °C, relative humidity = 76.9%, and precipitation = 0.145 mm 3), there was a greater speed in the decomposition process of organic matter. A greater availability of resources in a shorter time would result in faster consumption by decomposer fauna, which could explain the higher abundance of sarcophagids in the dry period (n=72).

As mentioned above, lower temperatures, higher humidity, and precipitation as observed in the rainy period would result in slower carcass consumption, leading to an increase in decomposition time ( Monteiro-Filho & Penereiro 1987). The same was observed by Rosa et al. (2009), who found in their study that the period with higher temperatures resulted in a faster decomposition process; however, in this case, the experiment was conducted in a Cerrado area where humidity was also higher, which differed from the present study.

In this context, being thermoconformers (depending on an external heat source), insects have their development rate directly dependent on the ambient temperature (Campobasso et al. 2001; Oliveira-Costa 2007). Therefore, at higher temperatures, their metabolism increases, accelerating their development, and thus, by voraciously feeding, decomposition is faster, potentially leading to an erroneous estimation of the post-mortem interval (PMI).