Los procesos de descomposición cadavéricos son un fenómeno ecológico asimilable a una sucesión heterotrófica, del que participan diversos insectos tales como: dípteros, coleópteros, himenópteros. Los coleópteros constituyen uno de los grupos predominantes en términos de diversidad y abundancia, su rango de importancia va desde lo económico a lo forense. Existen varias familias de coleópteros que participan de los procesos de descomposición de cadáveres de vertebrados, cumpliendo un rol trófico determinado y criando allí sus larvas. Ciertas características de dicho proceso tales como las etapas de la descomposición, pueden experimentar cambios debido a su localización geográfica. En Argentina, la temática referida a la fauna cadavérica ha sido poco abordada, particularmente en relación a los coleópteros. A fin de estudiar diferentes aspectos de la taxocenosis de coleópteros de interés forense en un área de Bahía Blanca, provincia de Buenos Aires, Argentina, se realizaron cuatro experiencias correspondientes a cada estación del año, utilizando como modelo experimental cadáveres de cerdo, los que fueron muestreados en forma diaria, junto con trampas de caídas. Se reconocieron cinco etapas de descomposición: Fresca, Hinchada, Descomposición Activa, Descomposición Avanzada y Restos. El proceso de descomposición fue más largo en Invierno. Respecto de la coleopterofauna, en total se encontraron en estado adulto, 12 familias y más de 54 especies de coleópteros de importancia forense con hábitos necrófagos, necrófilos y omnívoros. Se reportaron nuevos registros de interés forense para la provincia de Buenos Aires, Argentina y Sudamérica. Se evaluó la diversidad específica y abundancia promedio total de coleópteros hallados. La diversidad específica se comportó de manera similar entre las etapas de descomposición en cada una de las estaciones, Invierno y F+H resultaron la estación y etapa menos diversas, respectivamente. Por el contrario, la abundancia mostró interacción. Excepto en Verano, en todas las estaciones el número de coleópteros fue en aumento desde el inicio del proceso de descomposición, alcanzando el máximo en la Descomposición Avanzada. Por otra parte, se estudió la abundancia de las familias encontradas. Se observó que el número de ejemplares de Dermestidae, Staphylinidae, Histeridae, Cleridae y Scarabaeidae por etapa de descomposición, no se comportó de manera similar entre estaciones. Tenebrionidae no presentó diferencias en ninguna de sus fuentes de variación. Además se analizó la composición de familias de coleópteros. Dermestidae predominó en Invierno durante todo el proceso; Staphylinidae en la etapa F+H durante Primavera, Verano y Otoño; e Histeridae y Cleridae en las siguientes etapas durante dichas estaciones. Más aún, estas dos últimas familias pudieron separarse en dos grupos. Se analizó la abundancia y composición respecto de sus roles tróficos. Los necrófilos presentaron la mayor riqueza específica y abundancia. Los tres grupos (necrófilos, necrófagos y omnívoros) se encontraron en todas las estaciones. Las abundancias mostraron ciertas diferencias respecto de la frecuencia relativa. Los necrófilos (principalmente los estafilínidos) dominaron en las etapas tempranas, compartiendo la etapa Hinchada con los derméstidos (necrófagos) en Invierno. Los necrófagos fueron el gremio dominante durante el Invierno principalmente en las dos últimas etapas de la descomposición. Los omnívoros mostraron un mayor dominio en Verano durante la Descomposición Avanzada y Restos. Se colectaron larvas de Dermestidae, Histeridae, Tenebrionidae, Carabidae, Scarabaeidae, Staphylinidae, Nitidulidae y Cleridae. Invierno fue la estación con mayor cantidad de ejemplares y en general, estos se observaron y/o abundaron en la Descomposición Avanzada y Restos. Por otra parte, ambos métodos de muestreo (cadáveres y trampas de caída) se compararon para cada familia. En la mayoría de las familias se observó discrepancia por los métodos. Por lo que la complementación de ambas metodologías es importante y no debe obviarse. A fin de estudiar los ciclos de vida bajo condiciones controladas de algunas especies, se cultivaron ejemplares de Dermestes maculatus, Necrobia rufipes y Nitidula carnaria, colectados en las experiencias de campo. En el caso de D. maculatus se analizó el ciclo vital a cuatro temperaturas constantes (20ºC, 24ºC, 27ºC, 30ºC). Además se estudiaron parámetros morfométricos de larvas y pupas de D. maculatus; se analizaron dichos parámetros en relación al tiempo transcurrido y al estado larval; y a su vez, se evaluó el efecto de la temperatura. Se halló que la duración promedio del desarrollo embrionario, de los cuatro primeros estadios larvales, del estado pupal y de la duración total del ciclo, disminuyeron con el aumento de la temperatura. Se encontró que el desarrollo a todas las temperaturas presentó siete estadios larvales, registrándose además en el experimento de 20ºC ± 0,1ºC, un octavo estadio larval. Hasta el cuarto estadio larval se observó un comportamiento unimodal, mientras que se halló que el quinto estadio constituyó un punto decisivo en el desarrollo del individuo, determinando principalmente un comportamiento bimodal. En todas las temperaturas se encontró que a mayor número de estadios, más largo fue el desarrollo larval. En las poblaciones se observó un descenso en el tiempo que tarda el ciclo larval a medida que aumentaba la temperatura, siendo el modelo hiperbólico el que mejor ajustó. Se registró una relación positiva entre los parámetros morfométricos. Además se encontraron ciertos efectos de la temperatura sobre el desarrollo de las larvas y pupas lo que es interesante no sólo desde el aspecto biológico sino también del forense. Las condiciones de cría que se emplearon son nuevas para N. carnaria y las reportadas para N. rufipes son distintas a las descriptas en otros trabajos. Además, los datos del ciclo de vida de N. carnaria y también de la descripción de la larva madura, son los primeros en Sudamérica. Por último, se evaluaron los efectos tafonómicos que D. maculatus puede causar en tejidos de un cadáver. Tanto el estado adulto como el larval produjeron diferentes tipos de marcas como hoyos, estriaciones, rasguños y depresiones en distintos tipos de tejido como tegumentario, conectivo y muscular, en estado fresco y seco. Los márgenes de los hoyos no fueron perfectamente redondos debido a las mordidas de los insectos. También se observaron artefactos en la carne y hueso vacunos. Resultados preliminares sobre la acción de N. rufipes en tejido porcino indicarían que los efectos tafonómicos aparecen más tarde que los de D. maculatus. Es decir, los cléridos parecerían ser más lentos al consumir tejidos. / The cadaveric decomposition processes are ecological phenomena which can resemble heterotrophic succession and diverse insects such as dipteran, beetles, hymenopteran, participate in it. The beetles constitute one of the predominant groups in terms of diversity and abundance, their range of importance goes from economic to forensic topics. There are several families of beetles which take part in the decomposition of vertebrate cadavers, having a specific trophic role and rearing their larvae in that substrate. Certain characteristics of that process such as the stages of decomposition, can suffer changes due to the geographic localization. In Argentina, the subject referred to cadaveric fauna has been little addressed, particularly in relation to beetles. To study different aspects of the taxocenosis of beetles of forensic interest in an area of Bahía Blanca, province of Buenos Aires, Argentina, were performed four experiences, one per each season of the year, using pig cadavers as an experimental model which were sampled diary together with pitfall traps. Five stages of decomposition were recognized: Fresh, Bloated, Active Decay, Advanced Decay and Remains. The process of decomposition was longer in winter. Respect to the beetle fauna, a total of 12 families and more than 54 species of beetles of forensic importance with necrophagous, necrophilous and omnivorous habits were found in adult stage. New reports of forensic interest were registered for Buenos Aires province, Argentina and South America. The specific diversity and average total abundance of beetles were evaluated. The specific diversity behaved similarly between stages of decomposition in each season, winter and F+B were the season and stage less diverse, respectively. To the contrary, the abundance showed interaction. Except in summer, in all seasons the number of beetles increased from the beginning to the end of the decomposition process, reaching the maximum value in the Advanced Decay. Also the abundance of the families was studied. The number of specimens of Dermestidae, Staphylinidae, Histeridae, Cleridae and Scarabaeidae per decomposition stage did not behave in a similar manner between seasons. Tenebrionidae did not present differences in any of their variation sources. Besides, the composition of beetle families was analysed. Dermestidae predominated in winter during all the decomposition process; Staphylinidae in F+B stage during spring, summer and autumm; and Histeridae and Cleridae in the next stages during these seasons. Moreover, these two families could be separated into two groups. The abundance and composition with respect to their trophic roles were analysed. Necrophiles presented the mayor specific richness and abundance. Three groups (necrophiles, necrophages and omnivores) were found in all seasons. Abundance showed certain differences respect to the relative frequency. Necrophiles (principally rove beetles) dominated in the early stages shearing the Bloated stage with dermestids (necrophages) in winter. Necrophages were the dominant guild during winter principally in the last two stages. Omnivores showed a major dominance in summer during Advanced Decay and Remains. Larvae of Dermestidae, Histeridae, Tenebrionidae, Carabidae, Scarabaeidae, Staphylinidae, Nitidulidae and Cleridae were collected. Winter was the season with more specimens and in general, they were observed or were more abundant in the Advanced Decay and Remains. Both sampling methods (pig cadavers and pitfall traps) were compared for each family. In the majority of the families was observed discrepancy for both methods. So the complementation of both methodologies is important and must not be omitted. To study the life cycles of some species under controlled conditions, specimens of Dermestes maculatus, Necrobia rufipes and Nitidula carnaria collected from field experiences were cultured. In the case of D. maculatus was analysed the life cycle at four constant temperatures (20ºC, 24ºC, 27ºC, 30ºC). Besides were studied the morphometric parameters of larvae and pupae of D. maculatus; were analysed these parameters in relation to time and larval stages; and also, was evaluated the temperature effect. It was found that the average duration of the embryonic development, of the first four larval stages, of the pupal stage and of the total duration of the cycle decreased with increasing temperatures. Seven larval stages were observed at all temperatures, registering also at 20ºC ± 0.1ºC, an eighth stage. Until the fourth larval stage was found an unimodal behaviour, while the fifth stage was a decisive point in the development of the individual, determining principally a bimodal behaviour. In all the temperatures, was found that when the number of stages was major, the larval development was longer. In all populations was observed that when temperature increased, the time spent as larva decreased, being the hyperbolic model the best adjustment. A positive relation was registered between morphometric parameters. Besides certain effects of the temperature over the developments of larvae and pupae were found, being these results of biological and forensic interest. The rearing conditions used for N. rufipes are different from those reported in other works. Besides, data of the life cycle and rearing of N. carnaria and also a description of the mature larva are the first in South America. Lastly, was evaluated the thaphonomic effects that D. maculatus can cause in cadaver tissues. In both adult and larval stages, was observed different types of marks such as holes, striations, scratches and depressions in various types of tissues such as tegumentary, connective and muscular, in fresh and dried stages. The margins of holes were not perfectly rounded because of the insect bites. Also were registered artefacts in flesh and bone of cow. Preliminary results of N. rufipes´s action in pig tissue could indicate that the thaphonomic effects appear later than those caused by D. maculatus, meaning that clerids probably could be slower consuming tissues than dermestids.

Made available in DSpace on 2015-04-17T14:55:29Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 2522413 bytes, checksum: 2dcde9206193aa66227f1638607e57cd (MD5) Previous issue date: 2013-07-30 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / Beetles associated with decomposing carcasses in restinga environment, are being studied in this research, contributing information to forensic entomology, with respect to the estimated time of death of a body and translocation corpse. Four carcasses of pigs were used, two for each season in 2012. The carcasses were killed with a shot in the cranial region and placed in cages to prevent the action of scavengers. To collect beetles were used Shannon traps, pitfalls and collecting in the tray. We sampled 3,763 beetles belonging to 19 families and 96 species. The most abundant family was Histerid (n=1,406), followed by Staphylinidae (n=987) and Scarabaeidae (n=718). The family with the highest richness was Staphylinidae (S=23). The most species sampled were Euspilotus sp. 1 (n=930) Xerosaprinus diptychus (n=229) Euspilotus sp. 4 (n=155), Hypocaccus sp. (n=48) (Histeridae), Atheta sp. 1 (n=457), Hongophila sp. (n=269) Lissohypnus sp. (n=81), Philonthus sp. 1 (n=78) (Staphylinidae), Aidophus impressus (n=372), Dichotomius sp. gr geminatus (n=215), Parataenius simulator (n=64), Ateuchus sp. (n=46) (Scarabaeidae), Dermestes maculatus (n=143) (Dermestidae), Necrobia rufipes (n=104) (Cleridae) and Omorgus suberosus (n=78) (Trogidae). Due the difference in abundance and richness was observed seasonal behavior of beetles, since 80% were sampled in the rainy season and the richness ranged from 59 in this season to 26 in drought season. The succession of beetles varied from one station to another, probably due to the seasonal behvior. The nighttime show higher abundance of beetles (54%). The families with abundance above 70% during the night were Trogidae (78%), Tenebrionidae (74%) and Scarabaeidae (72%). None family had such value for daytime. The species referred to as potential forensic to restinga were D. maculates and N. rufipes by reproducing in the carcasses, and also Hypocaccus sp. and Bledius fernandezi by presenting a strict record of dunes and beach, similar environments studied here, suggesting that these species serve as indicators of the area. / Os besouros associados a carcaças em decomposição, em ambiente de restinga, estão sendo estudados no presente estudo, visando contribuir com informações para a Entomologia Forense, no que diz respeito à estimativa do tempo de morte de um corpo e translocação de cadáver. Quatro carcaças de suínos foram utilizadas como isca para atração dos insetos, duas para cada estação climática em 2012. As carcaças foram mortas com um tiro na região craniana e colocadas em gaiolas para impedir a ação de animais necrófagos de grande porte. Para coleta dos besouros foram utilizadas armadilhas Shannon, pitfalls e coletas em bandeja. Foram coletados 3.763 besouros pertencentes a 19 famílias e 96 espécies. A família mais abundante foi Histeridae (n=1.406), seguida por Staphylinidae (n=987) e Scarabaeidae (n=718). A família que apresentou maior riqueza foi Staphylinidae (S=23). As espécies mais coletadas foram: Euspilotus sp. 1 (n=930), Xerosaprinus diptychus (n=229), Euspilotus sp. 4 (n=155), Hypocaccus sp. (n=48) (Histeridae), Atheta sp. 1 (n=457), Homalotina sp. (n=269), Neohypnus sp. (n=81), Philonthus hepaticus (n=78) (Staphylinidae), Aidophus impressus (n=372), Dichotomius sp. gr. geminatus (n=215), Parataenius simulator (n=64), Ateuchus sp. (n=46) (Scarabaeidae), Dermestes maculatus (n=143) (Dermestidae), Necrobia rufipes (n=104) (Cleridae) e Omorgus suberosus (n=78) (Trogidae). Devido à diferença de abundância e riqueza foi observado comportamento sazonal dos besouros, visto que 80% foram coletados na estação chuvosa e a riqueza variou de 59 nesta estação para 26 na estiagem. A sucessão dos besouros variou de uma estação para outra, provavelmente devido o comportamento sazonal. A maior abundância dos besouros foi observada no período noturno (54%), sendo as famílias que apresentaram abundância acima de 70% no período noturno foram Trogidae (78%), Tenebrionidae (74%) e Scarabaeidae (72%). Nenhuma família apresentou tal valor para o período diurno. As espécies indicadas como potencial forense para a restinga foram Dermestes maculatus e Necrobia rufipes por se reproduzirem nas carcaças, e também Hypocaccus sp. e Bledius fernandezi por apresentarem registro estrito a ambientes de dunas e praia, semelhantes ao aqui estudado, sugerindo-se que essas espécies sirvam como indicadores de área.