GC-MS analysis of single-skins of ten Melanophryniscus rubriventris toads (five collections of two toads each) captured during their breeding season in NW Argentina has revealed a total of 127 alkaloids of which 56 had not been previously detected in any frog or toad. Included among these new alkaloids are 23 new diastereomers of previously reported alkaloids. What is particularly distinguishin...

With few exceptions, aposematically colored poison frogs sequester defensive alkaloids, unchanged, from dietary arthropods. In the Neotropics, myrmicine and formicine ants and the siphonotid millipede Rhinotus purpureus are dietary sources for alkaloids in dendrobatid poison frogs, yet the arthropod sources for Mantella poison frogs in Madagascar remained unknown. We report GC-MS analyses of ex...

Indicine N-oxide, a pyrrolizidine alkaloid N-oxide that exhibits antitumor activity without some of the toxic effects associated with other pyrrolizidine alkaloids, is metabolized to indicine in rabbits and humans. Indicine can be detected in the plasma and is excreted in the urine in a dose-dependent manner following the i.v. administration of indicine N-oxide. The p.o. administration of indic...

Plants are not passive victims of the myriad attackers that rely on them for nutrition. They have a suite of physical and chemical defences, and are even able to take advantage of the enemies of their enemies. These strategies are often only deployed upon attack, so may lead to indirect interactions between herbivores and phytopathogens. In this study we test for induced responses in wild popul...

Pyrrolizidine alkaloids (PAs) are typical compounds of plant secondary metabolism and are believed to be part of the plant's chemical defense. Within the monocotyledonous plants, PAs have been described in only a few genera, mainly orchids, including Phalaenopsis. Because phylogenetic analyses suggest an independent origin of PA biosynthesis within the monocot lineage, we have analyzed the deve...

The offspring of twice-mated female Utetheisa ornatrix show low incidence of mixed paternity. Most progeny are sired exclusively by one male, the larger one, irrespective of parental age, male pyrrolizidine alkaloid content, mating order, between-mating interval, or duration of copulation. Data are presented suggesting that the female herself may exert control over the process by which one set ...

Echium plantagineum and E. vulgare are congeneric exotics first introduced to Australia in the early 1800 s. There, E. plantagineum is now highly invasive, whereas E. vulgare has a limited distribution. Studies were conducted to evaluate distribution, ecology, genetics and secondary chemistry to shed light on factors associated with their respective invasive success. When sampled across geograp...

Local adaptation of parasites to their hosts due to coevolution is a central prediction of many theories in evolutionary biology. However, empirical studies looking for parasite local adaptation show great variation in outcomes, and the reasons for such variation are largely unknown. In a previous study, we showed adaptive differentiation in the arctiid moth Utetheisa ornatrix to its host plant...