Catarina Prado e Castro

Coleoptera of forensic interest: A study of seasonal community composition and succession in Lisbon, Portugal

Some Coleoptera are recognised as being forensically important as post-mortem interval (PMI) indicators, especially in the later stages of cadaver decomposition. Because insect species and their timings of appearance in cadavers vary according to geographic location, it is important to know their succession patterns, as well as seasonality at a regional level. In this study, we aimed to contribute to broaden this knowledge by surveying beetle communities from the Lisbon area during the four seasons of the year, using piglet carcasses as animal models. Five stages were recognised during the decomposition process and they could be separated taking into account the occurrence and abundance of the specific groups of Coleoptera collected. Decay stages in general recorded higher abundance and richness of beetle species. A total of 82 species were identified, belonging to 28 families, in a total of 1968 adult Coleoptera collected. Autumn yielded the highest values of species abundance and richness, while the lowest values were recorded during winter. Staphylinidae was the most abundant family in all seasons, although in spring and summer Dermestidae was also quite dominant. In general, most species were related to the decay stages, particularly Margarinotus brunneus (Histeridae) and Creophilus maxillosus (Staphylinidae), and also Saprinus detersus (Histeridae) and Thanatophilus sinuatus (Silphidae), while only few were related to the dry stage, namely Oligota pusillima (Staphylinidae) and Dermestidae spp. larvae. On the other hand, Anotylus complanatus and Atheta pertyi (Staphylinidae) were apparently more associated with the fresh and bloated stages, respectively. The presence of some species was markedly seasonal, allowing a season characterisation based on the occurrence of certain taxa, which can be useful for forensic purposes.

Piophila megastigmata (Diptera: Piophilidae): First records on human corpses

Piophila megastigmata McAlpine, 1978, for many years only known from South Africa, was recently recorded in Spain. The present work reports for the first time the occurrence of P. megastigmata in human corpses in Portugal. The species was also collected in succession studies conducted with piglet carcasses, where it coexisted with Stearibia nigriceps (Meigen, 1826), showing similar periods of presence in the carcass. However, P. megastigmata was more abundant than S. nigriceps in autumn, with the opposite in summer. During winter neither species was able to colonize carrion and in spring, only S. nigriceps. This first record of P. megastigmata in human corpses confirms it as a potentially useful forensic species in Europe. The species, well established in the Iberian Peninsula, probably has a wider distribution but has been previously overlooked and possibly confused with Piophila casei (Linnaeus, 1758) in many studies.

Blowflies (Diptera: Calliphoridae) activity in sun exposed and shaded carrion in Portugal

Abstract The first forensic entomological study performed in Portugal is presented. Two piglet (Sus scrofa L.) carcasses were used to determine adult Calliphoridae activity on carrion over a period of 121 days, all along the end of spring and the summer, both in a shaded and a sunny site. Five decomposition stages were observed and a total of 10723 adult Calliphoridae, belonging to 11 species, were collected. Calliphora vicina, Calliphora vomitoria, Chrysomya albiceps and Lucilia caesar were the dominant species in this study. Decomposition was faster on the carcass exposed to the sun and the number of Calliphoridae specimens was higher there than in the shaded site. It was found a significant effect of the decomposition stage in the number of specimens attracted to the carcass, as well as a significant effect of the interaction between the decomposition stage and insolation regime. Calliphora and Lucilia species did not show preference for sunny or shaded areas. Important differences in the Calliphoridae community structure were found compared to other regions of the Iberian Peninsula, reinforcing the need of further studies in different environments and regions of this geographical area in order to collect information about the local necrophagous fauna used in forensic practice.

First report on sarcosaprophagous Formicidae from Portugal (Insecta: Hymenoptera)

Summary The community structure, dynamics and succession patterns of the sarcosaprophagous Formicidae (Insecta, Hymenoptera) at the end of spring and summer, 2004, have been determined following a study carried out in Coimbra (Central Portugal) using piglet carcasses. A modified Schoenly trap was used to collect the fauna. Five decomposition stages were observed and 1061 ant workers, corresponding to six species, were collected and identified. The dominant species was Linepithema humile (Mayr 1868), for which its distribution throughout the decomposition process is shown. Comparisons are made with data from literature at two other localities in Spain. The information presented in this study represents the first report on the sarcosaprophagous Formicidae community that is present in Portugal. These data will contribute to enlarging our knowledge on the biology of this fauna, will provide interesting references for some species, and will be very useful for establishing a database that is critical in forensic practice.

First finding of larviposition in Calliphora loewi from an island relict forest

Larviposition is widespread in blowflies, but among Calliphora species this behavior has seldom been described. The evidence of larviposition in C. loewi is here reported for the first time and discussed in relation with other blowfly species exhibiting the same behavior. The blowfly C. loewi is considered oviparous but surprisingly, female specimens from Madeira Island (Portugal) were found to carry few large larvae (one to three larvae up to 5.1 mm in size) in the ovipositor and abdomen. The finding of larviposition behavior in C. loewi from Madeira Island is at present enigmatic and further studies are needed to clarify the reproductive biology of this species.

The blowflies of the Madeira Archipelago: species diversity, distribution and identification (Diptera, Calliphoridae s. l.)

Abstract Knowledge on the taxonomic diversity and distribution of blowflies from the Madeira Archipelago is updated. New and interesting findings are reported for poorly studied islands and islets of this archipelago, together with a brief analysis of the diversity of Macaronesian Calliphoridae s. l. Seven blowfly species were collected during this study, including the first records of Calliphora vicina Robineau-Desvoidy, 1830, Chrysomya albiceps (Wiedemann, 1819), Lucilia sericata (Meigen, 1826), Pollenia rudis (Fabricius, 1794) and Stomorhina lunata (Fabricius, 1805) from Porto Santo, and of Calliphora vicina, Lucilia sericata and Stomorhina lunata from Desertas Islands. The presence of Calliphora loewi Enderlein, 1903 in Madeira Laurisilva forest is discussed and its first instar larva is redescribed, revealing important differences in relation to its original description. An identification key to the adult Madeiran blowflies is provided for the first time.

Diversity of the Formicidae (Hymenoptera) carrion communities in Lisbon (Portugal): preliminary approach as seasonal and geographic indicators

ABSTRACT The value of the Formicidae (Insecta, Hymenoptera) community in forensic investigations is poorly studied in Portugal. In order to better understand the structure and dynamics of this group of insects in cadavers and their putative value in forensic investigations, studies were carried out in Lisbon area during one year. Piglet carcasses were used as a model of human decomposition. The entomofauna attracted to the carcasses was collected over a period of about 2 months in each season of the year. The collection of ants was performed at regular intervals, daily in the first 23 days and then with intervals of 2, 3 or 5 days until the end of the experiment. Five stages of cadaveric decomposition were recognized with the ants being present in all of them. Three hundred and nine specimens were captured: 7 in autumn, 6 in winter, 90 in spring and 206 in summer. These specimens belong to three subfamilies and seven different species. Four of them had never been mentioned before as being associated to cadavers in this geographical area. Spring and summer had the greater diversity of species and a larger number of individuals. Temnothorax luteus was the dominant species in spring and Tapinoma nigerrimum in summer. Corroborating the information of other similar studies carried out in the Iberian Peninsula, the sarcosaprophagous Formicidae community found in Lisbon is unique and different from other studied locations, which supports the need to perform regional studies. Our results shown that ants do not present a definite pattern of succession, but some species have the potential to be seasonal or geographic indicators.