ABSTRACT
Forensic entomology is a science that uses insect fauna as a tool to assist in criminal investigations and civil proceedings. Although the most researched insects are the Diptera and Coleoptera, ants may be present in all stages of decomposition. The aim of this study was to evaluate the role of ants and their action on blow flies during the decomposition process. Experiments were performed in which four pig carcasses were exposed in the cold and dry season (November/2012 and March/2013) and four in the hot and wet season (May/2013 and August/2013). Flies were the first insects to detect and interact with the carcasses, and six species of the Calliphoridae family were identified. Ants (Hymenoptera: Formicidae) were the second group, with six subfamilies identified. Myrmycinae represented 42% of the species, followed by Formicinae (28%), Ectatominae and Ponerinae (both 10%), and Ecitoninae and Dolichoderinae (both 5%). The ants acted on the carcasses as predators of visiting species, omnivores, and necrophagous, in all cases significantly affecting the decomposition time, slowing it down when the ants preyed on adult and immature insects consuming the carcass, or accelerating it by consuming the carcass and creating holes that could serve as gateways for the action of other organisms. The ants also generated artifacts that could lead to forensic misinterpretation.
Subject(s)
Ants/physiology , Diptera/physiology , Sus scrofa , Animals , Brazil , Cadaver , Diptera/growth & development , Entomology , Feeding Behavior , Forensic Sciences , Larva/growth & development , Larva/physiologyABSTRACT
Tropical ants commonly exhibit a hyper-dispersed pattern of spatial distribution of nests. In polydomous species, nests may be satellites, that is, secondary structures of the main nest, where the queen is found. In order to evaluate whether the ant Ectatomma opaciventre Roger (Formicidae: Ectatomminae) uses the strategy of building polydomous nests, the spatial distribution pattern of 33 nests in a 1,800 m(2) degraded area located in Rio Claro, SP, Brazil, were investigated using the nearest neighbor method. To complement the results of this investigation, the cuticular chemical profile of eight colonies was analyzed using Fourier transform infrared photoacoustic spectroscopy (FTIR-PAS). The nests of E. opaciventre presented a hyper-dispersed or regular distribution, which is the most common in ants. The analysis of the cuticular hydrocarbons apparently con-firmed the hypothesis that this species is polydomous, since the chemical profiles of all studied colonies with nests at different sites were very similar to the chemical signature of the single found queen and were also different from those of colonies used as control.
Subject(s)
Animal Distribution , Ants/physiology , Nesting Behavior , Social Behavior , Animals , Brazil , Spectroscopy, Fourier Transform InfraredABSTRACT
Fourier transform infrared photoacoustic spectroscopy (FTIR-PAS) was applied to nineteen fish species in Brazil's Upper Paraná River basin to identify differences in the structural composition of their scales. To differentiate the species, a canonical discriminant analysis was used to indicate the most important absorption peaks in the mid-infrared region. Significant differences were found in the chemical composition of scales among the studied fish species, with Wilk's lambda = 5.2 × 10(-6), F((13,18,394)) = 37.57, and P < 0.001, indicating that O-CH(2) wag at 1396 cm(-1) can be used as a biomarker of this species group. The species could be categorized into four groups according to phylogenetic similarity, suggesting that the O-CH(2) 1396 cm(-1) absorbance is related to the biological traits of each species. This procedure can also be used to complement evolutionary studies.
Subject(s)
Fishes/classification , Photoacoustic Techniques/methods , Spectroscopy, Fourier Transform Infrared/methods , Animals , Biomarkers/chemistry , Brazil , Discriminant Analysis , Fishes/genetics , Phylogeny , Skin/chemistryABSTRACT
Some aspects of the population ecology of Phallotorynus pankalos in a first-order stream of the Iguatemi River Basin are described based on samples taken from March/2007 to February/2008. A total of 2680 individuals, including 948 males and 1732 females was collected. Adult females are larger than males; theirs mean fecundity was estimated as 6.5 embryos/female. There was a strong correlation between standard length and ovary weight, relative ovary weight, and number of embryos. The size of the first maturation of 50 percent of female population was estimated as 18.24 mm of standard lenght. High female mortality was observed after the first reproduction and sex ratio presents seasonal variation with higher female proportion in the winter.(AU)
Para descrever alguns aspectos da ecologia populacional de Phallotorynus pankalos em um riacho de primeira ordem da bacia do rio Iguatemi foram realizadas amostragens de março/2007 a fevereiro/2008. Um total de 2680 indivíduos, distribuídos em 948 machos e 1732 fêmeas, foi coletado. Fêmeas adultas foram maiores que os machos e sua fecundidade média foi estimada em 6,5 embriões/fêmea. Foi observada forte correlação entre o comprimento padrão e o peso dos ovários, peso relativo dos ovários e número de embriões. O tamanho da primeira maturação de 50 por cento da população de fêmeas foi estimado em 18,24 mm de comprimento padrão. Observamos elevada mortalidade de fêmeas após a primeira reprodução e variação sazonal na proporção sexual, com maior proporção de fêmeas no inverno.(AU)
Subject(s)
Animals , Reproduction , Poecilia/anatomy & histology , Poecilia/embryology , Poecilia/physiology , Fertility , RiversABSTRACT
In Apis mellifera L. the venom gland (also called acid gland) is composed of secretory cells that surround a channel that opens into a reservoir devoid of musculature. This gland can present apical branching. In this study the frequency of branched venom glands in Africanized honeybee workers (A. mellifera) from eleven localities in the state of Mato Grosso do Sul was recorded. The relations among the length of the main duct, the length of the duct from the reservoir to the beginning of branching, the length of the branched segment (when present) and the total length of the gland were also analyzed. The frequency of branched glands varied from 50% to 83% in the workers, indicating that this characteristic is primitive in those bees. The results of the Analysis of Discriminant Functions indicated significant differences in the morphometrical segments of the venom gland (Wilks Lambda = 0.092; F (40, 55) = 3.43; P < 0.001), and permitted a differentiation of the populations studied. Using the Mantel test we verified that there does not exist a significant correlation between the morphologic characteristics and the geographical distance between the localities evaluated (Mantel r = -0.006, P = 0.48). The high frequency of workers with large venom gland in all the apiaries considered makes viable the development of a selection program in order to obtain bees with longer venom glands, aimed at the commercial production of venom by the beekeepers of those localities of Mato Grosso do Sul.
Subject(s)
Bees/anatomy & histology , Exocrine Glands/anatomy & histology , Animals , Brazil , VenomsABSTRACT
Em Apis mellifera L. a glândula de veneno (também conhecida como glândula ácida) é composta por células secretoras que circundam um canal que desemboca num reservatório sem musculatura. A glândula pode apresentar bifurcação apical. Neste trabalho foi registrada a freqüência de glândulas de veneno ramificadas em operárias de abelhas africanizadas provenientes de onze localidades do Mato Grosso do Sul. As relações entre o comprimento do ducto principal, o comprimento deste canal desde o reservatório até a inserção da ramificação, comprimento da ramificação (quando presente) e comprimento total da glândula também foram analisadas. A freqüência de glândulas ramificadas variou de 50 por cento a 83 por cento nas operárias provenientes das diferentes localidades, indicando que essa característica é plesiomórfica nessas abelhas. Os resultados da análise de funções discriminantes indicaram diferenças significativas na morfometria da glândula de veneno das abelhas das onze localidades (Wilks Lambda = 0,092; F(40,55) = 3,43; P < 0,001), permitindo assim uma diferenciação das populações que foram estudadas. Usando-se o teste de Mantel, verificou-se que não existe correlação significativa entre as características morfológicas e as distâncias geográficas para os locais avaliados (Mantel r = -0,006; P = 0,48). A elevada freqüência de operárias com glândula de veneno grande em todos os apiários considerados torna viável o desenvolvimento de um programa de seleção massal dirigida, para a obtenção de abelhas com glândulas de veneno mais longas, visando à produção comercial de veneno pelos apicultores daquelas localidades de Mato Grosso do Sul.
In Apis mellifera L. the venom gland (also called acid gland) is composed of secretory cells that surround a channel that opens into a reservoir devoid of musculature. This gland can present apical branching. In this study the frequency of branched venom glands in Africanized honeybee workers (A. mellifera) from eleven localities in the state of Mato Grosso do Sul was recorded. The relations among the length of the main duct, the length of the duct from the reservoir to the beginning of branching, the length of the branched segment (when present) and the total length of the gland were also analyzed. The frequency of branched glands varied from 50 percent to 83 percent in the workers, indicating that this characteristic is primitive in those bees. The results of the Analysis of Discriminant Functions indicated significant differences in the morphometrical segments of the venom gland (Wilks Lambda = 0.092; F (40, 55) = 3.43; P < 0.001), and permitted a differentiation of the populations studied. Using the Mantel test we verified that there does not exist a significant correlation between the morphologic characteristics and the geographical distance between the localities evaluated (Mantel r = -0.006, P = 0.48). The high frequency of workers with large venom gland in all the apiaries considered makes viable the development of a selection program in order to obtain bees with longer venom glands, aimed at the commercial production of venom by the beekeepers of those localities of Mato Grosso do Sul.
