Post-mortem volatiles of vertebrate tissue

Volatile emission during vertebrate decay is a complex process that is understood incompletely. It depends on many factors. The main factor is the metabolism of the microbial species present inside and on the vertebrate. In this review, we combine the results from studies on volatile organic compounds (VOCs) detected during this decay process and those on the biochemical formation of VOCs in order to improve our understanding of the decay process. Micro-organisms are the main producers of VOCs, which are by- or end-products of microbial metabolism. Many microbes are already present inside and on a vertebrate, and these can initiate microbial decay. In addition, micro-organisms from the environment colonize the cadaver. The composition of microbial communities is complex, and communities of different species interact with each other in succession. In comparison to the complexity of the decay process, the resulting volatile pattern does show some consistency. Therefore, the possibility of an existence of a time-dependent core volatile pattern, which could be used for applications in areas such as forensics or food science, is discussed. Possible microbial interactions that might alter the process of decay are highlighted

Pollination ecology of Magnolia ovata may explain the overall large flower size of the genus

Flowering and fruiting biology of Magnolia ovata was studied in Atlantic forests in the interior of São Paulo State, Brazil. The large, bisexual flowers are protogynous, nocturnal, thermogenic and emit a strong scent in two consecutive evenings. In the first night of anthesis, the flowers are in the pistillate stage and thermogenesis starts at about sunset and lasts about 3. h. In the second night, the flowers enter the staminate stage and produce heat for 4. h. Heat is generated by the petals, gynoecium and anthers. Temperatures measured inside the petals reach 26.7°C and 31.9°C in the pistillate and staminate stages, 6.0 and 10.6°C above ambient air, respectively. In the pistillate stage, the perianth opens after sunset and closes tightly a few hours later, and remains closed until the next evening. The initial opening and closing, however, is not synchronous for all flowers during the night. In the following evening, flowers in the staminate stage again open and remain so until the petals drop. Scent compounds, analyzed by GC-MS, contain C5-branched chain compounds, aliphatics, benzenoids and monoterpenoids. Emission of the most prominent compound, C5-branched methyl 2-methyl butyrate, commences before flower opening and continues throughout anthesis, but is accentuated in the thermogenic pistillate and staminate stages. Female and male individuals of only one beetle species, the dynastid scarab Cyclocephala literata, are attracted to the scented flowers in both pistillate and staminate stages. Once inside the flowers they feed on the petals and mate. Tests with synthetic methyl 2-methyl butyrate indicate that this compound is a strong attractant for the beetles. Because this scent compound is strongly emitted in both pistillate and staminate stages, the beetles fly indiscriminately between flowers of both stages. This behavior enhances pollen mixing and effective cross-pollination of the self-compatible species. The evolutionary history of Magnolia appears to be influenced by an ancestral condition of dynastid scarab beetle pollination. Large magnolia flowers are best explained as an archaic structure resulting from the initial association of tropical American species of section Talauma with large and voracious dynastid beetles. © 2011 Elsevier GmbH.Gerhard Gottsberger, Ilse Silberbauer-Gottsberger, Roger S. Seymour and Stefan Dötter