Costs and Benefits of Capsaicin-Mediated Control of Gut Retention in Dispersers of Wild Chilies (original) (raw)
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Plant domestication has commonly reduced levels of secondary metabolites known to confer resistance against insects. Chili pepper is a special case because the fruits of different varieties have been selected for lower and higher levels of capsaicin, the main compound associated with defense. This may have important consequences for insect herbivores and their natural enemies. Despite the widespread consumption of chili peppers worldwide, the effects of capsaicin on insects are poorly understood. Here, we investigated the effect of capsaicin on a generalist herbivore, Spodoptora latifascia (Lepidoptera: Noctuidae) and its ectoparasitoid, Euplectrus platyhypenae (Hymenoptera: Eulophidae). Using chili varieties with three pungency levels: non-pungent (Padron), mild (Cayenne) and highly pungent (Habanero), as well as artificial diets spiked with three different levels of synthetic capsaicin, we determined if higher capsaicin levels negatively affect the performance of these insects.Ove...
Oecologia, 2016
birds. Pungency had little influence on total short-term seed removal by animals, although prior work on this species indicates that capsaicin reduces mortality caused by fungi at longer time scales. Gut passage strongly reduced removal by insects, altering the relative impact of the three predator types. The weak impact of pungency on shortterm predation contrasts with previous studies, highlighting the context dependence of secondary metabolites. The strong impact of gut passage demonstrates that this mechanism alone can influence which seed predators consume seeds, and that impacts of gut passage can be larger than those of secondary metabolites, which are more commonly acknowledged as a defense mechanism.
A field test of the directed deterrence hypothesis in two species of wild chili
Oecologia, 2006
The directed deterrence hypothesis posits that secondary metabolites in ripe fruit function to deter fruit consumption by vertebrates that do not disperse seeds, while not impacting consumption by those that do. We tested this hypothesis in two species of wild chilies (Capsicum spp.). Both produce fruits that contain capsaicinoids, the compounds responsible for the pungency of chilies. Previous work suggests seed-dispersing birds but not seed-destroying rodents consume chili fruits, presumably because rodents are deterred by capsaicin. However, fruit removal from chili plants by rodents and other mammals has not been previously explored. Because laboratory rodents can develop a preference for capsaicin, it is quite possible that wild rodents are natural consumers of chili fruits. We monitored the fate of 125 marked fruits of Capsicum chacoense and 291 fruits of Capsicum annuum. For both species, essentially all fruit removal occurred during the day, when rodents are inactive. Video monitoring revealed fruit removal only by birds, mostly by species known to disperse chili seeds in viable condition. Furthermore, these species are from taxonomic groups that tend to specialize on lipid-rich fruits. Both species of chili produce fruits that are unusually high in lipids (35% in C. chacoense, 24% in C. annuum). These results support the directed deterrence hypothesis and suggest that fruiting plants distinguish between seed predators and seed dispersers by producing fruits that repel the former and attract the latter.
Journal of Chemical Ecology, 2006
The biogeography of pungency in three species of wild chili in the chaco and surrounding highland habitats of southeastern Bolivia is described. We report that Capsicum chacoense, C. baccatum, and C. eximium are polymorphic for production of capsaicin and its analogs, such that completely pungent and completely nonpungent individuals co-occur in some populations. In C. chacoense, the density of plants and the proportion of pungent plants increased with elevation. Above 900 m, all individuals in all populations except two were pungent; nonpungent individuals in at least one of the two polymorphic populations were likely a result of spreading by humans. The occurrence of pungent and nonpungent individuals in three species of ancestral Capsicum and the geographic variation of pungency within species suggest that production of capsaicin and its analogs entails both costs and benefits, which shift from one locality to another. Determining the selection pressures behind such shifts is necessary to understand the evolution of pungency in chilies.
The effect of chilli and its pungent ingredient capsaicin on gastrointestinal transit in the rat
Journal of Gastroenterology and Hepatology, 1993
The effect of chilli powder and its pungent ingredient capsaicin on gastrointestinal transit in the rat was studied. Fasted unanaesthetized male Sprague-Dawley rats (n = 144) received by gavage a test meal containing charcoal and cellulose in water or capsaicin solvent plus 51Cr as a radioactive marker. Either 100 or 200 mg of chilli powder (containing 0.13 and 0.26 mg of capsaicin, respectively) or 0.5 or 1 mg of capsaicin were added, the final volume of each meal being 1.5 mL. At 10 and 20 min, animals were killed and the amount of isotope that had left the stomach was measured, together with the distance the charcoal column had travelled along the small intestine. Compared to controls, animals given chilli powder emptied less of their gastric content at 10 and 20 min, an effect partly reproduced by capsaicin. However overall gastric-small intestinal transit was unaffected by chilli powder or capsaicin. Another 12 male Sprague-Dawley rats received, under light ether anaesthesia, on six occasions at 1-2 week intervals, the same six test meals as used in the previous experiment except that charcoal was not used. Total gut transit as measured by the amount of radioactive marker excreted in the stools at 18 and 24 h was unaffected by the use of chilli or capsaicin.
Evaluation of capsaicin in chili peppers and hot sauces by MISER HPLC-ESIMS
Analytical Methods, 2014
10 The advantages of MISER LC-MS (high throughput, simple readout of results) are 11 demonstrated in the analysis of E-capsaicin in chili peppers and hot sauces. The ready 12 availability of samples with a wide range of capsaicin content and the fast and easy 13 detection using the MISER (Multiple Injections in a Single Experimental Run) technique 14 makes this a potentially useful experiment to introduce novices to the important 15 analytical technique of LC-MS. In this study we describe a simple and rapid 16 chromatographic method for evaluation of E-capsaicin in chili peppers using HPLC with 17 80 % organic eluent in a Poroshell SB-C18 column coupled with electrospray ionization 18 mass spectrometry detection and MISER analysis. The misergrams obtained from 19 continuous sample injections every 0.73 min allows the convenient simultaneous 20 visualization of the outcomes of multiple experiments represented as single 21 chromatograms. A considerable variation in E-capsaicin levels is clearly visualized 22 among different types of peppers and sauces, with the ghost pepper (Bhut Jolokia) 23 showing the highest E-capsaicin concentration of the peppers sampled.